Section

[Code of Federal Regulations]
[Title 40, Volume 7]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR60.A1]

[Page 6]
Appendix A-1 to Part 60--Test Methods 1 through 2F

Method 1--Sample and velocity traverses for stationary sources
Method 1A--Sample and velocity traverses for stationary sources with
small stacks or ducts
Method 2--Determination of stack gas velocity and volumetric flow rate
(Type S pitot tube)
Method 2A--Direct measurement of gas volume through pipes and small
ducts
Method 2B--Determination of exhaust gas volume flow rate from gasoline
vapor incinerators
Method 2C--Determination of gas velocity and volumetric flow rate in
small stacks or ducts (standard pitot tube)
Method 2D--Measurement of gas volume flow rates in small pipes and ducts
Method 2E--Determination of landfill gas production flow rate
Method 2F--Determination of Stack Gas Velocity and Volumetric Flow Rate
With Three-Dimensional Probes
The test methods in this appendix are referred to in Sec. 60.8
(Performance Tests) and Sec. 60.11 (Compliance With Standards and
Maintenance Requirements) of 40 CFR part 60, subpart A (General
Provisions). Specific uses of these test methods are described in the
standards of performance contained in the subparts, beginning with
Subpart D.
Within each standard of performance, a section title ``Test Methods
and Procedures'' is provided to: (1) Identify the test methods to be
used as reference methods to the facility subject to the respective
standard and (2) identify any special instructions or conditions to be
followed when applying a method to the respective facility. Such
instructions (for example, establish sampling rates, volumes, or
temperatures) are to be used either in addition to, or as a substitute
for procedures in a test method. Similarly, for sources subject to
emission monitoring requirements, specific instructions pertaining to
any use of a test method as a reference method are provided in the
subpart or in Appendix B.
Inclusion of methods in this appendix is not intended as an
endorsement or denial of their applicability to sources that are not
subject to standards of performance. The methods are potentially
applicable to other sources; however, applicability should be confirmed
by careful and appropriate evaluation of the conditions prevalent at
such sources.
The approach followed in the formulation of the test methods
involves specifications for equipment, procedures, and performance. In
concept, a performance specification approach would be preferable in all
methods because this allows the greatest flexibility to the user. In
practice, however, this approach is impractical in most cases because
performance specifications cannot be established. Most of the methods
described herein, therefore, involve specific equipment specifications
and procedures, and only a few methods in this appendix rely on
performance criteria.
Minor changes in the test methods should not necessarily affect the
validity of the results and it is recognized that alternative and
equivalent methods exist. Section 60.8 provides authority for the
Administrator to specify or approve (1) equivalent methods, (2)
alternative methods, and (3) minor changes in the methodology of the
test methods. It
should be clearly understood that unless otherwise identified all such
methods and changes must have prior approval of the Administrator. An
owner employing such methods or deviations from the test methods without
obtaining prior approval does so at the risk of subsequent disapproval
and retesting with approved methods.
Within the test methods, certain specific equipment or procedures
are recognized as being acceptable or potentially acceptable and are
specifically identified in the methods. The items identified as
acceptable options may be used without approval but must be identified
in the test report. The potentially approvable options are cited as
``subject to the approval of the Administrator'' or as ``or
equivalent.'' Such potentially approvable techniques or alternatives may
be used at the discretion of the owner without prior approval. However,
detailed descriptions for applying these potentially approvable
techniques or alternatives are not provided in the test methods. Also,
the potentially approvable options are not necessarily acceptable in all
applications. Therefore, an owner electing to use such potentially
approvable techniques or alternatives is responsible for: (1) assuring
that the techniques or alternatives are in fact applicable and are
properly executed; (2) including a written description of the
alternative method in the test report (the written method must be clear
and must be capable of being performed without additional instruction,
and the degree of detail should be similar to the detail contained in
the test methods); and (3) providing any rationale or supporting data
necessary to show the validity of the alternative in the particular
application. Failure to meet these requirements can result in the
Administrator's disapproval of the alternative.

Method 1--Sample and Velocity Traverses for Stationary Sources

Note: This method does not include all of the specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling) essential to its
performance. Some material is incorporated by reference from other
methods in this part. Therefore, to obtain reliable results, persons
using this method should have a thorough knowledge of at least the
following additional test method: Method 2.

1.0 Scope and Application

1.1 Measured Parameters. The purpose of the method is to provide
guidance for the selection of sampling ports and traverse points at
which sampling for air pollutants will be performed pursuant to
regulations set forth in this part. Two procedures are presented: a
simplified procedure, and an alternative procedure (see Section 11.5).
The magnitude of cyclonic flow of effluent gas in a stack or duct is the
only parameter quantitatively measured in the simplified procedure.
1.2 Applicability. This method is applicable to gas streams flowing
in ducts, stacks, and flues. This method cannot be used when: (1) the
flow is cyclonic or swirling; or (2) a stack is smaller than 0.30 meter
(12 in.) in diameter, or 0.071 m\2\ (113 in.\2\) in cross-sectional
area. The simplified procedure cannot be used when the measurement site
is less than two stack or duct diameters downstream or less than a half
diameter upstream from a flow disturbance.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

Note: The requirements of this method must be considered before
construction of a new facility from which emissions are to be measured;
failure to do so may require subsequent alterations to the stack or
deviation from the standard procedure. Cases involving variants are
subject to approval by the Administrator.

2.0 Summary of Method

2.1 This method is designed to aid in the representative measurement
of pollutant emissions and/or total volumetric flow rate from a
stationary source. A measurement site where the effluent stream is
flowing in a known direction is selected, and the cross-section of the
stack is divided into a number of equal areas. Traverse points are then
located within each of these equal areas.

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method may not address all of the
safety problems associated with its use. It is the responsibility of the
user of this test method to establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to performing this test method.

6.0 Equipment and Supplies.

6.1 Apparatus. The apparatus described below is required only when
utilizing the alternative site selection procedure described in Section
11.5 of this method.
6.1.1 Directional Probe. Any directional probe, such as United
Sensor Type DA Three-Dimensional Directional Probe, capable of measuring
both the pitch and yaw angles of gas flows is acceptable. Before using
the probe, assign an identification number to the directional probe, and
permanently mark or engrave the number on the body of the probe. The
pressure holes of directional

[[Page 7]]

probes are susceptible to plugging when used in particulate-laden gas
streams. Therefore, a procedure for cleaning the pressure holes by
``back-purging'' with pressurized air is required.
6.1.2 Differential Pressure Gauges. Inclined manometers, U-tube
manometers, or other differential pressure gauges (e.g., magnehelic
gauges) that meet the specifications described in Method 2, Section 6.2.

Note: If the differential pressure gauge produces both negative and
positive readings, then both negative and positive pressure readings
shall be calibrated at a minimum of three points as specified in Method
2, Section 6.2.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection, Preservation, Storage, and Transport [Reserved]

9.0 Quality Control [Reserved]

10.0 Calibration and Standardization [Reserved]

11.0 Procedure

11.1 Selection of Measurement Site.
11.1.1 Sampling and/or velocity measurements are performed at a site
located at least eight stack or duct diameters downstream and two
diameters upstream from any flow disturbance such as a bend, expansion,
or contraction in the stack, or from a visible flame. If necessary, an
alternative location may be selected, at a position at least two stack
or duct diameters downstream and a half diameter upstream from any flow
disturbance.
11.1.2 An alternative procedure is available for determining the
acceptability of a measurement location not meeting the criteria above.
This procedure described in Section 11.5 allows for the determination of
gas flow angles at the sampling points and comparison of the measured
results with acceptability criteria.
11.2 Determining the Number of Traverse Points.
11.2.1 Particulate Traverses.
11.2.1.1 When the eight- and two-diameter criterion can be met, the
minimum number of traverse points shall be: (1) twelve, for circular or
rectangular stacks with diameters (or equivalent diameters) greater than
0.61 meter (24 in.); (2) eight, for circular stacks with diameters
between 0.30 and 0.61 meter (12 and 24 in.); and (3) nine, for
rectangular stacks with equivalent diameters between 0.30 and 0.61 meter
(12 and 24 in.).
11.2.1.2 When the eight- and two-diameter criterion cannot be met,
the minimum number of traverse points is determined from Figure 1-1.
Before referring to the figure, however, determine the istances from the
measurement site to the nearest upstream and downstream disturbances,
and divide each distance by the stack diameter or equivalent diameter,
to determine the distance in terms of the number of duct diameters.
Then, determine from Figure 1-1 the minimum number of traverse points
that corresponds: (1) to the number of duct diameters upstream; and (2)
to the number of diameters downstream. Select the higher of the two
minimum numbers of traverse points, or a greater value, so that for
circular stacks the number is a multiple of 4, and for rectangular
stacks, the number is one of those shown in Table 1-1.
11.2.2 Velocity (Non-Particulate) Traverses. When velocity or
volumetric flow rate is to be determined (but not particulate matter),
the same procedure as that used for particulate traverses (Section
11.2.1) is followed, except that Figure 1-2 may be used instead of
Figure 1-1.
11.3 Cross-Sectional Layout and Location of Traverse Points.
11.3.1 Circular Stacks.
11.3.1.1 Locate the traverse points on two perpendicular diameters
according to Table 1-2 and the example shown in Figure 1-3. Any equation
(see examples in References 2 and 3 in Section 16.0) that gives the same
values as those in Table 1-2 may be used in lieu of Table 1-2.
11.3.1.2 For particulate traverses, one of the diameters must
coincide with the plane containing the greatest expected concentration
variation (e.g., after bends); one diameter shall be congruent to the
direction of the bend. This requirement becomes less critical as the
distance from the disturbance increases; therefore, other diameter
locations may be used, subject to the approval of the Administrator.
11.3.1.3 In addition, for elliptical stacks having unequal
perpendicular diameters, separate traverse points shall be calculated
and located along each diameter. To determine the cross-sectional area
of the elliptical stack, use the following equation:

Square Area=D1 x D2 x 0.7854

Where: D1=Stack diameter 1
D2=Stack diameter 2

11.3.1.4 In addition, for stacks having diameters greater than 0.61
m (24 in.), no traverse points shall be within 2.5 centimeters (1.00
in.) of the stack walls; and for stack diameters equal to or less than
0.61 m (24 in.), no traverse points shall be located within 1.3 cm (0.50
in.) of the stack walls. To meet these criteria, observe the procedures
given below.
11.3.2 Stacks With Diameters Greater Than 0.61 m (24 in.).
11.3.2.1 When any of the traverse points as located in Section
11.3.1 fall within 2.5 cm (1.0 in.) of the stack walls, relocate them
away from the stack walls to: (1) a distance of 2.5 cm (1.0 in.); or (2)
a distance equal to

[[Page 8]]

the nozzle inside diameter, whichever is larger. These relocated
traverse points (on each end of a diameter) shall be the ``adjusted''
traverse points.
11.3.2.2 Whenever two successive traverse points are combined to
form a single adjusted traverse point, treat the adjusted point as two
separate traverse points, both in the sampling and/or velocity
measurement procedure, and in recording of the data.
11.3.3 Stacks With Diameters Equal To or Less Than 0.61 m (24 in.).
Follow the procedure in Section 11.3.1.1, noting only that any
``adjusted'' points should be relocated away from the stack walls to:
(1) a distance of 1.3 cm (0.50 in.); or (2) a distance equal to the
nozzle inside diameter, whichever is larger.
11.3.4 Rectangular Stacks.
11.3.4.1 Determine the number of traverse points as explained in
Sections 11.1 and 11.2 of this method. From Table 1-1, determine the
grid configuration. Divide the stack cross-section into as many equal
rectangular elemental areas as traverse points, and then locate a
traverse point at the centroid of each equal area according to the
example in Figure 1-4.
11.3.4.2 To use more than the minimum number of traverse points,
expand the ``minimum number of traverse points'' matrix (see Table 1-1)
by adding the extra traverse points along one or the other or both legs
of the matrix; the final matrix need not be balanced. For example, if a
4 x 3 ``minimum number of points'' matrix were expanded to 36 points,
the final matrix could be 9 x 4 or 12 x 3, and would not necessarily
have to be 6 x 6. After constructing the final matrix, divide the stack
cross-section into as many equal rectangular, elemental areas as
traverse points, and locate a traverse point at the centroid of each
equal area.
11.3.4.3 The situation of traverse points being too close to the
stack walls is not expected to arise with rectangular stacks. If this
problem should ever arise, the Administrator must be contacted for
resolution of the matter.
11.4 Verification of Absence of Cyclonic Flow.
11.4.1 In most stationary sources, the direction of stack gas flow
is essentially parallel to the stack walls. However, cyclonic flow may
exist (1) after such devices as cyclones and inertial demisters
following venturi scrubbers, or (2) in stacks having tangential inlets
or other duct configurations which tend to induce swirling; in these
instances, the presence or absence of cyclonic flow at the sampling
location must be determined. The following techniques are acceptable for
this determination.
11.4.2 Level and zero the manometer. Connect a Type S pitot tube to
the manometer and leak-check system. Position the Type S pitot tube at
each traverse point, in succession, so that the planes of the face
openings of the pitot tube are perpendicular to the stack cross-
sectional plane; when the Type S pitot tube is in this position, it is
at ``0[deg] reference.'' Note the differential pressure ([Delta]p)
reading at each traverse point. If a null (zero) pitot reading is
obtained at 0[deg] reference at a given traverse point, an acceptable
flow condition exists at that point. If the pitot reading is not zero at
0[deg] reference, rotate the pitot tube (up to 90[deg] yaw angle), until a null reading is obtained.
Carefully determine and record the value of the rotation angle ([alpha])
to the nearest degree. After the null technique has been applied at each
traverse point, calculate the average of the absolute values of [alpha];
assign [alpha] values of 0[deg] to those points for which no rotation
was required, and include these in the overall average. If the average
value of [alpha] is greater than 20[deg], the overall flow condition in
the stack is unacceptable, and alternative methodology, subject to the
approval of the Administrator, must be used to perform accurate sample
and velocity traverses.
11.5 The alternative site selection procedure may be used to
determine the rotation angles in lieu of the procedure outlined in
Section 11.4.
11.5.1 Alternative Measurement Site Selection Procedure. This
alternative applies to sources where measurement locations are less than
2 equivalent or duct diameters downstream or less than one-half duct
diameter upstream from a flow disturbance. The alternative should be
limited to ducts larger than 24 in. in diameter where blockage and wall
effects are minimal. A directional flow-sensing probe is used to measure
pitch and yaw angles of the gas flow at 40 or more traverse points; the
resultant angle is calculated and compared with acceptable criteria for
mean and standard deviation.

Note: Both the pitch and yaw angles are measured from a line passing
through the traverse point and parallel to the stack axis. The pitch
angle is the angle of the gas flow component in the plane that INCLUDES
the traverse line and is parallel to the stack axis. The yaw angle is
the angle of the gas flow component in the plane PERPENDICULAR to the
traverse line at the traverse point and is measured from the line
passing through the traverse point and parallel to the stack axis.

11.5.2 Traverse Points. Use a minimum of 40 traverse points for
circular ducts and 42 points for rectangular ducts for the gas flow
angle determinations. Follow the procedure outlined in Section 11.3 and
Table 1-1 or 1-2 for the location and layout of the traverse points. If
the measurement location is determined to be acceptable according to the
criteria in this alternative procedure, use the same traverse point
number and locations for sampling and velocity measurements.
11.5.3 Measurement Procedure.

[[Page 9]]

11.5.3.1 Prepare the directional probe and differential pressure
gauges as recommended by the manufacturer. Capillary tubing or surge
tanks may be used to dampen pressure fluctuations. It is recommended,
but not required, that a pretest leak check be conducted. To perform a
leak check, pressurize or use suction on the impact opening until a
reading of at least 7.6 cm (3 in.) H2O registers on the
differential pressure gauge, then plug the impact opening. The pressure
of a leak-free system will remain stable for at least 15 seconds.
11.5.3.2 Level and zero the manometers. Since the manometer level
and zero may drift because of vibrations and temperature changes,
periodically check the level and zero during the traverse.
11.5.3.3 Position the probe at the appropriate locations in the gas
stream, and rotate until zero deflection is indicated for the yaw angle
pressure gauge. Determine and record the yaw angle. Record the pressure
gauge readings for the pitch angle, and determine the pitch angle from
the calibration curve. Repeat this procedure for each traverse point.
Complete a ``back-purge'' of the pressure lines and the impact openings
prior to measurements of each traverse point.
11.5.3.4 A post-test check as described in Section 11.5.3.1 is
required. If the criteria for a leak-free system are not met, repair the
equipment, and repeat the flow angle measurements.
11.5.4 Calibration. Use a flow system as described in Sections
10.1.2.1 and 10.1.2.2 of Method 2. In addition, the flow system shall
have the capacity to generate two test-section velocities: one between
365 and 730 m/min (1,200 and 2,400 ft/min) and one between 730 and 1,100
m/min (2,400 and 3,600 ft/min).
11.5.4.1 Cut two entry ports in the test section. The axes through
the entry ports shall be perpendicular to each other and intersect in
the centroid of the test section. The ports should be elongated slots
parallel to the axis of the test section and of sufficient length to
allow measurement of pitch angles while maintaining the pitot head
position at the test-section centroid. To facilitate alignment of the
directional probe during calibration, the test section should be
constructed of plexiglass or some other transparent material. All
calibration measurements should be made at the same point in the test
section, preferably at the centroid of the test section.
11.5.4.2 To ensure that the gas flow is parallel to the central axis
of the test section, follow the procedure outlined in Section 11.4 for
cyclonic flow determination to measure the gas flow angles at the
centroid of the test section from two test ports located 90[deg] apart.
The gas flow angle measured in each port must be 2[deg] of 0[deg]. Straightening vanes should be
installed, if necessary, to meet this criterion.
11.5.4.3 Pitch Angle Calibration. Perform a calibration traverse
according to the manufacturer's recommended protocol in 5[deg]
increments for angles from -60[deg] to +60[deg] at one velocity in each
of the two ranges specified above. Average the pressure ratio values
obtained for each angle in the two flow ranges, and plot a calibration
curve with the average values of the pressure ratio (or other suitable
measurement factor as recommended by the manufacturer) versus the pitch
angle. Draw a smooth line through the data points. Plot also the data
values for each traverse point. Determine the differences between the
measured data values and the angle from the calibration curve at the
same pressure ratio. The difference at each comparison must be within
2[deg] for angles between 0[deg] and 40[deg] and within 3[deg] for
angles between 40[deg] and 60[deg].
11.5.4.4 Yaw Angle Calibration. Mark the three-dimensional probe to
allow the determination of the yaw position of the probe. This is
usually a line extending the length of the probe and aligned with the
impact opening. To determine the accuracy of measurements of the yaw
angle, only the zero or null position need be calibrated as follows:
Place the directional probe in the test section, and rotate the probe
until the zero position is found. With a protractor or other angle
measuring device, measure the angle indicated by the yaw angle indicator
on the three-dimensional probe. This should be within 2[deg] of 0[deg].
Repeat this measurement for any other points along the length of the
pitot where yaw angle measurements could be read in order to account for
variations in the pitot markings used to indicate pitot head positions.

12.0 Data Analysis and Calculations

12.1 Nomenclature.
L=length.
n=total number of traverse points.
Pi=pitch angle at traverse point i, degree.
Ravg=average resultant angle, degree.
Ri=resultant angle at traverse point i, degree.
Sd=standard deviation, degree.
W=width.
Yi=yaw angle at traverse point i, degree.
12.2 For a rectangular cross section, an equivalent diameter
(De) shall be calculated using the following equation, to
determine the upstream and downstream distances:
[GRAPHIC] [TIFF OMITTED] TR17OC00.037

12.3 If use of the alternative site selection procedure (Section
11.5 of this method) is required, perform the following calculations
using the equations below: the resultant angle at each traverse point,
the average resultant angle, and the standard deviation. Complete the
calculations retaining at least

[[Page 10]]

one extra significant figure beyond that of the acquired data. Round the
values after the final calculations.
12.3.1 Calculate the resultant angle at each traverse point:
[GRAPHIC] [TIFF OMITTED] TR17OC00.038

12.3.2 Calculate the average resultant for the measurements:
[GRAPHIC] [TIFF OMITTED] TR17OC00.039

12.3.3 Calculate the standard deviations:
[GRAPHIC] [TIFF OMITTED] TR17OC00.040

12.3.4 Acceptability Criteria. The measurement location is
acceptable if Ravg <= 20[deg] and Sd <= 10[deg].

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Determining Dust Concentration in a Gas Stream, ASME Performance
Test Code No. 27. New York. 1957.
2. DeVorkin, Howard, et al. Air Pollution Source Testing Manual. Air
Pollution Control District. Los Angeles, CA. November 1963.
3. Methods for Determining of Velocity, Volume, Dust and Mist
Content of Gases. Western Precipitation Division of Joy Manufacturing
Co. Los Angeles, CA. Bulletin WP-50. 1968.
4. Standard Method for Sampling Stacks for Particulate Matter. In:
1971 Book of ASTM Standards, Part 23. ASTM Designation D 2928-71.
Philadelphia, PA. 1971.
5. Hanson, H.A., et al. Particulate Sampling Strategies for Large
Power Plants Including Nonuniform Flow. USEPA, ORD, ESRL, Research
Triangle Park, NC. EPA-600/2-76-170. June 1976.
6. Entropy Environmentalists, Inc. Determination of the Optimum
Number of Sampling Points: An Analysis of Method 1 Criteria.
Environmental Protection Agency. Research Triangle Park, NC. EPA
Contract No. 68-01-3172, Task 7.
7. Hanson, H.A., R.J. Davini, J.K. Morgan, and A.A. Iversen.
Particulate Sampling Strategies for Large Power Plants Including
Nonuniform Flow. USEPA, Research Triangle Park, NC. Publication No. EPA-
600/2-76-170. June 1976. 350 pp.
8. Brooks, E.F., and R.L. Williams. Flow and Gas Sampling Manual.
U.S. Environmental Protection Agency. Research Triangle Park, NC.
Publication No. EPA-600/2-76-203. July 1976. 93 pp.
9. Entropy Environmentalists, Inc. Traverse Point Study. EPA
Contract No. 68-02-3172. June 1977. 19 pp.
10. Brown, J. and K. Yu. Test Report: Particulate Sampling Strategy
in Circular Ducts. Emission Measurement Branch. U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711. July 31, 1980. 12
pp.
11. Hawksley, P.G.W., S. Badzioch, and J.H. Blackett. Measurement of
Solids in Flue Gases. Leatherhead, England, The British Coal Utilisation
Research Association. 1961. pp. 129-133.
12. Knapp, K.T. The Number of Sampling Points Needed for
Representative Source Sampling. In: Proceedings of the Fourth National
Conference on Energy and Environment. Theodore, L. et al. (ed). Dayton,
Dayton Section of the American Institute of Chemical Engineers. October
3-7, 1976. pp. 563-568.
13. Smith, W.S. and D.J. Grove. A Proposed Extension of EPA Method 1
Criteria. Pollution Engineering. XV (8):36-37. August 1983.
14. Gerhart, P.M. and M.J. Dorsey. Investigation of Field Test
Procedures for Large Fans. University of Akron. Akron, OH. (EPRI
Contract CS-1651). Final Report (RP-1649-5). December 1980.
15. Smith, W.S. and D.J. Grove. A New Look at Isokinetic Sampling--
Theory and Applications. Source Evaluation Society Newsletter. VIII
(3):19-24. August 1983.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

[[Page 11]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.041

Table 1-1 Cross-Section Layout for Rectangular Stacks
------------------------------------------------------------------------
Number of tranverse points layout Matrix
------------------------------------------------------------------------
9...................................... 3x3
12..................................... 4x3
16..................................... 4x4
20..................................... 5x4
25..................................... 5x5
30..................................... 6x5
36..................................... 6x6
42..................................... 7x6
49..................................... 7x7
------------------------------------------------------------------------

[[Page 12]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.042

Table 1-2--Location of Traverse Points in Circular Stacks
[Percent of stack diameter from inside wall to tranverse point]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of traverse points on a diameter
Traverse point number on a diameter -----------------------------------------------------------------------------------------------
2 4 6 8 10 12 14 16 18 20 22 24
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................................... 14.6 6.7 4.4 3.2 2.6 2.1 1.8 1.6 1.4 1.3 1.1 1.1
2....................................................... 85.4 25.0 14.6 10.5 8.2 6.7 5.7 4.9 4.4 3.9 3.5 3.2
3....................................................... ...... 75.0 29.6 19.4 14.6 11.8 9.9 8.5 7.5 6.7 6.0 5.5
4....................................................... ...... 93.3 70.4 32.3 22.6 17.7 14.6 12.5 10.9 9.7 8.7 7.9
5....................................................... ...... ...... 85.4 67.7 34.2 25.0 20.1 16.9 14.6 12.9 11.6 10.5

[[Page 13]]

6....................................................... ...... ...... 95.6 80.6 65.8 35.6 26.9 22.0 18.8 16.5 14.6 13.2
7....................................................... ...... ...... ...... 89.5 77.4 64.4 36.6 28.3 23.6 20.4 18.0 16.1
8....................................................... ...... ...... ...... 96.8 85.4 75.0 63.4 37.5 29.6 25.0 21.8 19.4
9....................................................... ...... ...... ...... ...... 91.8 82.3 73.1 62.5 38.2 30.6 26.2 23.0
10...................................................... ...... ...... ...... ...... 97.4 88.2 79.9 71.7 61.8 38.8 31.5 27.2
11...................................................... ...... ...... ...... ...... ...... 93.3 85.4 78.0 70.4 61.2 39.3 32.3
12...................................................... ...... ...... ...... ...... ...... 97.9 90.1 83.1 76.4 69.4 60.7 39.8
13...................................................... ...... ...... ...... ...... ...... ...... 94.3 87.5 81.2 75.0 68.5 60.2
14...................................................... ...... ...... ...... ...... ...... ...... 98.2 91.5 85.4 79.6 73.8 67.7
15...................................................... ...... ...... ...... ...... ...... ...... ...... 95.1 89.1 83.5 78.2 72.8
16...................................................... ...... ...... ...... ...... ...... ...... ...... 98.4 92.5 87.1 82.0 77.0
17...................................................... ...... ...... ...... ...... ...... ...... ...... ...... 95.6 90.3 85.4 80.6
18...................................................... ...... ...... ...... ...... ...... ...... ...... ...... 98.6 93.3 88.4 83.9
19...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... 96.1 91.3 86.8
20...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... 98.7 94.0 89.5
21...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... 96.5 92.1
22...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... 98.9 94.5
23...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... 96.8
24...................................................... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... 99.9
--------------------------------------------------------------------------------------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR17OC00.043

Method 1A--Sample and Velocity Traverses for Stationary Sources With
Small Stacks or Ducts

1.0 Scope and Application

1.1 Measured Parameters. The purpose of the method is to provide
guidance for the selection of sampling ports and traverse points at
which sampling for air pollutants will be performed pursuant to
regulations set forth in this part.
1.2 Applicability. The applicability and principle of this method
are identical to Method 1, except its applicability is limited to stacks
or ducts. This method is applicable to flowing gas streams in ducts,
stacks, and flues of less than about 0.30 meter (12 in.) in diameter, or
0.071 m ² (113 in.²) in cross-sectional area, but
equal to or greater than about 0.10 meter (4 in.) in diameter, or 0.0081
m ² (12.57 in.²) in cross-sectional area. This
method cannot be used when the flow is cyclonic or swirling.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

[[Page 14]]

2.0 Summary of Method

2.1 The method is designed to aid in the representative measurement
of pollutant emissions and/or total volumetric flow rate from a
stationary source. A measurement site or a pair of measurement sites
where the effluent stream is flowing in a known direction is (are)
selected. The cross-section of the stack is divided into a number of
equal areas. Traverse points are then located within each of these equal
areas.
2.2 In these small diameter stacks or ducts, the conventional Method
5 stack assembly (consisting of a Type S pitot tube attached to a
sampling probe, equipped with a nozzle and thermocouple) blocks a
significant portion of the cross-section of the duct and causes
inaccurate measurements. Therefore, for particulate matter (PM) sampling
in small stacks or ducts, the gas velocity is measured using a standard
pitot tube downstream of the actual emission sampling site. The straight
run of duct between the PM sampling and velocity measurement sites
allows the flow profile, temporarily disturbed by the presence of the
sampling probe, to redevelop and stabilize.

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

6.0 Equipment and Supplies [Reserved]

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection, Preservation, Storage, and Transport [Reserved]

9.0 Quality Control [Reserved]

10.0 Calibration and Standardization [Reserved]

11.0 Procedure

11.1 Selection of Measurement Site.
11.1.1 Particulate Measurements--Steady or Unsteady Flow. Select a
particulate measurement site located preferably at least eight
equivalent stack or duct diameters downstream and 10 equivalent
diameters upstream from any flow disturbances such as bends, expansions,
or contractions in the stack, or from a visible flame. Next, locate the
velocity measurement site eight equivalent diameters downstream of the
particulate measurement site (see Figure 1A-1). If such locations are
not available, select an alternative particulate measurement location at
least two equivalent stack or duct diameters downstream and two and one-
half diameters upstream from any flow disturbance. Then, locate the
velocity measurement site two equivalent diameters downstream from the
particulate measurement site. (See Section 12.2 of Method 1 for
calculating equivalent diameters for a rectangular cross-section.)
11.1.2 PM Sampling (Steady Flow) or Velocity (Steady or Unsteady
Flow) Measurements. For PM sampling when the volumetric flow rate in a
duct is constant with respect to time, Section 11.1.1 of Method 1 may be
followed, with the PM sampling and velocity measurement performed at one
location. To demonstrate that the flow rate is constant (within 10
percent) when PM measurements are made, perform complete velocity
traverses before and after the PM sampling run, and calculate the
deviation of the flow rate derived after the PM sampling run from the
one derived before the PM sampling run. The PM sampling run is
acceptable if the deviation does not exceed 10 percent.
11.2 Determining the Number of Traverse Points.
11.2.1 Particulate Measurements (Steady or Unsteady Flow). Use
Figure 1-1 of Method 1 to determine the number of traverse points to use
at both the velocity measurement and PM sampling locations. Before
referring to the figure, however, determine the distances between both
the velocity measurement and PM sampling sites to the nearest upstream
and downstream disturbances. Then divide each distance by the stack
diameter or equivalent diameter to express the distances in terms of the
number of duct diameters. Then, determine the number of traverse points
from Figure 1-1 of Method 1 corresponding to each of these four
distances. Choose the highest of the four numbers of traverse points (or
a greater number) so that, for circular ducts the number is a multiple
of four; and for rectangular ducts, the number is one of those shown in
Table 1-1 of Method 1. When the optimum duct diameter location criteria
can be satisfied, the minimum number of traverse points required is
eight for circular ducts and nine for rectangular ducts.
11.2.2 PM Sampling (Steady Flow) or only Velocity (Non-Particulate)
Measurements. Use Figure 1-2 of Method 1 to determine number of traverse
points, following the same procedure used for PM sampling as described
in Section 11.2.1 of Method 1. When the optimum duct diameter location
criteria can be satisfied, the minimum number of traverse points
required is eight for circular ducts and nine for rectangular ducts.

[[Page 15]]

11.3 Cross-sectional Layout, Location of Traverse Points, and
Verification of the Absence of Cyclonic Flow. Same as Method 1, Sections
11.3 and 11.4, respectively.

12.0 Data Analysis and Calculations [Reserved]

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

Same as Method 1, Section 16.0, References 1 through 6, with the
addition of the following:
1. Vollaro, Robert F. Recommended Procedure for Sample Traverses in
Ducts Smaller Than 12 Inches in Diameter. U.S. Environmental Protection
Agency, Emission Measurement Branch, Research Triangle Park, North
Carolina. January 1977.

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.044

Method 2--Determination of Stack Gas Velocity and Volumetric Flow Rate
(Type S Pitot Tube)

1.0 Scope and Application.

1.1 This method is applicable for the determination of the average
velocity and the volumetric flow rate of a gas stream.
1.2 This method is not applicable at measurement sites that fail to
meet the criteria of Method 1, Section 11.1. Also, the method cannot be
used for direct measurement in cyclonic or swirling gas streams; Section
11.4 of Method 1 shows how to determine cyclonic or swirling flow
conditions. When unacceptable conditions exist, alternative procedures,
subject to the approval of the Administrator, must be employed to
produce accurate flow rate determinations. Examples of such alternative
procedures are: (1) to install straightening vanes; (2) to calculate the
total volumetric flow rate stoichiometrically, or (3) to move to another
measurement site at which the flow is acceptable.
1.3 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method.

2.1 The average gas velocity in a stack is determined from the gas
density and from measurement of the average velocity head with a Type S
(Stausscheibe or reverse type) pitot tube.

[[Page 16]]

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

6.0 Equipment and Supplies

Specifications for the apparatus are given below. Any other
apparatus that has been demonstrated (subject to approval of the
Administrator) to be capable of meeting the specifications will be
considered acceptable.
6.1 Type S Pitot Tube.
6.1.1 Pitot tube made of metal tubing (e.g., stainless steel) as
shown in Figure 2-1. It is recommended that the external tubing diameter
(dimension Dt, Figure 2-2b) be between 0.48 and 0.95 cm (\3/
16\ and \3/8\ inch). There shall be an equal distance from the base of
each leg of the pitot tube to its face-opening plane (dimensions
PA and PB, Figure 2-2b); it is recommended that
this distance be between 1.05 and 1.50 times the external tubing
diameter. The face openings of the pitot tube shall, preferably, be
aligned as shown in Figure 2-2; however, slight misalignments of the
openings are permissible (see Figure 2-3).
6.1.2 The Type S pitot tube shall have a known coefficient,
determined as outlined in Section 10.0. An identification number shall
be assigned to the pitot tube; this number shall be permanently marked
or engraved on the body of the tube. A standard pitot tube may be used
instead of a Type S, provided that it meets the specifications of
Sections 6.7 and 10.2. Note, however, that the static and impact
pressure holes of standard pitot tubes are susceptible to plugging in
particulate-laden gas streams. Therefore, whenever a standard pitot tube
is used to perform a traverse, adequate proof must be furnished that the
openings of the pitot tube have not plugged up during the traverse
period. This can be accomplished by comparing the velocity head
([Delta]p) measurement recorded at a selected traverse point (readable
[Delta]p value) with a second [Delta]p measurement recorded after ``back
purging'' with pressurized air to clean the impact and static holes of
the standard pitot tube. If the before and after [Delta]p measurements
are within 5 percent, then the traverse data are acceptable. Otherwise,
the data should be rejected and the traverse measurements redone. Note
that the selected traverse point should be one that demonstrates a
readable [Delta]p value. If ``back purging'' at regular intervals is
part of a routine procedure, then comparative [Delta]p measurements
shall be conducted as above for the last two traverse points that
exhibit suitable [Delta]p measurements.
6.2 Differential Pressure Gauge. An inclined manometer or equivalent
device. Most sampling trains are equipped with a 10 in. (water column)
inclined-vertical manometer, having 0.01 in. H20 divisions on
the 0 to 1 in. inclined scale, and 0.1 in. H20 divisions on
the 1 to 10 in. vertical scale. This type of manometer (or other gauge
of equivalent sensitivity) is satisfactory for the measurement of
[Delta]p values as low as 1.27 mm (0.05 in.) H20. However, a
differential pressure gauge of greater sensitivity shall be used
(subject to the approval of the Administrator), if any of the following
is found to be true: (1) the arithmetic average of all [Delta]p readings
at the traverse points in the stack is less than 1.27 mm (0.05 in.)
H20; (2) for traverses of 12 or more points, more than 10
percent of the individual [Delta]p readings are below 1.27 mm (0.05 in.)
H20; or (3) for traverses of fewer than 12 points, more than
one [Delta]p reading is below 1.27 mm (0.05 in.) H20.
Reference 18 (see Section 17.0) describes commercially available
instrumentation for the measurement of low-range gas velocities.
6.2.1 As an alternative to criteria (1) through (3) above, Equation
2-1 (Section 12.2) may be used to determine the necessity of using a
more sensitive differential pressure gauge. If T is greater than 1.05,
the velocity head data are unacceptable and a more sensitive
differential pressure gauge must be used.

Note: If differential pressure gauges other than inclined manometers
are used (e.g., magnehelic gauges), their calibration must be checked
after each test series. To check the calibration of a differential
pressure gauge, compare [Delta]p readings of the gauge with those of a
gauge-oil manometer at a minimum of three points, approximately
representing the range of [Delta]p values in the stack. If, at each
point, the values of [Delta]p as read by the differential pressure gauge
and gauge-oil manometer agree to within 5 percent, the differential
pressure gauge shall be considered to be in proper calibration.
Otherwise, the test series shall either be voided, or procedures to
adjust the measured [Delta]p values and final results shall be used,
subject to the approval of the Administrator.

6.3 Temperature Sensor. A thermocouple, liquid-filled bulb
thermometer, bimetallic thermometer, mercury-in-glass thermometer, or
other gauge capable of measuring temperatures to within 1.5 percent of
the minimum absolute stack temperature. The temperature sensor shall be
attached to the pitot tube such that the sensor tip does not touch any
metal; the gauge shall be in an interference-free arrangement with
respect to the pitot tube face openings (see Figure 2-1 and Figure 2-4).
Alternative positions may

[[Page 17]]

be used if the pitot tube-temperature gauge system is calibrated
according to the procedure of Section 10.0. Provided that a difference
of not more than 1 percent in the average velocity measurement is
introduced, the temperature gauge need not be attached to the pitot
tube. This alternative is subject to the approval of the Administrator.
6.4 Pressure Probe and Gauge. A piezometer tube and mercury- or
water-filled U-tube manometer capable of measuring stack pressure to
within 2.5 mm (0.1 in.) Hg. The static tap of a standard type pitot tube
or one leg of a Type S pitot tube with the face opening planes
positioned parallel to the gas flow may also be used as the pressure
probe.
6.5 Barometer. A mercury, aneroid, or other barometer capable of
measuring atmospheric pressure to within 2.54 mm (0.1 in.) Hg.

Note: The barometric pressure reading may be obtained from a nearby
National Weather Service station. In this case, the station value (which
is the absolute barometric pressure) shall be requested and an
adjustment for elevation differences between the weather station and
sampling point shall be made at a rate of minus 2.5 mm (0.1 in.) Hg per
30 m (100 ft) elevation increase or plus 2.5 mm (0.1 in.) Hg per 30 m
(100 ft.) for elevation decrease.

6.6 Gas Density Determination Equipment. Method 3 equipment, if
needed (see Section 8.6), to determine the stack gas dry molecular
weight, and Method 4 (reference method) or Method 5 equipment for
moisture content determination. Other methods may be used subject to
approval of the Administrator.
6.7 Calibration Pitot Tube. When calibration of the Type S pitot
tube is necessary (see Section 10.1), a standard pitot tube shall be
used for a reference. The standard pitot tube shall, preferably, have a
known coefficient, obtained either (1) directly from the National
Institute of Standards and Technology (NIST), Gaithersburg MD 20899,
(301) 975-2002, or (2) by calibration against another standard pitot
tube with an NIST-traceable coefficient. Alternatively, a standard pitot
tube designed according to the criteria given in Sections 6.7.1 through
6.7.5 below and illustrated in Figure 2-5 (see also References 7, 8, and
17 in Section 17.0) may be used. Pitot tubes designed according to these
specifications will have baseline coefficients of 0.99 0.01.
6.7.1 Standard Pitot Design.
6.7.1.1 Hemispherical (shown in Figure 2-5), ellipsoidal, or conical
tip.
6.7.1.2 A minimum of six diameters straight run (based upon D, the
external diameter of the tube) between the tip and the static pressure
holes.
6.7.1.3 A minimum of eight diameters straight run between the static
pressure holes and the centerline of the external tube, following the
90[deg] bend.
6.7.1.4 Static pressure holes of equal size (approximately 0.1 D),
equally spaced in a piezometer ring configuration.
6.7.1.5 90[deg] bend, with curved or mitered junction.
6.8 Differential Pressure Gauge for Type S Pitot Tube Calibration.
An inclined manometer or equivalent. If the single-velocity calibration
technique is employed (see Section 10.1.2.3), the calibration
differential pressure gauge shall be readable to the nearest 0.127 mm
(0.005 in.) H20. For multivelocity calibrations, the gauge
shall be readable to the nearest 0.127 mm (0.005 in.) H20 for
[Delta]p values between 1.27 and 25.4 mm (0.05 and 1.00 in.)
H20, and to the nearest 1.27 mm (0.05 in.) H20 for
[Delta]p values above 25.4 mm (1.00 in.) H20. A special, more
sensitive gauge will be required to read [Delta]p values below 1.27 mm
(0.05 in.) H20 (see Reference 18 in Section 16.0).

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

8.1 Set up the apparatus as shown in Figure 2-1. Capillary tubing or
surge tanks installed between the manometer and pitot tube may be used
to dampen [Delta]p fluctuations. It is recommended, but not required,
that a pretest leak-check be conducted as follows: (1) blow through the
pitot impact opening until at least 7.6 cm (3.0 in.) H20
velocity head registers on the manometer; then, close off the impact
opening. The pressure shall remain stable for at least 15 seconds; (2)
do the same for the static pressure side, except using suction to obtain
the minimum of 7.6 cm (3.0 in.) H20. Other leak-check
procedures, subject to the approval of the Administrator, may be used.
8.2 Level and zero the manometer. Because the manometer level and
zero may drift due to vibrations and temperature changes, make periodic
checks during the traverse (at least once per hour). Record all
necessary data on a form similar to that shown in Figure 2-6.
8.3 Measure the velocity head and temperature at the traverse points
specified by Method 1. Ensure that the proper differential pressure
gauge is being used for the range of [Delta]p values encountered (see
Section 6.2). If it is necessary to change to a more sensitive gauge, do
so, and remeasure the [Delta]p and temperature readings at each traverse
point. Conduct a post-test leak-check (mandatory), as described in
Section 8.1 above, to validate the traverse run.
8.4 Measure the static pressure in the stack. One reading is usually
adequate.
8.5 Determine the atmospheric pressure.
8.6 Determine the stack gas dry molecular weight. For combustion
processes or processes that emit essentially CO2,
O2, CO, and N2, use Method 3. For processes
emitting

[[Page 18]]

essentially air, an analysis need not be conducted; use a dry molecular
weight of 29.0. For other processes, other methods, subject to the
approval of the Administrator, must be used.
8.7 Obtain the moisture content from Method 4 (reference method, or
equivalent) or from Method 5.
8.8 Determine the cross-sectional area of the stack or duct at the
sampling location. Whenever possible, physically measure the stack
dimensions rather than using blueprints. Do not assume that stack
diameters are equal. Measure each diameter distance to verify its
dimensions.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.1-10.4..................... Sampling Ensure accurate
equipment measurement of stack
calibration. gas flow rate,
sample volume.
------------------------------------------------------------------------

10.0 Calibration and Standardization

10.1 Type S Pitot Tube. Before its initial use, carefully examine
the Type S pitot tube top, side, and end views to verify that the face
openings of the tube are aligned within the specifications illustrated
in Figures 2-2 and 2-3. The pitot tube shall not be used if it fails to
meet these alignment specifications. After verifying the face opening
alignment, measure and record the following dimensions of the pitot
tube: (a) the external tubing diameter (dimension Dt, Figure
2-2b); and (b) the base-to-opening plane distances (dimensions
PA and PB, Figure 2-2b). If Dt is
between 0.48 and 0.95 cm \3/16\ and \3/8\ in.), and if PA and
PB are equal and between 1.05 and 1.50 Dt, there
are two possible options: (1) the pitot tube may be calibrated according
to the procedure outlined in Sections 10.1.2 through 10.1.5, or (2) a
baseline (isolated tube) coefficient value of 0.84 may be assigned to
the pitot tube. Note, however, that if the pitot tube is part of an
assembly, calibration may still be required, despite knowledge of the
baseline coefficient value (see Section 10.1.1). If Dt,
PA, and PB are outside the specified limits, the
pitot tube must be calibrated as outlined in Sections 10.1.2 through
10.1.5.
10.1.1 Type S Pitot Tube Assemblies. During sample and velocity
traverses, the isolated Type S pitot tube is not always used; in many
instances, the pitot tube is used in combination with other source-
sampling components (e.g., thermocouple, sampling probe, nozzle) as part
of an ``assembly.'' The presence of other sampling components can
sometimes affect the baseline value of the Type S pitot tube coefficient
(Reference 9 in Section 17.0); therefore, an assigned (or otherwise
known) baseline coefficient value may or may not be valid for a given
assembly. The baseline and assembly coefficient values will be identical
only when the relative placement of the components in the assembly is
such that aerodynamic interference effects are eliminated. Figures 2-4,
2-7, and 2-8 illustrate interference-free component arrangements for
Type S pitot tubes having external tubing diameters between 0.48 and
0.95 cm (\3/16\ and \3/8\ in.). Type S pitot tube assemblies that fail
to meet any or all of the specifications of Figures 2-4, 2-7, and 2-8
shall be calibrated according to the procedure outlined in Sections
10.1.2 through 10.1.5, and prior to calibration, the values of the
intercomponent spacings (pitot-nozzle, pitot-thermocouple, pitot-probe
sheath) shall be measured and recorded.

Note: Do not use a Type S pitot tube assembly that is constructed
such that the impact pressure opening plane of the pitot tube is below
the entry plane of the nozzle (see Figure 2-6B).

10.1.2 Calibration Setup. If the Type S pitot tube is to be
calibrated, one leg of the tube shall be permanently marked A, and the
other, B. Calibration shall be performed in a flow system having the
following essential design features:
10.1.2.1 The flowing gas stream must be confined to a duct of
definite cross-sectional area, either circular or rectangular. For
circular cross sections, the minimum duct diameter shall be 30.48 cm (12
in.); for rectangular cross sections, the width (shorter side) shall be
at least 25.4 cm (10 in.).
10.1.2.2 The cross-sectional area of the calibration duct must be
constant over a distance of 10 or more duct diameters. For a rectangular
cross section, use an equivalent diameter, calculated according to
Equation 2-2 (see Section 12.3), to determine the number of duct
diameters. To ensure the presence of stable, fully developed flow
patterns at the calibration site, or ``test section,'' the site must be
located at least eight diameters downstream and two diameters upstream
from the nearest disturbances.

Note: The eight- and two-diameter criteria are not absolute; other
test section locations may be used (subject to approval of the
Administrator), provided that the flow at the test site has been
demonstrated to be or found stable and parallel to the duct axis.

10.1.2.3 The flow system shall have the capacity to generate a test-
section velocity around 910 m/min (3,000 ft/min). This velocity must be
constant with time to guarantee steady flow during calibration. Note
that Type S pitot tube coefficients obtained by

[[Page 19]]

single-velocity calibration at 910 m/min (3,000 ft/min) will generally
be valid to 3 percent for the measurement of
velocities above 300 m/min (1,000 ft/min) and to 6
percent for the measurement of velocities between 180 and 300 m/min (600
and 1,000 ft/min). If a more precise correlation between the pitot tube
coefficient, (Cp), and velocity is desired, the flow system
should have the capacity to generate at least four distinct, time-
invariant test-section velocities covering the velocity range from 180
to 1,500 m/min (600 to 5,000 ft/min), and calibration data shall be
taken at regular velocity intervals over this range (see References 9
and 14 in Section 17.0 for details).
10.1.2.4 Two entry ports, one for each of the standard and Type S
pitot tubes, shall be cut in the test section. The standard pitot entry
port shall be located slightly downstream of the Type S port, so that
the standard and Type S impact openings will lie in the same cross-
sectional plane during calibration. To facilitate alignment of the pitot
tubes during calibration, it is advisable that the test section be
constructed of Plexiglas^TM or some other transparent
material.
10.1.3 Calibration Procedure. Note that this procedure is a general
one and must not be used without first referring to the special
considerations presented in Section 10.1.5. Note also that this
procedure applies only to single-velocity calibration. To obtain
calibration data for the A and B sides of the Type S pitot tube, proceed
as follows:
10.1.3.1 Make sure that the manometer is properly filled and that
the oil is free from contamination and is of the proper density. Inspect
and leak-check all pitot lines; repair or replace if necessary.
10.1.3.2 Level and zero the manometer. Switch on the fan, and allow
the flow to stabilize. Seal the Type S pitot tube entry port.
10.1.3.3 Ensure that the manometer is level and zeroed. Position the
standard pitot tube at the calibration point (determined as outlined in
Section 10.1.5.1), and align the tube so that its tip is pointed
directly into the flow. Particular care should be taken in aligning the
tube to avoid yaw and pitch angles. Make sure that the entry port
surrounding the tube is properly sealed.
10.1.3.4 Read [Delta]pstd, and record its value in a data
table similar to the one shown in Figure 2-9. Remove the standard pitot
tube from the duct, and disconnect it from the manometer. Seal the
standard entry port.
10.1.3.5 Connect the Type S pitot tube to the manometer and leak-
check. Open the Type S tube entry port. Check the manometer level and
zero. Insert and align the Type S pitot tube so that its A side impact
opening is at the same point as was the standard pitot tube and is
pointed directly into the flow. Make sure that the entry port
surrounding the tube is properly sealed.
10.1.3.6 Read [Delta]ps, and enter its value in the data
table. Remove the Type S pitot tube from the duct, and disconnect it
from the manometer.
10.1.3.7 Repeat Steps 10.1.3.3 through 10.1.3.6 until three pairs of
[Delta]p readings have been obtained for the A side of the Type S pitot
tube.
10.1.3.8 Repeat Steps 10.1.3.3 through 10.1.3.7 for the B side of
the Type S pitot tube.
10.1.3.9 Perform calculations as described in Section 12.4. Use the
Type S pitot tube only if the values of [sigma]A and
[sigma]B are less than or equal to 0.01 and if the absolute
value of the difference between Cp(A) and Cp(B) is
0.01 or less.
10.1.4 Special Considerations.
10.1.4.1 Selection of Calibration Point.
10.1.4.1.1 When an isolated Type S pitot tube is calibrated, select
a calibration point at or near the center of the duct, and follow the
procedures outlined in Section 10.1.3. The Type S pitot coefficients
measured or calculated, (i.e., Cp(A) and Cp(B))
will be valid, so long as either: (1) the isolated pitot tube is used;
or (2) the pitot tube is used with other components (nozzle,
thermocouple, sample probe) in an arrangement that is free from
aerodynamic interference effects (see Figures 2-4, 2-7, and 2-8).
10.1.4.1.2 For Type S pitot tube-thermocouple combinations (without
probe assembly), select a calibration point at or near the center of the
duct, and follow the procedures outlined in Section 10.1.3. The
coefficients so obtained will be valid so long as the pitot tube-
thermocouple combination is used by itself or with other components in
an interference-free arrangement (Figures 2-4, 2-7, and 2-8).
10.1.4.1.3 For Type S pitot tube combinations with complete probe
assemblies, the calibration point should be located at or near the
center of the duct; however, insertion of a probe sheath into a small
duct may cause significant cross-sectional area interference and
blockage and yield incorrect coefficient values (Reference 9 in Section
17.0). Therefore, to minimize the blockage effect, the calibration point
may be a few inches off-center if necessary. The actual blockage effect
will be negligible when the theoretical blockage, as determined by a
projected-area model of the probe sheath, is 2 percent or less of the
duct cross-sectional area for assemblies without external sheaths
(Figure 2-10a), and 3 percent or less for assemblies with external
sheaths (Figure 2-10b).
10.1.4.2 For those probe assemblies in which pitot tube-nozzle
interference is a factor (i.e., those in which the pitot-nozzle
separation distance fails to meet the specifications illustrated in
Figure 2-7A), the value of Cp(s) depends upon the amount of
free space between the tube and nozzle and, therefore,

[[Page 20]]

is a function of nozzle size. In these instances, separate calibrations
shall be performed with each of the commonly used nozzle sizes in place.
Note that the single-velocity calibration technique is acceptable for
this purpose, even though the larger nozzle sizes (0.635 cm
or \1/4\ in.) are not ordinarily used for isokinetic sampling at
velocities around 910 m/min (3,000 ft/min), which is the calibration
velocity. Note also that it is not necessary to draw an isokinetic
sample during calibration (see Reference 19 in Section 17.0).
10.1.4.3 For a probe assembly constructed such that its pitot tube
is always used in the same orientation, only one side of the pitot tube
need be calibrated (the side which will face the flow). The pitot tube
must still meet the alignment specifications of Figure 2-2 or 2-3,
however, and must have an average deviation ([sigma]) value of 0.01 or
less (see Section 10.1.4.4).
10.1.5 Field Use and Recalibration.
10.1.5.1 Field Use.
10.1.5.1.1 When a Type S pitot tube (isolated or in an assembly) is
used in the field, the appropriate coefficient value (whether assigned
or obtained by calibration) shall be used to perform velocity
calculations. For calibrated Type S pitot tubes, the A side coefficient
shall be used when the A side of the tube faces the flow, and the B side
coefficient shall be used when the B side faces the flow. Alternatively,
the arithmetic average of the A and B side coefficient values may be
used, irrespective of which side faces the flow.
10.1.5.1.2 When a probe assembly is used to sample a small duct,
30.5 to 91.4 cm (12 to 36 in.) in diameter, the probe sheath sometimes
blocks a significant part of the duct cross-section, causing a reduction
in the effective value of Cp(s). Consult Reference 9 (see
Section 17.0) for details. Conventional pitot-sampling probe assemblies
are not recommended for use in ducts having inside diameters smaller
than 30.5 cm (12 in.) (see Reference 16 in Section 17.0).
10.1.5.2 Recalibration.
10.1.5.2.1 Isolated Pitot Tubes. After each field use, the pitot
tube shall be carefully reexamined in top, side, and end views. If the
pitot face openings are still aligned within the specifications
illustrated in Figure 2-2 and Figure 2-3, it can be assumed that the
baseline coefficient of the pitot tube has not changed. If, however, the
tube has been damaged to the extent that it no longer meets the
specifications of Figure 2-2 and Figure 2-3, the damage shall either be
repaired to restore proper alignment of the face openings, or the tube
shall be discarded.
10.1.5.2.2 Pitot Tube Assemblies. After each field use, check the
face opening alignment of the pitot tube, as in Section 10.1.5.2.1.
Also, remeasure the intercomponent spacings of the assembly. If the
intercomponent spacings have not changed and the face opening alignment
is acceptable, it can be assumed that the coefficient of the assembly
has not changed. If the face opening alignment is no longer within the
specifications of Figure 2-2 and Figure 2-3, either repair the damage or
replace the pitot tube (calibrating the new assembly, if necessary). If
the intercomponent spacings have changed, restore the original spacings,
or recalibrate the assembly.
10.2 Standard Pitot Tube (if applicable). If a standard pitot tube
is used for the velocity traverse, the tube shall be constructed
according to the criteria of Section 6.7 and shall be assigned a
baseline coefficient value of 0.99. If the standard pitot tube is used
as part of an assembly, the tube shall be in an interference-free
arrangement (subject to the approval of the Administrator).
10.3 Temperature Sensors.
10.3.1 After each field use, calibrate dial thermometers, liquid-
filled bulb thermometers, thermocouple-potentiometer systems, and other
sensors at a temperature within 10 percent of the average absolute stack
temperature. For temperatures up to 405 [deg]C (761 [deg]F), use an ASTM
mercury-in-glass reference thermometer, or equivalent, as a reference.
Alternatively, either a reference thermocouple and potentiometer
(calibrated against NIST standards) or thermometric fixed points (e.g.,
ice bath and boiling water, corrected for barometric pressure) may be
used. For temperatures above 405 [deg]C (761 [deg]F), use a reference
thermocouple-potentiometer system calibrated against NIST standards or
an alternative reference, subject to the approval of the Administrator.
10.3.2 The temperature data recorded in the field shall be
considered valid. If, during calibration, the absolute temperature
measured with the sensor being calibrated and the reference sensor agree
within 1.5 percent, the temperature data taken in the field shall be
considered valid. Otherwise, the pollutant emission test shall either be
considered invalid or adjustments (if appropriate) of the test results
shall be made, subject to the approval of the Administrator.
10.4 Barometer. Calibrate the barometer used against a mercury
barometer.

11.0 Analytical Procedure

Sample collection and analysis are concurrent for this method (see
Section 8.0).

12.0 Data Analysis and Calculations

Carry out calculations, retaining at least one extra significant
figure beyond that of the acquired data. Round off figures after final
calculation.
12.1 Nomenclature.
A=Cross-sectional area of stack, m\2\ (ft\2\).
Bws=Water vapor in the gas stream (from Method 4 (reference
method) or Method 5), proportion by volume.

[[Page 21]]

Cp=Pitot tube coefficient, dimensionless.
Cp(s)=Type S pitot tube coefficient, dimensionless.
Cp(std)=Standard pitot tube coefficient; use 0.99 if the
coefficient is unknown and the tube is designed according to the
criteria of Sections 6.7.1 to 6.7.5 of this method.
De=Equivalent diameter.
K=0.127 mm H2O (metric units). 0.005 in. H2O
(English units).
Kp=Velocity equation constant.
L=Length.
Md=Molecular weight of stack gas, dry basis (see Section
8.6), g/g-mole (lb/lb-mole).
Ms=Molecular weight of stack gas, wet basis, g/g-mole (lb/lb-
mole).
n=Total number of traverse points.
Pbar=Barometric pressure at measurement site, mm Hg (in. Hg).
Pg=Stack static pressure, mm Hg (in. Hg).
Ps=Absolute stack pressure (Pbar + Pg),
mm Hg (in. Hg),
Pstd=Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
Qsd=Dry volumetric stack gas flow rate corrected to standard
conditions, dscm/hr (dscf/hr).
T=Sensitivity factor for differential pressure gauges.
Ts=Stack temperature, [deg]C ( [deg]F).
Ts(abs)=Absolute stack temperature, [deg]K ([deg]R).
=273 + Ts for metric units,
=460 + Ts for English units.
Tstd=Standard absolute temperature, 293 [deg]K (528 [deg]R).
Vs=Average stack gas velocity, m/sec (ft/sec).
W=Width.
[Delta]p=Velocity head of stack gas, mm H2O (in.
H20).
[Delta]pi=Individual velocity head reading at traverse point
``i'', mm (in.) H2O.
[Delta]pstd=Velocity head measured by the standard pitot
tube, cm (in.) H2O.
[Delta]ps=Velocity head measured by the Type S pitot tube, cm
(in.) H2O.
3600=Conversion Factor, sec/hr.
18.0=Molecular weight of water, g/g-mole (lb/lb-mole).

12.2 Calculate T as follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.045

12.3 Calculate De as follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.046

12.4 Calibration of Type S Pitot Tube.
12.4.1 For each of the six pairs of [Delta]p readings (i.e., three
from side A and three from side B) obtained in Section 10.1.3, calculate
the value of the Type S pitot tube coefficient according to Equation 2-
3:
[GRAPHIC] [TIFF OMITTED] TR17OC00.047

12.4.2 Calculate Cp(A), the mean A-side coefficient, and
Cp(B), the mean B-side coefficient. Calculate the difference
between these two average values.
12.4.3 Calculate the deviation of each of the three A-side values of
Cp(s) from Cp(A), and the deviation of each of the
three B-side values of Cp(s) from Cp(B), using
Equation 2-4:
[GRAPHIC] [TIFF OMITTED] TR17OC00.048

12.4.4 Calculate [sigma] the average deviation from the mean, for
both the A and B sides of the pitot tube. Use Equation 2-5:
[GRAPHIC] [TIFF OMITTED] TR17OC00.049

12.5 Molecular Weight of Stack Gas.
[GRAPHIC] [TIFF OMITTED] TR17OC00.050

12.6 Average Stack Gas Velocity.
[GRAPHIC] [TIFF OMITTED] TR17OC00.051

[[Page 22]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.052

[GRAPHIC] [TIFF OMITTED] TR17OC00.053

12.7 Average Stack Gas Dry Volumetric Flow Rate.
[GRAPHIC] [TIFF OMITTED] TR17OC00.054

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Mark, L.S. Mechanical Engineers' Handbook. New York. McGraw-Hill
Book Co., Inc. 1951.
2. Perry, J.H., ed. Chemical Engineers' Handbook. New York. McGraw-
Hill Book Co., Inc. 1960.
3. Shigehara, R.T., W.F. Todd, and W.S. Smith. Significance of
Errors in Stack Sampling Measurements. U.S. Environmental Protection
Agency, Research Triangle Park, N.C. (Presented at the Annual Meeting of
the Air Pollution Control Association, St. Louis, MO., June 14-19,
1970).
4. Standard Method for Sampling Stacks for Particulate Matter. In:
1971 Book of ASTM Standards, Part 23. Philadelphia, PA. 1971. ASTM
Designation D 2928-71.
5. Vennard, J.K. Elementary Fluid Mechanics. New York. John Wiley
and Sons, Inc. 1947.
6. Fluid Meters--Their Theory and Application. American Society of
Mechanical Engineers, New York, N.Y. 1959.
7. ASHRAE Handbook of Fundamentals. 1972. p. 208.
8. Annual Book of ASTM Standards, Part 26. 1974. p. 648.
9. Vollaro, R.F. Guidelines for Type S Pitot Tube Calibration. U.S.
Environmental Protection Agency, Research Triangle Park, N.C. (Presented
at 1st Annual Meeting, Source Evaluation Society, Dayton, OH, September
18, 1975.)
10. Vollaro, R.F. A Type S Pitot Tube Calibration Study. U.S.
Environmental Protection Agency, Emission Measurement Branch, Research
Triangle Park, N.C. July 1974.
11. Vollaro, R.F. The Effects of Impact Opening Misalignment on the
Value of the Type S Pitot Tube Coefficient. U.S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle Park,
NC. October 1976.
12. Vollaro, R.F. Establishment of a Baseline Coefficient Value for
Properly Constructed Type S Pitot Tubes. U.S. Environmental Protection
Agency, Emission Measurement Branch, Research Triangle Park, NC.
November 1976.
13. Vollaro, R.F. An Evaluation of Single-Velocity Calibration
Technique as a Means of Determining Type S Pitot Tube Coefficients. U.S.
Environmental Protection Agency, Emission Measurement Branch, Research
Triangle Park, NC. August 1975.
14. Vollaro, R.F. The Use of Type S Pitot Tubes for the Measurement
of Low Velocities. U.S. Environmental Protection Agency, Emission
Measurement Branch, Research Triangle Park, NC. November 1976.
15. Smith, Marvin L. Velocity Calibration of EPA Type Source
Sampling Probe. United Technologies Corporation, Pratt and Whitney
Aircraft Division, East Hartford, CT. 1975.
16. Vollaro, R.F. Recommended Procedure for Sample Traverses in
Ducts Smaller than 12 Inches in Diameter. U.S. Environmental Protection
Agency, Emission Measurement Branch, Research Triangle Park, NC.
November 1976.
17. Ower, E. and R.C. Pankhurst. The Measurement of Air Flow, 4th
Ed. London, Pergamon Press. 1966.

[[Page 23]]

18. Vollaro, R.F. A Survey of Commercially Available Instrumentation
for the Measurement of Low-Range Gas Velocities. U.S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle Park,
NC. November 1976. (Unpublished Paper).
19. Gnyp, A.W., et al. An Experimental Investigation of the Effect
of Pitot Tube-Sampling Probe Configurations on the Magnitude of the S
Type Pitot Tube Coefficient for Commercially Available Source Sampling
Probes. Prepared by the University of Windsor for the Ministry of the
Environment, Toronto, Canada. February 1975.

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.055

[[Page 24]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.056

[[Page 25]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.057

[[Page 26]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.058

[GRAPHIC] [TIFF OMITTED] TR17OC00.059

PLANT___________________________________________________________________
DATE____________________________________________________________________

[[Page 27]]

RUN NO._________________________________________________________________
STACK DIA. OR DIMENSIONS, m (in.)_______________________________________
BAROMETRIC PRESS., mm Hg (in. Hg)_______________________________________
CROSS SECTIONAL AREA, m\2\ (ft\2\)______________________________________
OPERATORS_______________________________________________________________
PITOT TUBE I.D. NO._____________________________________________________
AVG. COEFFICIENT, Cp =__________________________________________________
LAST DATE CALIBRATED____________________________________________________

------------------------------------------------------------------------

-------------------------------------------------------------------------

------------------------------------------------------------------------

SCHEMATIC OF STACK CROSS SECTION

--------------------------------------------------------------------------------------------------------------------------------------------------------
Stack temperature
Traverse Pt. No. Vel. Hd., [Delta]p ----------------------------------------------- Pg mm Hg (in. Hg) ([Delta]p)\1/2\
mm (in.) H2O Ts, [deg]C ( [deg]F) Ts, [deg]K ([deg]R)
--------------------------------------------------------------------------------------------------------------------------------------------------------

------------------------------------

------------------------------------
Average(1)
--------------------------------------------------------------------------------------------------------------------------------------------------------

Figure 2-6. Velocity Traverse Data

[[Page 28]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.060

[GRAPHIC] [TIFF OMITTED] TR17OC00.061

PITOT TUBE IDENTIFICATION NUMBER:_______________________________________
DATE:___________________________________________________________________
CALIBRATED BY:__________________________________________________________

``A'' Side Calibration
----------------------------------------------------------------------------------------------------------------
[Delta]Pstd cm [Delta]P(s) cm H2O Deviation Cp(s)--
Run No. H2O (in H2O) (in H2O) Cp(s) Cp(A)
----------------------------------------------------------------------------------------------------------------
1
--------------------------------
2
--------------------------------
3
--------------------------------

[[Page 29]]

Cp, avg
(SIDE A)
----------------------------------------------------------------------------------------------------------------

``B'' Side Calibration
----------------------------------------------------------------------------------------------------------------
[Delta]Pstd cm [Delta]P(s) cm H2O Deviation Cp(s)--
Run No. H2O (in H2O) (in H2O) Cp(s) Cp(B)
----------------------------------------------------------------------------------------------------------------
1
--------------------------------
2
--------------------------------
3
--------------------------------
Cp, avg
(SIDE B)
----------------------------------------------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TR17OC00.062

[Cp, avg (side A)--Cp, avg (side B)]*
*Must be less than or equal to 0.01

Figure 2-9. Pitot Tube Calibration Data

[[Page 30]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.063

Method 2A--Direct Measurement of Gas Volume Through Pipes and Small
Ducts

1.0 Scope and Application

1.1 This method is applicable for the determination of gas flow
rates in pipes and small ducts, either in-line or at exhaust positions,
within the temperature range of 0 to 50 [deg]C (32 to 122 [deg]F).
1.2 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 A gas volume meter is used to measure gas volume directly.
Temperature and pressure measurements are made to allow correction of
the volume to standard conditions.

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

[[Page 31]]

and health practices and determine the applicability of regulatory
limitations prior to performing this test method.

6.0 Equipment and Supplies

Specifications for the apparatus are given below. Any other
apparatus that has been demonstrated (subject to approval of the
Administrator) to be capable of meeting the specifications will be
considered acceptable.
6.1 Gas Volume Meter. A positive displacement meter, turbine meter,
or other direct measuring device capable of measuring volume to within 2
percent. The meter shall be equipped with a temperature sensor (accurate
to within 2 percent of the minimum absolute
temperature) and a pressure gauge (accurate to within 2.5 mm Hg). The manufacturer's recommended capacity of
the meter shall be sufficient for the expected maximum and minimum flow
rates for the sampling conditions. Temperature, pressure, corrosive
characteristics, and pipe size are factors necessary to consider in
selecting a suitable gas meter.
6.2 Barometer. A mercury, aneroid, or other barometer capable of
measuring atmospheric pressure to within 2.5 mm
Hg.

Note: In many cases, the barometric reading may be obtained from a
nearby National Weather Service station, in which case the station value
(which is the absolute barometric pressure) shall be requested and an
adjustment for elevation differences between the weather station and
sampling point shall be applied at a rate of minus 2.5 mm (0.1 in.) Hg
per 30 m (100 ft) elevation increase or vice versa for elevation
decrease.

6.3 Stopwatch. Capable of measurement to within 1 second.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

8.1 Installation. As there are numerous types of pipes and small
ducts that may be subject to volume measurement, it would be difficult
to describe all possible installation schemes. In general, flange
fittings should be used for all connections wherever possible. Gaskets
or other seal materials should be used to assure leak-tight connections.
The volume meter should be located so as to avoid severe vibrations and
other factors that may affect the meter calibration.
8.2 Leak Test.
8.2.1 A volume meter installed at a location under positive pressure
may be leak-checked at the meter connections by using a liquid leak
detector solution containing a surfactant. Apply a small amount of the
solution to the connections. If a leak exists, bubbles will form, and
the leak must be corrected.
8.2.2 A volume meter installed at a location under negative pressure
is very difficult to test for leaks without blocking flow at the inlet
of the line and watching for meter movement. If this procedure is not
possible, visually check all connections to assure leak-tight seals.
8.3 Volume Measurement.
8.3.1 For sources with continuous, steady emission flow rates,
record the initial meter volume reading, meter temperature(s), meter
pressure, and start the stopwatch. Throughout the test period, record
the meter temperatures and pressures so that average values can be
determined. At the end of the test, stop the timer, and record the
elapsed time, the final volume reading, meter temperature, and pressure.
Record the barometric pressure at the beginning and end of the test run.
Record the data on a table similar to that shown in Figure 2A-1.
8.3.2 For sources with noncontinuous, non-steady emission flow
rates, use the procedure in Section 8.3.1 with the addition of the
following: Record all the meter parameters and the start and stop times
corresponding to each process cyclical or noncontinuous event.

9.0 Quality Control

10.0 Calibration and Standardization

10.1 Volume Meter.
10.1.1 The volume meter is calibrated against a standard reference
meter prior to its initial use in the field. The reference meter is a
spirometer or liquid displacement meter with a capacity consistent with
that of the test meter.
10.1.2 Alternatively, a calibrated, standard pitot may be used as
the reference meter in conjunction with a wind tunnel assembly. Attach
the test meter to the wind tunnel so that the total flow passes through
the test meter. For each calibration run, conduct a 4-point traverse
along one stack diameter at a position at least eight diameters of
straight tunnel downstream and two diameters upstream of any bend,
inlet, or air mover. Determine the traverse point locations as specified
in Method 1. Calculate the reference volume using the velocity values
following the procedure in Method 2, the wind tunnel cross-sectional
area, and the run time.

[[Page 32]]

10.1.3 Set up the test meter in a configuration similar to that used
in the field installation (i.e., in relation to the flow moving device).
Connect the temperature sensor and pressure gauge as they are to be used
in the field. Connect the reference meter at the inlet of the flow line,
if appropriate for the meter, and begin gas flow through the system to
condition the meters. During this conditioning operation, check the
system for leaks.
10.1.4 The calibration shall be performed during at least three
different flow rates. The calibration flow rates shall be about 0.3,
0.6, and 0.9 times the rated maximum flow rate of the test meter.
10.1.5 For each calibration run, the data to be collected include:
reference meter initial and final volume readings, the test meter
initial and final volume reading, meter average temperature and
pressure, barometric pressure, and run time. Repeat the runs at each
flow rate at least three times.
10.1.6 Calculate the test meter calibration coefficient as indicated
in Section 12.2.
10.1.7 Compare the three Ym values at each of the flow
rates tested and determine the maximum and minimum values. The
difference between the maximum and minimum values at each flow rate
should be no greater than 0.030. Extra runs may be required to complete
this requirement. If this specification cannot be met in six successive
runs, the test meter is not suitable for use. In addition, the meter
coefficients should be between 0.95 and 1.05. If these specifications
are met at all the flow rates, average all the Ym values from
runs meeting the specifications to obtain an average meter calibration
coefficient, Ym.
10.1.8 The procedure above shall be performed at least once for each
volume meter. Thereafter, an abbreviated calibration check shall be
completed following each field test. The calibration of the volume meter
shall be checked with the meter pressure set at the average value
encountered during the field test. Three calibration checks (runs) shall
be performed using this average flow rate value. Calculate the average
value of the calibration factor. If the calibration has changed by more
than 5 percent, recalibrate the meter over the full range of flow as
described above.

Note: If the volume meter calibration coefficient values obtained
before and after a test series differ by more than 5 percent, the test
series shall either be voided, or calculations for the test series shall
be performed using whichever meter coefficient value (i.e., before or
after) gives the greater value of pollutant emission rate.

10.2 Temperature Sensor. After each test series, check the
temperature sensor at ambient temperature. Use an American Society for
Testing and Materials (ASTM) mercury-in-glass reference thermometer, or
equivalent, as a reference. If the sensor being checked agrees within 2
percent (absolute temperature) of the reference, the temperature data
collected in the field shall be considered valid. Otherwise, the test
data shall be considered invalid or adjustments of the results shall be
made, subject to the approval of the Administrator.
10.3 Barometer. Calibrate the barometer used against a mercury
barometer prior to the field test.

11.0 Analytical Procedure

Sample collection and analysis are concurrent for this method (see
Section 8.0).

12.0 Data Analysis and Calculations

Carry out calculations, retaining at least one extra decimal figure
beyond that of the acquired data. Round off figures after final
calculation.

12.1 Nomenclature.

f=Final reading.
i=Initial reading.
Pbar=Barometric pressure, mm Hg.
Pg=Average static pressure in volume meter, mm Hg.
Qs=Gas flow rate, m³/min, standard conditions.
s=Standard conditions, 20 [deg]C and 760 mm Hg.
Tr=Reference meter average temperature, [deg]K ([deg]R).
Tm=Test meter average temperature, [deg]K ([deg]R).
Vr=Reference meter volume reading, m³.
Vm=Test meter volume reading, m³.
Ym=Test meter calibration coefficient, dimensionless.
[thetas]=Elapsed test period time, min.
12.2 Test Meter Calibration Coefficient.
[GRAPHIC] [TIFF OMITTED] TR17OC00.064

12.3 Volume.

[[Page 33]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.065

12.4 Gas Flow Rate.
[GRAPHIC] [TIFF OMITTED] TR17OC00.066

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Rom, Jerome J. Maintenance, Calibration, and Operation of
Isokinetic Source Sampling Equipment. U.S. Environmental Protection
Agency, Research Triangle Park, NC. Publication No. APTD-0576. March
1972.
2. Wortman, Martin, R. Vollaro, and P.R. Westlin. Dry Gas Volume
Meter Calibrations. Source Evaluation Society Newsletter. Vol. 2, No. 2.
May 1977.
3. Westlin, P.R., and R.T. Shigehara. Procedure for Calibrating and
Using Dry Gas Volume Meters as Calibration Standards. Source Evaluation
Society Newsletter. Vol. 3, No. 1. February 1978.

17.0 Tables, Diagrams, Flowcharts, and Validation Data [Reserved]

Method 2B--Determination of Exhaust Gas Volume Flow Rate From Gasoline
Vapor Incinerators

Note: This method does not include all of the specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling and analytical)
essential to its performance. Some material is incorporated by reference
from other methods in this part. Therefore, to obtain reliable results,
persons using this method should also have a thorough knowledge of at
least the following additional test methods: Method 1, Method 2, Method
2A, Method 10, Method 25A, Method 25B.

1.0 Scope and Application

1.1 This method is applicable for the determination of exhaust
volume flow rate from incinerators that process gasoline vapors
consisting primarily of alkanes, alkenes, and/or arenes (aromatic
hydrocarbons). It is assumed that the amount of auxiliary fuel is
negligible.
1.2 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 Organic carbon concentration and volume flow rate are measured
at the incinerator inlet using either Method 25A or Method 25B and
Method 2A, respectively. Organic carbon, carbon dioxide
(CO2), and carbon monoxide (CO) concentrations are measured
at the outlet using either Method 25A or Method 25B and Method 10,
respectively. The ratio of total carbon at the incinerator inlet and
outlet is multiplied by the inlet volume to determine the exhaust volume
flow rate.

3.0 Definitions

Same as Section 3.0 of Method 10 and Method 25A.

4.0 Interferences

Same as Section 4.0 of Method 10.

5.0 Safety

5.1 This method may involve hazardous materials, operations, and
equipment. This test method may not address all of the safety problems
associated with its use. It is the responsibility of the user of this
test method to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to
performing this test method.

6.0 Equipment and Supplies

Same as Section 6.0 of Method 2A, Method 10, and Method 25A and/or
Method 25B as applicable, with the addition of the following:
6.1 This analyzer must meet the specifications set forth in Section
6.1.2 of Method 10, except that the span shall be 15 percent
CO2 by volume.

7.0 Reagents and Standards

Same as Section 7.0 of Method 10 and Method 25A, with the following
addition and exceptions:
7.1 Carbon Dioxide Analyzer Calibration. CO2 gases
meeting the specifications set forth in Section 7 of Method 6C are
required.
7.2 Hydrocarbon Analyzer Calibration. Methane shall not be used as a
calibration gas when performing this method.
7.3 Fuel Gas. If Method 25B is used to measure the organic carbon
concentrations at both the inlet and exhaust, no fuel gas is required.

[[Page 34]]

8.0 Sample Collection and Analysis

8.1 Pre-test Procedures. Perform all pre-test procedures (e.g.,
system performance checks, leak checks) necessary to determine gas
volume flow rate and organic carbon concentration in the vapor line to
the incinerator inlet and to determine organic carbon, carbon monoxide,
and carbon dioxide concentrations at the incinerator exhaust, as
outlined in Method 2A, Method 10, and Method 25A and/or Method 25B as
applicable.
8.2 Sampling. At the beginning of the test period, record the
initial parameters for the inlet volume meter according to the
procedures in Method 2A and mark all of the recorder strip charts to
indicate the start of the test. Conduct sampling and analysis as
outlined in Method 2A, Method 10, and Method 25A and/or Method 25B as
applicable. Continue recording inlet organic and exhaust CO2,
CO, and organic concentrations throughout the test. During periods of
process interruption and halting of gas flow, stop the timer and mark
the recorder strip charts so that data from this interruption are not
included in the calculations. At the end of the test period, record the
final parameters for the inlet volume meter and mark the end on all of
the recorder strip charts.
8.3 Post-test Procedures. Perform all post-test procedures (e.g.,
drift tests, leak checks), as outlined in Method 2A, Method 10, and
Method 25A and/or Method 25B as applicable.

9.0 Quality Control

Same as Section 9.0 of Method 2A, Method 10, and Method 25A.

10.0 Calibration and Standardization

Same as Section 10.0 of Method 2A, Method 10, and Method 25A.

Note: If a manifold system is used for the exhaust analyzers, all
the analyzers and sample pumps must be operating when the analyzer
calibrations are performed.

10.1 If an analyzer output does not meet the specifications of the
method, invalidate the test data for the period. Alternatively,
calculate the exhaust volume results using initial calibration data and
using final calibration data and report both resulting volumes. Then,
for emissions calculations, use the volume measurement resulting in the
greatest emission rate or concentration.

11.0 Analytical Procedure

Sample collection and analysis are concurrent for this method (see
Section 8.0).

12.0 Data Analysis and Calculations

Carry out the calculations, retaining at least one extra decimal
figure beyond that of the acquired data. Round off figures after the
final calculation.
12.1 Nomenclature.

Coe=Mean carbon monoxide concentration in system exhaust,
ppm.
(CO2)2=Ambient carbon dioxide concentration, ppm
(if not measured during the test period, may be assumed to equal 300
ppm).
(CO2)e=Mean carbon dioxide concentration in system
exhaust, ppm.
HCe=Mean organic concentration in system exhaust as defined
by the calibration gas, ppm.
Hci=Mean organic concentration in system inlet as defined by
the calibration gas, ppm.
Ke=Hydrocarbon calibration gas factor for the exhaust
hydrocarbon analyzer, unitless [equal to the number of carbon atoms per
molecule of the gas used to calibrate the analyzer (2 for ethane, 3 for
propane, etc.)].
Ki=Hydrocarbon calibration gas factor for the inlet
hydrocarbon analyzer, unitless.
Ves=Exhaust gas volume, m\3\.
Vis=Inlet gas volume, m\3\.
Qes=Exhaust gas volume flow rate, m\3\/min.
Qis=Inlet gas volume flow rate, m\3\/min.
[thetas]=Sample run time, min.
s=Standard conditions: 20 [deg]C, 760 mm Hg.

12.2 Concentrations. Determine mean concentrations of inlet
organics, outlet CO2, outlet CO, and outlet organics
according to the procedures in the respective methods and the analyzers'
calibration curves, and for the time intervals specified in the
applicable regulations.
12.3 Exhaust Gas Volume. Calculate the exhaust gas volume as
follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.067

12.4 Exhaust Gas Volume Flow Rate. Calculate the exhaust gas volume
flow rate as follows:
[GRAPHIC] [TIFF OMITTED] TR17OC00.210

[[Page 35]]

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

Same as Section 16.0 of Method 2A, Method 10, and Method 25A.

17.0 Tables, Diagrams, Flowcharts, and Validation Data [Reserved]

Method 2C--Determination of Gas Velocity and Volumetric Flow Rate in
Small Stacks or Ducts (Standard Pitot Tube)

Note: This method does not include all of the specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling) essential to its
performance. Some material is incorporated by reference from other
methods in this part. Therefore, to obtain reliable results, persons
using this method should also have a thorough knowledge of at least the
following additional test methods: Method 1, Method 2.

1.0 Scope and Application

1.1 This method is applicable for the determination of average
velocity and volumetric flow rate of gas streams in small stacks or
ducts. Limits on the applicability of this method are identical to those
set forth in Method 2, Section 1.0, except that this method is limited
to stationary source stacks or ducts less than about 0.30 meter (12 in.)
in diameter, or 0.071 m\2\ (113 in.\2\) in cross-sectional area, but
equal to or greater than about 0.10 meter (4 in.) in diameter, or 0.0081
m\2\ (12.57 in.\2\) in cross-sectional area.
1.2 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 The average gas velocity in a stack or duct is determined from
the gas density and from measurement of velocity heads with a standard
pitot tube.

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

6.0 Equipment and Supplies

Same as Method 2, Section 6.0, with the exception of the following:
6.1 Standard Pitot Tube (instead of Type S). A standard pitot tube
which meets the specifications of Section 6.7 of Method 2. Use a
coefficient of 0.99 unless it is calibrated against another standard
pitot tube with a NIST-traceable coefficient (see Section 10.2 of Method
2).
6.2 Alternative Pitot Tube. A modified hemispherical-nosed pitot
tube (see Figure 2C-1), which features a shortened stem and enlarged
impact and static pressure holes. Use a coefficient of 0.99 unless it is
calibrated as mentioned in Section 6.1 above. This pitot tube is useful
in particulate liquid droplet-laden gas streams when a ``back purge'' is
ineffective.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

8.1 Follow the general procedures in Section 8.0 of Method 2, except
conduct the measurements at the traverse points specified in Method 1A.
The static and impact pressure holes of standard pitot tubes are
susceptible to plugging in particulate-laden gas streams. Therefore,
adequate proof that the openings of the pitot tube have not plugged
during the traverse period must be furnished; this can be done by taking
the velocity head ([Delta]p) heading at the final traverse point,
cleaning out the impact and static holes of the standard pitot tube by
``back-purging'' with pressurized air, and then taking another [Delta]p
reading. If the [Delta]p readings made before and after the air purge
are the same (within 5 percent) the traverse is
acceptable. Otherwise, reject the run. Note that if the [Delta]p at the
final traverse point is unsuitably low, another point may be selected.
If ``back purging'' at regular intervals is part of the procedure, then
take comparative [Delta]p readings, as above, for the last two back
purges at which suitably high [Delta]p readings are observed.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.0.......................... Sampling Ensure accurate
equipment measurement of stack
calibration. gas velocity head.
------------------------------------------------------------------------

[[Page 36]]

10.0 Calibration and Standardization

Same as Method 2, Sections 10.2 through 10.4.

11.0 Analytical Procedure

Sample collection and analysis are concurrent for this method (see
Section 8.0).

12.0 Calculations and Data Analysis

Same as Method 2, Section 12.0.

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

Same as Method 2, Section 16.0.

17.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.068

Method 2D--Measurement of Gas Volume Flow Rates in Small Pipes and Ducts

Note: This method does not include all of the specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling) essential to its
performance. Some material is incorporated by reference from other
methods in this part. Therefore, to obtain reliable results, persons
using this method should also have a thorough knowledge of at least the
following additional test methods: Method 1, Method 2, and Method 2A.

1.0 Scope and Application

1.1 This method is applicable for the determination of the
volumetric flow rates of gas streams in small pipes and ducts. It can be
applied to intermittent or variable gas flows only with particular
caution.
1.2 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 All the gas flow in the pipe or duct is directed through a
rotameter, orifice plate or similar device to measure flow rate or
pressure drop. The device has been previously calibrated in a manner
that insures its proper calibration for the gas being measured. Absolute
temperature and pressure measurements are made to allow correction of
volumetric flow rates to standard conditions.

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

[[Page 37]]

6.0 Equipment and Supplies

Specifications for the apparatus are given below. Any other
apparatus that has been demonstrated (subject to approval of the
Administrator) to be capable of meeting the specifications will be
considered acceptable.
6.1 Gas Metering Rate or Flow Element Device. A rotameter, orifice
plate, or other volume rate or pressure drop measuring device capable of
measuring the stack flow rate to within 5 percent.
The metering device shall be equipped with a temperature gauge accurate
to within 2 percent of the minimum absolute stack
temperature and a pressure gauge (accurate to within 5 mm Hg). The capacity of the metering device shall be
sufficient for the expected maximum and minimum flow rates at the stack
gas conditions. The magnitude and variability of stack gas flow rate,
molecular weight, temperature, pressure, dewpoint, and corrosive
characteristics, and pipe or duct size are factors to consider in
choosing a suitable metering device.
6.2 Barometer. Same as Method 2, Section 6.5.
6.3 Stopwatch. Capable of measurement to within 1 second.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

8.1 Installation and Leak Check. Same as Method 2A, Sections 8.1 and
8.2, respectively.
8.2 Volume Rate Measurement.
8.2.1 Continuous, Steady Flow. At least once an hour, record the
metering device flow rate or pressure drop reading, and the metering
device temperature and pressure. Make a minimum of 12 equally spaced
readings of each parameter during the test period. Record the barometric
pressure at the beginning and end of the test period. Record the data on
a table similar to that shown in Figure 2D-1.
8.2.2 Noncontinuous and Nonsteady Flow. Use volume rate devices with
particular caution. Calibration will be affected by variation in stack
gas temperature, pressure and molecular weight. Use the procedure in
Section 8.2.1 with the addition of the following: Record all the
metering device parameters on a time interval frequency sufficient to
adequately profile each process cyclical or noncontinuous event. A
multichannel continuous recorder may be used.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.0.......................... Sampling Ensure accurate
equipment measurement of stack
calibration. gas flow rate or
sample volume.
------------------------------------------------------------------------

10.0 Calibration and Standardization

Same as Method 2A, Section 10.0, with the following exception:
10.1 Gas Metering Device. Same as Method 2A, Section 10.1, except
calibrate the metering device with the principle stack gas to be
measured (examples: air, nitrogen) against a standard reference meter. A
calibrated dry gas meter is an acceptable reference meter. Ideally,
calibrate the metering device in the field with the actual gas to be
metered. For metering devices that have a volume rate readout, calculate
the test metering device calibration coefficient, Ym, for
each run shown in Equation 2D-2 Section 12.3.
10.2 For metering devices that do not have a volume rate readout,
refer to the manufacturer's instructions to calculate the Vm2
corresponding to each Vr.
10.3 Temperature Gauge. Use the procedure and specifications in
Method 2A, Section 10.2. Perform the calibration at a temperature that
approximates field test conditions.
10.4 Barometer. Calibrate the barometer to be used in the field test
with a mercury barometer prior to the field test.

11.0 Analytical Procedure.

Sample collection and analysis are concurrent for this method (see
Section 8.0).

12.0 Data Analysis and Calculations

12.1 Nomenclature.
Pbar=Barometric pressure, mm Hg (in. Hg).
Pm=Test meter average static pressure, mm Hg (in. Hg).
Qr=Reference meter volume flow rate reading, m\3\/min (ft\3\/
min).
Qm=Test meter volume flow rate reading, m\3\/min (ft\3\/min).
Tr=Absolute reference meter average temperature, [deg]K
([deg]R).
Tm=Absolute test meter average temperature, [deg]K ([deg]R).
Kl=0.3855 [deg]K/mm Hg for metric units,=17.65 [deg]R/in. Hg
for English units.
12.2 Gas Flow Rate.
[GRAPHIC] [TIFF OMITTED] TR17OC00.069

12.3 Test Meter Device Calibration Coefficient. Calculation for
testing metering device calibration coefficient, Ym.

[[Page 38]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.070

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Spink, L.K. Principles and Practice of Flowmeter Engineering. The
Foxboro Company. Foxboro, MA. 1967.
2. Benedict, R.P. Fundamentals of Temperature, Pressure, and Flow
Measurements. John Wiley & Sons, Inc. New York, NY. 1969.
3. Orifice Metering of Natural Gas. American Gas Association.
Arlington, VA. Report No. 3. March 1978. 88 pp.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

Plant___________________________________________________________________
Date____________________________________________________________________
Run No._________________________________________________________________
Sample location_________________________________________________________
Barometric pressure (mm Hg):
Start___________________________________________________________________
Finish__________________________________________________________________
Operators_______________________________________________________________
Metering device No._____________________________________________________
Calibration coefficient_________________________________________________
Calibration gas_________________________________________________________
Date to recalibrate_____________________________________________________

----------------------------------------------------------------------------------------------------------------
Temperature
Time Flow rate reading Static Pressure ---------------------------------------
[mm Hg (in. Hg)] [deg]C ( [deg]F) [deg]K ([deg]R)
----------------------------------------------------------------------------------------------------------------

---------------------------------

---------------------------------
Average
----------------------------------------------------------------------------------------------------------------

Figure 2D-1. Volume Flow Rate Measurement Data

Method 2E--Determination of Landfill Gas Production Flow Rate

1.0 Scope and Application

1.1 Applicability. This method applies to the measurement of
landfill gas (LFG) production flow rate from municipal solid waste
landfills and is used to calculate the flow rate of nonmethane organic
compounds (NMOC) from landfills.
1.2 Data Quality Objectives. Adherence to the requirements of this
method will enhance the quality of the data obtained from air pollutant
sampling methods.

2.0 Summary of Method

2.1 Extraction wells are installed either in a cluster of three or
at five dispersed locations in the landfill. A blower is used to extract
LFG from the landfill. LFG composition, landfill pressures, and orifice
pressure differentials from the wells are measured and the landfill gas
production flow rate is calculated.

[[Page 39]]

3.0 Definitions [Reserved]

4.0 Interferences [Reserved]

5.0 Safety

5.1 Since this method is complex, only experienced personnel should
perform the test. Landfill gas contains methane, therefore explosive
mixtures may exist at or near the landfill. It is advisable to take
appropriate safety precautions when testing landfills, such as
refraining from smoking and installing explosion-proof equipment.

6.0 Equipment and Supplies

6.1 Well Drilling Rig. Capable of boring a 0.61 m (24 in.) diameter
hole into the landfill to a minimum of 75 percent of the landfill depth.
The depth of the well shall not extend to the bottom of the landfill or
the liquid level.
6.2 Gravel. No fines. Gravel diameter should be appreciably larger
than perforations stated in Sections 6.10 and 8.2.
6.3 Bentonite.
6.4 Backfill Material. Clay, soil, and sandy loam have been found to
be acceptable.
6.5 Extraction Well Pipe. Minimum diameter of 3 in., constructed of
polyvinyl chloride (PVC), high density polyethylene (HDPE), fiberglass,
stainless steel, or other suitable nonporous material capable of
transporting landfill gas.
6.6 Above Ground Well Assembly. Valve capable of adjusting gas flow,
such as a gate, ball, or butterfly valve; sampling ports at the well
head and outlet; and a flow measuring device, such as an in-line orifice
meter or pitot tube. A schematic of the aboveground well head assembly
is shown in Figure 2E-1.
6.7 Cap. Constructed of PVC or HDPE.
6.8 Header Piping. Constructed of PVC or HDPE.
6.9 Auger. Capable of boring a 0.15-to 0.23-m (6-to 9-in.) diameter
hole to a depth equal to the top of the perforated section of the
extraction well, for pressure probe installation.
6.10 Pressure Probe. Constructed of PVC or stainless steel (316),
0.025-m (1-in.). Schedule 40 pipe. Perforate the bottom two-thirds. A
minimum requirement for perforations is slots or holes with an open area
equivalent to four 0.006-m (\1/4\-in.) diameter holes spaced 90[deg]
apart every 0.15 m (6 in.).
6.11 Blower and Flare Assembly. Explosion-proof blower, capable of
extracting LFG at a flow rate of 8.5 m ³/min (300 ft
³/min), a water knockout, and flare or incinerator.
6.12 Standard Pitot Tube and Differential Pressure Gauge for Flow
Rate Calibration with Standard Pitot. Same as Method 2, Sections 6.7 and
6.8.
6.13 Orifice Meter. Orifice plate, pressure tabs, and pressure
measuring device to measure the LFG flow rate.
6.14 Barometer. Same as Method 4, Section 6.1.5.
6.15 Differential Pressure Gauge. Water-filled U-tube manometer or
equivalent, capable of measuring within 0.02 mm Hg (0.01 in.
H2O), for measuring the pressure of the pressure probes.

7.0 Reagents and Standards. Not Applicable

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Placement of Extraction Wells. The landfill owner or operator
may install a single cluster of three extraction wells in a test area or
space five equal-volume wells over the landfill. The cluster wells are
recommended but may be used only if the composition, age of the refuse,
and the landfill depth of the test area can be determined.
8.1.1 Cluster Wells. Consult landfill site records for the age of
the refuse, depth, and composition of various sections of the landfill.
Select an area near the perimeter of the landfill with a depth equal to
or greater than the average depth of the landfill and with the average
age of the refuse between 2 and 10 years old. Avoid areas known to
contain nondecomposable materials, such as concrete and asbestos. Locate
the cluster wells as shown in Figure 2E-2.
8.1.1.1 The age of the refuse in a test area will not be uniform, so
calculate a weighted average age of the refuse as shown in Section 12.2.
8.1.2 Equal Volume Wells. Divide the sections of the landfill that
are at least 2 years old into five areas representing equal volumes.
Locate an extraction well near the center of each area.
8.2 Installation of Extraction Wells. Use a well drilling rig to dig
a 0.6 m (24 in.) diameter hole in the landfill to a minimum of 75
percent of the landfill depth, not to extend to the bottom of the
landfill or the liquid level. Perforate the bottom two thirds of the
extraction well pipe. A minimum requirement for perforations is holes or
slots with an open area equivalent to 0.01-m (0.5-in.) diameter holes
spaced 90[deg] apart every 0.1 to 0.2 m (4 to 8 in.). Place the
extraction well in the center of the hole and backfill with gravel to a
level 0.30 m (1 ft) above the perforated section. Add a layer of
backfill material 1.2 m (4 ft) thick. Add a layer of bentonite 0.9 m (3
ft) thick, and backfill the remainder of the hole with cover material or
material equal in permeability to the existing cover material. The
specifications for extraction well installation are shown in Figure 2E-
3.
8.3 Pressure Probes. Shallow pressure probes are used in the check
for infiltration of air into the landfill, and deep pressure probes are
use to determine the radius of influence. Locate pressure probes along
three radial arms approximately 120[deg] apart at distances of 3, 15,
30, and 45 m (10, 50, 100, and

[[Page 40]]

150 ft) from the extraction well. The tester has the option of locating
additional pressure probes at distances every 15 m (50 feet) beyond 45 m
(150 ft). Example placements of probes are shown in Figure 2E-4. The 15-
, 30-, and 45-m, (50-, 100-, and 150-ft) probes from each well, and any
additional probes located along the three radial arms (deep probes),
shall extend to a depth equal to the top of the perforated section of
the extraction wells. All other probes (shallow probes) shall extend to
a depth equal to half the depth of the deep probes.
8.3.1 Use an auger to dig a hole, 0.15- to 0.23-m (6-to 9-in.) in
diameter, for each pressure probe. Perforate the bottom two thirds of
the pressure probe. A minimum requirement for perforations is holes or
slots with an open area equivalent to four 0.006-m (0.25-in.) diameter
holes spaced 90[deg] apart every 0.15 m (6 in.). Place the pressure
probe in the center of the hole and backfill with gravel to a level 0.30
m (1 ft) above the perforated section. Add a layer of backfill material
at least 1.2 m (4 ft) thick. Add a layer of bentonite at least 0.3 m (1
ft) thick, and backfill the remainder of the hole with cover material or
material equal in permeability to the existing cover material. The
specifications for pressure probe installation are shown in Figure 2E-5.
8.4 LFG Flow Rate Measurement. Place the flow measurement device,
such as an orifice meter, as shown in Figure 2E-1. Attach the wells to
the blower and flare assembly. The individual wells may be ducted to a
common header so that a single blower, flare assembly, and flow meter
may be used. Use the procedures in Section 10.1 to calibrate the flow
meter.
8.5 Leak-Check. A leak-check of the above ground system is required
for accurate flow rate measurements and for safety. Sample LFG at the
well head sample port and at the outlet sample port. Use Method 3C to
determine nitrogen (N2) concentrations. Determine the
difference between the well head and outlet N2 concentrations
using the formula in Section 12.3. The system passes the leak-check if
the difference is less than 10,000 ppmv.
8.6 Static Testing. Close the control valves on the well heads
during static testing. Measure the gauge pressure (Pg) at
each deep pressure probe and the barometric pressure (Pbar)
every 8 hours (hr) for 3 days. Convert the gauge pressure of each deep
pressure probe to absolute pressure using the equation in Section 12.4.
Record as Pi (initial absolute pressure).
8.6.1 For each probe, average all of the 8-hr deep pressure probe
readings (Pi) and record as Pia (average absolute
pressure). Pia is used in Section 8.7.5 to determine the
maximum radius of influence.
8.6.2 Measure the static flow rate of each well once during static
testing.
8.7 Short-Term Testing. The purpose of short-term testing is to
determine the maximum vacuum that can be applied to the wells without
infiltration of ambient air into the landfill. The short-term testing is
performed on one well at a time. Burn all LFG with a flare or
incinerator.
8.7.1 Use the blower to extract LFG from a single well at a rate at
least twice the static flow rate of the respective well measured in
Section 8.6.2. If using a single blower and flare assembly and a common
header system, close the control valve on the wells not being measured.
Allow 24 hr for the system to stabilize at this flow rate.
8.7.2 Test for infiltration of air into the landfill by measuring
the gauge pressures of the shallow pressure probes and using Method 3C
to determine the LFG N2 concentration. If the LFG
N2 concentration is less than 5 percent and all of the
shallow probes have a positive gauge pressure, increase the blower
vacuum by 3.7 mm Hg (2 in. H2O), wait 24 hr, and repeat the
tests for infiltration. Continue the above steps of increasing blower
vacuum by 3.7 mm Hg (2 in. H2O), waiting 24 hr, and testing
for infiltration until the concentration of N2 exceeds 5
percent or any of the shallow probes have a negative gauge pressure.
When this occurs,reduce the blower vacuum to the maximum setting at
which the N2 concentration was less than 5 percent and the
gauge pressures of the shallow probes are positive.
8.7.3 At this blower vacuum, measure atmospheric pressure
(Pbar) every 8 hr for 24 hr, and record the LFG flow rate
(Qs) and the probe gauge pressures (Pf) for all of
the probes. Convert the gauge pressures of the deep probes to absolute
pressures for each 8-hr reading at Qs as shown in Section
12.4.
8.7.4 For each probe, average the 8-hr deep pressure probe absolute
pressure readings and record as Pfa (the final average
absolute pressure).
8.7.5 For each probe, compare the initial average pressure
(Pia) from Section 8.6.1 to the final average pressure
(Pfa). Determine the furthermost point from the well head
along each radial arm where Pfa <= Pia. This
distance is the maximum radius of influence (Rm), which is
the distance from the well affected by the vacuum. Average these values
to determine the average maximum radius of influence (Rma).
8.7.6 Calculate the depth (Dst) affected by the
extraction well during the short term test as shown in Section 12.6. If
the computed value of Dst exceeds the depth of the landfill,
set Dst equal to the landfill depth.
8.7.7 Calculate the void volume (V) for the extraction well as shown
in Section 12.7.
8.7.8 Repeat the procedures in Section 8.7 for each well.
8.8 Calculate the total void volume of the test wells
(Vv) by summing the void volumes (V) of each well.

[[Page 41]]

8.9 Long-Term Testing. The purpose of long-term testing is to
extract two void volumes of LFG from the extraction wells. Use the
blower to extract LFG from the wells. If a single Blower and flare
assembly and common header system are used, open all control valves and
set the blower vacuum equal to the highest stabilized blower vacuum
demonstrated by any individual well in Section 8.7. Every 8 hr, sample
the LFG from the well head sample port, measure the gauge pressures of
the shallow pressure probes, the blower vacuum, the LFG flow rate, and
use the criteria for infiltration in Section 8.7.2 and Method 3C to test
for infiltration. If infiltration is detected, do not reduce the blower
vacuum, instead reduce the LFG flow rate from the well by adjusting the
control valve on the well head. Adjust each affected well individually.
Continue until the equivalent of two total void volumes (Vv)
have been extracted, or until Vt=2Vv.
8.9.1 Calculate Vt, the total volume of LFG extracted
from the wells, as shown in Section 12.8.
8.9.2 Record the final stabilized flow rate as Qf and the
gauge pressure for each deep probe. If, during the long term testing,
the flow rate does not stabilize, calculate Qf by averaging
the last 10 recorded flow rates.
8.9.3 For each deep probe, convert each gauge pressure to absolute
pressure as in Section 12.4. Average these values and record as
Psa. For each probe, compare Pia to
Psa. Determine the furthermost point from the well head along
each radial arm where Psa <= Pia. This distance is
the stabilized radius of influence. Average these values to determine
the average stabilized radius of influence (Rsa).
8.10 Determine the NMOC mass emission rate using the procedures in
Section 12.9 through 12.15.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
10.1.......................... LFG flow rate Ensures accurate
meter measurement of LFG
calibration. flow rate and sample
volume
------------------------------------------------------------------------

10.0 Calibration and Standardization

10.1 LFG Flow Rate Meter (Orifice) Calibration Procedure. Locate a
standard pitot tube in line with an orifice meter. Use the procedures in
Section 8, 12.5, 12.6, and 12.7 of Method 2 to determine the average dry
gas volumetric flow rate for at least five flow rates that bracket the
expected LFG flow rates, except in Section 8.1, use a standard pitot
tube rather than a Type S pitot tube. Method 3C may be used to determine
the dry molecular weight. It may be necessary to calibrate more than one
orifice meter in order to bracket the LFG flow rates. Construct a
calibration curve by plotting the pressure drops across the orifice
meter for each flow rate versus the average dry gas volumetric flow rate
in m\3\/min of the gas.

11.0 Procedures [Reserved]

12.0 Data Analysis and Calculations

12.1 Nomenclature.
A=Age of landfill, yr.
Aavg=Average age of the refuse tested, yr.
Ai=Age of refuse in the ith fraction, yr.
Ar=Acceptance rate, Mg/yr.
CNMOC=NMOC concentration, ppmv as hexane
(CNMOC=Ct/6).
Co=Concentration of N2 at the outlet, ppmv.
Ct=NMOC concentration, ppmv (carbon equivalent) from Method
25C.
Cw=Concentration of N2 at the wellhead, ppmv.
D=Depth affected by the test wells, m.
Dst=Depth affected by the test wells in the short-term test,
m.
e=Base number for natural logarithms (2.718).
f=Fraction of decomposable refuse in the landfill.
fi=Fraction of the refuse in the ith section.
k=Landfill gas generation constant, yr^-1.
Lo=Methane generation potential, m\3\/Mg.
Lo'=Revised methane generation potential to account for the
amount of nondecomposable material in the landfill, m\3\/Mg.
Mi=Mass of refuse in the ith section, Mg.
Mr=Mass of decomposable refuse affected by the test well, Mg.
Pbar=Atmospheric pressure, mm Hg.
Pf=Final absolute pressure of the deep pressure probes during
short-term testing, mm Hg.
Pfa=Average final absolute pressure of the deep pressure
probes during short-term testing, mm Hg.
Pgf=final gauge pressure of the deep pressure probes, mm Hg.
Pgi=Initial gauge pressure of the deep pressure probes, mm
Hg.
Pi=Initial absolute pressure of the deep pressure probes
during static testing, mm Hg.
Pia=Average initial absolute pressure of the deep pressure
probes during static testing, mm Hg.
Ps=Final absolute pressure of the deep pressure probes during
long-term testing, mm Hg.

[[Page 42]]

Psa=Average final absolute pressure of the deep pressure
probes during long-term testing, mm Hg.
Qf=Final stabilized flow rate, m\3\/min.
Qi=LFG flow rate measured at orifice meter during the ith
interval, m\3\/min.
Qs=Maximum LFG flow rate at each well determined by short-
term test, m\3\/min.
Qt=NMOC mass emission rate, m\3\/min.
Rm=Maximum radius of influence, m.
Rma=Average maximum radius of influence, m.
Rs=Stabilized radius of influence for an individual well, m.
Rsa=Average stabilized radius of influence, m.
ti=Age of section i, yr.
tt=Total time of long-term testing, yr.
tvi=Time of the ith interval (usually 8), hr.
V=Void volume of test well, m\3\.
Vr=Volume of refuse affected by the test well, m\3\.
Vt=Total volume of refuse affected by the long-term testing,
m\3\.
Vv=Total void volume affected by test wells, m\3\.
WD=Well depth, m.
[rho]=Refuse density, Mg/m\3\ (Assume 0.64 Mg/m\3\ if data are
unavailable).

12.2 Use the following equation to calculate a weighted average age
of landfill refuse.
[GRAPHIC] [TIFF OMITTED] TR17OC00.071

12.3 Use the following equation to determine the difference in
N2 concentrations (ppmv) at the well head and outlet
location.
[GRAPHIC] [TIFF OMITTED] TR17OC00.072

12.4 Use the following equation to convert the gauge pressure
(Pg) of each initial deep pressure probe to absolute pressure
(Pi).
[GRAPHIC] [TIFF OMITTED] TR17OC00.073

12.5 Use the following equation to convert the gauge pressures of
the deep probes to absolute pressures for each 8-hr reading at
Qs.
[GRAPHIC] [TIFF OMITTED] TR17OC00.074

12.6 Use the following equation to calculate the depth
(Dst) affected by the extraction well during the short-term
test.
[GRAPHIC] [TIFF OMITTED] TR17OC00.075

12.7 Use the following equation to calculate the void volume for the
extraction well (V).
[GRAPHIC] [TIFF OMITTED] TR17OC00.076

12.8 Use the following equation to calculate Vt, the
total volume of LFG extracted from the wells.
[GRAPHIC] [TIFF OMITTED] TR17OC00.077

12.9 Use the following equation to calculate the depth affected by
the test well. If using cluster wells, use the average depth of the
wells for WD. If the value of D is greater than the depth of the
landfill, set D equal to the landfill depth.
[GRAPHIC] [TIFF OMITTED] TR17OC00.078

12.10 Use the following equation to calculate the volume of refuse
affected by the test well.
[GRAPHIC] [TIFF OMITTED] TR17OC00.079

12.11 Use the following equation to calculate the mass affected by
the test well.
[GRAPHIC] [TIFF OMITTED] TR17OC00.080

12.12 Modify Lo to account for the nondecomposable refuse
in the landfill.
[GRAPHIC] [TIFF OMITTED] TR17OC00.081

12.13 In the following equation, solve for k (landfill gas
generation constant) by iteration. A suggested procedure is to select a
value for k, calculate the left side of the equation, and if not equal
to zero, select another value for k. Continue this process until the
left hand side of the equation equals zero, 0.001.
[GRAPHIC] [TIFF OMITTED] TR17OC00.082

12.14 Use the following equation to determine landfill NMOC mass
emission rate if the yearly acceptance rate of refuse has been
consistent (10 percent) over the life of the landfill.
[GRAPHIC] [TIFF OMITTED] TR17OC00.083

12.15 Use the following equation to determine landfill NMOC mass
emission rate if the acceptance rate has not been consistent over the
life of the landfill.

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[GRAPHIC] [TIFF OMITTED] TR17OC00.084

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Same as Method 2, Appendix A, 40 CFR Part 60.
2. Emcon Associates, Methane Generation and Recovery from Landfills.
Ann Arbor Science, 1982.
3. The Johns Hopkins University, Brown Station Road Landfill Gas
Resource Assessment, Volume 1: Field Testing and Gas Recovery
Projections. Laurel, Maryland: October 1982.
4. Mandeville and Associates, Procedure Manual for Landfill Gases
Emission Testing.
5. Letter and attachments from Briggum, S., Waste Management of
North America, to Thorneloe, S., EPA. Response to July 28, 1988 request
for additional information. August 18, 1988.
6. Letter and attachments from Briggum, S., Waste Management of
North America, to Wyatt, S., EPA. Response to December 7, 1988 request
for additional information. January 16, 1989.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

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[GRAPHIC] [TIFF OMITTED] TR17OC00.089

Method 2F--Determination of Stack Gas Velocity And Volumetric Flow Rate
With Three-Dimensional Probes

Note: This method does not include all of the specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling) essential to its
performance. Some material has been incorporated from other methods in
this part. Therefore, to obtain reliable results, those using this
method should have a thorough knowledge of at least the following
additional test methods: Methods 1, 2, 3 or 3A, and 4.

1.0 Scope and Application

1.1 This method is applicable for the determination of yaw angle, pitch
angle, axial velocity and the volumetric flow rate of a gas

[[Page 49]]

stream in a stack or duct using a three-dimensional (3-D) probe. This
method may be used only when the average stack or duct gas velocity is
greater than or equal to 20 ft/sec. When the above condition cannot be
met, alternative procedures, approved by the Administrator, U.S.
Environmental Protection Agency, shall be used to make accurate flow
rate determinations.

2.0 Summary of Method

2.1 A 3-D probe is used to determine the velocity pressure and the
yaw and pitch angles of the flow velocity vector in a stack or duct. The
method determines the yaw angle directly by rotating the probe to null
the pressure across a pair of symmetrically placed ports on the probe
head. The pitch angle is calculated using probe-specific calibration
curves. From these values and a determination of the stack gas density,
the average axial velocity of the stack gas is calculated. The average
gas volumetric flow rate in the stack or duct is then determined from
the average axial velocity.

3.0 Definitions

3.1. Angle-measuring Device Rotational Offset (RADO). The rotational
position of an angle-measuring device relative to the reference scribe
line, as determined during the pre-test rotational position check
described in section 8.3.
3.2 Axial Velocity. The velocity vector parallel to the axis of the
stack or duct that accounts for the yaw and pitch angle components of
gas flow. The term ``axial'' is used herein to indicate that the
velocity and volumetric flow rate results account for the measured yaw
and pitch components of flow at each measurement point.
3.3 Calibration Pitot Tube. The standard (Prandtl type) pitot tube
used as a reference when calibrating a 3-D probe under this method.
3.4 Field Test. A set of measurements conducted at a specific unit
or exhaust stack/duct to satisfy the applicable regulation (e.g., a
three-run boiler performance test, a single-or multiple-load nine-run
relative accuracy test).
3.5 Full Scale of Pressure-measuring Device. Full scale refers to
the upper limit of the measurement range displayed by the device. For
bi-directional pressure gauges, full scale includes the entire pressure
range from the lowest negative value to the highest positive value on
the pressure scale.
3.6 Main probe. Refers to the probe head and that section of probe
sheath directly attached to the probe head. The main probe sheath is
distinguished from probe extensions, which are sections of sheath added
onto the main probe to extend its reach.
3.7 ``May,'' ``Must,'' ``Shall,'' ``Should,'' and the imperative
form of verbs.
3.7.1 ``May'' is used to indicate that a provision of this method is
optional.
3.7.2 ``Must,'' ``Shall,'' and the imperative form of verbs (such as
``record'' or ``enter'') are used to indicate that a provision of this
method is mandatory.
3.7.3 ``Should'' is used to indicate that a provision of this method
is not mandatory, but is highly recommended as good practice.
3.8 Method 1. Refers to 40 CFR part 60, appendix A, ``Method 1--
Sample and velocity traverses for stationary sources.''
3.9 Method 2. Refers to 40 CFR part 60, appendix A, ``Method 2--
Determination of stack gas velocity and volumetric flow rate (Type S
pitot tube).''
3.10 Method 2G. Refers to 40 CFR part 60, appendix A, ``Method 2G--
Determination of stack gas velocity and volumetric flow rate with two-
dimensional probes.''
3.11 Nominal Velocity. Refers to a wind tunnel velocity setting that
approximates the actual wind tunnel velocity to within 1.5 m/sec (5 ft/sec).
3.12 Pitch Angle. The angle between the axis of the stack or duct
and the pitch component of flow, i.e., the component of the total
velocity vector in a plane defined by the traverse line and the axis of
the stack or duct. (Figure 2F-1 illustrates the ``pitch plane.'') From
the standpoint of a tester facing a test port in a vertical stack, the
pitch component of flow is the vector of flow moving from the center of
the stack toward or away from that test port. The pitch angle is the
angle described by this pitch component of flow and the vertical axis of
the stack.
3.13 Readability. For the purposes of this method, readability for
an analog measurement device is one half of the smallest scale division.
For a digital measurement device, it is the number of decimals displayed
by the device.
3.14 Reference Scribe Line. A line permanently inscribed on the main
probe sheath (in accordance with section 6.1.6.1) to serve as a
reference mark for determining yaw angles.
3.15 Reference Scribe Line Rotational Offset (RSLO). The
rotational position of a probe's reference scribe line relative to the
probe's yaw-null position, as determined during the yaw angle
calibration described in section 10.5.
3.16 Response Time. The time required for the measurement system to
fully respond to a change from zero differential pressure and ambient
temperature to the stable stack or duct pressure and temperature
readings at a traverse point.
3.17 Tested Probe. A 3-D probe that is being calibrated.
3.18 Three-dimensional (3-D) Probe. A directional probe used to
determine the velocity pressure and yaw and pitch angles in a flowing
gas stream.

[[Page 50]]

3.19 Traverse Line. A diameter or axis extending across a stack or
duct on which measurements of differential pressure and flow angles are
made.
3.20 Wind Tunnel Calibration Location. A point, line, area, or
volume within the wind tunnel test section at, along, or within which
probes are calibrated. At a particular wind tunnel velocity setting, the
average velocity pressures at specified points at, along, or within the
calibration location shall vary by no more than 2 percent or 0.3 mm
H2O (0.01 in. H2O), whichever is less restrictive,
from the average velocity pressure at the calibration pitot tube
location. Air flow at this location shall be axial, i.e., yaw and pitch
angles within 3[deg]. Compliance with these flow
criteria shall be demonstrated by performing the procedures prescribed
in sections 10.1.1 and 10.1.2. For circular tunnels, no part of the
calibration location may be closer to the tunnel wall than 10.2 cm (4
in.) or 25 percent of the tunnel diameter, whichever is farther from the
wall. For elliptical or rectangular tunnels, no part of the calibration
location may be closer to the tunnel wall than 10.2 cm (4 in.) or 25
percent of the applicable cross-sectional axis, whichever is farther
from the wall.
3.21 Wind Tunnel with Documented Axial Flow. A wind tunnel facility
documented as meeting the provisions of sections 10.1.1 (velocity
pressure cross-check) and 10.1.2 (axial flow verification) using the
procedures described in these sections or alternative procedures
determined to be technically equivalent.
3.22 Yaw Angle. The angle between the axis of the stack or duct and
the yaw component of flow, i.e., the component of the total velocity
vector in a plane perpendicular to the traverse line at a particular
traverse point. (Figure 2F-1 illustrates the ``yaw plane.'') From the
standpoint of a tester facing a test port in a vertical stack, the yaw
component of flow is the vector of flow moving to the left or right from
the center of the stack as viewed by the tester. (This is sometimes
referred to as ``vortex flow,'' i.e., flow around the centerline of a
stack or duct.) The yaw angle is the angle described by this yaw
component of flow and the vertical axis of the stack. The algebraic sign
convention is illustrated in Figure 2F-2.
3.23 Yaw Nulling. A procedure in which a probe is rotated about its
axis in a stack or duct until a zero differential pressure reading
(``yaw null'') is obtained. When a 3-D probe is yaw-nulled, its impact
pressure port (P1) faces directly into the direction of flow
in the stack or duct and the differential pressure between pressure
ports P2 and P3 is zero.

4.0 Interferences [Reserved]

5.0 Safety

5.1 This test method may involve hazardous operations and the use of
hazardous materials or equipment. This method does not purport to
address all of the safety problems associated with its use. It is the
responsibility of the user to establish and implement appropriate safety
and health practices and to determine the applicability of regulatory
limitations before using this test method.

6.0 Equipment and Supplies

6.1 Three-dimensional Probes. The 3-D probes as specified in
subsections 6.1.1 through 6.1.3 below qualify for use based on
comprehensive wind tunnel and field studies involving both inter-and
intra-probe comparisons by multiple test teams. Other types of probes
shall not be used unless approved by the Administrator. Each 3-D probe
shall have a unique identification number or code permanently marked on
the main probe sheath. The minimum recommended diameter of the sensing
head of any probe used under this method is 2.5 cm (1 in.). Each probe
shall be calibrated prior to use according to the procedures in section
10. Manufacturer-supplied calibration data shall be used as example
information only, except when the manufacturer calibrates the 3-D probe
as specified in section 10 and provides complete documentation.
6.1.1 Five-hole prism-shaped probe. This type of probe consists of
five pressure taps in the flat facets of a prism-shaped sensing head.
The pressure taps are numbered 1 through 5, with the pressures measured
at each hole referred to as P1, P2, P3,
P4, and P5, respectively. Figure 2F-3 is an
illustration of the placement of pressure taps on a commonly available
five-hole prism-shaped probe, the 2.5-cm (1-in.) DAT probe. (Note:
Mention of trade names or specific products does not constitute
endorsement by the U.S. Environmental Protection Agency.) The numbering
arrangement for the prism-shaped sensing head presented in Figure 2F-3
shall be followed for correct operation of the probe. A brief
description of the probe measurements involved is as follows: the
differential pressure P2-P3 is used to yaw null
the probe and determine the yaw angle; the differential pressure
P4-P5 is a function of pitch angle; and the
differential pressure P1-P2 is a function of total
velocity.
6.1.2 Five-hole spherical probe. This type of probe consists of five
pressure taps in a spherical sensing head. As with the prism-shaped
probe, the pressure taps are numbered 1 through 5, with the pressures
measured at each hole referred to as P1, P2,
P3, P4, and P5, respectively. However,
the P4 and P5 pressure taps are in the reverse
location

[[Page 51]]

from their respective positions on the prism-shaped probe head. The
differential pressure P2-P3 is used to yaw null
the probe and determine the yaw angle; the differential pressure
P4-P5 is a function of pitch angle; and the
differential pressure P1-P2 is a function of total
velocity. A diagram of a typical spherical probe sensing head is
presented in Figure 2F-4. Typical probe dimensions are indicated in the
illustration.
6.1.3 A manual 3-D probe refers to a five-hole prism-shaped or
spherical probe that is positioned at individual traverse points and yaw
nulled manually by an operator. An automated 3-D probe refers to a
system that uses a computer-controlled motorized mechanism to position
the five-hole prism-shaped or spherical head at individual traverse
points and perform yaw angle determinations.
6.1.4 Other three-dimensional probes. [Reserved]
6.1.5 Probe sheath. The probe shaft shall include an outer sheath
to: (1) provide a surface for inscribing a permanent reference scribe
line, (2) accommodate attachment of an angle-measuring device to the
probe shaft, and (3) facilitate precise rotational movement of the probe
for determining yaw angles. The sheath shall be rigidly attached to the
probe assembly and shall enclose all pressure lines from the probe head
to the farthest position away from the probe head where an angle-
measuring device may be attached during use in the field. The sheath of
the fully assembled probe shall be sufficiently rigid and straight at
all rotational positions such that, when one end of the probe shaft is
held in a horizontal position, the fully extended probe meets the
horizontal straightness specifications indicated in section 8.2 below.
6.1.6 Scribe lines.
6.1.6.1 Reference scribe line. A permanent line, no greater than 1.6
mm (1/16 in.) in width, shall be inscribed on each manual probe that
will be used to determine yaw angles of flow. This line shall be placed
on the main probe sheath in accordance with the procedures described in
section 10.4 and is used as a reference position for installation of the
yaw angle-measuring device on the probe. At the discretion of the
tester, the scribe line may be a single line segment placed at a
particular position on the probe sheath (e.g., near the probe head),
multiple line segments placed at various locations along the length of
the probe sheath (e.g., at every position where a yaw angle-measuring
device may be mounted), or a single continuous line extending along the
full length of the probe sheath.
6.1.6.2 Scribe line on probe extensions. A permanent line may also
be inscribed on any probe extension that will be attached to the main
probe in performing field testing. This allows a yaw angle-measuring
device mounted on the extension to be readily aligned with the reference
scribe line on the main probe sheath.
6.1.6.3 Alignment specifications. This specification shall be met
separately, using the procedures in section 10.4.1, on the main probe
and on each probe extension. The rotational position of the scribe line
or scribe line segments on the main probe or any probe extension must
not vary by more than 2[deg]. That is, the difference between the
minimum and maximum of all of the rotational angles that are measured
along the full length of the main probe or the probe extension must not
exceed 2[deg].
6.1.7 Probe and system characteristics to ensure horizontal
stability.
6.1.7.1 For manual probes, it is recommended that the effective
length of the probe (coupled with a probe extension, if necessary) be at
least 0.9 m (3 ft.) longer than the farthest traverse point mark on the
probe shaft away from the probe head. The operator should maintain the
probe's horizontal stability when it is fully inserted into the stack or
duct. If a shorter probe is used, the probe should be inserted through a
bushing sleeve, similar to the one shown in Figure 2F-5, that is
installed on the test port; such a bushing shall fit snugly around the
probe and be secured to the stack or duct entry port in such a manner as
to maintain the probe's horizontal stability when fully inserted into
the stack or duct.
6.1.7.2 An automated system that includes an external probe casing
with a transport system shall have a mechanism for maintaining
horizontal stability comparable to that obtained by manual probes
following the provisions of this method. The automated probe assembly
shall also be constructed to maintain the alignment and position of the
pressure ports during sampling at each traverse point. The design of the
probe casing and transport system shall allow the probe to be removed
from the stack or duct and checked through direct physical measurement
for angular position and insertion depth.
6.1.8 The tubing that is used to connect the probe and the pressure-
measuring device should have an inside diameter of at least 3.2 mm (1/8
in.), to reduce the time required for pressure equilibration, and should
be as short as practicable.
6.2 Yaw Angle-measuring Device. One of the following devices shall
be used for measurement of the yaw angle of flow.
6.2.1 Digital inclinometer. This refers to a digital device capable
of measuring and displaying the rotational position of the probe to
within 1[deg]. The device shall be able to be
locked into position on the probe sheath or probe extension, so that it
indicates the probe's rotational position throughout the test. A
rotational position collar block that can be attached to the probe
sheath (similar

[[Page 52]]

to the collar shown in Figure 2F-6) may be required to lock the digital
inclinometer into position on the probe sheath.
6.2.2 Protractor wheel and pointer assembly. This apparatus, similar
to that shown in Figure 2F-7, consists of the following components.
6.2.2.1 A protractor wheel that can be attached to a port opening
and set in a fixed rotational position to indicate the yaw angle
position of the probe's scribe line relative to the longitudinal axis of
the stack or duct. The protractor wheel must have a measurement ring on
its face that is no less than 17.8 cm (7 in.) in diameter, shall be able
to be rotated to any angle and then locked into position on the stack or
duct port, and shall indicate angles to a resolution of 1[deg].
6.2.2.2 A pointer assembly that includes an indicator needle mounted
on a collar that can slide over the probe sheath and be locked into a
fixed rotational position on the probe sheath. The pointer needle shall
be of sufficient length, rigidity, and sharpness to allow the tester to
determine the probe's angular position to within 1[deg] from the
markings on the protractor wheel. Corresponding to the position of the
pointer, the collar must have a scribe line to be used in aligning the
pointer with the scribe line on the probe sheath.
6.2.3 Other yaw angle-measuring devices. Other angle-measuring
devices with a manufacturer's specified precision of 1[deg] or better
may be used, if approved by the Administrator.
6.3 Probe Supports and Stabilization Devices. When probes are used
for determining flow angles, the probe head should be kept in a stable
horizontal position. For probes longer than 3.0 m (10 ft.), the section
of the probe that extends outside the test port shall be secured. Three
alternative devices are suggested for maintaining the horizontal
position and stability of the probe shaft during flow angle
determinations and velocity pressure measurements: (1) Monorails
installed above each port, (2) probe stands on which the probe shaft may
be rested, or (3) bushing sleeves of sufficient length secured to the
test ports to maintain probes in a horizontal position. Comparable
provisions shall be made to ensure that automated systems maintain the
horizontal position of the probe in the stack or duct. The physical
characteristics of each test platform may dictate the most suitable type
of stabilization device. Thus, the choice of a specific stabilization
device is left to the judgment of the testers.
6.4 Differential Pressure Gauges. The pressure ([Delta]P) measuring
devices used during wind tunnel calibrations and field testing shall be
either electronic manometers (e.g., pressure transducers), fluid
manometers, or mechanical pressure gauges (e.g.,
Magnehelic^[Delta] gauges). Use of electronic manometers is
recommended. Under low velocity conditions, use of electronic manometers
may be necessary to obtain acceptable measurements.
6.4.1 Differential pressure-measuring device. This refers to a
device capable of measuring pressure differentials and having a
readability of 1 percent of full scale. The device
shall be capable of accurately measuring the maximum expected pressure
differential. Such devices are used to determine the following pressure
measurements: velocity pressure, static pressure, yaw-null pressure, and
pitch-angle pressure. For an inclined-vertical manometer, the
readability specification of 1 percent shall be
met separately using the respective full-scale upper limits of the
inclined and vertical portions of the scales. To the extent practicable,
the device shall be selected such that most of the pressure readings are
between 10 and 90 percent of the device's full-scale measurement range
(as defined in section 3.5). Typical velocity pressure (P1-
P2) ranges for both the prism-shaped probe and the spherical
probe are 0 to 1.3 cm H2O (0 to 0.5 in. H2O), 0 to
5.1 cm H2O (0 to 2 in. H2O), and 0 to 12.7 cm
H2O (0 to 5 in. H2O). The pitch angle
(P4-P5) pressure range is typically -6.4 to +6.4
mm H2O (-0.25 to +0.25 in. H2O) or -12.7 to +12.7
mm H2O (-0.5 to +0.5 in. H2O) for the prism-shaped
probe, and -12.7 to +12.7 mm H2O (-0.5 to +0.5 in.
H2O) or -5.1 to +5.1 cm H2O (-2 to +2 in.
H2O) for the spherical probe. The pressure range for the yaw
null (P2-P3) readings is typically -12.7 to +12.7
mm H2O (-0.5 to +0.5 in. H2O) for both probe
types. In addition, pressure-measuring devices should be selected such
that the zero does not drift by more than 5 percent of the average
expected pressure readings to be encountered during the field test. This
is particularly important under low pressure conditions.
6.4.2 Gauge used for yaw nulling. The differential pressure-
measuring device chosen for yaw nulling the probe during the wind tunnel
calibrations and field testing shall be bi-directional, i.e., capable of
reading both positive and negative differential pressures. If a
mechanical, bi-directional pressure gauge is chosen, it shall have a
full-scale range no greater than 2.6 cm H2O (1 in.
H2O) [i.e., -1.3 to +1.3 cm H2O (-0.5 in. to +0.5
in.)].
6.4.3 Devices for calibrating differential pressure-measuring
devices. A precision manometer (e.g., a U-tube, inclined, or inclined-
vertical manometer, or micromanometer) or NIST (National Institute of
Standards and Technology) traceable pressure source shall be used for
calibrating differential pressure-measuring devices. The device shall be
maintained under laboratory conditions or in a similar protected
environment (e.g., a climate-controlled trailer). It shall not be used
in field tests. The precision manometer shall have a scale gradation of
0.3 mm H2O (0.01 in. H2O), or less, in the range
of 0 to 5.1 cm H2O (0 to 2 in. H2O) and 2.5 mm
H2O (0.1 in. H2O),

[[Page 53]]

or less, in the range of 5.1 to 25.4 cm H2O (2 to 10 in.
H2O). The manometer shall have manufacturer's documentation
that it meets an accuracy specification of at least 0.5 percent of full
scale. The NIST-traceable pressure source shall be recertified annually.
6.4.4 Devices used for post-test calibration check. A precision
manometer meeting the specifications in section 6.4.3, a pressure-
measuring device or pressure source with a documented calibration
traceable to NIST, or an equivalent device approved by the Administrator
shall be used for the post-test calibration check. The pressure-
measuring device shall have a readability equivalent to or greater than
the tested device. The pressure source shall be capable of generating
pressures between 50 and 90 percent of the range of the tested device
and known to within 1 percent of the full scale of
the tested device. The pressure source shall be recertified annually.
6.5 Data Display and Capture Devices. Electronic manometers (if
used) shall be coupled with a data display device (such as a digital
panel meter, personal computer display, or strip chart) that allows the
tester to observe and validate the pressure measurements taken during
testing. They shall also be connected to a data recorder (such as a data
logger or a personal computer with data capture software) that has the
ability to compute and retain the appropriate average value at each
traverse point, identified by collection time and traverse point.
6.6 Temperature Gauges. For field tests, a thermocouple or
resistance temperature detector (RTD) capable of measuring temperature
to within 3[deg]C (5[deg]F)
of the stack or duct temperature shall be used. The thermocouple shall
be attached to the probe such that the sensor tip does not touch any
metal and is located on the opposite side of the probe head from the
pressure ports so as not to interfere with the gas flow around the probe
head. The position of the thermocouple relative to the pressure port
face openings shall be in the same configuration as used for the probe
calibrations in the wind tunnel. Temperature gauges used for wind tunnel
calibrations shall be capable of measuring temperature to within 0.6[deg]C (1[deg]F) of the
temperature of the flowing gas stream in the wind tunnel.
6.7 Stack or Duct Static Pressure Measurement. The pressure-
measuring device used with the probe shall be as specified in section
6.4 of this method. The static tap of a standard (Prandtl type) pitot
tube or one leg of a Type S pitot tube with the face opening planes
positioned parallel to the gas flow may be used for this measurement.
Also acceptable is the pressure differential reading of P1-
Pbar from a five-hole prism-shaped probe (e.g., Type DA or
DAT probe) with the P1 pressure port face opening positioned
parallel to the gas flow in the same manner as the Type S probe.
However, the spherical probe, as specified in section 6.1.2, is unable
to provide this measurement and shall not be used to take static
pressure measurements. Static pressure measurement is further described
in section 8.11.
6.8 Barometer. Same as Method 2, section 2.5.
6.9 Gas Density Determination Equipment. Method 3 or 3A shall be
used to determine the dry molecular weight of the stack gas. Method 4
shall be used for moisture content determination and computation of
stack gas wet molecular weight. Other methods may be used, if approved
by the Administrator.
6.10 Calibration Pitot Tube. Same as Method 2, section 2.7.
6.11 Wind Tunnel for Probe Calibration. Wind tunnels used to
calibrate velocity probes must meet the following design specifications.
6.11.1 Test section cross-sectional area. The flowing gas stream
shall be confined within a circular, rectangular, or elliptical duct.
The cross-sectional area of the tunnel must be large enough to ensure
fully developed flow in the presence of both the calibration pitot tube
and the tested probe. The calibration site, or ``test section,'' of the
wind tunnel shall have a minimum diameter of 30.5 cm (12 in.) for
circular or elliptical duct cross-sections or a minimum width of 30.5 cm
(12 in.) on the shorter side for rectangular cross-sections. Wind
tunnels shall meet the probe blockage provisions of this section and the
qualification requirements prescribed in section 10.1. The projected
area of the portion of the probe head, shaft, and attached devices
inside the wind tunnel during calibration shall represent no more than 4
percent of the cross-sectional area of the tunnel. The projected area
shall include the combined area of the calibration pitot tube and the
tested probe if both probes are placed simultaneously in the same cross-
sectional plane in the wind tunnel, or the larger projected area of the
two probes if they are placed alternately in the wind tunnel.
6.11.2 Velocity range and stability. The wind tunnel should be
capable of maintaining velocities between 6.1 m/sec and 30.5 m/sec (20
ft/sec and 100 ft/sec). The wind tunnel shall produce fully developed
flow patterns that are stable and parallel to the axis of the duct in
the test section.
6.11.3 Flow profile at the calibration location. The wind tunnel
shall provide axial flow within the test section calibration location
(as defined in section 3.20). Yaw and pitch angles in the calibration
location shall be within 3[deg] of 0[deg]. The
procedure for determining that this requirement has been met is
described in section 10.1.2.
6.11.4 Entry ports in the wind tunnel test section.

[[Page 54]]

6.11.4.1 Port for tested probe. A port shall be constructed for the
tested probe. The port should have an elongated slot parallel to the
axis of the duct at the test section. The elongated slot should be of
sufficient length to allow attaining all the pitch angles at which the
probe will be calibrated for use in the field. To facilitate alignment
of the probe during calibration, the test section should include a
window constructed of a transparent material to allow the tested probe
to be viewed. This port shall be located to allow the head of the tested
probe to be positioned within the calibration location (as defined in
section 3.20) at all pitch angle settings.
6.11.4.2 Port for verification of axial flow. Depending on the
equipment selected to conduct the axial flow verification prescribed in
section 10.1.2, a second port, located 90[deg] from the entry port for
the tested probe, may be needed to allow verification that the gas flow
is parallel to the central axis of the test section. This port should be
located and constructed so as to allow one of the probes described in
section 10.1.2.2 to access the same test point(s) that are accessible
from the port described in section 6.11.4.1.
6.11.4.3 Port for calibration pitot tube. The calibration pitot tube
shall be used in the port for the tested probe or a separate entry port.
In either case, all measurements with the calibration pitot tube shall
be made at the same point within the wind tunnel over the course of a
probe calibration. The measurement point for the calibration pitot tube
shall meet the same specifications for distance from the wall and for
axial flow as described in section 3.20 for the wind tunnel calibration
location.
6.11.5 Pitch angle protractor plate. A protractor plate shall be
attached directly under the port used with the tested probe and set in a
fixed position to indicate the pitch angle position of the probe
relative to the longitudinal axis of the wind tunnel duct (similar to
Figure 2F-8). The protractor plate shall indicate angles in 5[deg]
increments with a minimum resolution of 2[deg].
The tested probe shall be able to be locked into position at the desired
pitch angle delineated on the protractor. The probe head position shall
be maintained within the calibration location (as defined in section
3.20) in the test section of the wind tunnel during all tests across the
range of pitch angles.

7.0 Reagents and Standards [Reserved]

8.0 Sample Collection and Analysis

8.1 Equipment Inspection and Set-Up
8.1.1 All probes, differential pressure-measuring devices, yaw
angle-measuring devices, thermocouples, and barometers shall have a
current, valid calibration before being used in a field test. (See
sections 10.3.3, 10.3.4, and 10.5 through10.10 for the applicable
calibration requirements.)
8.1.2 Before each field use of a 3-D probe, perform a visual
inspection to verify the physical condition of the probe head according
to the procedures in section 10.2. Record the inspection results on a
form similar to Table 2F-1. If there is visible damage to the 3-D probe,
the probe shall not be used until it is recalibrated.
8.1.3 After verifying that the physical condition of the probe head
is acceptable, set up the apparatus using lengths of flexible tubing
that are as short as practicable. Surge tanks installed between the
probe and pressure-measuring device may be used to dampen pressure
fluctuations provided that an adequate measurement response time (see
section 8.8) is maintained.
8.2 Horizontal Straightness Check. A horizontal straightness check
shall be performed before the start of each field test, except as
otherwise specified in this section. Secure the fully assembled probe
(including the probe head and all probe shaft extensions) in a
horizontal position using a stationary support at a point along the
probe shaft approximating the location of the stack or duct entry port
when the probe is sampling at the farthest traverse point from the stack
or duct wall. The probe shall be rotated to detect bends. Use an angle-
measuring device or trigonometry to determine the bend or sag between
the probe head and the secured end. (See Figure 2F-9.) Probes that are
bent or sag by more than 5[deg] shall not be used. Although this check
does not apply when the probe is used for a vertical traverse, care
should be taken to avoid the use of bent probes when conducting vertical
traverses. If the probe is constructed of a rigid steel material and
consists of a main probe without probe extensions, this check need only
be performed before the initial field use of the probe, when the probe
is recalibrated, when a change is made to the design or material of the
probe assembly, and when the probe becomes bent. With such probes, a
visual inspection shall be made of the fully assembled probe before each
field test to determine if a bend is visible. The probe shall be rotated
to detect bends. The inspection results shall be documented in the field
test report. If a bend in the probe is visible, the horizontal
straightness check shall be performed before the probe is used.
8.3 Rotational Position Check. Before each field test, and each time
an extension is added to the probe during a field test, a rotational
position check shall be performed on all manually operated probes
(except as noted in section 8.3.5, below) to ensure that, throughout
testing, the angle-measuring device is either: aligned to within 1[deg] of the rotational position of the reference
scribe line; or is affixed to the probe such that the rotational offset
of the device from the reference scribe line is known to within 1[deg]. This check shall consist of direct measurements
of the

[[Page 55]]

rotational positions of the reference scribe line and angle-measuring
device sufficient to verify that these specifications are met. Annex A
in section 18 of this method gives recommended procedures for performing
the rotational position check, and Table 2F-2 gives an example data
form. Procedures other than those recommended in Annex A in section 18
may be used, provided they demonstrate whether the alignment
specification is met and are explained in detail in the field test
report.
8.3.1 Angle-measuring device rotational offset. The tester shall
maintain a record of the angle-measuring device rotational offset,
RADO, as defined in section 3.1. Note that RADO is
assigned a value of 0[deg] when the angle-measuring device is aligned to
within 1[deg] of the rotational position of the
reference scribe line. The RADO shall be used to determine
the yaw angle of flow in accordance with section 8.9.4.
8.3.2 Sign of angle-measuring device rotational offset. The sign of
RADO is positive when the angle-measuring device (as viewed
from the ``tail'' end of the probe) is positioned in a clockwise
direction from the reference scribe line and negative when the device is
positioned in a counterclockwise direction from the reference scribe
line.
8.3.3 Angle-measuring devices that can be independently adjusted
(e.g., by means of a set screw), after being locked into position on the
probe sheath, may be used. However, the RADO must also take
into account this adjustment.
8.3.4 Post-test check. If probe extensions remain attached to the
main probe throughout the field test, the rotational position check
shall be repeated, at a minimum, at the completion of the field test to
ensure that the angle-measuring device has remained within 2[deg] of its rotational position established prior to
testing. At the discretion of the tester, additional checks may be
conducted after completion of testing at any sample port or after any
test run. If the 2[deg] specification is not met,
all measurements made since the last successful rotational position
check must be repeated. Section 18.1.1.3 of Annex A provides an example
procedure for performing the post-test check.
8.3.5 Exceptions.
8.3.5.1 A rotational position check need not be performed if, for
measurements taken at all velocity traverse points, the yaw angle-
measuring device is mounted and aligned directly on the reference scribe
line specified in sections 6.1.6.1 and 6.1.6.3 and no independent
adjustments, as described in section 8.3.3, are made to the device's
rotational position.
8.3.5.2 If extensions are detached and re-attached to the probe
during a field test, a rotational position check need only be performed
the first time an extension is added to the probe, rather than each time
the extension is re-attached, if the probe extension is designed to be
locked into a mechanically fixed rotational position (e.g., through use
of interlocking grooves) that can re-establish the initial rotational
position to within 1[deg].
8.4 Leak Checks. A pre-test leak check shall be conducted before
each field test. A post-test check shall be performed at the end of the
field test, but additional leak checks may be conducted after any test
run or group of test runs. The post-test check may also serve as the
pre-test check for the next group of test runs. If any leak check is
failed, all runs since the last passed leak check are invalid. While
performing the leak check procedures, also check each pressure device's
responsiveness to the changes in pressure.
8.4.1 To perform the leak check, pressurize the probe's
P1 pressure port until at least 7.6 cm H2O (3 in.
H2O) pressure, or a pressure corresponding to approximately
75 percent of the pressure-measuring device's measurement scale,
whichever is less, registers on the device; then, close off the pressure
port. The pressure shall remain stable [2.5 mm
H2O (0.10 in. H2O)] for at
least 15 seconds. Check the P2, P3, P4,
and P5 pressure ports in the same fashion. Other leak-check
procedures may be used, if approved by the Administrator.
8.5 Zeroing the Differential Pressure-measuring Device. Zero each
differential pressure-measuring device, including the device used for
yaw nulling, before each field test. At a minimum, check the zero after
each field test. A zero check may also be performed after any test run
or group of test runs. For fluid manometers and mechanical pressure
gauges (e.g., Magnehelic^[Delta] gauges), the zero reading
shall not deviate from zero by more than 0.8 mm
H2O (0.03 in. H2O) or one
minor scale division, whichever is greater, between checks. For
electronic manometers, the zero reading shall not deviate from zero
between checks by more than: 0.3 mm H2O
(0.01 in. H2O), for full scales less
than or equal to 5.1 cm H2O (2.0 in. H2O); or
0.8 mm H2O (0.03
in. H2O), for full scales greater than 5.1 cm H2O
(2.0 in. H2O). (Note: If negative zero drift is not directly
readable, estimate the reading based on the position of the gauge oil in
the manometer or of the needle on the pressure gauge.) In addition, for
all pressure-measuring devices except those used exclusively for yaw
nulling, the zero reading shall not deviate from zero by more than 5
percent of the average measured differential pressure at any distinct
process condition or load level. If any zero check is failed at a
specific process condition or load level, all runs conducted at that
process condition or load level since the last passed zero check are
invalid.
8.6 Traverse Point Verification. The number and location of the
traverse points shall be selected based on Method 1 guidelines.

[[Page 56]]

The stack or duct diameter and port nipple lengths, including any
extension of the port nipples into stack or duct, shall be verified the
first time the test is performed; retain and use this information for
subsequent field tests, updating it as required. Physically measure the
stack or duct dimensions or use a calibrated laser device; do not use
engineering drawings of the stack or duct. The probe length necessary to
reach each traverse point shall be recorded to within 6.4 mm (1/4 in.) and, for manual
probes, marked on the probe sheath. In determining these lengths, the
tester shall take into account both the distance that the port flange
projects outside of the stack and the depth that any port nipple extends
into the gas stream. The resulting point positions shall reflect the
true distances from the inside wall of the stack or duct, so that when
the tester aligns any of the markings with the outside face of the stack
port, the probe's impact port shall be located at the appropriate
distance from the inside wall for the respective Method 1 traverse
point. Before beginning testing at a particular location, an out-of-
stack or duct verification shall be performed on each probe that will be
used to ensure that these position markings are correct. The distances
measured during the verification must agree with the previously
calculated distances to within 1/4 in. For manual
probes, the traverse point positions shall be verified by measuring the
distance of each mark from the probe's P1 pressure port. A
comparable out-of-stack test shall be performed on automated probe
systems. The probe shall be extended to each of the prescribed traverse
point positions. Then, the accuracy of the positioning for each traverse
point shall be verified by measuring the distance between the port
flange and the probe's P1 pressure port.
8.7 Probe Installation. Insert the probe into the test port. A solid
material shall be used to seal the port.
8.8 System Response Time. Determine the response time of the probe
measurement system. Insert and position the ``cold'' probe (at ambient
temperature and pressure) at any Method 1 traverse point. Read and
record the probe's P1-P2 differential pressure,
temperature, and elapsed time at 15-second intervals until stable
readings for both pressure and temperature are achieved. The response
time is the longer of these two elapsed times. Record the response time.
8.9 Sampling.
8.9.1 Yaw angle measurement protocol. With manual probes, yaw angle
measurements may be obtained in two alternative ways during the field
test, either by using a yaw angle-measuring device (e.g., digital
inclinometer) affixed to the probe, or using a protractor wheel and
pointer assembly. For horizontal traversing, either approach may be
used. For vertical traversing, i.e., when measuring from on top or into
the bottom of a horizontal duct, only the protractor wheel and pointer
assembly may be used. With automated probes, curve-fitting protocols may
be used to obtain yaw-angle measurements.
8.9.1.1 If a yaw angle-measuring device affixed to the probe is to
be used, lock the device on the probe sheath, aligning it either on the
reference scribe line or in the rotational offset position established
under section 8.3.1.
8.9.1.2 If a protractor wheel and pointer assembly is to be used,
follow the procedures in Annex B of this method.
8.9.1.3 Other yaw angle-determination procedures. If approved by the
Administrator, other procedures for determining yaw angle may be used,
provided that they are verified in a wind tunnel to be able to perform
the yaw angle calibration procedure as described in section 10.5.
8.9.2 Sampling strategy. At each traverse point, first yaw-null the
probe, as described in section 8.9.3, below. Then, with the probe
oriented into the direction of flow, measure and record the yaw angle,
the differential pressures and the temperature at the traverse point,
after stable readings are achieved, in accordance with sections 8.9.4
and 8.9.5. At the start of testing in each port (i.e., after a probe has
been inserted into the flue gas stream), allow at least the response
time to elapse before beginning to take measurements at the first
traverse point accessed from that port. Provided that the probe is not
removed from the flue gas stream, measurements may be taken at
subsequent traverse points accessed from the same test port without
waiting again for the response time to elapse.
8.9.3 Yaw-nulling procedure. In preparation for yaw angle
determination, the probe must first be yaw nulled. After positioning the
probe at the appropriate traverse point, perform the following
procedures.
8.9.3.1 Rotate the probe until a null differential pressure reading
(the difference in pressures across the P2 and P3
pressure ports is zero, i.e., P2=P3) is indicated
by the yaw angle pressure gauge. Read and record the angle displayed by
the angle-measuring device.
8.9.3.2 Sign of the measured angle. The angle displayed on the
angle-measuring device is considered positive when the probe's impact
pressure port (as viewed from the ``tail'' end of the probe) is oriented
in a clockwise rotational position relative to the stack or duct axis
and is considered negative when the probe's impact pressure port is
oriented in a counterclockwise rotational position (see Figure 2F-10).
8.9.4 Yaw angle determination. After performing the yaw-nulling
procedure in section

[[Page 57]]

8.9.3, determine the yaw angle of flow according to one of the following
procedures. Special care must be observed to take into account the signs
of the recorded angle and all offsets.
8.9.4.1 Direct-reading. If all rotational offsets are zero or if the
angle-measuring device rotational offset (RADO) determined in
section 8.3 exactly compensates for the scribe line rotational offset
(RSLO) determined in section 10.5, then the magnitude of the
yaw angle is equal to the displayed angle-measuring device reading from
section 8.9.3.1. The algebraic sign of the yaw angle is determined in
accordance with section 8.9.3.2.

Note: Under certain circumstances (e.g., testing of horizontal
ducts), a 90[deg] adjustment to the angle-measuring device readings may
be necessary to obtain the correct yaw angles.

8.9.4.2 Compensation for rotational offsets during data reduction.
When the angle-measuring device rotational offset does not compensate
for reference scribe line rotational offset, the following procedure
shall be used to determine the yaw angle:
(a) Enter the reading indicated by the angle-measuring device from
section 8.9.3.1.
(b) Associate the proper algebraic sign from section 8.9.3.2 with
the reading in step (a).
(c) Subtract the reference scribe line rotational offset,
RSLO, from the reading in step (b).
(d) Subtract the angle-measuring device rotational offset,
RADO, if any, from the result obtained in step (c).
(e) The final result obtained in step (d) is the yaw angle of flow.

Note: It may be necessary to first apply a 90[deg] adjustment to the
reading in step (a), in order to obtain the correct yaw angle.

8.9.4.3 Record the yaw angle measurements on a form similar to Table
2F-3.
8.9.5 Velocity determination. Maintain the probe rotational position
established during the yaw angle determination. Then, begin recording
the pressure-measuring device readings for the impact pressure
(P1-P2) and pitch angle pressure (P4-
P5). These pressure measurements shall be taken over a
sampling period of sufficiently long duration to ensure representative
readings at each traverse point. If the pressure measurements are
determined from visual readings of the pressure device or display, allow
sufficient time to observe the pulsation in the readings to obtain a
sight-weighted average, which is then recorded manually. If an automated
data acquisition system (e.g., data logger, computer-based data
recorder, strip chart recorder) is used to record the pressure
measurements, obtain an integrated average of all pressure readings at
the traverse point. Stack or duct gas temperature measurements shall be
recorded, at a minimum, once at each traverse point. Record all
necessary data as shown in the example field data form (Table 2F-3).
8.9.6 Alignment check. For manually operated probes, after the
required yaw angle and differential pressure and temperature
measurements have been made at each traverse point, verify (e.g., by
visual inspection) that the yaw angle-measuring device has remained in
proper alignment with the reference scribe line or with the rotational
offset position established in section 8.3. If, for a particular
traverse point, the angle-measuring device is found to be in proper
alignment, proceed to the next traverse point; otherwise, re-align the
device and repeat the angle and differential pressure measurements at
the traverse point. In the course of a traverse, if a mark used to
properly align the angle-measuring device (e.g., as described in section
18.1.1.1) cannot be located, re-establish the alignment mark before
proceeding with the traverse.
8.10 Probe Plugging. Periodically check for plugging of the pressure
ports by observing the responses on pressure differential readouts.
Plugging causes erratic results or sluggish responses. Rotate the probe
to determine whether the readouts respond in the expected direction. If
plugging is detected, correct the problem and repeat the affected
measurements.
8.11 Static Pressure. Measure the static pressure in the stack or
duct using the equipment described in section 6.7.
8.11.1 If a Type DA or DAT probe is used for this measurement,
position the probe at or between any traverse point(s) and rotate the
probe until a null differential pressure reading is obtained at
P2-P3. Rotate the probe 90[deg]. Disconnect the
P2 pressure side of the probe and read the pressure
P1-Pbar and record as the static pressure. (Note:
The spherical probe, specified in section 6.1.2, is unable to provide
this measurement and shall not be used to take static pressure
measurements.)
8.11.2 If a Type S probe is used for this measurement, position the
probe at or between any traverse point(s) and rotate the probe until a
null differential pressure reading is obtained. Disconnect the tubing
from one of the pressure ports; read and record the [Delta]P. For
pressure devices with one-directional scales, if a deflection in the
positive direction is noted with the negative side disconnected, then
the static pressure is positive. Likewise, if a deflection in the
positive direction is noted with the positive side disconnected, then
the static pressure is negative.
8.12 Atmospheric Pressure. Determine the atmospheric pressure at the
sampling elevation during each test run following the procedure
described in section 2.5 of Method 2.

[[Page 58]]

8.13 Molecular Weight. Determine the stack gas dry molecular weight.
For combustion processes or processes that emit essentially
CO2, O2, CO, and N2, use Method 3 or
3A. For processes emitting essentially air, an analysis need not be
conducted; use a dry molecular weight of 29.0. Other methods may be
used, if approved by the Administrator.
8.14 Moisture. Determine the moisture content of the stack gas using
Method 4 or equivalent.
8.15 Data Recording and Calculations. Record all required data on a
form similar to Table 2F-3.
8.15.1 Selection of appropriate calibration curves. Choose the
appropriate pair of F1 and F2 versus pitch angle
calibration curves, created as described in section 10.6.
8.15.2 Pitch angle derivation. Use the appropriate calculation
procedures in section 12.2 to find the pitch angle ratios that are
applicable at each traverse point. Then, find the pitch angles
corresponding to these pitch angle ratios on the ``F1 versus
pitch angle'' curve for the probe.
8.15.3 Velocity calibration coefficient derivation. Use the pitch
angle obtained following the procedures described in section 8.15.2 to
find the corresponding velocity calibration coefficients from the
``F2 versus pitch angle'' calibration curve for the probe.
8.15.4 Calculations. Calculate the axial velocity at each traverse
point using the equations presented in section 12.2 to account for the
yaw and pitch angles of flow. Calculate the test run average stack gas
velocity by finding the arithmetic average of the point velocity results
in accordance with sections 12.3 and 12.4, and calculate the stack gas
volumetric flow rate in accordance with section 12.5 or 12.6, as
applicable.

9.0 Quality Control

9.1 Quality Control Activities. In conjunction with the yaw angle
determination and the pressure and temperature measurements specified in
section 8.9, the following quality control checks should be performed.
9.1.1 Range of the differential pressure gauge. In accordance with
the specifications in section 6.4, ensure that the proper differential
pressure gauge is being used for the range of [Delta]P values
encountered. If it is necessary to change to a more sensitive gauge,
replace the gauge with a gauge calibrated according to section 10.3.3,
perform the leak check described in section 8.4 and the zero check
described in section 8.5, and repeat the differential pressure and
temperature readings at each traverse point.
9.1.2 Horizontal stability check. For horizontal traverses of a
stack or duct, visually check that the probe shaft is maintained in a
horizontal position prior to taking a pressure reading. Periodically,
during a test run, the probe's horizontal stability should be verified
by placing a carpenter's level, a digital inclinometer, or other angle-
measuring device on the portion of the probe sheath that extends outside
of the test port. A comparable check should be performed by automated
systems.

10.0 Calibration

10.1 Wind Tunnel Qualification Checks. To qualify for use in
calibrating probes, a wind tunnel shall have the design features
specified in section 6.11 and satisfy the following qualification
criteria. The velocity pressure cross-check in section 10.1.1 and axial
flow verification in section 10.1.2 shall be performed before the
initial use of the wind tunnel and repeated immediately after any
alteration occurs in the wind tunnel's configuration, fans, interior
surfaces, straightening vanes, controls, or other properties that could
reasonably be expected to alter the flow pattern or velocity stability
in the tunnel. The owner or operator of a wind tunnel used to calibrate
probes according to this method shall maintain records documenting that
the wind tunnel meets the requirements of sections 10.1.1 and 10.1.2 and
shall provide these records to the Administrator upon request.
10.1.1 Velocity pressure cross-check. To verify that the wind tunnel
produces the same velocity at the tested probe head as at the
calibration pitot tube impact port, perform the following cross-check.
Take three differential pressure measurements at the fixed calibration
pitot tube location, using the calibration pitot tube specified in
section 6.10, and take three measurements with the calibration pitot
tube at the wind tunnel calibration location, as defined in section
3.20. Alternate the measurements between the two positions. Perform this
procedure at the lowest and highest velocity settings at which the
probes will be calibrated. Record the values on a form similar to Table
2F-4. At each velocity setting, the average velocity pressure obtained
at the wind tunnel calibration location shall be within 2 percent or 2.5 mm H2O (0.01 in.
H2O), whichever is less restrictive, of the average velocity
pressure obtained at the fixed calibration pitot tube location. This
comparative check shall be performed at 2.5-cm (1-in.), or smaller,
intervals across the full length, width, and depth (if applicable) of
the wind tunnel calibration location. If the criteria are not met at
every tested point, the wind tunnel calibration location must be
redefined, so that acceptable results are obtained at every point.
Include the results of the velocity pressure cross-check in the
calibration data section of the field test report. (See section 16.1.4.)
10.1.2 Axial flow verification. The following procedures shall be
performed to demonstrate that there is fully developed axial flow within
the calibration location

[[Page 59]]

and at the calibration pitot tube location. Two testing options are
available to conduct this check.
10.1.2.1 Using a calibrated 3-D probe. A 3-D probe that has been
previously calibrated in a wind tunnel with documented axial flow (as
defined in section 3.21) may be used to conduct this check. Insert the
calibrated 3-D probe into the wind tunnel test section using the tested
probe port. Following the procedures in sections 8.9 and 12.2 of this
method, determine the yaw and pitch angles at all the point(s) in the
test section where the velocity pressure cross-check, as specified in
section 10.1.1, is performed. This includes all the points in the
calibration location and the point where the calibration pitot tube will
be located. Determine the yaw and pitch angles at each point. Repeat
these measurements at the highest and lowest velocities at which the
probes will be calibrated. Record the values on a form similar to Table
2F-5. Each measured yaw and pitch angle shall be within 3[deg] of 0[deg]. Exceeding the limits indicates
unacceptable flow in the test section. Until the problem is corrected
and acceptable flow is verified by repetition of this procedure, the
wind tunnel shall not be used for calibration of probes. Include the
results of the axial flow verification in the calibration data section
of the field test report. (See section 16.1.4.)
10.1.2.2 Using alternative probes. Axial flow verification may be
performed using an uncalibrated prism-shaped 3-D probe (e.g., DA or DAT
probe) or an uncalibrated wedge probe. (Figure 2F-11 illustrates a
typical wedge probe.) This approach requires use of two ports: the
tested probe port and a second port located 90[deg] from the tested
probe port. Each port shall provide access to all the points within the
wind tunnel test section where the velocity pressure cross-check, as
specified in section 10.1.1, is conducted. The probe setup shall include
establishing a reference yaw-null position on the probe sheath to serve
as the location for installing the angle-measuring device. Physical
design features of the DA, DAT, and wedge probes are relied on to
determine the reference position. For the DA or DAT probe, this
reference position can be determined by setting a digital inclinometer
on the flat facet where the P1 pressure port is located and
then identifying the rotational position on the probe sheath where a
second angle-measuring device would give the same angle reading. The
reference position on a wedge probe shaft can be determined either
geometrically or by placing a digital inclinometer on each side of the
wedge and rotating the probe until equivalent readings are obtained.
With the latter approach, the reference position is the rotational
position on the probe sheath where an angle-measuring device would give
a reading of 0[deg]. After installing the angle-measuring device in the
reference yaw-null position on the probe sheath, determine the yaw angle
from the tested port. Repeat this measurement using the 90[deg] offset
port, which provides the pitch angle of flow. Determine the yaw and
pitch angles at all the point(s) in the test section where the velocity
pressure cross-check, as specified in section 10.1.1, is performed. This
includes all the points in the wind tunnel calibration location and the
point where the calibration pitot tube will be located. Perform this
check at the highest and lowest velocities at which the probes will be
calibrated. Record the values on a form similar to Table 2F-5. Each
measured yaw and pitch angle shall be within 3[deg] of 0[deg]. Exceeding the limits indicates
unacceptable flow in the test section. Until the problem is corrected
and acceptable flow is verified by repetition of this procedure, the
wind tunnel shall not be used for calibration of probes. Include the
results in the probe calibration report.
10.1.3 Wind tunnel audits.
10.1.3.1 Procedure. Upon the request of the Administrator, the owner
or operator of a wind tunnel shall calibrate a 3-D audit probe in
accordance with the procedures described in sections 10.3 through 10.6.
The calibration shall be performed at two velocities and over a pitch
angle range that encompasses the velocities and pitch angles typically
used for this method at the facility. The resulting calibration data and
curves shall be submitted to the Agency in an audit test report. These
results shall be compared by the Agency to reference calibrations of the
audit probe at the same velocity and pitch angle settings obtained at
two different wind tunnels.
10.1.3.2 Acceptance criteria. The audited tunnel's calibration is
acceptable if all of the following conditions are satisfied at each
velocity and pitch setting for the reference calibration obtained from
at least one of the wind tunnels. For pitch angle settings between -
15[deg] and +15[deg], no velocity calibration coefficient (i.e.,
F2) may differ from the corresponding reference value by more
than 3 percent. For pitch angle settings outside of this range (i.e.,
less than -15[deg] and greater than +15[deg]), no velocity calibration
coefficient may differ by more than 5 percent from the corresponding
reference value. If the acceptance criteria are not met, the audited
wind tunnel shall not be used to calibrate probes for use under this
method until the problems are resolved and acceptable results are
obtained upon completion of a subsequent audit.
10.2 Probe Inspection. Before each calibration of a 3-D probe,
carefully examine the physical condition of the probe head. Particular
attention shall be paid to the edges of the pressure ports and the
surfaces surrounding these ports. Any dents, scratches, or asymmetries
on the edges of the pressure ports and any scratches or indentations on

[[Page 60]]

the surfaces surrounding the pressure ports shall be noted because of
the potential effect on the probe's pressure readings. If the probe has
been previously calibrated, compare the current condition of the probe's
pressure ports and surfaces to the results of the inspection performed
during the probe's most recent wind tunnel calibration. Record the
results of this inspection on a form and in diagrams similar to Table
2F-1. The information in Table 2F-1 will be used as the basis for
comparison during the probe head inspections performed before each
subsequent field use.
10.3 Pre-Calibration Procedures. Prior to calibration, a scribe line
shall have been placed on the probe in accordance with section 10.4. The
yaw angle and velocity calibration procedures shall not begin until the
pre-test requirements in sections 10.3.1 through 10.3.4 have been met.
10.3.1 Perform the horizontal straightness check described in
section 8.2 on the probe assembly that will be calibrated in the wind
tunnel.
10.3.2 Perform a leak check in accordance with section 8.4.
10.3.3 Except as noted in section 10.3.3.3, calibrate all
differential pressure-measuring devices to be used in the probe
calibrations, using the following procedures. At a minimum, calibrate
these devices on each day that probe calibrations are performed.
10.3.3.1 Procedure. Before each wind tunnel use, all differential
pressure-measuring devices shall be calibrated against the reference
device specified in section 6.4.3 using a common pressure source.
Perform the calibration at three reference pressures representing 30,
60, and 90 percent of the full-scale range of the pressure-measuring
device being calibrated. For an inclined-vertical manometer, perform
separate calibrations on the inclined and vertical portions of the
measurement scale, considering each portion of the scale to be a
separate full-scale range. [For example, for a manometer with a 0- to
2.5-cm H2O (0- to 1-in. H2O) inclined scale and a
2.5- to 12.7-cm H2O (1- to 5-in. H2O) vertical
scale, calibrate the inclined portion at 7.6, 15.2, and 22.9 mm
H2O (0.3, 0.6, and 0.9 in. H2O), and calibrate the
vertical portion at 3.8, 7.6, and 11.4 cm H2O (1.5, 3.0, and
4.5 in. H2O).] Alternatively, for the vertical portion of the
scale, use three evenly spaced reference pressures, one of which is
equal to or higher than the highest differential pressure expected in
field applications.
10.3.3.2 Acceptance criteria. At each pressure setting, the two
pressure readings made using the reference device and the pressure-
measuring device being calibrated shall agree to within 2 percent of full scale of the device being calibrated
or 0.5 mm H2O (0.02 in. H2O), whichever is less
restrictive. For an inclined-vertical manometer, these requirements
shall be met separately using the respective full-scale upper limits of
the inclined and vertical portions of the scale. Differential pressure-
measuring devices not meeting the 2 percent of full scale or
0.5 mm H2O (0.02 in. H2O) calibration requirement
shall not be used.
10.3.3.3 Exceptions. Any precision manometer that meets the
specifications for a reference device in section 6.4.3 and that is not
used for field testing does not require calibration, but must be leveled
and zeroed before each wind tunnel use. Any pressure device used
exclusively for yaw nulling does not require calibration, but shall be
checked for responsiveness to rotation of the probe prior to each wind
tunnel use.
10.3.4 Calibrate digital inclinometers on each day of wind tunnel or
field testing (prior to beginning testing) using the following
procedures. Calibrate the inclinometer according to the manufacturer's
calibration procedures. In addition, use a triangular block (illustrated
in Figure 2F-12) with a known angle, [theta] independently determined
using a protractor or equivalent device, between two adjacent sides to
verify the inclinometer readings.

Note: If other angle-measuring devices meeting the provisions of
section 6.2.3 are used in place of a digital inclinometer, comparable
calibration procedures shall be performed on such devices.)

Secure the triangular block in a fixed position. Place the inclinometer
on one side of the block (side A) to measure the angle of inclination
(R1). Repeat this measurement on the adjacent side of the
block (side B) using the inclinometer to obtain a second angle reading
(R2). The difference of the sum of the two readings from
180[deg] (i.e., 180[deg] -R1 -R2) shall be within
2[deg] of the known angle, [Theta]
10.4 Placement of Reference Scribe Line. Prior to the first
calibration of a probe, a line shall be permanently inscribed on the
main probe sheath to serve as a reference mark for determining yaw
angles. Annex C in section 18 of this method gives a guideline for
placement of the reference scribe line.
10.4.1 This reference scribe line shall meet the specifications in
sections 6.1.6.1 and 6.1.6.3 of this method. To verify that the
alignment specification in section 6.1.6.3 is met, secure the probe in a
horizontal position and measure the rotational angle of each scribe line
and scribe line segment using an angle-measuring device that meets the
specifications in section 6.2.1 or 6.2.3. For any scribe line that is
longer than 30.5 cm (12 in.), check the line's rotational position at
30.5-cm (12-in.) intervals. For each line segment that is 30.5 cm (12
in.) or less in length, check the rotational position at the two
endpoints of the segment. To meet the alignment specification in section
6.1.6.3, the minimum and maximum of all of the rotational angles that
are measured along the full

[[Page 61]]

length of the main probe must not differ by more than 2[deg].

Note: A short reference scribe line segment [e.g., 15.2 cm (6 in.)
or less in length] meeting the alignment specifications in section
6.1.6.3 is fully acceptable under this method. See section 18.1.1.1 of
Annex A for an example of a probe marking procedure, suitable for use
with a short reference scribe line.

10.4.2 The scribe line should be placed on the probe first and then
its offset from the yaw-null position established (as specified in
section 10.5). The rotational position of the reference scribe line
relative to the yaw-null position of the probe, as determined by the yaw
angle calibration procedure in section 10.5, is defined as the reference
scribe line rotational offset, RSLO. The reference scribe
line rotational offset shall be recorded and retained as part of the
probe's calibration record.
10.4.3 Scribe line for automated probes. A scribe line may not be
necessary for an automated probe system if a reference rotational
position of the probe is built into the probe system design. For such
systems, a ``flat'' (or comparable, clearly identifiable physical
characteristic) should be provided on the probe casing or flange plate
to ensure that the reference position of the probe assembly remains in a
vertical or horizontal position. The rotational offset of the flat (or
comparable, clearly identifiable physical characteristic) needed to
orient the reference position of the probe assembly shall be recorded
and maintained as part of the automated probe system's specifications.
10.5 Yaw Angle Calibration Procedure. For each probe used to measure
yaw angles with this method, a calibration procedure shall be performed
in a wind tunnel meeting the specifications in section 10.1 to determine
the rotational position of the reference scribe line relative to the
probe's yaw-null position. This procedure shall be performed on the main
probe with all devices that will be attached to the main probe in the
field [such as thermocouples or resistance temperature detectors (RTDs)]
that may affect the flow around the probe head. Probe shaft extensions
that do not affect flow around the probe head need not be attached
during calibration. At a minimum, this procedure shall include the
following steps.
10.5.1 Align and lock the angle-measuring device on the reference
scribe line. If a marking procedure (such as that described in section
18.1.1.1) is used, align the angle-measuring device on a mark within
1[deg] of the rotational position of the reference
scribe line. Lock the angle-measuring device onto the probe sheath at
this position.
10.5.2 Zero the pressure-measuring device used for yaw nulling.
10.5.3 Insert the probe assembly into the wind tunnel through the
entry port, positioning the probe's impact port at the calibration
location. Check the responsiveness of the pressure-measurement device to
probe rotation, taking corrective action if the response is
unacceptable.
10.5.4 Ensure that the probe is in a horizontal position, using a
carpenter's level.
10.5.5 Rotate the probe either clockwise or counterclockwise until a
yaw null (P2=P3) is obtained.
10.5.6 Use the reading displayed by the angle-measuring device at
the yaw-null position to determine the magnitude of the reference scribe
line rotational offset, RSLO, as defined in section 3.15.
Annex D in section 18 of this method provides a recommended procedure
for determining the magnitude of RSLO with a digital
inclinometer and a second procedure for determining the magnitude of
RSLO with a protractor wheel and pointer device. Table 2F-6
presents an example data form and Table 2F-7 is a look-up table with the
recommended procedure. Procedures other than those recommended in Annex
D in section 18 may be used, if they can determine RSLO to
within 1[deg] and are explained in detail in the
field test report. The algebraic sign of RSLO will either be
positive, if the rotational position of the reference scribe line (as
viewed from the ``tail'' end of the probe) is clockwise, or negative, if
counterclockwise with respect to the probe's yaw-null position. (This is
illustrated in Figure 2F-13.)
10.5.7 The steps in sections 10.5.3 through 10.5.6 shall be
performed twice at each of the velocities at which the probe will be
calibrated (in accordance with section 10.6). Record the values of
RSLO.
10.5.8 The average of all of the RSLO values shall be
documented as the reference scribe line rotational offset for the probe.
10.5.9 Use of reference scribe line offset. The reference scribe
line rotational offset shall be used to determine the yaw angle of flow
in accordance with section 8.9.4.
10.6 Pitch Angle and Velocity Pressure Calibrations. Use the
procedures in sections 10.6.1 through 10.6.16 to generate an appropriate
set (or sets) of pitch angle and velocity pressure calibration curves
for each probe. The calibration procedure shall be performed on the main
probe and all devices that will be attached to the main probe in the
field (e.g., thermocouple or RTDs) that may affect the flow around the
probe head. Probe shaft extensions that do not affect flow around the
probe head need not be attached during calibration. (Note: If a sampling
nozzle is part of the assembly, a wind tunnel demonstration shall be
performed that shows the probe's ability to measure velocity and yaw
null is not impaired when the nozzle is drawing a sample.) The
calibration

[[Page 62]]

procedure involves generating two calibration curves, F1
versus pitch angle and F2 versus pitch angle. To generate
these two curves, F1 and F2 shall be derived using
Equations 2F-1 and 2F-2, below. Table 2F-8 provides an example wind
tunnel calibration data sheet, used to log the measurements needed to
derive these two calibration curves.
10.6.1 Calibration velocities. The tester may calibrate the probe at
two nominal wind tunnel velocity settings of 18.3 m/sec and 27.4 m/sec
(60 ft/sec and 90 ft/sec) and average the results of these calibrations,
as described in section 10.6.16.1, in order to generate a set of
calibration curves. If this option is selected, this single set of
calibration curves may be used for all field applications over the
entire velocity range allowed by the method. Alternatively, the tester
may customize the probe calibration for a particular field test
application (or for a series of applications), based on the expected
average velocity(ies) at the test site(s). If this option is selected,
generate each set of calibration curves by calibrating the probe at two
nominal wind tunnel velocity settings, at least one of which is greater
than or equal to the expected average velocity(ies) for the field
application(s), and average the results as described in section
10.6.16.1. Whichever calibration option is selected, the probe
calibration coefficients (F2 values) obtained at the two
nominal calibration velocities shall, for the same pitch angle setting,
meet the conditions specified in section 10.6.16.
10.6.2 Pitch angle calibration curve (F1 versus pitch
angle). The pitch angle calibration involves generating a calibration
curve of calculated F1 values versus tested pitch angles,
where F1 is the ratio of the pitch pressure to the velocity
pressure, i.e.,
[GRAPHIC] [TIFF OMITTED] TR14MY99.049

See Figure 2F-14 for an example F1 versus pitch angle
calibration curve.
10.6.3 Velocity calibration curve (F2 versus pitch
angle). The velocity calibration involves generating a calibration curve
of the 3-D probe's F2 coefficient against the tested pitch
angles, where
[GRAPHIC] [TIFF OMITTED] TR14MY99.050

and
Cp=calibration pitot tube coefficient, and
[Delta]Pstd=velocity pressure from the calibration pitot
tube.

See Figure 2F-15 for an example F2 versus pitch angle
calibration curve.
10.6.4 Connect the tested probe and calibration pitot probe to their
respective pressure-measuring devices. Zero the pressure-measuring
devices. Inspect and leak-check all pitot lines; repair or replace, if
necessary. Turn on the fan, and allow the wind tunnel air flow to
stabilize at the first of the two selected nominal velocity settings.
10.6.5 Position the calibration pitot tube at its measurement
location (determined as outlined in section 6.11.4.3), and align the
tube so that its tip is pointed directly into the flow. Ensure that the
entry port surrounding the tube is properly sealed. The calibration
pitot tube may either remain in the wind tunnel throughout the
calibration, or be removed from the wind tunnel while measurements are
taken with the probe being calibrated.
10.6.6 Set up the pitch protractor plate on the tested probe's entry
port to establish the pitch angle positions of the probe to within
2[deg].
10.6.7 Check the zero setting of each pressure-measuring device.
10.6.8 Insert the tested probe into the wind tunnel and align it so
that its P1 pressure port is pointed directly into the flow
and is positioned within the calibration location (as defined in section
3.20). Secure the probe at the 0[deg] pitch angle position. Ensure that
the entry port surrounding the probe is properly sealed.
10.6.9 Read the differential pressure from the calibration pitot
tube ([Delta]Pstd), and record its value. Read the barometric
pressure to within 2.5 mm Hg (0.1 in. Hg) and the temperature in the wind tunnel to
within 0.6[deg]C (1[deg]F). Record these values on a data form similar
to Table 2F-8.
10.6.10 After the tested probe's differential pressure gauges have
had sufficient time to stabilize, yaw null the probe, then obtain
differential pressure readings for (P1-P2) and
(P4-P5). Record the yaw angle and differential
pressure readings. After taking these readings, ensure that the tested
probe has remained at the yaw-null position.
10.6.11 Either take paired differential pressure measurements with
both the calibration pitot tube and tested probe (according to sections
10.6.9 and 10.6.10) or take readings only with the tested probe
(according to section 10.6.10) in 5[deg] increments over the pitch-angle
range for which the probe is to be calibrated. The calibration pitch-
angle range shall be symmetric around 0[deg] and shall exceed the
largest pitch angle expected in the field by 5[deg]. At a minimum,
probes shall be calibrated over the range of -15[deg] to +15[deg]. If
paired calibration pitot tube and tested probe measurements are not
taken at each pitch angle setting, the differential pressure from the
calibration pitot tube shall be read, at a minimum, before taking the
tested probe's differential pressure reading at the first pitch angle
setting and after taking the tested probe's differential pressure
readings

[[Page 63]]

at the last pitch angle setting in each replicate.
10.6.12 Perform a second replicate of the procedures in sections
10.6.5 through 10.6.11 at the same nominal velocity setting.
10.6.13 For each replicate, calculate the F1 and
F2 values at each pitch angle. At each pitch angle, calculate
the percent difference between the two F2 values using
Equation 2F-3.
[GRAPHIC] [TIFF OMITTED] TR14MY99.051

If the percent difference is less than or equal to 2 percent,
calculate an average F1 value and an average F2
value at that pitch angle. If the percent difference is greater than 2
percent and less than or equal to 5 percent, perform a third repetition
at that angle and calculate an average F1 value and an
average F2 value using all three repetitions. If the percent
difference is greater than 5 percent, perform four additional
repetitions at that angle and calculate an average F1 value
and an average F2 value using all six repetitions. When
additional repetitions are required at any pitch angle, move the probe
by at least 5[deg] and then return to the specified pitch angle before
taking the next measurement. Record the average values on a form similar
to Table 2F-9.
10.6.14 Repeat the calibration procedures in sections 10.6.5 through
10.6.13 at the second selected nominal wind tunnel velocity setting.
10.6.15 Velocity drift check. The following check shall be
performed, except when paired calibration pitot tube and tested probe
pressure measurements are taken at each pitch angle setting. At each
velocity setting, calculate the percent difference between consecutive
differential pressure measurements made with the calibration pitot tube.
If a measurement differs from the previous measurement by more than 2
percent or 0.25 mm H2O (0.01 in. H2O), whichever
is less restrictive, the calibration data collected between these
calibration pitot tube measurements may not be used, and the
measurements shall be repeated.
10.6.16 Compare the averaged F2 coefficients obtained
from the calibrations at the two selected nominal velocities, as
follows. At each pitch angle setting, use Equation 2F-3 to calculate the
difference between the corresponding average F2 values at the
two calibration velocities. At each pitch angle in the -15[deg] to
+15[deg] range, the percent difference between the average F2
values shall not exceed 3.0 percent. For pitch angles outside this range
(i.e., less than -15[deg]0 and greater than +15[deg]), the percent
difference shall not exceed 5.0 percent.
10.6.16.1 If the applicable specification in section 10.6.16 is met
at each pitch angle setting, average the results obtained at the two
nominal calibration velocities to produce a calibration record of
F1 and F2 at each pitch angle tested. Record these
values on a form similar to Table 2F-9. From these values, generate one
calibration curve representing F1 versus pitch angle and a
second curve representing F2 versus pitch angle. Computer
spreadsheet programs may be used to graph the calibration data and to
develop polynomial equations that can be used to calculate pitch angles
and axial velocities.
10.6.16.2 If the applicable specification in section 10.6.16 is
exceeded at any pitch angle setting, the probe shall not be used unless:
(1) the calibration is repeated at that pitch angle and acceptable
results are obtained or (2) values of F1 and F2
are obtained at two nominal velocities for which the specifications in
section 10.6.16 are met across the entire pitch angle range.
10.7 Recalibration. Recalibrate the probe using the procedures in
section 10 either within 12 months of its first field use after its most
recent calibration or after 10 field tests (as defined in section 3.4),
whichever occurs later. In addition, whenever there is visible damage to
the 3-D head, the probe shall be recalibrated before it is used again.
10.8 Calibration of pressure-measuring devices used in field tests.
Before its initial use in a field test, calibrate each pressure-
measuring device (except those used exclusively for yaw nulling) using
the three-point calibration procedure described in section 10.3.3. The
device shall be recalibrated according to the procedure in section
10.3.3 no later than 90 days after its first field use following its
most recent calibration. At the discretion of the tester, more frequent
calibrations (e.g., after a field test) may be performed. No
adjustments, other than adjustments to the zero setting, shall be made
to the device between calibrations.
10.8.1 Post-test calibration check. A single-point calibration check
shall be performed on each pressure-measuring device after completion of
each field test. At the discretion of the tester, more frequent single-
point calibration checks (e.g., after one or more field test runs) may
be performed. It is recommended that the post-test check be performed
before leaving the field test site. The check shall be performed at a
pressure between 50 and 90 percent of full scale by taking a common
pressure reading with the tested device and a reference pressure-
measuring device (as described in section 6.4.4) or by challenging the
tested device with a reference pressure source (as described in section
6.4.4) or by performing an equivalent check using a reference device
approved by the Administrator.
10.8.2 Acceptance criterion. At the selected pressure setting, the
pressure readings made using the reference device and the tested device
shall agree to within 3 percent of

[[Page 64]]

full scale of the tested device or 0.8 mm H2O (0.03 in.
H2O), whichever is less restrictive. If this specification is
met, the test data collected during the field test are valid. If the
specification is not met, all test data collected since the last
successful calibration or calibration check are invalid and shall be
repeated using a pressure-measuring device with a current, valid
calibration. Any device that fails the calibration check shall not be
used in a field test until a successful recalibration is performed
according to the procedures in section 10.3.3.
10.9 Temperature Gauges. Same as Method 2, section 4.3. The
alternative thermocouple calibration procedures outlined in Emission
Measurement Center (EMC) Approved Alternative Method (ALT-011)
``Alternative Method 2 Thermocouple Calibration Procedure'' may be
performed. Temperature gauges shall be calibrated no more than 30 days
prior to the start of a field test or series of field tests and
recalibrated no more than 30 days after completion of a field test or
series of field tests.
10.10 Barometer. Same as Method 2, section 4.4. The barometer shall
be calibrated no more than 30 days prior to the start of a field test or
series of field tests.

11.0 Analytical Procedure

Sample collection and analysis are concurrent for this method (see
section 8.0).

12.0 Data Analysis and Calculations

These calculations use the measured yaw angle, derived pitch angle,
and the differential pressure and temperature measurements at individual
traverse points to derive the axial flue gas velocity (va(i))
at each of those points. The axial velocity values at all traverse
points that comprise a full stack or duct traverse are then averaged to
obtain the average axial flue gas velocity (va (avg)). Round
off figures only in the final calculation of reported values.
12.1 Nomenclature

A=Cross-sectional area of stack or duct, m \2\ (ft \2\).
Bws=Water vapor in the gas stream (from Method 4 or
alternative), proportion by volume.
Kp Conversion factor (a constant),
[GRAPHIC] [TIFF OMITTED] TR14MY99.052

for the metric system, and
[GRAPHIC] [TIFF OMITTED] TR14MY99.053

for the English system.

Md=Molecular weight of stack or duct gas, dry basis (see
section 8.13), g/g-mole (lb/lb-mole).
Ms=Molecular weight of stack or duct gas, wet basis, g/g-mole
(lb/lb-mole).
[GRAPHIC] [TIFF OMITTED] TR14MY99.054

Pbar=Barometric pressure at measurement site, mm Hg (in. Hg).
Pg=Stack or duct static pressure, mm H2O (in.
H2O).
Ps=Absolute stack or duct pressure, mm Hg (in. Hg),
[GRAPHIC] [TIFF OMITTED] TR14MY99.055

Pstd=Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
13.6=Conversion from mm H2O (in. H2O) to mm Hg
(in. Hg).
Qsd=Average dry-basis volumetric stack or duct gas flow rate
corrected to standard conditions, dscm/hr (dscf/hr).
Qsw=Average wet-basis volumetric stack or duct gas flow rate
corrected to standard conditions, wscm/hr (wscf/hr).
Ts(avg)=Average absolute stack or duct gas temperature across
all traverse points.
ts(i)=Stack or duct gas temperature, C (F), at traverse point
i.
Ts(i)=Absolute stack or duct gas temperature, K (R), at
traverse point i,
[GRAPHIC] [TIFF OMITTED] TR14MY99.056

for the metric system, and
[GRAPHIC] [TIFF OMITTED] TR14MY99.057

for the English system.
Tstd=Standard absolute temperature, 293[deg]K (528[deg]R).
F1(i)=Pitch angle ratio, applicable at traverse point i,
dimensionless.
F2(i)=3-D probe velocity calibration coefficient, applicable
at traverse point i, dimensionless.
(P4-P5)i=Pitch differential pressure of
stack or duct gas flow, mm H2O (in. H2O), at
traverse point i.
(P1-P2)i=Velocity head (differential
pressure) of stack or duct gas flow, mm H2O (in.
H2O), at traverse point i.
va(i)=Reported stack or duct gas axial velocity, m/sec (ft/
sec), at traverse point i.
va(avg)=Average stack or duct gas axial velocity, m/sec (ft/
sec), across all traverse points.
3,600=Conversion factor, sec/hr.
18.0=Molecular weight of water, g/g-mole (lb/lb-mole).
[theta]y(i)=Yaw angle, degrees, at traverse point i.
[theta]p(i)=Pitch angle, degrees, at traverse point i.
n=Number of traverse points.

12.2 Traverse Point Velocity Calculations. Perform the following
calculations from the

[[Page 65]]

measurements obtained at each traverse point.
12.2.1 Selection of calibration curves. Select calibration curves as
described in section 10.6.1.
12.2.2 Traverse point pitch angle ratio. Use Equation 2F-1, as
described in section 10.6.2, to calculate the pitch angle ratio,
F1(i), at each traverse point.
12.2.3 Pitch angle. Use the pitch angle ratio, F1(i), to
derive the pitch angle, [theta]p(i), at traverse point i from
the F1 versus pitch angle calibration curve generated under
section 10.6.16.1.
12.2.4 Velocity calibration coefficient. Use the pitch angle,
[theta]p(i), to obtain the probe velocity calibration
coefficient, F2(i), at traverse point i from the ``velocity
pressure calibration curve,'' i.e., the F2 versus pitch angle
calibration curve generated under section 10.6.16.1.
12.2.5 Axial velocity. Use the following equation to calculate the
axial velocity, va(i), from the differential pressure
(P1-P2)i and yaw angle,
[theta]y(i), measured at traverse point i and the previously
calculated values for the velocity calibration coefficient,
F2(i), absolute stack or duct standard temperature,
Ts(i), absolute stack or duct pressure, Ps,
molecular weight, Ms, and pitch angle,
``[theta]p(i).
[GRAPHIC] [TIFF OMITTED] TR14MY99.058

12.2.6 Handling multiple measurements at a traverse point. For
pressure or temperature devices that take multiple measurements at a
traverse point, the multiple measurements (or where applicable, their
square roots) may first be averaged and the resulting average values
used in the equations above. Alternatively, the individual measurements
may be used in the equations above and the resulting multiple calculated
values may then be averaged to obtain a single traverse point value.
With either approach, all of the individual measurements recorded at a
traverse point must be used in calculating the applicable traverse point
value.
12.3 Average Axial Velocity in Stack or Duct. Use the reported
traverse point axial velocity in the following equation.
[GRAPHIC] [TIFF OMITTED] TR14MY99.059

12.4 Acceptability of Results. The test results are acceptable and
the calculated value of va(avg) may be reported as the
average axial velocity for the test run if the conditions in either
section 12.4.1 or 12.4.2 are met.
12.4.1 The calibration curves were generated at nominal velocities
of 18.3 m/sec and 27.4 m/sec (60 ft/sec and 90 ft/sec).
12.4.2 The calibration curves were generated at nominal velocities
other than 18.3 m/sec and 27.4 m/sec (60 ft/sec and 90 ft/sec), and the
value of va(avg) obtained using Equation 2F-9 is less than or
equal to at least one of the nominal velocities used to derive the
F1 and F2 calibration curves.
12.4.3 If the conditions in neither section 12.4.1 nor section
12.4.2 are met, the test results obtained in Equation 2F-9 are not
acceptable, and the steps in sections 12.2 and 12.3 must be repeated
using a set of F1 and F2 calibration curves that
satisfies the conditions specified in section 12.4.1 or 12.4.2.
12.5 Average Gas Wet Volumetric Flow Rate in Stack or Duct. Use the
following equation to compute the average volumetric flow rate on a wet
basis.
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12.6 Average Gas Dry Volumetric Flow Rate in Stack or Duct. Use the
following equation to compute the average volumetric flow rate on a dry
basis.

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13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Reporting

16.1 Field Test Reports. Field test reports shall be submitted to
the Agency according to applicable regulatory requirements. Field test
reports should, at a minimum, include the following elements.
16.1.1 Description of the source. This should include the name and
location of the test site, descriptions of the process tested, a
description of the combustion source, an accurate diagram of stack or
duct cross-sectional area at the test site showing the dimensions of the
stack or duct, the location of the test ports, and traverse point
locations and identification numbers or codes. It should also include a
description and diagram of the stack or duct layout, showing the
distance of the test location from the nearest upstream and downstream
disturbances and all structural elements (including breachings, baffles,
fans, straighteners, etc.) affecting the flow pattern. If the source and
test location descriptions have been previously submitted to the Agency
in a document (e.g., a monitoring plan or test plan), referencing the
document in lieu of including this information in the field test report
is acceptable.
16.1.2 Field test procedures. These should include a description of
test equipment and test procedures. Testing conventions, such as
traverse point numbering and measurement sequence (e.g., sampling from
center to wall, or wall to center), should be clearly stated. Test port
identification and directional reference for each test port should be
included on the appropriate field test data sheets.
16.1.3 Field test data.
16.1.3.1 Summary of results. This summary should include the dates
and times of testing and the average axial gas velocity and the average
flue gas volumetric flow results for each run and tested condition.
16.1.3.2 Test data. The following values for each traverse point
should be recorded and reported:

(a) P1-P2 and P4-P5
differential pressures
(b) Stack or duct gas temperature at traverse point i
(ts(i))
(c) Absolute stack or duct gas temperature at traverse point i
(Ts(i))
(d) Yaw angle at each traverse point i ([theta]y(i))
(e) Pitch angle at each traverse point i ([theta]p(i))
(f) Stack or duct gas axial velocity at traverse point i
(va(i))

16.1.3.3 The following values should be reported once per run:

(a) Water vapor in the gas stream (from Method 4 or alternative),
proportion by volume (Bws), measured at the frequency
specified in the applicable regulation
(b) Molecular weight of stack or duct gas, dry basis (Md)
(c) Molecular weight of stack or duct gas, wet basis (Ms)
(d) Stack or duct static pressure (Pg)
(e) Absolute stack or duct pressure (Ps)
(f) Carbon dioxide concentration in the flue gas, dry basis (\0/
0\d CO2)
(g) Oxygen concentration in the flue gas, dry basis (\0/
0\d O2)
(h) Average axial stack or duct gas velocity (va(avg))
across all traverse points
(i) Gas volumetric flow rate corrected to standard conditions, dry
or wet basis as required by the applicable regulation (Qsd or
Qsw)

16.1.3.4 The following should be reported once per complete set of test
runs:

(a) Cross-sectional area of stack or duct at the test location (A)
(b) Measurement system response time (sec)
(c) Barometric pressure at measurement site (Pbar)

16.1.4 Calibration data. The field test report should include
calibration data for all probes and test equipment used in the field
test. At a minimum, the probe calibration data reported to the Agency
should include the following:

(a) Date of calibration
(b) Probe type
(c) Probe identification number(s) or code(s)
(d) Probe inspection sheets
(e) Pressure measurements and intermediate calculations of
F1 and F2 at each pitch angle used to obtain
calibration curves in accordance with section 10.6 of this method
(f) Calibration curves (in graphic or equation format) obtained in
accordance with sections 10.6.11 of this method
(g) Description and diagram of wind tunnel used for the calibration,
including dimensions of cross-sectional area and position and size of
the test section
(h) Documentation of wind tunnel qualification tests performed in
accordance with section 10.1 of this method

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16.1.5 Quality Assurance. Specific quality assurance and quality
control procedures used during the test should be described.

17.0 Bibliography

(1) 40 CFR Part 60, Appendix A, Method 1--Sample and velocity
traverses for stationary sources.
(2) 40 CFR Part 60, Appendix A, Method 2H--Determination of stack
gas velocity taking into account velocity decay near the stack wall.
(3) 40 CFR Part 60, Appendix A, Method 2--Determination of stack gas
velocity and volumetric flow rate (Type S pitot tube).
(4) 40 CFR Part 60, Appendix A, Method 3--Gas analysis for carbon
dioxide, oxygen, excess air, and dry molecular weight.
(5) 40 CFR Part 60, Appendix A, Method 3A--Determination of oxygen
and carbon dioxide concentrations in emissions from stationary sources
(instrumental analyzer procedure).
(6) 40 CFR Part 60, Appendix A, Method 4--Determination of moisture
content in stack gases.
(7) Emission Measurement Center (EMC) Approved Alternative Method
(ALT-011) ``Alternative Method 2 Thermocouple Calibration Procedure.''
(8) Electric Power Research Institute, Interim Report EPRI TR-
106698, ``Flue Gas Flow Rate Measurement Errors,'' June 1996.
(9) Electric Power Research Institute, Final Report EPRI TR-108110,
``Evaluation of Heat Rate Discrepancy from Continuous Emission
Monitoring Systems,'' August 1997.
(10) Fossil Energy Research Corporation, Final Report, ``Velocity
Probe Tests in Non-axial Flow Fields,'' November 1998, Prepared for the
U.S. Environmental Protection Agency.
(11) Fossil Energy Research Corporation, ``Additional Swirl Tunnel
Tests: E-DAT and T-DAT Probes,'' February 24, 1999, Technical Memorandum
Prepared for U.S. Environmental Protection Agency, P.O. No. 7W-1193-
NALX.
(12) Massachusetts Institute of Technology, Report WBWT-TR-1317,
``Calibration of Eight Wind Speed Probes Over a Reynolds Number Range of
46,000 to 725,000 Per Foot, Text and Summary Plots,'' Plus appendices,
October 15, 1998, Prepared for The Cadmus Group, Inc.
(13) National Institute of Standards and Technology, Special
Publication 250, ``NIST Calibration Services Users Guide 1991,'' Revised
October 1991, U.S. Department of Commerce, p. 2.
(14) National Institute of Standards and Technology, 1998, ``Report
of Special Test of Air Speed Instrumentation, Four Prandtl Probes, Four
S-Type Probes, Four French Probes, Four Modified Kiel Probes,'' Prepared
for the U.S. Environmental Protection Agency under IAG
DW13938432-01-0.
(15) National Institute of Standards and Technology, 1998, ``Report
of Special Test of Air Speed Instrumentation, Five Autoprobes,''
Prepared for the U.S. Environmental Protection Agency under IAG
DW13938432-01-0.
(16) National Institute of Standards and Technology, 1998, ``Report
of Special Test of Air Speed Instrumentation, Eight Spherical Probes,''
Prepared for the U.S. Environmental Protection Agency under IAG
DW13938432-01-0.
(17) National Institute of Standards and Technology, 1998, ``Report
of Special Test of Air Speed Instrumentation, Four DAT Probes,''
Prepared for the U.S. Environmental Protection Agency under IAG
DW13938432-01-0.
(18) Norfleet, S.K., ``An Evaluation of Wall Effects on Stack Flow
Velocities and Related Overestimation Bias in EPA's Stack Flow Reference
Methods,'' EPRI CEMS User's Group Meeting, New Orleans, Louisiana, May
13-15, 1998.
(19) Page, J.J., E.A. Potts, and R.T. Shigehara, ``3-D Pitot Tube
Calibration Study,'' EPA Contract No. 68-D1-0009, Work Assignment No. I-
121, March 11, 1993.
(20) Shigehara, R.T., W.F. Todd, and W.S. Smith, ``Significance of
Errors in Stack Sampling Measurements,'' Presented at the Annual Meeting
of the Air Pollution Control Association, St. Louis, Missouri, June 14-
19, 1970.
(21) The Cadmus Group, Inc., May 1999, ``EPA Flow Reference Method
Testing and Analysis: Findings Report,'' EPA/430-R-99-009.
(22) The Cadmus Group, Inc., 1998, ``EPA Flow Reference Method
Testing and Analysis: Data Report, Texas Utilities, DeCordova Steam
Electric Station, Volume I: Test Description and Appendix A (Data
Distribution Package),'' EPA/430-R-98-015a.
(23) The Cadmus Group, Inc., 1998, ``EPA Flow Reference Method
Testing and Analysis: Data Report, Texas Utilities, Lake Hubbard Steam
Electric Station, Volume I: Test Description and Appendix A (Data
Distribution Package),'' EPA/430-R-98-017a.
(24) The Cadmus Group, Inc., 1998, ``EPA Flow Reference Method
Testing and Analysis: Data Report, Pennsylvania Electric Co., G.P.U.
Genco Homer City Station: Unit 1, Volume I: Test Description and
Appendix A (Data Distribution Package),'' EPA/430-R-98-018a.
(25) The Cadmus Group, Inc., 1997, ``EPA Flow Reference Method
Testing and Analysis: Wind Tunnel Experimental Results,'' EPA/430-R-97-
013.

18.0 Annexes

Annex A, C, and D describe recommended procedures for meeting
certain provisions in sections 8.3, 10.4, and 10.5 of this method. Annex
B describes procedures to be followed

[[Page 68]]

when using the protractor wheel and pointer assembly to measure yaw
angles, as provided under section 8.9.1.
18.1 Annex A--Rotational Position Check. The following are
recommended procedures that may be used to satisfy the rotational
position check requirements of section 8.3 of this method and to
determine the angle-measuring device rotational offset RADO.
18.1.1 Rotational position check with probe outside stack. Where
physical constraints at the sampling location allow full assembly of the
probe outside the stack and insertion into the test port, the following
procedures should be performed before the start of testing. Two angle-
measuring devices that meet the specifications in section 6.2.1 or 6.2.3
are required for the rotational position check. An angle measuring
device whose position can be independently adjusted (e.g., by means of a
set screw) after being locked into position on the probe sheath shall
not be used for this check unless the independent adjustment is set so
that the device performs exactly like a device without the capability
for independent adjustment. That is, when aligned on the probe such a
device must give the same reading as a device that does not have the
capability of being independently adjusted. With the fully assembled
probe (including probe shaft extensions, if any) secured in a horizontal
position, affix one yaw angle-measuring device to the probe sheath and
lock it into position on the reference scribe line specified in section
6.1.6.1. Position the second angle-measuring device using the procedure
in section 18.1.1.1 or 18.1.1.2.
18.1.1.1 Marking procedure. The procedures in this section should be
performed at each location on the fully assembled probe where the yaw
angle-measuring device will be mounted during the velocity traverse.
Place the second yaw angle-measuring device on the main probe sheath (or
extension) at the position where a yaw angle will be measured during the
velocity traverse. Adjust the position of the second angle-measuring
device until it indicates the same angle (1[deg])
as the reference device, and affix the second device to the probe sheath
(or extension). Record the angles indicated by the two angle-measuring
devices on a form similar to Table 2F-2. In this position, the second
angle-measuring device is considered to be properly positioned for yaw
angle measurement. Make a mark, no wider than 1.6 mm (1/16 in.), on the
probe sheath (or extension), such that the yaw angle-measuring device
can be re-affixed at this same properly aligned position during the
velocity traverse.
18.1.1.2 Procedure for probe extensions with scribe lines. If,
during a velocity traverse the angle-measuring device will be affixed to
a probe extension having a scribe line as specified in section 6.1.6.2,
the following procedure may be used to align the extension's scribe line
with the reference scribe line instead of marking the extension as
described in section 18.1.1.1. Attach the probe extension to the main
probe. Align and lock the second angle-measuring device on the probe
extension's scribe line. Then, rotate the extension until both measuring
devices indicate the same angle (1[deg]). Lock the
extension at this rotational position. Record the angles indicated by
the two angle-measuring devices on a form similar to Table 2F-2. An
angle-measuring device may be aligned at any position on this scribe
line during the velocity traverse, if the scribe line meets the
alignment specification in section 6.1.6.3.
18.1.1.3 Post-test rotational position check. If the fully assembled
probe includes one or more extensions, the following check should be
performed immediately after the completion of a velocity traverse. At
the discretion of the tester, additional checks may be conducted after
completion of testing at any sample port. Without altering the alignment
of any of the components of the probe assembly used in the velocity
traverse, secure the fully assembled probe in a horizontal position.
Affix an angle-measuring device at the reference scribe line specified
in section 6.1.6.1. Use the other angle-measuring device to check the
angle at each location where the device was checked prior to testing.
Record the readings from the two angle-measuring devices.
18.1.2 Rotational position check with probe in stack. This section
applies only to probes that, due to physical constraints, cannot be
inserted into the test port as fully assembled with all necessary
extensions needed to reach the inner-most traverse point(s).
18.1.2.1 Perform the out-of-stack procedure in section 18.1.1 on the
main probe and any attached extensions that will be initially inserted
into the test port.
18.1.2.2 Use the following procedures to perform additional
rotational position check(s) with the probe in the stack, each time a
probe extension is added. Two angle-measuring devices are required. The
first of these is the device that was used to measure yaw angles at the
preceding traverse point, left in its properly aligned measurement
position. The second angle-measuring device is positioned on the added
probe extension. Use the applicable procedures in section 18.1.1.1 or
18.1.1.2 to align, adjust, lock, and mark (if necessary) the position of
the second angle-measuring device to within 1[deg]
of the first device. Record the readings of the two devices on a form
similar to Table 2F-2.
18.1.2.3 The procedure in section 18.1.2.2 should be performed at
the first port where measurements are taken. The procedure should be
repeated each time a probe extension is re-attached at a subsequent
port, unless the probe extensions are designed to be locked into a
mechanically fixed rotational

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position (e.g., through use of interlocking grooves), which can be
reproduced from port to port as specified in section 8.3.5.2.
18.2 Annex B--Angle Measurement Protocol for Protractor Wheel and
Pointer Device. The following procedure shall be used when a protractor
wheel and pointer assembly, such as the one described in section 6.2.2
and illustrated in Figure 2F-7 is used to measure the yaw angle of flow.
With each move to a new traverse point, unlock, re-align, and re-lock
the probe, angle-pointer collar, and protractor wheel to each other. At
each such move, particular attention is required to ensure that the
scribe line on the angle pointer collar is either aligned with the
reference scribe line on the main probe sheath or is at the rotational
offset position established under section 8.3.1. The procedure consists
of the following steps:
18.2.1 Affix a protractor wheel to the entry port for the test probe
in the stack or duct.
18.2.2 Orient the protractor wheel so that the 0[deg] mark
corresponds to the longitudinal axis of the stack or duct. For stacks,
vertical ducts, or ports on the side of horizontal ducts, use a digital
inclinometer meeting the specifications in section 6.2.1 to locate the
0[deg] orientation. For ports on the top or bottom of horizontal ducts,
identify the longitudinal axis at each test port and permanently mark
the duct to indicate the 0[deg] orientation. Once the protractor wheel
is properly aligned, lock it into position on the test port.
18.2.3 Move the pointer assembly along the probe sheath to the
position needed to take measurements at the first traverse point. Align
the scribe line on the pointer collar with the reference scribe line or
at the rotational offset position established under section 8.3.1.
Maintaining this rotational alignment, lock the pointer device onto the
probe sheath. Insert the probe into the entry port to the depth needed
to take measurements at the first traverse point.
18.2.4 Perform the yaw angle determination as specified in sections
8.9.3 and 8.9.4 and record the angle as shown by the pointer on the
protractor wheel. Then, take velocity pressure and temperature
measurements in accordance with the procedure in section 8.9.5. Perform
the alignment check described in section 8.9.6.
18.2.5 After taking velocity pressure measurements at that traverse
point, unlock the probe from the collar and slide the probe through the
collar to the depth needed to reach the next traverse point.
18.2.6 Align the scribe line on the pointer collar with the
reference scribe line on the main probe or at the rotational offset
position established under section 8.3.1. Lock the collar onto the
probe.
18.2.7 Repeat the steps in sections 18.2.4 through 18.2.6 at the
remaining traverse points accessed from the current stack or duct entry
port.
18.2.8 After completing the measurement at the last traverse point
accessed from a port, verify that the orientation of the protractor
wheel on the test port has not changed over the course of the traverse
at that port. For stacks, vertical ducts, or ports on the side of
horizontal ducts, use a digital inclinometer meeting the specifications
in section 6.2.1 to check the rotational position of the 0[deg] mark on
the protractor wheel. For ports on the top or bottom of horizontal
ducts, observe the alignment of the angle wheel 0[deg] mark relative to
the permanent 0[deg] mark on the duct at that test port. If these
observed comparisons exceed 2[deg] of 0[deg], all
angle and pressure measurements taken at that port since the protractor
wheel was last locked into position on the port shall be repeated.
18.2.9 Move to the next stack or duct entry port and repeat the
steps in sections 18.2.1 through 18.2.8.
18.3 Annex C--Guideline for Reference Scribe Line Placement. Use of
the following guideline is recommended to satisfy the requirements of
section 10.4 of this method. The rotational position of the reference
scribe line should be either 90[deg] or 180[deg] from the probe's impact
pressure port.
18.4 Annex D--Determination of Reference Scribe Line Rotational
Offset. The following procedures are recommended for determining the
magnitude and sign of a probe's reference scribe line rotational offset,
RSLO. Separate procedures are provided for two types of
angle-measuring devices: digital inclinometers and protractor wheel and
pointer assemblies.
18.4.1 Perform the following procedures on the main probe with all
devices that will be attached to the main probe in the field [such as
thermocouples or resistance temperature detectors (RTDs)] that may
affect the flow around the probe head. Probe shaft extensions that do
not affect flow around the probe head need not be attached during
calibration.
18.4.2 The procedures below assume that the wind tunnel duct used
for probe calibration is horizontal and that the flow in the calibration
wind tunnel is axial as determined by the axial flow verification check
described in section 10.1.2. Angle-measuring devices are assumed to
display angles in alternating 0[deg] to 90[deg] and 90[deg] to 0[deg]
intervals. If angle-measuring devices with other readout conventions are
used or if other calibration wind tunnel duct configurations are used,
make the appropriate calculational corrections.
18.4.2.1 Position the angle-measuring device in accordance with one
of the following procedures.
18.4.2.1.1 If using a digital inclinometer, affix the calibrated
digital inclinometer to

[[Page 70]]

the probe. If the digital inclinometer can be independently adjusted
after being locked into position on the probe sheath (e.g., by means of
a set screw), the independent adjustment must be set so that the device
performs exactly like a device without the capability for independent
adjustment. That is, when aligned on the probe the device must give the
same readings as a device that does not have the capability of being
independently adjusted. Either align it directly on the reference scribe
line or on a mark aligned with the scribe line determined according to
the procedures in section 18.1.1.1. Maintaining this rotational
alignment, lock the digital inclinometer onto the probe sheath.
18.4.2.1.2 If using a protractor wheel and pointer device, orient
the protractor wheel on the test port so that the 0[deg] mark is aligned
with the longitudinal axis of the wind tunnel duct. Maintaining this
alignment, lock the wheel into place on the wind tunnel test port. Align
the scribe line on the pointer collar with the reference scribe line or
with a mark aligned with the reference scribe line, as determined under
section 18.1.1.1. Maintaining this rotational alignment, lock the
pointer device onto the probe sheath.
18.4.2.2 Zero the pressure-measuring device used for yaw nulling.
18.4.2.3 Insert the probe assembly into the wind tunnel through the
entry port, positioning the probe's impact port at the calibration
location. Check the responsiveness of the pressure-measuring device to
probe rotation, taking corrective action if the response is
unacceptable.
18.4.2.4 Ensure that the probe is in a horizontal position using a
carpenter's level.
18.4.2.5 Rotate the probe either clockwise or counterclockwise until
a yaw null (P2=P3) is obtained.
18.4.2.6 Read and record the value of [theta]null, the
angle indicated by the angle-measuring device at the yaw-null position.
Record the angle reading on a form similar to Table 2F-6. Do not
associate an algebraic sign with this reading.
18.4.2.7 Determine the magnitude and algebraic sign of the reference
scribe line rotational offset, RSLO. The magnitude of
RSLO will be equal to either [theta]null or
(90[deg]-[theta]null), depending on the angle-measuring
device used. (See Table 2F-7 for a summary.) The algebraic sign of
RSLO will either be positive, if the rotational position of
the reference scribe line is clockwise, or negative, if counterclockwise
with respect to the probe's yaw-null position. Figure 2F-13 illustrates
how the magnitude and sign of RSLO are determined.
18.4.2.8 Perform the steps in sections 18.4.2.3 through 18.4.2.7
twice at each of the two calibration velocities selected for the probe
under section 10.6. Record the values of RSLO in a form
similar to Table 2F-6.
18.4.2.9 The average of all RSLO values is the reference
scribe line rotational offset for the probe.

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[36 FR 24877, Dec. 23, 1971]

Editorial Note: For Federal Register citations affecting part 60,
appendix A-1, see the List of CFR Sections Affected, which appears in
the Finding Aids section of the printed volume and on GPO Access.

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