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.A5]

[Page 340]

Appendix A-5 to Part 60--Test Methods 11 through 15A

Method 11--Determination of hydrogen sulfide content of fuel gas streams
in petroleum refineries
Method 12--Determination of inorganic lead emissions from stationary
sources
Method 13A--Determination of total fluoride emissions from stationary
sources--SPADNS zirconium lake method
Method 13B--Determination of total fluoride emissions from stationary
sources--Specific ion electrode method
Method 14--Determination of fluoride emissions from potroom roof
monitors for primary aluminum plants
Method 14A-- Determination of Total Fluoride Emissions from Selected
Sources at Primary Aluminum Production Facilities
Method 15--Determination of hydrogen sulfide, carbonyl sulfide, and
carbon disulfide emissions from stationary sources
Method 15A--Determination of total reduced sulfur emissions from sulfur
recovery plants in petroleum refineries
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 11--Determination of Hydrogen Sulfide Content of Fuel Gas Streams
in Petroleum Refineries

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Hydrogen sulfide (H2S)........... 7783-06-4 8 mg/m\3\--740 mg/
m\3\, (6 ppm--520
ppm).
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of the H2S content of fuel gas streams at petroleum
refineries.
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 A sample is extracted from a source and passed through a series
of midget impingers containing a cadmium sulfate (CdSO4)
solution; H2S is absorbed, forming cadmium sulfide (CdS). The
latter compound is then measured iodometrically.

3.0 Definitions [Reserved]

4.0 Interferences

4.1 Any compound that reduces iodine (I2) or oxidizes the
iodide ion will interfere in this procedure, provided it is collected in
the CdSO4 impingers. Sulfur dioxide in concentrations of up
to 2,600 mg/m\3\ is removed with an impinger containing a hydrogen
peroxide (H2O2) solution. Thiols precipitate with

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H2S. In the absence of H2S, only traces of thiols
are collected. When methane-and ethane-thiols at a total level of 300
mg/m\3\ are present in addition to H2S, the results vary from
2 percent low at an H2S concentration of 400 mg/m\3\ to 14
percent high at an H2S concentration of 100 mg/m\3\. Carbonyl
sulfide at a concentration of 20 percent does not interfere. Certain
carbonyl-containing compounds react with iodine and produce recurring
end points. However, acetaldehyde and acetone at concentrations of 1 and
3 percent, respectively, do not interfere.
4.2 Entrained H2O2 produces a negative
interference equivalent to 100 percent of that of an equimolar quantity
of H2S. Avoid the ejection of H2O2 into
the CdSO4 impingers.

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.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide. Irritating to eyes, skin, nose, and lungs.
30% H2O2 is a strong oxidizing agent. Avoid
contact with skin, eyes, and combustible material. Wear gloves when
handling.
5.2.2 Hydrochloric Acid. Highly toxic. Vapors are highly irritating
to eyes, skin, nose, and lungs, causing severe damage. May cause
bronchitis, pneumonia, or edema of lungs. Exposure to concentrations of
0.13 to 0.2 percent can be lethal in minutes. Will react with metals,
producing hydrogen.

6.0 Equipment and Supplies

6.1 Sample Collection. The following items are needed for sample
collection:
6.1.1 Sampling Line. Teflon tubing, 6- to 7- mm (\1/4\-in.) ID, to
connect the sampling train to the sampling valve.
6.1.2 Impingers. Five midget impingers, each with 30-ml capacity.
The internal diameter of the impinger tip must be 1 mm 0.05 mm. The impinger tip must be positioned 4 to 6 mm
from the bottom of the impinger.
6.1.3 Tubing. Glass or Teflon connecting tubing for the impingers.
6.1.4 Ice Water Bath. To maintain absorbing solution at a low
temperature.
6.1.5 Drying Tube. Tube packed with 6- to 16- mesh indicating-type
silica gel, or equivalent, to dry the gas sample and protect the meter
and pump. If the silica gel has been used previously, dry at 175 [deg]C
(350 [deg]F) for 2 hours. New silica gel may be used as received.
Alternatively, other types of desiccants (equivalent or better) may be
used, subject to approval of the Administrator.

Note: Do not use more than 30 g of silica gel. Silica gel adsorbs
gases such as propane from the fuel gas stream, and use of excessive
amounts of silica gel could result in errors in the determination of
sample volume.

6.1.6 Sampling Valve. Needle valve, or equivalent, to adjust gas
flow rate. Stainless steel or other corrosion-resistant material.
6.1.7 Volume Meter. Dry gas meter (DGM), sufficiently accurate to
measure the sample volume within 2 percent, calibrated at the selected
flow rate (about 1.0 liter/min) and conditions actually encountered
during sampling. The meter shall be equipped with a temperature sensor
(dial thermometer or equivalent) capable of measuring temperature to
within 3 [deg]C (5.4 [deg]F). The gas meter should have a petcock, or
equivalent, on the outlet connector which can be closed during the leak-
check. Gas volume for one revolution of the meter must not be more than
10 liters.
6.1.8 Rate Meter. Rotameter, or equivalent, to measure flow rates in
the range from 0.5 to 2 liters/min (1 to 4 ft\3\/hr).
6.1.9 Graduated Cylinder. 25-ml size.
6.1.10 Barometer. Mercury, aneroid, or other barometer capable of
measuring atmospheric pressure to within 2.5 mm Hg (0.1 in. Hg). 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 the sampling point
shall be applied at a rate of minus 2.5 mm Hg (0.1 in Hg) per 30 m (100
ft) elevation increase or vice-versa for elevation decrease.
6.1.11 U-tube Manometer. 0-; to 30-cm water column, for leak-check
procedure.
6.1.12 Rubber Squeeze Bulb. To pressurize train for leak-check.
6.1.13 Tee, Pinchclamp, and Connecting Tubing. For leak-check.
6.1.14 Pump. Diaphragm pump, or equivalent. Insert a small surge
tank between the pump and rate meter to minimize the pulsation effect of
the diaphragm pump on the rate meter. The pump is used for the air purge
at the end of the sample run; the pump is not ordinarily used during
sampling, because fuel gas streams are usually sufficiently pressurized
to force sample gas through the train at the required flow rate.

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The pump need not be leak-free unless it is used for sampling.
6.1.15 Needle Valve or Critical Orifice. To set air purge flow to 1
liter/min.
6.1.16 Tube Packed with Active Carbon. To filter air during purge.
6.1.17 Volumetric Flask. One 1000-ml.
6.1.18 Volumetric Pipette. One 15-ml.
6.1.19 Pressure-Reduction Regulator. Depending on the sampling
stream pressure, a pressure-reduction regulator may be needed to reduce
the pressure of the gas stream entering the Teflon sample line to a safe
level.
6.1.20 Cold Trap. If condensed water or amine is present in the
sample stream, a corrosion-resistant cold trap shall be used immediately
after the sample tap. The trap shall not be operated below 0 [deg]C (32
[deg]F) to avoid condensation of C3 or C4
hydrocarbons.
6.2 Sample Recovery. The following items are needed for sample
recovery:
6.2.1 Sample Container. Iodine flask, glass-stoppered, 500-ml size.
6.2.2 Volumetric Pipette. One 50-ml.
6.2.3 Graduated Cylinders. One each 25- and 250-ml.
6.2.4 Erlenmeyer Flasks. 125-ml.
6.2.5 Wash Bottle.
6.2.6 Volumetric Flasks. Three 1000-ml.
6.3 Sample Analysis. The following items are needed for sample
analysis:
6.3.1 Flask. Glass-stoppered iodine flask, 500-ml.
6.3.2 Burette. 50-ml.
6.3.3 Erlenmeyer Flask. 125-ml.
6.3.4 Volumetric Pipettes. One 25-ml; two each 50- and 100-ml.
6.3.5 Volumetric Flasks. One 1000-ml; two 500-ml.
6.3.6 Graduated Cylinders. One each 10- and 100-ml.

7.0 Reagents and Standards

Note: Unless otherwise indicated, it is intended that all reagents
conform to the specifications established by the Committee on Analytical
Reagents of the American Chemical Society, where such specifications are
available. Otherwise, use the best available grade.

7.1 Sample Collection. The following reagents are required for
sample collection:
7.1.1 CdSO4 Absorbing Solution. Dissolve 41 g of
3CdSO48H2O and 15 ml of 0.1 M sulfuric acid in a
1-liter volumetric flask that contains approximately \3/4\ liter of
water. Dilute to volume with deionized, distilled water. Mix thoroughly.
The pH should be 3 0.1. Add 10 drops of Dow-
Corning Antifoam B. Shake well before use. This solution is stable for
at least one month. If Antifoam B is not used, a more labor-intensive
sample recovery procedure is required (see Section 11.2).
7.1.2 Hydrogen Peroxide, 3 Percent. Dilute 30 percent
H2O2 to 3 percent as needed. Prepare fresh daily.
7.1.3 Water. Deionized distilled to conform to ASTM D 1193-77 or 91,
Type 3 (incorporated by reference--see Sec. 60.17). The
KMnO4 test for oxidizable organic matter may be omitted when
high concentrations of organic matter are not expected to be present.
7.2 Sample Recovery. The following reagents are needed for sample
recovery:
7.2.1 Water. Same as Section 7.1.3.
7.2.2 Hydrochloric Acid (HCl) Solution, 3 M. Add 240 ml of
concentrated HCl (specific gravity 1.19) to 500 ml of water in a 1-liter
volumetric flask. Dilute to 1 liter with water. Mix thoroughly.
7.2.3 Iodine (I2) Solution, 0.1 N. Dissolve 24 g of
potassium iodide (KI) in 30 ml of water. Add 12.7 g of resublimed iodine
(I2) to the KI solution. Shake the mixture until the
I2 is completely dissolved. If possible, let the solution
stand overnight in the dark. Slowly dilute the solution to 1 liter with
water, with swirling. Filter the solution if it is cloudy. Store
solution in a brown-glass reagent bottle.
7.2.4 Standard I2 Solution, 0.01 N. Pipette 100.0 ml of
the 0.1 N iodine solution into a 1-liter volumetric flask, and dilute to
volume with water. Standardize daily as in Section 10.2.1. This solution
must be protected from light. Reagent bottles and flasks must be kept
tightly stoppered.
7.3 Sample Analysis. The following reagents and standards are needed
for sample analysis:
7.3.1 Water. Same as in Section 7.1.3.
7.3.2 Standard Sodium Thiosulfate Solution, 0.1 N. Dissolve 24.8 g
of sodium thiosulfate pentahydrate
(Na2S2O3[middot]5H2O) or
15.8 g of anhydrous sodium thiosulfate
(Na2S2O3) in 1 liter of water, and add
0.01 g of anhydrous sodium carbonate (Na2CO3) and
0.4 ml of chloroform (CHCl3) to stabilize. Mix thoroughly by
shaking or by aerating with nitrogen for approximately 15 minutes, and
store in a glass-stoppered, reagent bottle. Standardize as in Section
10.2.2.
7.3.3 Standard Sodium Thiosulfate Solution, 0.01 N. Pipette 50.0 ml
of the standard 0.1 N Na2S2O3 solution
into a volumetric flask, and dilute to 500 ml with water.

Note: A 0.01 N phenylarsine oxide (C6H5AsO)
solution may be prepared instead of 0.01 N
Na2S2O3 (see Section 7.3.4).

7.3.4 Standard Phenylarsine Oxide Solution, 0.01 N. Dissolve 1.80 g
of (C6H5AsO) in 150 ml of 0.3 N sodium hydroxide.
After settling, decant 140 ml of this solution into 800 ml of water.
Bring the solution to pH 6-7 with 6 N HCl, and dilute to 1 liter with
water. Standardize as in Section 10.2.3.
7.3.5 Starch Indicator Solution. Suspend 10 g of soluble starch in
100 ml of water, and add 15 g of potassium hydroxide (KOH) pellets. Stir
until dissolved, dilute with 900 ml of water, and let stand for 1 hour.
Neutralize the alkali with concentrated HCl, using an

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indicator paper similar to Alkacid test ribbon, then add 2 ml of glacial
acetic acid as a preservative.

Note: Test starch indicator solution for decomposition by titrating
with 0.01 N I2 solution, 4 ml of starch solution in 200 ml of
water that contains 1 g of KI. If more than 4 drops of the 0.01 N
I2 solution are required to obtain the blue color, a fresh
solution must be prepared.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Sampling Train Preparation. Assemble the sampling train as shown
in Figure 11-1, connecting the five midget impingers in series. Place 15
ml of 3 percent H2O2 solution in the first
impinger. Leave the second impinger empty. Place 15 ml of the
CdSO4 solution in the third, fourth, and fifth impingers.
Place the impinger assembly in an ice water bath container, and place
water and crushed ice around the impingers. Add more ice during the run,
if needed.
8.2 Leak-Check Procedure.
8.2.1 Connect the rubber bulb and manometer to the first impinger,
as shown in Figure 11-1. Close the petcock on the DGM outlet. Pressurize
the train to 25 cm water with the bulb, and close off the tubing
connected to the rubber bulb. The train must hold 25 cm water pressure
with not more than a 1 cm drop in pressure in a 1-minute interval.
Stopcock grease is acceptable for sealing ground glass joints.
8.2.2 If the pump is used for sampling, it is recommended, but not
required, that the pump be leak-checked separately, either prior to or
after the sampling run. To leak-check the pump, proceed as follows:
Disconnect the drying tube from the impinger assembly. Place a vacuum
gauge at the inlet to either the drying tube or the pump, pull a vacuum
of 250 mm Hg (10 in. Hg), plug or pinch off the outlet of the flow
meter, and then turn off the pump. The vacuum should remain stable for
at least 30 seconds. If performed prior to the sampling run, the pump
leak-check should precede the leak-check of the sampling train described
immediately above; if performed after the sampling run, the pump leak-
check should follow the sampling train leak-check.
8.3 Purge the connecting line between the sampling valve and the
first impinger by disconnecting the line from the first impinger,
opening the sampling valve, and allowing process gas to flow through the
line for one to two minutes. Then, close the sampling valve, and
reconnect the line to the impinger train. Open the petcock on the dry
gas meter outlet. Record the initial DGM reading.
8.4 Open the sampling valve, and then adjust the valve to obtain a
rate of approximately 1 liter/min (0.035 cfm). Maintain a constant
(10 percent) flow rate during the test. Record the
DGM temperature.
8.5 Sample for at least 10 minutes. At the end of the sampling time,
close the sampling valve, and record the final volume and temperature
readings. Conduct a leak-check as described in Section 8.2 above.
8.6 Disconnect the impinger train from the sampling line. Connect
the charcoal tube and the pump as shown in Figure 11-1. Purge the train
[at a rate of 1 liter/min (0.035 ft\3\/min)] with clean ambient air for
15 minutes to ensure that all H2S is removed from the
H2O2. For sample recovery, cap the open ends, and
remove the impinger train to a clean area that is away from sources of
heat. The area should be well lighted, but not exposed to direct
sunlight.
8.7 Sample Recovery.
8.7.1 Discard the contents of the H2O2
impinger. Carefully rinse with water the contents of the third, fourth,
and fifth impingers into a 500-ml iodine flask.

Note: The impingers normally have only a thin film of CdS remaining
after a water rinse. If Antifoam B was not used or if significant
quantities of yellow CdS remain in the impingers, the alternative
recovery procedure in Section 11.2 must be used.

8.7.2 Proceed to Section 11 for the analysis.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.2, 10.1..................... Sampling Ensure accurate
equipment leak- measurement of
check and sample volume.
calibration.
11.2.......................... Replicate Ensure precision of
titrations of titration
blanks. determinations.
------------------------------------------------------------------------

10.0 Calibration and Standardization

Note: Maintain a log of all calibrations.

10.1 Calibration. Calibrate the sample collection equipment as
follows.
10.1.1 Dry Gas Meter.
10.1.1.1 Initial Calibration. The DGM shall be calibrated before its
initial use in the field. Proceed as follows: First, assemble the
following components in series: Drying tube, needle valve, pump,
rotameter, and DGM. Then, leak-check the metering system as follows:
Place a vacuum gauge (at least 760 mm Hg) at the inlet to the drying
tube, and pull a vacuum of 250 mm Hg (10 in. Hg); plug or pinch off the
outlet of the flow meter, and then turn off the pump. The vacuum shall
remain stable for at least 30 seconds. Carefully

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release the vacuum gauge before releasing the flow meter end. Next,
calibrate the DGM (at the sampling flow rate specified by the method) as
follows: Connect an appropriately sized wet-test meter (e.g., 1 liter
per revolution) to the inlet of the drying tube. Make three independent
calibration runs, using at least five revolutions of the DGM per run.
Calculate the calibration factor, Y (wet-test meter calibration volume
divided by the DGM volume, both volumes adjusted to the same reference
temperature and pressure), for each run, and average the results. If any
Y value deviates by more than 2 percent from the average, the DGM is
unacceptable for use. Otherwise, use the average as the calibration
factor for subsequent test runs.
10.1.1.2 Post-Test Calibration Check. After each field test series,
conduct a calibration check as in Section 10.1.1.1, above, except for
the following two variations: (a) three or more revolutions of the DGM
may be used and (b) only two independent runs need be made. If the
calibration factor does not deviate by more than 5 percent from the
initial calibration factor (determined in Section 10.1.1.1), then the
DGM volumes obtained during the test series are acceptable. If the
calibration factor deviates by more than 5 percent, recalibrate the DGM
as in Section 10.1.1.1, and for the calculations, use the calibration
factor (initial or recalibration) that yields the lower gas volume for
each test run.
10.1.2 Temperature Sensors. Calibrate against mercury-in-glass
thermometers.
10.1.3 Rate Meter. The rate meter need not be calibrated, but should
be cleaned and maintained according to the manufacturer's instructions.
10.1.4 Barometer. Calibrate against a mercury barometer.
10.2 Standardization.
10.2.1 Iodine Solution Standardization. Standardize the 0.01 N
I2 solution daily as follows: Pipette 25 ml of the
I2 solution into a 125-ml Erlenmeyer flask. Add 2 ml of 3 M
HCl. Titrate rapidly with standard 0.01 N
Na2S2O3 solution or with 0.01 N
C6H5AsO until the solution is light yellow, using
gentle mixing. Add four drops of starch indicator solution, and continue
titrating slowly until the blue color just disappears. Record the volume
of Na2S2O3 solution used,
VSI, or the volume of C6H5AsO solution
used, VAI, in ml. Repeat until replicate values agree within
0.05 ml. Average the replicate titration values which agree within 0.05
ml, and calculate the exact normality of the I2 solution
using Equation 11-3. Repeat the standardization daily.
10.2.2 Sodium Thiosulfate Solution Standardization. Standardize the
0.1 N Na2S2O3 solution as follows:
Oven-dry potassium dichromate (K2Cr2O7)
at 180 to 200 [deg]C (360 to 390 [deg]F). To the nearest milligram,
weigh 2 g of the dichromate (W). Transfer the dichromate to a 500-ml
volumetric flask, dissolve in water, and dilute to exactly 500 ml. In a
500-ml iodine flask, dissolve approximately 3 g of KI in 45 ml of water,
then add 10 ml of 3 M HCl solution. Pipette 50 ml of the dichromate
solution into this mixture. Gently swirl the contents of the flask once,
and allow it to stand in the dark for 5 minutes. Dilute the solution
with 100 to 200 ml of water, washing down the sides of the flask with
part of the water. Titrate with 0.1 N
Na2S2O3 until the solution is light
yellow. Add 4 ml of starch indicator and continue titrating slowly to a
green end point. Record the volume of
Na2S2O3 solution used, VS,
in ml. Repeat until replicate values agree within 0.05 ml. Calculate the
normality using Equation 11-1. Repeat the standardization each week or
after each test series, whichever time is shorter.
10.2.3 Phenylarsine Oxide Solution Standardization. Standardize the
0.01 N C6H5AsO (if applicable) as follows: Oven-
dry K2Cr2O7 at 180 to 200 [deg]C (360
to 390 [deg]F). To the nearest milligram, weigh 2 g of the dichromate
(W). Transfer the dichromate to a 500-ml volumetric flask, dissolve in
water, and dilute to exactly 500 ml. In a 500-ml iodine flask, dissolve
approximately 0.3 g of KI in 45 ml of water, then add 10 ml of 3 M HCl.
Pipette 5 ml of the dichromate solution into the iodine flask. Gently
swirl the contents of the flask once, and allow it to stand in the dark
for 5 minutes. Dilute the solution with 100 to 200 ml of water, washing
down the sides of the flask with part of the water. Titrate with 0.01 N
C6H5AsO until the solution is light yellow. Add 4
ml of starch indicator, and continue titrating slowly to a green end
point. Record the volume of C6H5AsO used,
VA, in ml. Repeat until replicate analyses agree within 0.05
ml. Calculate the normality using Equation 11-2. Repeat the
standardization each week or after each test series, whichever time is
shorter.

11.0 Analytical Procedure

Conduct the titration analyses in a clean area away from direct
sunlight.
11.1 Pipette exactly 50 ml of 0.01 N I2 solution into a
125-ml Erlenmeyer flask. Add 10 ml of 3 M HCl to the solution.
Quantitatively rinse the acidified I2 into the iodine flask.
Stopper the flask immediately, and shake briefly.
11.2 Use these alternative procedures if Antifoam B was not used or
if significant quantities of yellow CdS remain in the impingers. Extract
the remaining CdS from the third, fourth, and fifth impingers using the
acidified I2 solution. Immediately after pouring the
acidified I2 into an impinger, stopper it and shake for a few
moments, then transfer the liquid to the iodine flask. Do not transfer
any rinse portion from one impinger to another; transfer it directly to
the iodine flask. Once the acidified I2 solution has been

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poured into any glassware containing CdS, the container must be tightly
stoppered at all times except when adding more solution, and this must
be done as quickly and carefully as possible. After adding any acidified
I2 solution to the iodine flask, allow a few minutes for
absorption of the H2S before adding any further rinses.
Repeat the I2 extraction until all CdS is removed from the
impingers. Extract that part of the connecting glassware that contains
visible CdS. Quantitatively rinse all the I2 from the
impingers, connectors, and the beaker into the iodine flask using water.
Stopper the flask and shake briefly.
11.3 Allow the iodine flask to stand about 30 minutes in the dark
for absorption of the H2S into the I2, then
complete the titration analysis as outlined in Sections 11.5 and 11.6.

Note: Iodine evaporates from acidified I2 solutions.
Samples to which acidified I2 has been added may not be
stored, but must be analyzed in the time schedule stated above.

11.4 Prepare a blank by adding 45 ml of CdSO4 absorbing
solution to an iodine flask. Pipette exactly 50 ml of 0.01 N
I2 solution into a 125-ml Erlenmeyer flask. Add 10 ml of 3 M
HCl. Stopper the flask, shake briefly, let stand 30 minutes in the dark,
and titrate with the samples.

Note: The blank must be handled by exactly the same procedure as
that used for the samples.

11.5 Using 0.01 N Na2S2O3 solution
(or 0.01 N C6H5AsO, if applicable), rapidly
titrate each sample in an iodine flask using gentle mixing, until
solution is light yellow. Add 4 ml of starch indicator solution, and
continue titrating slowly until the blue color just disappears. Record
the volume of Na2S2O3 solution used,
VTT, or the volume of C6H5AsO solution
used, VAT, in ml.
11.6 Titrate the blanks in the same manner as the samples. Run
blanks each day until replicate values agree within 0.05 ml. Average the
replicate titration values which agree within 0.05 ml.

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 only after
the final calculation.
12.1 Nomenclature.

CH2S=Concentration of H2S at standard conditions,
mg/dscm.
NA=Normality of standard C6H5AsO
solution, g-eq/liter.
NI=Normality of standard I2 solution, g-eq/liter.
NS=Normality of standard ([sime]0.1 N)
Na2S2O3 solution, g-eq/liter.
NT=Normality of standard ([sime]0.01 N)
Na2S2O3 solution, assumed to be 0.1 NS,
g-eq/liter.
Pbar=Barometric pressure at the sampling site, mm Hg.
Pstd=Standard absolute pressure, 760 mm Hg.
Tm=Average DGM temperature, [deg]K.
Tstd=Standard absolute temperature, 293 [deg]K.
VA=Volume of C6H5AsO solution used for
standardization, ml.
VAI=Volume of standard C6H5AsO solution
used for titration analysis, ml.
VI=Volume of standard I2 solution used for
standardization, ml.
VIT=Volume of standard I2 solution used for
titration analysis, normally 50 ml.
Vm=Volume of gas sample at meter conditions, liters.
Vm(std)=Volume of gas sample at standard conditions, liters.
VSI=Volume of ``0.1 N
Na2S2O3 solution used for
standardization, ml.
VT=Volume of standard ([sime]0.01 N)
Na2S2O3 solution used in standardizing
iodine solution (see Section 10.2.1), ml.
VTT=Volume of standard (0.01 N)
Na2S2O3 solution used for titration
analysis, ml.
W=Weight of K2Cr2O7 used to standardize
Na2s2O3 or
C6H5AsO solutions, as applicable (see Sections
10.2.2 and 10.2.3), g.
Y=DGM calibration factor.
12.2 Normality of the Standard ([sime]0.1 N) Sodium Thiosulfate
Solution.
[GRAPHIC] [TIFF OMITTED] TR17OC00.238

Where:

2.039=Conversion factor
=(6 g-eq I2/mole
K2Cr2O7) (1,000 ml/liter)/(294.2 g
K2Cr2O7/mole) (10 aliquot factor)

12.3 Normality of Standard Phenylarsine Oxide Solution (if
applicable).
[GRAPHIC] [TIFF OMITTED] TR17OC00.239

Where:

0.2039=Conversion factor.
=(6 g-eq I2/mole
K2Cr2O7) (1,000 ml/liter)/(294.2 g
K2Cr2O7/mole) (100 aliquot factor)

12.4 Normality of Standard Iodine Solution.
[GRAPHIC] [TIFF OMITTED] TR17OC00.240

Note: If C6H5AsO is used instead of
Na2S2O3, replace NT and
VT in Equation 11-3 with NA and VAS,
respectively (see Sections 10.2.1 and 10.2.3).

12.5 Dry Gas Volume. Correct the sample volume measured by the DGM
to standard conditions (20 [deg]C and 760 mm Hg).

[[Page 346]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.241

12.6 Concentration of H2S. Calculate the concentration of
H2S in the gas stream at standard conditions using Equation
11-5:
[GRAPHIC] [TIFF OMITTED] TR17OC00.242

Where:

17.04 x 10\3\=Conversion factor
=(34.07 g/mole H2S) (1,000 liters/m\3\) (1,000mg/g)/
(1,000 ml/liter) (2H2S eq/mole)

Note: If C6H5AsO is used instead of
NaS22O3, replace NA and VAT
in Equation 11-5 with NA and VAT, respectively
(see Sections 11.5 and 10.2.3).

13.0 Method Performance

13.1 Precision. Collaborative testing has shown the intra-laboratory
precision to be 2.2 percent and the inter-laboratory precision to be 5
percent.
13.2 Bias. The method bias was shown to be -4.8 percent when only
H2S was present. In the presence of the interferences cited
in Section 4.0, the bias was positive at low H2S
concentration and negative at higher concentrations. At 230 mg
H2S/m\3\, the level of the compliance standard, the bias was
+2.7 percent. Thiols had no effect on the precision.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. Determination of Hydrogen Sulfide, Ammoniacal Cadmium Chloride
Method. API Method 772-54. In: Manual on Disposal of Refinery Wastes,
Vol. V: Sampling and Analysis of Waste Gases and Particulate Matter.
American Petroleum Institute, Washington, D.C. 1954.
2. Tentative Method of Determination of Hydrogen Sulfide and
Mercaptan Sulfur in Natural Gas. Natural Gas Processors Association,
Tulsa, OK. NGPA Publication No. 2265-65. 1965.
3. Knoll, J.D., and M.R. Midgett. Determination of Hydrogen Sulfide
in Refinery Fuel Gases. Environmental Monitoring Series, Office of
Research and Development, USEPA. Research Triangle Park, NC 27711. EPA
600/4-77-007.
4. Scheil, G.W., and M.C. Sharp. Standardization of Method 11 at a
Petroleum Refinery. Midwest Research Institute Draft Report for USEPA.
Office of Research and Development. Research Triangle Park, NC 27711.
EPA Contract No. 68-02-1098. August 1976. EPA 600/4-77-088a (Volume 1)
and EPA 600/4-77-088b (Volume 2).

17.0 Tables, Diagrams, Flowcharts, and Validation Data

[[Page 347]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.243

Method 12--Determination of Inorganic Lead Emissions From Stationary
Sources

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 have a thorough knowledge of at least
the following additional test methods: Method 1, Method 2, Method 3, and
Method 5.

1.0 Scope and Application

1.1 Analytes.

[[Page 348]]

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Inorganic Lead Compounds as lead 7439-92-1 see Section 13.3.
(Pb).
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of inorganic lead emissions from stationary sources, only as specified
in an applicable subpart of the regulations.
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 Particulate and gaseous Pb emissions are withdrawn
isokinetically from the source and are collected on a filter and in
dilute nitric acid. The collected samples are digested in acid solution
and are analyzed by atomic absorption spectrophotometry using an air/
acetylene flame.

3.0 Definitions [Reserved]

4.0 Interferences

4.1 Copper. High concentrations of copper may interfere with the
analysis of Pb at 217.0 nm. This interference can be avoided by
analyzing the samples at 283.3 nm.
4.2 Matrix Effects. Analysis for Pb by flame atomic absorption
spectrophotometry is sensitive to the chemical composition and to the
physical properties (e.g., viscosity, pH) of the sample. The analytical
procedure requires the use of the Method of Standard Additions to check
for these matrix effects, and requires sample analysis using the Method
of Standard Additions if significant matrix effects are found to be
present.

5.0 Safety

6.0 Equipment and Supplies

6.1 Sample Collection. A schematic of the sampling train used in
performing this method is shown in Figure 12-1 in Section 18.0; it is
similar to the Method 5 train. The following items are needed for sample
collection:
6.1.1 Probe Nozzle, Probe Liner, Pitot Tube, Differential Pressure
Gauge, Filter Holder, Filter Heating System, Temperature Sensor,
Metering System, Barometer, and Gas Density Determination Equipment.
Same as Method 5, Sections 6.1.1.1 through 6.1.1.7, 6.1.1.9, 6.1.2, and
6.1.3, respectively.
6.1.2 Impingers. Four impingers connected in series with leak-free
ground glass fittings or any similar leak-free noncontaminating fittings
are needed. For the first, third, and fourth impingers, use the
Greenburg-Smith design, modified by replacing the tip with a 1.3 cm (\1/
2\ in.) ID glass tube extending to about 1.3 cm (\1/2\ in.) from the
bottom of the flask. For the second impinger, use the Greenburg-Smith
design with the standard tip.
6.1.3 Temperature Sensor. Place a temperature sensor, capable of
measuring temperature to within 1 [deg]C (2 [deg]F) at the outlet of the
fourth impinger for monitoring purposes.
6.2 Sample Recovery. The following items are needed for sample
recovery:
6.2.1 Probe-Liner and Probe-Nozzle Brushes, Petri Dishes, Graduated
Cylinder and/or Balance, Plastic Storage Containers, and Funnel and
Rubber Policeman. Same as Method 5, Sections 6.2.1 and 6.2.4 through
6.2.7, respectively.
6.2.2 Wash Bottles. Glass (2).
6.2.3 Sample Storage Containers. Chemically resistant, borosilicate
glass bottles, for 0.1 N nitric acid (HNO3) impinger and
probe solutions and washes, 1000-ml. Use screw-cap liners that are
either rubber-backed Teflon or leak-free and resistant to chemical
attack by 0.1 N HNO3. (Narrow mouth glass bottles have been
found to be less prone to leakage.)
6.2.4 Funnel. Glass, to aid in sample recovery.
6.3 Sample Analysis. The following items are needed for sample
analysis:
6.3.1 Atomic Absorption Spectrophotometer. With lead hollow cathode
lamp and burner for air/acetylene flame.
6.3.2 Hot Plate.

[[Page 349]]

6.3.3 Erlenmeyer Flasks. 125-ml, 24/40 standard taper.
6.3.4 Membrane Filters. Millipore SCWPO 4700, or equivalent.
6.3.5 Filtration Apparatus. Millipore vacuum filtration unit, or
equivalent, for use with the above membrane filter.
6.3.6 Volumetric Flasks. 100-ml, 250-ml, and 1000-ml.

7.0 Reagents and Standards

7.1 Sample Collection. The following reagents are needed for sample
collection:
7.1.1 Filter. Gelman Spectro Grade, Reeve Angel 934 AH, MSA 1106 BH,
all with lot assay for Pb, or other high-purity glass fiber filters,
without organic binder, exhibiting at least 99.95 percent efficiency
(<0.05 percent penetration) on 0.3 micron dioctyl phthalate smoke
particles. Conduct the filter efficiency test using ASTM D 2986-71, 78,
or 95a (incorporated by reference--see Sec. 60.17) or use test data
from the supplier's quality control program.
7.1.2 Silica Gel, Crushed Ice, and Stopcock Grease. Same as Method
5, Sections 7.1.2, 7.1.4, and 7.1.5, respectively.
7.1.3 Water. Deionized distilled, to conform to ASTM D 1193-77 or
91, Type 3 (incorporated by reference--see Sec. 60.17). If high
concentrations of organic matter are not expected to be present, the
potassium permanganate test for oxidizable organic matter may be
omitted.
7.1.4 Nitric Acid, 0.1 N. Dilute 6.5 ml of concentrated
HNO3 to 1 liter with water. (It may be desirable to run
blanks before field use to eliminate a high blank on test samples.)
7.2 Sample Recovery. 0.1 N HNO3 (Same as in Section 7.1.4
above).
7.3 Sample Analysis. The following reagents and standards are needed
for sample analysis:
7.3.1 Water. Same as in Section 7.1.3.
7.3.2 Nitric Acid, Concentrated.
7.3.3 Nitric Acid, 50 Percent (v/v). Dilute 500 ml of concentrated
HNO3 to 1 liter with water.
7.3.4 Stock Lead Standard Solution, 1000 [micro]g Pb/ml. Dissolve
0.1598 g of lead nitrate [Pb(NO3)2] in about 60 ml
water, add 2 ml concentrated HNO3, and dilute to 100 ml with
water.
7.3.5 Working Lead Standards. Pipet 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0
ml of the stock lead standard solution (Section 7.3.4) into 250-ml
volumetric flasks. Add 5 ml of concentrated HNO3 to each
flask, and dilute to volume with water. These working standards contain
0.0, 4.0, 8.0, 12.0, 16.0, and 20.0 [micro]g Pb/ml, respectively.
Prepare, as needed, additional standards at other concentrations in a
similar manner.
7.3.6 Air. Suitable quality for atomic absorption spectrophotometry.
7.3.7 Acetylene. Suitable quality for atomic absorption
spectrophotometry.
7.3.8 Hydrogen Peroxide, 3 Percent (v/v). Dilute 10 ml of 30 percent
H2O2 to 100 ml with water.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Pretest Preparation. Follow the same general procedure given in
Method 5, Section 8.1, except that the filter need not be weighed.
8.2 Preliminary Determinations. Follow the same general procedure
given in Method 5, Section 8.2.
8.3 Preparation of Sampling Train. Follow the same general procedure
given in Method 5, Section 8.3, except place 100 ml of 0.1 N
HNO3 (instead of water) in each of the first two impingers.
As in Method 5, leave the third impinger empty and transfer
approximately 200 to 300 g of preweighed silica gel from its container
to the fourth impinger. Set up the train as shown in Figure 12-1.
8.4 Leak-Check Procedures. Same as Method 5, Section 8.4.
8.5 Sampling Train Operation. Same as Method 5, Section 8.5.
8.6 Calculation of Percent Isokinetic. Same as Method 5, Section
8.6.
8.7 Sample Recovery. Same as Method 5, Sections 8.7.1 through
8.7.6.1, with the addition of the following:
8.7.1 Container No. 2 (Probe).
8.7.1.1 Taking care that dust on the outside of the probe or other
exterior surfaces does not get into the sample, quantitatively recover
sample matter and any condensate from the probe nozzle, probe fitting,
probe liner, and front half of the filter holder by washing these
components with 0.1 N HNO3 and placing the wash into a glass
sample storage container. Measure and record (to the nearest 2 ml) the
total amount of 0.1 N HNO3 used for these rinses. Perform the
0.1 N HNO3 rinses as follows:
8.7.1.2 Carefully remove the probe nozzle, and rinse the inside
surfaces with 0.1 N HNO3 from a wash bottle while brushing
with a stainless steel, Nylon-bristle brush. Brush until the 0.1 N
HNO3 rinse shows no visible particles, then make a final
rinse of the inside surface with 0.1 N HNO3.
8.7.1.3 Brush and rinse with 0.1 N HNO3 the inside parts
of the Swagelok fitting in a similar way until no visible particles
remain.
8.7.1.4 Rinse the probe liner with 0.1 N HNO3. While
rotating the probe so that all inside surfaces will be rinsed with 0.1 N

[[Page 350]]

HNO3, tilt the probe, and squirt 0.1 N HNO3 into
its upper end. Let the 0.1 N HNO3 drain from the lower end
into the sample container. A glass funnel may be used to aid in
transferring liquid washes to the container. Follow the rinse with a
probe brush. Hold the probe in an inclined position, squirt 0.1 N
HNO3 into the upper end of the probe as the probe brush is
being pushed with a twisting action through the probe; hold the sample
container underneath the lower end of the probe, and catch any 0.1 N
HNO3 and sample matter that is brushed from the probe. Run
the brush through the probe three times or more until no visible sample
matter is carried out with the 0.1 N HNO3 and none remains on
the probe liner on visual inspection. With stainless steel or other
metal probes, run the brush through in the above prescribed manner at
least six times, since metal probes have small crevices in which sample
matter can be entrapped. Rinse the brush with 0.1 N HNO3, and
quantitatively collect these washings in the sample container. After the
brushing, make a final rinse of the probe as described above.
8.7.1.5 It is recommended that two people clean the probe to
minimize loss of sample. Between sampling runs, keep brushes clean and
protected from contamination.
8.7.1.6 After ensuring that all joints are wiped clean of silicone
grease, brush and rinse with 0.1 N HNO3 the inside of the
from half of the filter holder. Brush and rinse each surface three times
or more, if needed, to remove visible sample matter. Make a final rinse
of the brush and filter holder. After all 0.1 N HNO3 washings
and sample matter are collected in the sample container, tighten the lid
on the sample container so that the fluid will not leak out when it is
shipped to the laboratory. Mark the height of the fluid level to
determine whether leakage occurs during transport. Label the container
to identify its contents clearly.
8.7.2 Container No. 3 (Silica Gel). Note the color of the indicating
silica gel to determine if it has been completely spent, and make a
notation of its condition. Transfer the silica gel from the fourth
impinger to the original container, and seal. A funnel may be used to
pour the silica gel from the impinger and a rubber policeman may be used
to remove the silica gel from the impinger. It is not necessary to
remove the small amount of particles that may adhere to the walls and
are difficult to remove. Since the gain in weight is to be used for
moisture calculations, do not use any water or other liquids to transfer
the silica gel. If a balance is available in the field, follow the
procedure for Container No. 3 in Section 11.4.2.
8.7.3 Container No. 4 (Impingers). Due to the large quantity of
liquid involved, the impinger solutions may be placed in several
containers. Clean each of the first three impingers and connecting
glassware in the following manner:
8.7.3.1. Wipe the impinger ball joints free of silicone grease, and
cap the joints.
8.7.3.2. Rotate and agitate each impinger, so that the impinger
contents might serve as a rinse solution.
8.7.3.3. Transfer the contents of the impingers to a 500-ml
graduated cylinder. Remove the outlet ball joint cap, and drain the
contents through this opening. Do not separate the impinger parts (inner
and outer tubes) while transferring their contents to the cylinder.
Measure the liquid volume to within 2 ml. Alternatively, determine the
weight of the liquid to within 0.5 g. Record in the log the volume or
weight of the liquid present, along with a notation of any color or film
observed in the impinger catch. The liquid volume or weight is needed,
along with the silica gel data, to calculate the stack gas moisture
content (see Method 5, Figure 5-6).
8.7.3.4. Transfer the contents to Container No. 4.

Note: In Sections 8.7.3.5 and 8.7.3.6, measure and record the total
amount of 0.1 N HNO3 used for rinsing.

8.7.3.5. Pour approximately 30 ml of 0.1 N HNO3 into each
of the first three impingers and agitate the impingers. Drain the 0.1 N
HNO3 through the outlet arm of each impinger into Container
No. 4. Repeat this operation a second time; inspect the impingers for
any abnormal conditions.
8.7.3.6. Wipe the ball joints of the glassware connecting the
impingers free of silicone grease and rinse each piece of glassware
twice with 0.1 N HNO3; transfer this rinse into Container No.
4. Do not rinse or brush the glass-fritted filter support. Mark the
height of the fluid level to determine whether leakage occurs during
transport. Label the container to identify its contents clearly.
8.8 Blanks.
8.8.1 Nitric Acid. Save 200 ml of the 0.1 N HNO3 used for
sampling and cleanup as a blank. Take the solution directly from the
bottle being used and place into a glass sample container labeled ``0.1
N HNO3 blank.''
8.8.2 Filter. Save two filters from each lot of filters used in
sampling. Place these filters in a container labeled ``filter blank.''

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

[[Page 351]]

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardizations

Note: Maintain a laboratory log of all calibrations.

10.1 Sampling Equipment. Same as Method 5, Section 10.0.
10.2 Spectrophotometer.
10.2.1 Measure the absorbance of the standard solutions using the
instrument settings recommended by the spectrophotometer manufacturer.
Repeat until good agreement (3 percent) is
obtained between two consecutive readings. Plot the absorbance (y-axis)
versus concentration in [micro]g Pb/ml (x-axis). Draw or compute a
straight line through the linear portion of the curve. Do not force the
calibration curve through zero, but if the curve does not pass through
the origin or at least lie closer to the origin than 0.003 absorbance units, check for incorrectly prepared
standards and for curvature in the calibration curve.
10.2.2 To determine stability of the calibration curve, run a blank
and a standard after every five samples, and recalibrate as necessary.

11.0 Analytical Procedures

11.1 Sample Loss Check. Prior to analysis, check the liquid level in
Containers Number 2 and Number 4. Note on the analytical data sheet
whether leakage occurred during transport. If a noticeable amount of
leakage occurred, either void the sample or take steps, subject to the
approval of the Administrator, to adjust the final results.
11.2 Sample Preparation.
11.2.1 Container No. 1 (Filter). Cut the filter into strips and
transfer the strips and all loose particulate matter into a 125-ml
Erlenmeyer flask. Rinse the petri dish with 10 ml of 50 percent
HNO3 to ensure a quantitative transfer, and add to the flask.

Note: If the total volume required in Section 11.2.3 is expected to
exceed 80 ml, use a 250-ml flask in place of the 125-ml flask.

11.2.2 Containers No. 2 and No. 4 (Probe and Impingers). Combine the
contents of Containers No. 2 and No. 4, and evaporate to dryness on a
hot plate.
11.2.3 Sample Extraction for Lead.
11.2.3.1 Based on the approximate stack gas particulate
concentration and the total volume of stack gas sampled, estimate the
total weight of particulate sample collected. Next, transfer the residue
from Containers No. 2 and No. 4 to the 125-ml Erlenmeyer flask that
contains the sampling filter using a rubber policeman and 10 ml of 50
percent HNO3 for every 100 mg of sample collected in the
train or a minimum of 30 ml of 50 percent HNO3, whichever is
larger.
11.2.3.2 Place the Erlenmeyer flask on a hot plate, and heat with
periodic stirring for 30 minutes at a temperature just below boiling. If
the sample volume falls below 15 ml, add more 50 percent
HNO3. Add 10 ml of 3 percent H2O2, and
continue heating for 10 minutes. Add 50 ml of hot (80 [deg]C, 176
[deg]F) water, and heat for 20 minutes. Remove the flask from the hot
plate, and allow to cool. Filter the sample through a Millipore membrane
filter, or equivalent, and transfer the filtrate to a 250-ml volumetric
flask. Dilute to volume with water.
11.2.4 Filter Blank. Cut each filter into strips, and place each
filter in a separate 125-ml Erlenmeyer flask. Add 15 ml of 50 percent
HNO3, and treat as described in Section 11.2.3 using 10 ml of
3 percent H2O2 and 50 ml of hot water. Filter and
dilute to a total volume of 100 ml using water.
11.2.5 Nitric Acid Blank, 0.1 N. Take the entire 200 ml of 0.1 N
HNO3 to dryness on a steam bath, add 15 ml of 50 percent
HNO3, and treat as described in Section 11.2.3 using 10 ml of
3 percent H202 and 50 ml of hot water. Dilute to a
total volume of 100 ml using water.
11.3 Spectrophotometer Preparation. Turn on the power; set the
wavelength, slit width, and lamp current; and adjust the background
corrector as instructed by the manufacturer's manual for the particular
atomic absorption spectrophotometer. Adjust the burner and flame
characteristics as necessary.
11.4 Analysis.
11.4.1 Lead Determination. Calibrate the spectrophotometer as
outlined in Section 10.2, and determine the absorbance for each source
sample, the filter blank, and 0.1 N HNO3 blank. Analyze each
sample three times in this manner. Make appropriate dilutions, as
needed, to bring all sample Pb concentrations into the linear absorbance
range of the spectrophotometer. Because instruments vary between
manufacturers, no detailed operating instructions will be given here.
Instead, the instructions provided with the particular instrument should
be followed. If the Pb concentration of a sample is

[[Page 352]]

at the low end of the calibration curve and high accuracy is required,
the sample can be taken to dryness on a hot plate and the residue
dissolved in the appropriate volume of water to bring it into the
optimum range of the calibration curve.
11.4.2 Container No. 3 (Silica Gel). This step may be conducted in
the field. Weigh the spent silica gel (or silica gel plus impinger) to
the nearest 0.5 g; record this weight.
11.5 Check for Matrix Effects. Use the Method of Standard Additions
as follows to check at least one sample from each source for matrix
effects on the Pb results:
11.5.1 Add or spike an equal volume of standard solution to an
aliquot of the sample solution.
11.5.2 Measure the absorbance of the resulting solution and the
absorbance of an aliquot of unspiked sample.
11.5.3 Calculate the Pb concentration Cm in [micro]g/ml
of the sample solution using Equation 12-1 in Section 12.5.
Volume corrections will not be required if the solutions as analyzed
have been made to the same final volume. Therefore, Cm and
Ca represent Pb concentration before dilutions.
Method of Standard Additions procedures described on pages 9-4 and
9-5 of the section entitled ``General Information'' of the Perkin Elmer
Corporation Atomic Absorption Spectrophotometry Manual, Number 303-0152
(Reference 1 in Section 17.0) may also be used. In any event, if the
results of the Method of Standard Additions procedure used on the single
source sample do not agree to within 5 percent of
the value obtained by the routine atomic absorption analysis, then
reanalyze all samples from the source using the Method of Standard
Additions procedure.

12.0 Data Analysis and Calculations

12.1 Nomenclature.

Am=Absorbance of the sample solution.
An=Cross-sectional area of nozzle, m\2\ (ft\2\).
At=Absorbance of the spiked sample solution.
Bws=Water in the gas stream, proportion by volume.
Ca=Lead concentration in standard solution, [micro]g/ml.
Cm=Lead concentration in sample solution analyzed during
check for matrix effects, [micro]g/ml.
Cs=Lead concentration in stack gas, dry basis, converted to
standard conditions, mg/dscm (gr/dscf).
I=Percent of isokinetic sampling.
L1=Individual leakage rate observed during the leak-check
conducted prior to the first component change, m\3\/min (ft\3\/min)
La=Maximum acceptable leakage rate for either a pretest leak-
check or for a leak-check following a component change; equal to 0.00057
m\3\/min (0.020 cfm) or 4 percent of the average sampling rate,
whichever is less.
Li=Individual leakage rate observed during the leak-check
conducted prior to the ``ith'' component change (i=1, 2, 3 * * * n),
m\3\/min (cfm).
Lp=Leakage rate observed during the post-test leak-check,
m\3\/min (cfm).
mt=Total weight of lead collected in the sample, [micro]g.
Mw=Molecular weight of water, 18.0 g/g-mole (18.0 lb/lb-
mole).
Pbar=Barometric pressure at the sampling site, mm Hg (in.
Hg).
Ps=Absolute stack gas pressure, mm Hg (in. Hg).
Pstd=Standard absolute pressure, 760 mm Hg (29.92 in. Hg).
R=Ideal gas constant, 0.06236 [(mm Hg) (m\3\)]/[([deg]K) (g-mole)]
{21.85 [(in. Hg) (ft\3\)]/[([deg]R) (lb-mole)]{time} .
Tm=Absolute average dry gas meter temperature (see Figure 5-3
of Method 5), [deg]K ([deg]R).
Tstd=Standard absolute temperature, 293 [deg]K (528 [deg]R).
vs=Stack gas velocity, m/sec (ft/sec).
Vm=Volume of gas sample as measured by the dry gas meter, dry
basis, m\3\ (ft\3\).
Vm(std)=Volume of gas sample as measured by the dry gas
meter, corrected to standard conditions, m\3\ (ft\3\).
Vw(std)=Volume of water vapor collected in the sampling
train, corrected to standard conditions, m\3\ (ft\3\).
Y=Dry gas meter calibration factor.
[Delta]H=Average pressure differential across the orifice meter (see
Figure 5-3 of Method 5), mm H2O (in. H2O).
[thetas]=Total sampling time, min.
[thetas]l=Sampling time interval, from the beginning of a run
until the first component change, min.
[thetas]i=Sampling time interval, between two successive
component changes, beginning with the interval between the first and
second changes, min.
[thetas]p=Sampling time interval, from the final (n\th\)
component change until the end of the sampling run, min.
[rho]w=Density of water, 0.9982 g/ml (0.002201 lb/ml).

12.2 Average Dry Gas Meter Temperatures (Tm) and Average
Orifice Pressure Drop ([Delta]H). See data sheet (Figure 5-3 of Method
5).
12.3 Dry Gas Volume, Volume of Water Vapor, and Moisture Content.
Using data obtained in this test, calculate Vm(std),
Vw(std), and Bws according to the procedures
outlined in Method 5, Sections 12.3 through 12.5.
12.4 Total Lead in Source Sample. For each source sample, correct
the average absorbance for the contribution of the filter blank and the
0.1 N HNO3 blank. Use the calibration curve and this
corrected absorbance to determine the Pb concentration in the sample
aspirated into the spectrophotometer. Calculate the total Pb content
mt (in

[[Page 353]]

[micro]g) in the original source sample; correct for all the dilutions
that were made to bring the Pb concentration of the sample into the
linear range of the spectrophotometer.
12.5 Sample Lead Concentration. Calculate the Pb concentration of
the sample using the following equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.244

12.6 Lead Concentration. Calculate the stack gas Pb concentration
Cs using Equation 12-2:
[GRAPHIC] [TIFF OMITTED] TR17OC00.245

Where:

K3=0.001 mg/[micro]g for metric units.
=1.54 x 10^-5 gr/[micro]g for English units

12.7 Stack Gas Velocity and Volumetric Flow Rate. Calculate the
average stack gas velocity and volumetric flow rate using data obtained
in this method and the equations in Sections 12.2 and 12.3 of Method 2.
12.8 Isokinetic Variation. Same as Method 5, Section 12.11.

13.0 Method Performance

13.1 Precision. The within-laboratory precision, as measured by the
coefficient of variation, ranges from 0.2 to 9.5 percent relative to a
run-mean concentration. These values were based on tests conducted at a
gray iron foundry, a lead storage battery manufacturing plant, a
secondary lead smelter, and a lead recovery furnace of an alkyl lead
manufacturing plant. The concentrations encountered during these tests
ranged from 0.61 to 123.3 mg Pb/m\3\.
13.2 Analytical Range. For a minimum analytical accuracy of 10 percent, the lower limit of the range is 100
[micro]g. The upper limit can be extended considerably by dilution.
13.3 Analytical Sensitivity. Typical sensitivities for a 1-percent
change in absorption (0.0044 absorbance units) are 0.2 and 0.5 [micro]g
Pb/ml for the 217.0 and 283.3 nm lines, respectively.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Alternative Procedures

16.1 Simultaneous Determination of Particulate and Lead Emissions.
Method 5 may be used to simultaneously determine Pb provided: (1)
acetone is used to remove particulate from the probe and inside of the
filter holder as specified by Method 5, (2) 0.1 N HNO3 is
used in the impingers, (3) a glass fiber filter with a low Pb background
is used, and (4) the entire train contents, including the impingers, are
treated and analyzed for Pb as described in Sections 8.0 and 11.0 of
this method.
16.2 Filter Location. A filter may be used between the third and
fourth impingers provided the filter is included in the analysis for Pb.
16.3 In-Stack Filter. An in-stack filter may be used provided: (1) A
glass-lined probe and at least two impingers, each containing 100 ml of
0.1 N HNO3 after the in-stack filter, are used and (2) the
probe and impinger contents are recovered and analyzed for Pb. Recover
sample from the nozzle with acetone if a particulate analysis is to be
made.

17.0 References

Same as Method 5, Section 17.0, References 2, 3, 4, 5, and 7, with
the addition of the following:

1. Perkin Elmer Corporation. Analytical Methods for Atomic
Absorption Spectrophotometry. Norwalk, Connecticut. September 1976.
2. American Society for Testing and Materials. Annual Book of ASTM
Standards, Part 31: Water, Atmospheric Analysis. Philadelphia, PA 1974.
p. 40-42.
3. Kelin, R., and C. Hach. Standard Additions--Uses and Limitations
in Spectrophotometric Analysis. Amer. Lab. 9:21-27. 1977.
4. Mitchell, W.J., and M.R. Midgett. Determining Inorganic and Alkyl
Lead Emissions from Stationary Sources. U.S. Environmental Protection
Agency. Emission Monitoring and Support Laboratory. Research Triangle
Park, NC. (Presented at National APCA Meeting, Houston. June 26, 1978).

18.0 Tables, Diagrams, Flowcharts, and Validation Data

[[Page 354]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.246

Method 13A--Determination of Total Fluoride Emissions From Stationary
Sources (Spadns Zirconium Lake Method)

1.0 Scope and Application

1.1 Analytes.

[[Page 355]]

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Total fluorides as Fluorine.... 7782-41-4 Not determined.
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of fluoride (F^-) emissions from sources as specified in the
regulations. It does not measure fluorocarbons, such as Freons.
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

Gaseous and particulate F^- are withdrawn isokinetically
from the source and collected in water and on a filter. The total
F^- is then determined by the SPADNS Zirconium Lake
Colorimetric method.

3.0 Definitions [Reserved]

4.0 Interferences

4.1 Chloride. Large quantities of chloride will interfere with the
analysis, but this interference can be prevented by adding silver
sulfate into the distillation flask (see Section 11.3). If chloride ion
is present, it may be easier to use the specific ion electrode method of
analysis (Method 13B).
4.2 Grease. Grease on sample-exposed surfaces may cause low
F^- results due to adsorption.

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 to determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive Reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burn as thermal burn.
5.2.1 Hydrochloric Acid (HCl). Highly toxic. Vapors are highly
irritating to eyes, skin, nose, and lungs, causing severe damage. May
cause bronchitis, pneumonia, or edema of lungs. Exposure to
concentrations of 0.13 to 0.2 percent can be lethal in minutes. Will
react with metals, producing hydrogen.
5.2.2 Sodium Hydroxide (NaOH). Causes severe damage to eye tissues
and to skin. Inhalation causes irritation to nose, throat, and lungs.
Reacts exothermically with limited amounts of water.
5.2.3 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 1 mg/m\3\ for 8 hours will cause lung damage or, in higher
concentrations, death. Provide ventilation to limit inhalation. Reacts
violently with metals and organics.

6.0 Equipment and Supplies

6.1 Sample Collection. A schematic of the sampling train used in
performing this method is shown in Figure 13A-1; it is similar to the
Method 5 sampling train except that the filter position is
interchangeable. The sampling train consists of the following
components:
6.1.1 Probe Nozzle, Pitot Tube, Differential Pressure Gauge, Filter
Heating System, Temperature Sensor, Metering System, Barometer, and Gas
Density Determination Equipment. Same as Method 5, Sections 6.1.1.1,
6.1.1.3 through 6.1.1.7, 6.1.1.9, 6.1.2, and 6.1.3, respectively. The
filter heating system and temperature sensor are needed only when
moisture condensation is a problem.
6.1.2 Probe Liner. Borosilicate glass or 316 stainless steel. When
the filter is located immediately after the probe, a probe heating
system may be used to prevent filter plugging resulting from moisture
condensation, but the temperature in the probe shall not be allowed to
exceed 120 14 [deg]C (248 25
[deg]F).
6.1.3 Filter Holder. With positive seal against leakage from the
outside or around the filter. If the filter is located between the probe
and first impinger, use borosilicate glass or stainless steel with a 20-
mesh stainless steel screen filter support and a silicone rubber gasket;
do not use a glass frit or a sintered metal filter support. If the
filter is located between the third and fourth impingers, borosilicate
glass with a glass frit filter support and a silicone rubber gasket may
be used. Other materials of construction may be used, subject to the
approval of the Administrator.
6.1.4 Impingers. Four impingers connected as shown in Figure 13A-1
with ground-glass (or equivalent), vacuum-tight fittings. For the first,
third, and fourth impingers, use the Greenburg-Smith design, modified by
replacing the tip with a 1.3-cm (\1/2\ in.) ID glass tube extending to
1.3 cm (\1/2\ in.) from the bottom of the flask. For the second
impinger, use a

[[Page 356]]

Greenburg-Smith impinger with the standard tip. Modifications (e.g.,
flexible connections between the impingers or materials other than
glass) may be used, subject to the approval of the Administrator. Place
a temperature sensor, capable of measuring temperature to within 1
[deg]C (2 [deg]F), at the outlet of the fourth impinger for monitoring
purposes.
6.2 Sample Recovery. The following items are needed for sample
recovery:
6.2.1 Probe-liner and Probe-Nozzle Brushes, Wash Bottles, Graduated
Cylinder and/or Balance, Plastic Storage Containers, Funnel and Rubber
Policeman, and Funnel. Same as Method 5, Sections 6.2.1, 6.2.2 and 6.2.5
to 6.2.8, respectively.
6.2.2 Sample Storage Container. Wide-mouth, high-density
polyethylene bottles for impinger water samples, 1 liter.
6.3 Sample Preparation and Analysis. The following items are needed
for sample preparation and analysis:
6.3.1 Distillation Apparatus. Glass distillation apparatus assembled
as shown in Figure 13A-2.
6.3.2 Bunsen Burner.
6.3.3 Electric Muffle Furnace. Capable of heating to 600 [deg]C
(1100 [deg]F).
6.3.4 Crucibles. Nickel, 75- to 100-ml.
6.3.5 Beakers. 500-ml and 1500-ml.
6.3.6 Volumetric Flasks. 50-ml.
6.3.7 Erlenmeyer Flasks or Plastic Bottles. 500-ml.
6.3.8 Constant Temperature Bath. Capable of maintaining a constant
temperature of 1.0 [deg]C at room temperature
conditions.
6.3.9 Balance. 300-g capacity, to measure to 0.5 g.
6.3.10 Spectrophotometer. Instrument that measures absorbance at 570
nm and provides at least a 1-cm light path.
6.3.11 Spectrophotometer Cells. 1-cm path length.

7.0 Reagents and Standards

Unless otherwise indicated, all reagents are to conform to the
specifications established by the Committee on Analytical Reagents of
the American Chemical Society, where such specifications are available.
Otherwise, use the best available grade.
7.1 Sample Collection. The following reagents are needed for sample
collection:
7.1.1 Filters.
7.1.1.1 If the filter is located between the third and fourth
impingers, use a Whatman No. 1 filter, or equivalent, sized to fit the
filter holder.
7.1.1.2 If the filter is located between the probe and first
impinger, use any suitable medium (e.g., paper, organic membrane) that
can withstand prolonged exposure to temperatures up to 135 [deg]C (275
[deg]F), and has at least 95 percent collection efficiency (<5 percent
penetration) for 0.3 [micro]m dioctyl phthalate smoke particles. Conduct
the filter efficiency test before the test series, using ASTM D 2986-71,
78, or 95a (incorporated by reference--see Sec. 60.17), or use test
data from the supplier's quality control program. The filter must also
have a low F^- blank value (<0.015 mg F^-/cm\2\ of
filter area). Before the test series, determine the average
F^- blank value of at least three filters (from the lot to be
used for sampling) using the applicable procedures described in Sections
8.3 and 8.4 of this method. In general, glass fiber filters have high
and/or variable F^- blank values, and will not be acceptable
for use.
7.1.2 Water. Deionized distilled, to conform to ASTM D 1193-77 or
91, Type 3 (incorporated by reference--see Sec. 60.17). If high
concentrations of organic matter are not expected to be present, the
potassium permanganate test for oxidizable organic matter may be
deleted.
7.1.3 Silica Gel, Crushed Ice, and Stopcock Grease. Same as Method
5, Sections 7.1.2, 7.1.4, and 7.1.5, respectively.
7.2 Sample Recovery. Water, as described in Section 7.1.2, is needed
for sample recovery.
7.3 Sample Preparation and Analysis. The following reagents and
standards are needed for sample preparation and analysis:
7.3.1 Calcium Oxide (CaO). Certified grade containing 0.005 percent
F^- or less.
7.3.2 Phenolphthalein Indicator. Dissolve 0.1 g of phenolphthalein
in a mixture of 50 ml of 90 percent ethanol and 50 ml of water.
7.3.3 Silver Sulfate (Ag2SO4).
7.3.4 Sodium Hydroxide (NaOH), Pellets.
7.3.5 Sulfuric Acid (H2SO4), Concentrated.
7.3.6 Sulfuric Acid, 25 Percent (v/v). Mix 1 part of concentrated
H2SO4 with 3 parts of water.
7.3.7 Filters. Whatman No. 541, or equivalent.
7.3.8 Hydrochloric Acid (HCl), Concentrated.
7.3.9 Water. Same as in Section 7.1.2.
7.3.10 Fluoride Standard Solution, 0.01 mg F^-/ml. Dry
approximately 0.5 g of sodium fluoride (NaF) in an oven at 110 [deg]C
(230 [deg]F) for at least 2 hours. Dissolve 0.2210 g of NaF in 1 liter
of water. Dilute 100 ml of this solution to 1 liter with water.
7.3.11 SPADNS Solution [4,5 Dihydroxyl-3-(p-Sulfophenylazo)-2,7-
Naphthalene-Disulfonic Acid Trisodium Salt]. Dissolve 0.960 0.010 g of SPADNS reagent in 500 ml water. If stored in
a well-sealed bottle protected from the sunlight, this solution is
stable for at least 1 month.
7.3.12 Spectrophotometer Zero Reference Solution. Add 10 ml of
SPADNS solution to 100 ml water, and acidify with a solution prepared by
diluting 7 ml of concentrated HCl to 10 ml with deionized, distilled
water. Prepare daily.
7.3.13 SPADNS Mixed Reagent. Dissolve 0.135 0.005 g of zirconyl chloride octahydrate
(ZrOCl2 8H2O) in 25 ml of water. Add 350 ml

[[Page 357]]

of concentrated HCl, and dilute to 500 ml with deionized, distilled
water. Mix equal volumes of this solution and SPADNS solution to form a
single reagent. This reagent is stable for at least 2 months.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Pretest Preparation. Follow the general procedure given in
Method 5, Section 8.1, except that the filter need not be weighed.
8.2 Preliminary Determinations. Follow the general procedure given
in Method 5, Section 8.2, except that the nozzle size must be selected
such that isokinetic sampling rates below 28 liters/min (1.0 cfm) can be
maintained.
8.3 Preparation of Sampling Train. Follow the general procedure
given in Method 5, Section 8.3, except for the following variation:
Assemble the train as shown in Figure 13A-1 with the filter between the
third and fourth impingers. Alternatively, if a 20-mesh stainless steel
screen is used for the filter support, the filter may be placed between
the probe and first impinger. A filter heating system to prevent
moisture condensation may be used, but shall not allow the temperature
to exceed 120 14 [deg]C (248 25 [deg]F). Record the filter location on the data sheet
(see Section 8.5).
8.4 Leak-Check Procedures. Follow the leak-check procedures given in
Method 5, Section 8.4.
8.5 Sampling Train Operation. Follow the general procedure given in
Method 5, Section 8.5, keeping the filter and probe temperatures (if
applicable) at 120 14 [deg]C (248 25 [deg]F) and isokinetic sampling rates below 28
liters/min (1.0 cfm). For each run, record the data required on a data
sheet such as the one shown in Method 5, Figure 5-3.
8.6 Sample Recovery. Proper cleanup procedure begins as soon as the
probe is removed from the stack at the end of the sampling period. Allow
the probe to cool.
8.6.1 When the probe can be safely handled, wipe off all external
particulate matter near the tip of the probe nozzle, and place a cap
over it to keep from losing part of the sample. Do not cap off the probe
tip tightly while the sampling train is cooling down as this would
create a vacuum in the filter holder, thus drawing water from the
impingers into the filter holder.
8.6.2 Before moving the sample train to the cleanup site, remove the
probe from the sample train, wipe off any silicone grease, and cap the
open outlet of the probe. Be careful not to lose any condensate that
might be present. Remove the filter assembly, wipe off any silicone
grease from the filter holder inlet, and cap this inlet. Remove the
umbilical cord from the last impinger, and cap the impinger. After
wiping off any silicone grease, cap off the filter holder outlet and any
open impinger inlets and outlets. Ground-glass stoppers, plastic caps,
or serum caps may be used to close these openings.
8.6.3 Transfer the probe and filter-impinger assembly to the cleanup
area. This area should be clean and protected from the wind so that the
chances of contaminating or losing the sample will be minimized.
8.6.4 Inspect the train prior to and during disassembly, and note
any abnormal conditions. Treat the samples as follows:
8.6.4.1 Container No. 1 (Probe, Filter, and Impinger Catches).
8.6.4.1.1 Using a graduated cylinder, measure to the nearest ml, and
record the volume of the water in the first three impingers; include any
condensate in the probe in this determination. Transfer the impinger
water from the graduated cylinder into a polyethylene container. Add the
filter to this container. (The filter may be handled separately using
procedures subject to the Administrator's approval.) Taking care that
dust on the outside of the probe or other exterior surfaces does not get
into the sample, clean all sample-exposed surfaces (including the probe
nozzle, probe fitting, probe liner, first three impingers, impinger
connectors, and filter holder) with water. Use less than 500 ml for the
entire wash. Add the washings to the sample container. Perform the water
rinses as follows:
8.6.4.1.2 Carefully remove the probe nozzle and rinse the inside
surface with water from a wash bottle. Brush with a Nylon bristle brush,
and rinse until the rinse shows no visible particles, after which make a
final rinse of the inside surface. Brush and rinse the inside parts of
the Swagelok fitting with water in a similar way.
8.6.4.1.3 Rinse the probe liner with water. While squirting the
water into the upper end of the probe, tilt and rotate the probe so that
all inside surfaces will be wetted with water. Let the water drain from
the lower end into the sample container. A funnel (glass or
polyethylene) may be used to aid in transferring the liquid washes to
the container. Follow the rinse with a probe brush. Hold the probe in an
inclined position, and squirt water into the upper end as the probe
brush is being pushed with a twisting action through the probe. Hold the
sample container underneath the lower end of the probe, and catch any
water and particulate matter that is brushed from the probe. Run the
brush through the probe three times or more. With stainless steel or
other metal probes, run the brush through in the above prescribed manner
at least six times since metal probes have small crevices in which
particulate matter can be entrapped. Rinse the brush with water, and
quantitatively collect these washings in the sample container. After the
brushing, make a final rinse of the probe as described above.
8.6.4.1.4 It is recommended that two people clean the probe to
minimize sample

[[Page 358]]

losses. Between sampling runs, keep brushes clean and protected from
contamination.
8.6.4.1.5 Rinse the inside surface of each of the first three
impingers (and connecting glassware) three separate times. Use a small
portion of water for each rinse, and brush each sample-exposed surface
with a Nylon bristle brush, to ensure recovery of fine particulate
matter. Make a final rinse of each surface and of the brush.
8.6.4.1.6 After ensuring that all joints have been wiped clean of
the silicone grease, brush and rinse with water the inside of the filter
holder (front-half only, if filter is positioned between the third and
fourth impingers). Brush and rinse each surface three times or more if
needed. Make a final rinse of the brush and filter holder.
8.6.4.1.7 After all water washings and particulate matter have been
collected in the sample container, tighten the lid so that water will
not leak out when it is shipped to the laboratory. Mark the height of
the fluid level to transport. Label the container clearly to identify
its contents.
8.6.4.2 Container No. 2 (Sample Blank). Prepare a blank by placing
an unused filter in a polyethylene container and adding a volume of
water equal to the total volume in Container No. 1. Process the blank in
the same manner as for Container No. 1.
8.6.4.3 Container No. 3 (Silica Gel). Note the color of the
indicating silica gel to determine whether it has been completely spent,
and make a notation of its condition. Transfer the silica gel from the
fourth impinger to its original container, and seal. A funnel may be
used to pour the silica gel and a rubber policeman to remove the silica
gel from the impinger. It is not necessary to remove the small amount of
dust particles that may adhere to the impinger wall and are difficult to
remove. Since the gain in weight is to be used for moisture
calculations, do not use any water or other liquids to transfer the
silica gel. If a balance is available in the field, follow the
analytical procedure for Container No. 3 in Section 11.4.2.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.4, 10.1..................... Sampling Ensure accurate
equipment leak- measurement of stack
check and gas flow rate and
calibration. sample volume.
10.2.......................... Spectrophotometer Evaluate analytical
calibration. technique,
preparation of
standards.
11.3.3........................ Interference/ Minimize negative
recovery effects of used
efficiency check acid.
during
distillation.
------------------------------------------------------------------------

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardization

Note: Maintain a laboratory log of all calibrations.

10.1 Sampling Equipment. Calibrate the probe nozzle, pitot tube,
metering system, probe heater, temperature sensors, and barometer
according to the procedures outlined in Method 5, Sections 10.1 through
10.6. Conduct the leak-check of the metering system according to the
procedures outlined in Method 5, Section 8.4.1.
10.2 Spectrophotometer.
10.2.1 Prepare the blank standard by adding 10 ml of SPADNS mixed
reagent to 50 ml of water.
10.2.2 Accurately prepare a series of standards from the 0.01 mg
F^-/ml standard fluoride solution (Section 7.3.10) by diluting
0, 2, 4, 6, 8, 10, 12, and 14 ml to 100 ml with deionized, distilled
water. Pipet 50 ml from each solution, and transfer each to a separate
100-ml beaker. Then add 10 ml of SPADNS mixed reagent (Section 7.3.13)
to each. These standards will contain 0, 10, 20, 30, 40, 50, 60, and 70
[micro]g F^-(0 to 1.4 [micro]g/ml), respectively.
10.2.3 After mixing, place the blank and calibration standards in a
constant temperature bath for 30 minutes before reading the absorbance
with the spectrophotometer. Adjust all samples to this same temperature
before analyzing.
10.2.4 With the spectrophotometer at 570 nm, use the blank standard
to set the absorbance to zero. Determine the absorbance of the
standards.
10.2.5 Prepare a calibration curve by plotting [micro]g
F^-/50 ml versus absorbance on linear graph paper. Prepare the
standard curve initially and thereafter whenever the SPADNS mixed
reagent is newly made. Also, run a calibration standard with each set of
samples and, if it differs from the calibration curve by more than
2 percent, prepare a new standard curve.

11.0 Analytical Procedures

11.1 Sample Loss Check. Note the liquid levels in Containers No. 1
and No. 2, determine whether leakage occurred during transport, and note
this finding on the analytical data sheet. If noticeable leakage has
occurred, either void the sample or use methods, subject to the approval
of the Administrator, to correct the final results.

[[Page 359]]

11.2 Sample Preparation. Treat the contents of each sample container
as described below:
11.2.1 Container No. 1 (Probe, Filter, and Impinger Catches). Filter
this container's contents, including the sampling filter, through
Whatman No. 541 filter paper, or equivalent, into a 1500-ml beaker.
11.2.1.1 If the filtrate volume exceeds 900 ml, make the filtrate
basic (red to phenolphthalein) with NaOH, and evaporate to less than 900
ml.
11.2.1.2 Place the filtered material (including sampling filter) in
a nickel crucible, add a few ml of water, and macerate the filters with
a glass rod.
11.2.1.2.1 Add 100 mg CaO to the crucible, and mix the contents
thoroughly to form a slurry. Add two drops of phenolphthalein indicator.
Place the crucible in a hood under infrared lamps or on a hot plate at
low heat. Evaporate the water completely. During the evaporation of the
water, keep the slurry basic (red to phenolphthalein) to avoid loss of
F^-. If the indicator turns colorless (acidic) during the
evaporation, add CaO until the color turns red again.
11.2.1.2.2 After evaporation of the water, place the crucible on a
hot plate under a hood, and slowly increase the temperature until the
Whatman No. 541 and sampling filters char. It may take several hours to
char the filters completely.
11.2.1.2.3 Place the crucible in a cold muffle furnace. Gradually
(to prevent smoking) increase the temperature to 600 [deg]C (1100
[deg]F), and maintain this temperature until the contents are reduced to
an ash. Remove the crucible from the furnace, and allow to cool.
11.2.1.2.4 Add approximately 4 g of crushed NaOH to the crucible,
and mix. Return the crucible to the muffle furnace, and fuse the sample
for 10 minutes at 600 [deg]C.
11.2.1.2.5 Remove the sample from the furnace, and cool to ambient
temperature. Using several rinsings of warm water, transfer the contents
of the crucible to the beaker containing the filtrate. To ensure
complete sample removal, rinse finally with two 20-ml portions of 25
percent H2SO4, and carefully add to the beaker.
Mix well, and transfer to a 1-liter volumetric flask. Dilute to volume
with water, and mix thoroughly. Allow any undissolved solids to settle.
11.2.2 Container No. 2 (Sample Blank). Treat in the same manner as
described in Section 11.2.1 above.
11.2.3 Adjustment of Acid/Water Ratio in Distillation Flask. Place
400 ml of water in the distillation flask, and add 200 ml of
concentrated H2SO4. Add some soft glass beads and
several small pieces of broken glass tubing, and assemble the apparatus
as shown in Figure 13A-2. Heat the flask until it reaches a temperature
of 175 [deg]C (347 [deg]F) to adjust the acid/water ratio for subsequent
distillations. Discard the distillate.

Caution: Use a protective shield when carrying out this procedure.
Observe standard precautions when mixing H2SO4
with water. Slowly add the acid to the flask with constant swirling.

11.3 Distillation.
11.3.1 Cool the contents of the distillation flask to below 80
[deg]C (180 [deg]F). Pipet an aliquot of sample containing less than
10.0 mg F^- directly into the distillation flask, and add
water to make a total volume of 220 ml added to the distillation flask.
(To estimate the appropriate aliquot size, select an aliquot of the
solution, and treat as described in Section 11.4.1. This will be an
approximation of the F^- content because of possible
interfering ions.)

Note: If the sample contains chloride, add 5 mg of
Ag2SO4 to the flask for every mg of chloride.

11.3.2 Place a 250-ml volumetric flask at the condenser exit. Heat
the flask as rapidly as possible with a Bunsen burner, and collect all
the distillate up to 175 [deg]C (347 [deg]F). During heatup, play the
burner flame up and down the side of the flask to prevent bumping.
Conduct the distillation as rapidly as possible (15 minutes or less).
Slow distillations have been found to produce low F^-
recoveries. Be careful not to exceed 175 [deg]C (347 [deg]F) to avoid
causing H2SO4 to distill over. If F^-
distillation in the mg range is to be followed by a distillation in the
fractional mg range, add 220 ml of water and distill it over as in the
acid adjustment step to remove residual F^- from the
distillation system.
11.3.3 The acid in the distillation flask may be used until there is
carry-over of interferences or poor F^- recovery. Check for
interference and for recovery efficiency every tenth distillation using
a water blank and a standard solution. Change the acid whenever the
F^- recovery is less than 90 percent or the blank value
exceeds 0.1 [micro]g/ml.
11.4 Sample Analysis.
11.4.1 Containers No. 1 and No. 2.
11.4.1.1 After distilling suitable aliquots from Containers No. 1
and No. 2 according to Section 11.3, dilute the distillate in the
volumetric flasks to exactly 250 ml with water, and mix thoroughly.
Pipet a suitable aliquot of each sample distillate (containing 10 to 40
[micro]g F^-/ml) into a beaker, and dilute to 50 ml with
water. Use the same aliquot size for the blank. Add 10 ml of SPADNS
mixed reagent (Section 7.3.13), and mix thoroughly.
11.4.1.2 After mixing, place the sample in a constant-temperature
bath containing the standard solutions for 30 minutes before reading the
absorbance on the spectrophotometer.

Note: After the sample and colorimetric reagent are mixed, the color
formed is stable for approximately 2 hours. Also, a 3 [deg]C (5.4
[deg]F) temperature difference between the sample and standard solutions
produces an error

[[Page 360]]

of approximately 0.005 mg F^-/liter. To avoid this error, the
absorbencies of the sample and standard solutions must be measured at
the same temperature.

11.4.1.3 Set the spectrophotometer to zero absorbance at 570 nm with
the zero reference solution (Section 7.3.12), and check the
spectrophotometer calibration with the standard solution (Section
7.3.10). Determine the absorbance of the samples, and determine the
concentration from the calibration curve. If the concentration does not
fall within the range of the calibration curve, repeat the procedure
using a different size aliquot.
11.4.2 Container No. 3 (Silica Gel). Weigh the spent silica gel (or
silica gel plus impinger) to the nearest 0.5 g using a balance. This
step may be conducted in the field.

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. Other forms of the equations may be used, provided that
they yield equivalent results.
12.1 Nomenclature.

Ad=Aliquot of distillate taken for color development, ml.
At=Aliquot of total sample added to still, ml.
Bws=Water vapor in the gas stream, portion by volume.
Cs=Concentration of F^- in stack gas, mg/dscm (gr/
dscf).
Fc=F^- concentration from the calibration curve,
[micro]g.
Ft=Total F^- in sample, mg.
Tm=Absolute average dry gas meter (DGM) temperature (see
Figure 5-3 of Method 5), [deg]K ([deg]R).
Ts=Absolute average stack gas temperature (see Figure 5-3 of
Method 5), [deg]K ([deg]R).
Vd=Volume of distillate as diluted, ml.
Vm(std)=Volume of gas sample as measured by DGM at standard
conditions, dscm (dscf).
Vt=Total volume of F^- sample, after final
dilution, ml.
Vw(std)=Volume of water vapor in the gas sample at standard
conditions, scm (scf)

12.2 Average DGM Temperature and Average Orifice Pressure Drop (see
Figure 5-3 of Method 5).
12.3 Dry Gas Volume. Calculate Vm(std), and adjust for
leakage, if necessary, using Equation 5-1 of Method 5.
12.4 Volume of Water Vapor and Moisture Content. Calculate
Vw(std) and Bws from the data obtained in this
method. Use Equations 5-2 and 5-3 of Method 5.
12.5 Total Fluoride in Sample. Calculate the amount of F^-
in the sample using the following equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.247

Where:

K=10^-3 mg/[micro]g (metric units)
=1.54 x 10^-5 gr/[micro]g (English units)

12.6 Fluoride Concentration in Stack Gas. Determine the
F^- concentration in the stack gas using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.248

12.7 Isokinetic Variation. Same as Method 5, Section 12.11.

13.0 Method Performance

The following estimates are based on a collaborative test done at a
primary aluminum smelter. In the test, six laboratories each sampled the
stack simultaneously using two sampling trains for a total of 12 samples
per sampling run. Fluoride concentrations encountered during the test
ranged from 0.1 to 1.4 mg F^-/m\3\.
13.1 Precision. The intra- and inter-laboratory standard deviations,
which include sampling and analysis errors, were 0.044 mg F^-/
m\3\ with 60 degrees of freedom and 0.064 mg F^-/m\3\ with
five degrees of freedom, respectively.
13.2 Bias. The collaborative test did not find any bias in the
analytical method.
13.3 Range. The range of this method is 0 to 1.4 [micro]g
F-/ml.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Alternative Procedures

16.1 Compliance with ASTM D 3270-73T, 80, 91, or 95 (incorporated by
reference--see Sec. 60.17) ``Analysis of Fluoride Content of the
Atmosphere and Plant Tissues (Semiautomated Method) is an acceptable
alternative for the requirements specified in Sections 11.2, 11.3, and
11.4.1 when applied to suitable aliquots of Containers 1 and 2 samples.

17.0 References

1. Bellack, Ervin. Simplified Fluoride Distillation Method. J. of
the American Water Works Association. 50:5306. 1958.
2. Mitchell, W.J., J.C. Suggs, and F.J. Bergman. Collaborative Study
of EPA Method 13A and Method 13B. Publication No. EPA-300/4-77-050. U.S.
Environmental Protection Agency, Research Triangle Park, NC. December
1977.
3. Mitchell, W.J., and M.R. Midgett. Adequacy of Sampling Trains and
Analytical

[[Page 361]]

Procedures Used for Fluoride. Atm. Environ. 10:865-872. 1976.

18.0 Tables, Diagrams, Flowcharts, and Validation Data
[GRAPHIC] [TIFF OMITTED] TR17OC00.249

[[Page 362]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.250

Method 13B--Determination of Total Fluoride Emissions From Stationary
Sources (Specific Ion Electrode Method)

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Total fluorides as Fluorine.... 7782-41-4 Not determined.
------------------------------------------------------------------------

2.0 Summary

Gaseous and particulate F^- are withdrawn isokinetically
from the source and collected in water and on a filter. The total
F^- is then determined by the specific ion electrode method.

3.0 Definitions [Reserved]

4.0 Interferences

Grease on sample-exposed surfaces may cause low F^-
results because of adsorption.

5.0 Safety

5.1 Disclaimer. This method may involve hazardous materials,
operations, and equipment. This test method does not purport to address
all of the safety problems associated with its use. It is the
responsibility of the

[[Page 363]]

user of this test method to establish appropriate safety and health
practices and to determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive Reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burn as thermal burn.
5.2.1 Sodium Hydroxide (NaOH). Causes severe damage to eye tissues
and to skin. Inhalation causes irritation to nose, throat, and lungs.
Reacts exothermically with limited amounts of water.
5.2.2 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 1 mg/m\3\ for 8 hours will cause lung damage or, in higher
concentrations, death. Provide ventilation to limit inhalation. Reacts
violently with metals and organics.

6.0 Equipment and Supplies

6.1 Sample Collection and Sample Recovery. Same as Method 13A,
Sections 6.1 and 6.2, respectively.
6.2 Sample Preparation and Analysis. The following items are
required for sample preparation and analysis:
6.2.1 Distillation Apparatus, Bunsen Burner, Electric Muffle
Furnace, Crucibles, Beakers, Volumetric Flasks, Erlenmeyer Flasks or
Plastic Bottles, Constant Temperature Bath, and Balance. Same as Method
13A, Sections 6.3.1 to 6.3.9, respectively.
6.2.2 Fluoride Ion Activity Sensing Electrode.
6.2.3 Reference Electrode. Single junction, sleeve type.
6.2.4 Electrometer. A pH meter with millivolt-scale capable of
0.1-mv resolution, or a specific ion meter made
specifically for specific ion electrode use.
6.2.5 Magnetic Stirrer and Tetrafluoroethylene (TFE) Fluorocarbon-
Coated Stirring Bars.
6.2.6 Beakers. Polyethylene, 100-ml.

7.0 Reagents and Standards

8.0 Sample Collection, Preservation, Storage, and Transport

Same as Method 13A, Section 8.0.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.0, 10.1..................... Sampling Ensure accurate
equipment leak- measurement of stack
check and gas flow rate and
calibration. sample volume.
10.2.......................... Fluoride Evaluate analytical
electrode. technique,
preparation of
standards.
11.1.......................... Interference/ Minimize negative
recovery effects of used
efficiency-check acid.
during
distillation.
------------------------------------------------------------------------

[[Page 364]]

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardizations

Note: Maintain a laboratory log of all calibrations.

10.1 Sampling Equipment. Same as Method 13A, Section 10.1.
10.2 Fluoride Electrode. Prepare fluoride standardizing solutions by
serial dilution of the 0.1 M fluoride standard solution. Pipet 10 ml of
0.1 M fluoride standard solution into a 100-ml volumetric flask, and
make up to the mark with water for a 10^-2 M standard
solution. Use 10 ml of 10^-2 M solution to make a
10^-3 M solution in the same manner. Repeat the dilution
procedure, and make 10^-4 and 10^-5 M solutions.
10.2.1 Pipet 50 ml of each standard into a separate beaker. Add 50
ml of TISAB to each beaker. Place the electrode in the most dilute
standard solution. When a steady millivolt reading is obtained, plot the
value on the linear axis of semilog graph paper versus concentration on
the log axis. Plot the nominal value for concentration of the standard
on the log axis, (e.g., when 50 ml of 10^-2 M standard is
diluted with 50 ml of TISAB, the concentration is still designated
``10^-2 M'').
10.2.2 Between measurements, soak the fluoride sensing electrode in
water for 30 seconds, and then remove and blot dry. Analyze the
standards going from dilute to concentrated standards. A straight-line
calibration curve will be obtained, with nominal concentrations of
10^-4, 10^-3, 10^-2, 10^-1
fluoride molarity on the log axis plotted versus electrode potential (in
mv) on the linear scale. Some electrodes may be slightly nonlinear
between 10^-5 and 10^-4 M. If this occurs, use
additional standards between these two concentrations.
10.2.3 Calibrate the fluoride electrode daily, and check it hourly.
Prepare fresh fluoride standardizing solutions daily (10^-2 M
or less). Store fluoride standardizing solutions in polyethylene or
polypropylene containers.

Note: Certain specific ion meters have been designed specifically
for fluoride electrode use and give a direct readout of fluoride ion
concentration. These meters may be used in lieu of calibration curves
for fluoride measurements over a narrow concentration ranges. Calibrate
the meter according to the manufacturer's instructions.

11.0 Analytical Procedures

11.1 Sample Loss Check, Sample Preparation, and Distillation. Same
as Method 13A, Sections 11.1 through 11.3, except that the Note
following Section 11.3.1 is not applicable.
11.2 Analysis.
11.2.1 Containers No. 1 and No. 2. Distill suitable aliquots from
Containers No. 1 and No. 2. Dilute the distillate in the volumetric
flasks to exactly 250 ml with water, and mix thoroughly. Pipet a 25-ml
aliquot from each of the distillate into separate beakers. Add an equal
volume of TISAB, and mix. The sample should be at the same temperature
as the calibration standards when measurements are made. If ambient
laboratory temperature fluctuates more than 2
[deg]C from the temperature at which the calibration standards were
measured, condition samples and standards in a constant-temperature bath
before measurement. Stir the sample with a magnetic stirrer during
measurement to minimize electrode response time. If the stirrer
generates enough heat to change solution temperature, place a piece of
temperature insulating material, such as cork, between the stirrer and
the beaker. Hold dilute samples (below 10^-4 M fluoride ion
content) in polyethylene beakers during measurement.
11.2.2 Insert the fluoride and reference electrodes into the
solution. When a steady millivolt reading is obtained, record it. This
may take several minutes. Determine concentration from the calibration
curve. Between electrode measurements, rinse the electrode with water.
11.2.3 Container No. 3 (Silica Gel). Same as in Method 13A, Section
11.4.2.

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. Same as Method 13A, Section 12.1, with the
addition of the following:

M=F^- concentration from calibration curve, molarity.

12.2 Average DGM Temperature and Average Orifice Pressure Drop, Dry
Gas Volume, Volume of Water Vapor and Moisture Content, Fluoride
Concentration in Stack Gas, and Isokinetic Variation. Same as Method
13A, Sections 12.2 to 12.4, 12.6, and 12.7, respectively.
12.3 Total Fluoride in Sample. Calculate the amount of F^-
in the sample using Equation 13B-1:
[GRAPHIC] [TIFF OMITTED] TR17OC00.251

Where:

K=19 [(mg[middot]l)/(mole[middot]ml)] (metric units)
=0.292 [(gr[middot]l)/(mole[middot]ml)] (English units)

13.0 Method Performance

[[Page 365]]

sampling run. Fluoride concentrations encountered during the test ranged
from 0.1 to 1.4 mg F^-/m\3\.
13.1 Precision. The intra-laboratory and inter-laboratory standard
deviations, which include sampling and analysis errors, are 0.037 mg
F^-/m\3\ with 60 degrees of freedom and 0.056 mg
F^-/m\3\ with five degrees of freedom, respectively.
13.2 Bias. The collaborative test did not find any bias in the
analytical method.
13.3 Range. The range of this method is 0.02 to 2,000 [micro]g
F^-/ml; however, measurements of less than 0.1 [micro]g
F^-/ml require extra care.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 Alternative Procedures

16.1 Compliance with ASTM D 3270-73T, 91, 95 ``Analysis for Fluoride
Content of the Atmosphere and Plant Tissues (Semiautomated Method)'' is
an acceptable alternative for the distillation and analysis requirements
specified in Sections 11.1 and 11.2 when applied to suitable aliquots of
Containers 1 and 2 samples.

17.0 References

Same as Method 13A, Section 16.0, References 1 and 2, with the
following addition:

1. MacLeod, Kathryn E., and Howard L. Crist. Comparison of the
SPADNS-Zirconium Lake and Specific Ion Electrode Methods of Fluoride
Determination in Stack Emission Samples. Analytical Chemistry. 45:1272-
1273. 1973.

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

Method 14--Determination of Fluoride Emissions From Potroom Roof
Monitors for Primary Aluminum Plants

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Total fluorides as Fluorine....... 7782-41-4 Not determined.
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of fluoride emissions from roof monitors at primary aluminum reduction
plant potroom groups.
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 Gaseous and particulate fluoride roof monitor emissions are
drawn into a permanent sampling manifold through several large nozzles.
The sample is transported from the sampling manifold to ground level
through a duct. The fluoride content of the gas in the duct is
determined using either Method 13A or Method 13B. Effluent velocity and
volumetric flow rate are determined using anemometers located in the
roof monitor.

3.0 Definitions

Potroom means a building unit which houses a group of electrolytic
cells in which aluminum is produced.
Potroom group means an uncontrolled potroom, a potroom which is
controlled individually, or a group of potrooms or potroom segments
ducted to a common control system.
Roof monitor means that portion of the roof of a potroom where gases
not captured at the cell exit from the potroom.

4.0 Interferences

Same as Section 4.0 of either Method 13A or Method 13B, with the
addition of the following:
4.1 Magnetic Field Effects. Anemometer readings can be affected by
potroom magnetic field effects. Section 6.1 provides for minimization of
this interference through proper shielding or encasement of anemometer
components.

5.0 Safety

[[Page 366]]

6.0 Equipment and Supplies

Same as Section 6.0 of either Method 13A or Method 13B, as
applicable, with the addition of the following:
6.1 Velocity Measurement Apparatus.
6.1.1 Anemometer Specifications. Propeller anemometers, or
equivalent. Each anemometer shall meet the following specifications:
6.1.1.1 Its propeller shall be made of polystyrene, or similar
material of uniform density. To ensure uniformity of performance among
propellers, it is desirable that all propellers be made from the same
mold.
6.1.1.2 The propeller shall be properly balanced, to optimize
performance.
6.1.1.3 When the anemometer is mounted horizontally, its threshold
velocity shall not exceed 15 m/min (50 ft/min).
6.1.1.4 The measurement range of the anemometer shall extend to at
least 600 m/min (2,000 ft/min).
6.1.1.5 The anemometer shall be able to withstand prolonged exposure
to dusty and corrosive environments; one way of achieving this is to
purge the bearings of the anemometer continuously with filtered air
during operation.
6.1.1.6 All anemometer components shall be properly shielded or
encased, such that the performance of the anemometer is uninfluenced by
potroom magnetic field effects.
6.1.1.7 A known relationship shall exist between the electrical
output signal from the anemometer generator and the propeller shaft rpm
(see Section 10.2.1). Anemometers having other types of output signals
(e.g., optical) may be used, subject to the approval of the
Administrator. If other types of anemometers are used, there must be a
known relationship between output signal and shaft rpm (see Section
10.2.2).
6.1.1.8 Each anemometer shall be equipped with a suitable readout
system (see Section 6.1.3).
6.1.2 Anemometer Installation Requirements.
6.1.2.1 Single, Isolated Potroom. If the affected facility consists
of a single, isolated potroom (or potroom segment), install at least one
anemometer for every 85 m (280 ft) of roof monitor length. If the length
of the roof monitor divided by 85 m (280 ft) is not a whole number,
round the fraction to the nearest whole number to determine the number
of anemometers needed. For monitors that are less than 130 m (430 ft) in
length, use at least two anemometers. Divide the monitor cross-section
into as many equal areas as anemometers, and locate an anemometer at the
centroid of each equal area. See exception in Section 6.1.2.3.
6.1.2.2 Two or More Potrooms. If the affected facility consists of
two or more potrooms (or potroom segments) ducted to a common control
device, install anemometers in each potroom (or segment) that contains a
sampling manifold. Install at least one anemometer for every 85 m (280
ft) of roof monitor length of the potroom (or segment). If the potroom
(or segment) length divided by 85 m (280 ft) is not a whole number,
round the fraction to the nearest whole number to determine the number
of anemometers needed. If the potroom (or segment) length is less than
130 m (430 ft), use at least two anemometers. Divide the potroom (or
segment) monitor cross-section into as many equal areas as anemometers,
and locate an anemometer at the centroid of each equal area. See
exception in Section 6.1.2.3.
6.1.2.3 Placement of Anemometer at the Center of Manifold. At least
one anemometer shall be installed in the immediate vicinity (i.e.,
within 10 m (33 ft)) of the center of the manifold (see Section 6.2.1).
For its placement in relation to the width of the monitor, there are two
alternatives. The first is to make a velocity traverse of the width of
the roof monitor where an anemometer is to be placed and install the
anemometer at a point of average velocity along this traverse. The
traverse may be made with any suitable low velocity measuring device,
and shall be made during normal process operating conditions. The second
alternative is to install the anemometer half-way across the width of
the roof monitor. In this latter case, the velocity traverse need not be
conducted.
6.1.3 Recorders. Recorders that are equipped with suitable auxiliary
equipment (e.g., transducers) for converting the output signal from each
anemometer to a continuous recording of air flow velocity or to an
integrated measure of volumetric flowrate shall be used. A suitable
recorder is one that allows the output signal from the propeller
anemometer to be read to within 1 percent when the velocity is between
100 and 120 m/min (330 and 390 ft/min). For the purpose of recording
velocity, ``continuous'' shall mean one readout per 15-minute or shorter
time interval. A constant amount of time shall elapse between readings.
Volumetric flow rate may be determined by an electrical count of
anemometer revolutions. The recorders or counters shall permit
identification of the velocities or flowrates measured by each
individual anemometer.
6.1.4 Pitot Tube. Standard-type pitot tube, as described in Section
6.7 of Method 2, and having a coefficient of 0.99 0.01.
6.1.5 Pitot Tube (Optional). Isolated, Type S pitot, as described in
Section 6.1 of Method 2, and having a known coefficient, determined as
outlined in Section 4.1 of Method 2.
6.1.6 Differential Pressure Gauge. Inclined manometer, or
equivalent, as described in Section 6.1.2 of Method 2.
6.2 Roof Monitor Air Sampling System.

[[Page 367]]

6.2.1 Manifold System and Ductwork. A minimum of one manifold system
shall be installed for each potroom group. The manifold system and
ductwork shall meet the following specifications:
6.2.1.1 The manifold system and connecting duct shall be permanently
installed to draw an air sample from the roof monitor to ground level. A
typical installation of a duct for drawing a sample from a roof monitor
to ground level is shown in Figure 14-1 in Section 17.0. A plan of a
manifold system that is located in a roof monitor is shown in Figure 14-
2. These drawings represent a typical installation for a generalized
roof monitor. The dimensions on these figures may be altered slightly to
make the manifold system fit into a particular roof monitor, but the
general configuration shall be followed.
6.2.1.2 There shall be eight nozzles, each having a diameter of 0.40
to 0.50 m.
6.2.1.3 The length of the manifold system from the first nozzle to
the eighth shall be 35 m (115 ft) or eight percent of the length of the
potroom (or potroom segment) roof monitor, whichever is greater.
Deviation from this requirement is subject to the approval of the
Administrator.
6.2.1.4 The duct leading from the roof monitor manifold system shall
be round with a diameter of 0.30 to 0.40 m (1.0 to 1.3 ft). All
connections in the ductwork shall be leak-free.
6.2.1.5 As shown in Figure 14-2, each of the sample legs of the
manifold shall have a device, such as a blast gate or valve, to enable
adjustment of the flow into each sample nozzle.
6.2.1.6 The manifold system shall be located in the immediate
vicinity of one of the propeller anemometers (see Section 8.1.1.4) and
as close as possible to the midsection of the potroom (or potroom
segment). Avoid locating the manifold system near the end of a potroom
or in a section where the aluminum reduction pot arrangement is not
typical of the rest of the potroom (or potroom segment). The sample
nozzles shall be centered in the throat of the roof monitor (see Figure
14-1).
6.2.1.7 All sample-exposed surfaces within the nozzles, manifold,
and sample duct shall be constructed with 316 stainless steel.
Alternatively, aluminum may be used if a new ductwork is conditioned
with fluoride-laden roof monitor air for a period of six weeks before
initial testing. Other materials of construction may be used if it is
demonstrated through comparative testing, to the satisfaction of the
Administrator, that there is no loss of fluorides in the system.
6.2.1.8 Two sample ports shall be located in a vertical section of
the duct between the roof monitor and the exhaust fan (see Section
6.2.2). The sample ports shall be at least 10 duct diameters downstream
and three diameters upstream from any flow disturbance such as a bend or
contraction. The two sample ports shall be situated 90[deg] apart. One
of the sample ports shall be situated so that the duct can be traversed
in the plane of the nearest upstream duct bend.
6.2.2 Exhaust Fan. An industrial fan or blower shall be attached to
the sample duct at ground level (see Figure 14-1). This exhaust fan
shall have a capacity such that a large enough volume of air can be
pulled through the ductwork to maintain an isokinetic sampling rate in
all the sample nozzles for all flow rates normally encountered in the
roof monitor. The exhaust fan volumetric flow rate shall be adjustable
so that the roof monitor gases can be drawn isokinetically into the
sample nozzles. This control of flow may be achieved by a damper on the
inlet to the exhauster or by any other workable method.
6.3 Temperature Measurement Apparatus. To monitor and record the
temperature of the roof monitor effluent gas, and consisting of the
following:
6.3.1 Temperature Sensor. A temperature sensor shall be installed in
the roof monitor near the sample duct. The temperature sensor shall
conform to the specifications outlined in Method 2, Section 6.3.
6.3.2 Signal Transducer. Transducer, to change the temperature
sensor voltage output to a temperature readout.
6.3.3 Thermocouple Wire. To reach from roof monitor to signal
transducer and recorder.
6.3.4 Recorder. Suitable recorder to monitor the output from the
thermocouple signal transducer.

7.0 Reagents and Standards

Same as Section 7.0 of either Method 13A or Method 13B, as
applicable.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Roof Monitor Velocity Determination.
8.1.1 Velocity Estimate(s) for Setting Isokinetic Flow. To assist in
setting isokinetic flow in the manifold sample nozzles, the anticipated
average velocity in the section of the roof monitor containing the
sampling manifold shall be estimated before each test run. Any
convenient means to make this estimate may be used (e.g., the velocity
indicated by the anemometer in the section of the roof monitor
containing the sampling manifold may be continuously monitored during
the 24-hour period before the test run). If there is question as to
whether a single estimate of average velocity is adequate for an entire
test run (e.g., if velocities are anticipated to be significantly
different during different potroom operations), the test run may be
divided into two

[[Page 368]]

or more ``sub-runs,'' and a different estimated average velocity may be
used for each sub-run (see Section 8.4.2).
8.1.2 Velocity Determination During a Test Run. During the actual
test run, record the velocity or volumetric flowrate readings of each
propeller anemometer in the roof monitor. Readings shall be taken from
each anemometer at equal time intervals of 15 minutes or less (or
continuously).
8.2 Temperature Recording. Record the temperature of the roof
monitor effluent gases at least once every 2 hours during the test run.
8.3 Pretest Ductwork Conditioning. During the 24-hour period
immediately preceding the test run, turn on the exhaust fan, and draw
roof monitor air through the manifold system and ductwork. Adjust the
fan to draw a volumetric flow through the duct such that the velocity of
gas entering the manifold nozzles approximates the average velocity of
the air exiting the roof monitor in the vicinity of the sampling
manifold.
8.4 Manifold Isokinetic Sample Rate Adjustment(s).
8.4.1 Initial Adjustment. Before the test run (or first sub-run, if
applicable; see Sections 8.1.1 and 8.4.2), adjust the fan such that air
enters the manifold sample nozzles at a velocity equal to the
appropriate estimated average velocity determined under Section 8.1.1.
Use Equation 14-1 (Section 12.2.2) to determine the correct stream
velocity needed in the duct at the sampling location, in order for
sample gas to be drawn isokinetically into the manifold nozzles. Next,
verify that the correct stream velocity has been achieved, by performing
a pitot tube traverse of the sample duct (using either a standard or
Type S pitot tube); use the procedure outlined in Method 2.
8.4.2 Adjustments During Run. If the test run is divided into two or
more ``sub-runs'' (see Section 8.1.1), additional isokinetic rate
adjustment(s) may become necessary during the run. Any such adjustment
shall be made just before the start of a sub-run, using the procedure
outlined in Section 8.4.1 above.

Note: Isokinetic rate adjustments are not permissible during a sub-
run.

8.5 Pretest Preparation, Preliminary Determinations, Preparation of
Sampling Train, Leak-Check Procedures, Sampling Train Operation, and
Sample Recovery. Same as Method 13A, Sections 8.1 through 8.6, with the
exception of the following:
8.5.1 A single train shall be used for the entire sampling run.
Alternatively, if two or more sub-runs are performed, a separate train
may be used for each sub-run; note, however, that if this option is
chosen, the area of the sampling nozzle shall be the same (2 percent) for each train. If the test run is divided
into sub-runs, a complete traverse of the duct shall be performed during
each sub-run.
8.5.2 Time Per Run. Each test run shall last 8 hours or more; if
more than one run is to be performed, all runs shall be of approximately
the same (10 percent) length. If questions exist
as to the representativeness of an 8-hour test, a longer period should
be selected. Conduct each run during a period when all normal operations
are performed underneath the sampling manifold. For most recently-
constructed plants, 24 hours are required for all potroom operations and
events to occur in the area beneath the sampling manifold. During the
test period, all pots in the potroom group shall be operated such that
emissions are representative of normal operating conditions in the
potroom group.

9.0 Quality Control

9.1 Miscellaneous Quality Control Measures.

------------------------------------------------------------------------
Quality Control
Section Measure Effect
------------------------------------------------------------------------
8.0, 10.0..................... Sampling Ensure accurate
equipment leak- measurement of gas
check and flow rate in duct
calibration. and of sample
volume.
10.3, 10.4.................... Initial and Ensure accurate and
periodic precise measurement
performance of roof monitor
checks of roof effluent gas
monitor effluent temperature and flow
gas rate.
characterization
apparatus.
11.0.......................... Interference/ Minimize negative
recovery effects of used
efficiency check acid.
during
distillation.
------------------------------------------------------------------------

9.2 Volume Metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardization

Same as Section 10.0 of either Method 13A or Method 13B, as
applicable, with the addition of the following:
10.1 Manifold Intake Nozzles. The manifold intake nozzles shall be
calibrated when the manifold system is installed or, alternatively, the
manifold may be preassembled and the nozzles calibrated on the ground
prior to installation. The following procedures shall be observed:
10.1.1 Adjust the exhaust fan to draw a volumetric flow rate (refer
to Equation 14-1) such that the entrance velocity into each manifold
nozzle approximates the average effluent velocity in the roof monitor.
10.1.2 Measure the velocity of the air entering each nozzle by
inserting a standard pitot tube into a 2.5 cm or less diameter hole

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(see Figure 14-2) located in the manifold between each blast gate (or
valve) and nozzle. Note that a standard pitot tube is used, rather than
a type S, to eliminate possible velocity measurement errors due to
cross-section blockage in the small (0.13 m diameter) manifold leg
ducts. The pitot tube tip shall be positioned at the center of each
manifold leg duct. Take care to ensure that there is no leakage around
the pitot tube, which could affect the indicated velocity in the
manifold leg.
10.1.3 If the velocity of air being drawn into each nozzle is not
the same, open or close each blast gate (or valve) until the velocity in
each nozzle is the same. Fasten each blast gate (or valve) so that it
will remain in position, and close the pitot port holes.
10.2 Initial Calibration of Propeller Anemometers.
10.2.1 Anemometers that meet the specifications outlined in Section
6.1.1 need not be calibrated, provided that a reference performance
curve relating anemometer signal output to air velocity (covering the
velocity range of interest) is available from the manufacturer. If a
reference performance curve is not available from the manufacturer, such
a curve shall be generated.
For the purpose of this method, a ``reference'' performance curve is
defined as one that has been derived from primary standard calibration
data, with the anemometer mounted vertically. ``Primary standard'' data
are obtainable by: (a) direct calibration of one or more of the
anemometers by the National Institute of Standards and Technology
(NIST); (b) NIST-traceable calibration; or (c) Calibration by direct
measurement of fundamental parameters such as length and time (e.g., by
moving the anemometers through still air at measured rates of speed, and
recording the output signals).
10.2.2 Anemometers having output signals other than electrical
(e.g., optical) may be used, subject to the approval of the
Administrator. If other types of anemometers are used, a reference
performance curve shall be generated, using procedures subject to the
approval of the Administrator.
10.2.3 The reference performance curve shall be derived from at
least the following three points: 60 15, 900
100, and 1800 100 rpm.
10.3 Initial Performance Checks. Conduct these checks within 60 days
before the first performance test.
10.3.1 Anemometers. A performance-check shall be conducted as
outlined in Sections 10.3.1.1 through 10.3.1.3. Alternatively, any other
suitable method that takes into account the signal output, propeller
condition, and threshold velocity of the anemometer may be used, subject
to the approval of the Administrator.
10.3.1.1 Check the signal output of the anemometer by using an
accurate rpm generator (see Figure 14-3) or synchronous motors to spin
the propeller shaft at each of the three rpm settings described in
Section 10.2.3, and measuring the output signal at each setting. If, at
each setting, the output signal is within 5 percent of the
manufacturer's value, the anemometer can be used. If the anemometer
performance is unsatisfactory, the anemometer shall either be replaced
or repaired.
10.3.1.2 Check the propeller condition, by visually inspecting the
propeller, making note of any significant damage or warpage; damaged or
deformed propellers shall be replaced.
10.3.1.3 Check the anemometer threshold velocity as follows: With
the anemometer mounted as shown in Figure 14-4(A), fasten a known weight
(a straight-pin will suffice) to the anemometer propeller at a fixed
distance from the center of the propeller shaft. This will generate a
known torque; for example, a 0.1-g weight, placed 10 cm from the center
of the shaft, will generate a torque of 1.0 g-cm. If the known torque
causes the propeller to rotate downward, approximately 90[deg] [see
Figure 14-4(B)], then the known torque is greater than or equal to the
starting torque; if the propeller fails to rotate approximately 90[deg],
the known torque is less than the starting torque. By trying different
combinations of weight and distance, the starting torque of a particular
anemometer can be satisfactorily estimated. Once an estimate of the
starting torque has been obtained, the threshold velocity of the
anemometer (for horizontal mounting) can be estimated from a graph such
as Figure 14-5 (obtained from the manufacturer). If the horizontal
threshold velocity is acceptable [<15 m/min (50 ft/min), when this
technique is used], the anemometer can be used. If the threshold
velocity of an anemometer is found to be unacceptably high, the
anemometer shall either be replaced or repaired.
10.3.2 Recorders and Counters. Check the calibration of each
recorder and counter (see Section 6.1.2) at a minimum of three points,
approximately spanning the expected range of velocities. Use the
calibration procedures recommended by the manufacturer, or other
suitable procedures (subject to the approval of the Administrator). If a
recorder or counter is found to be out of calibration by an average
amount greater than 5 percent for the three calibration points, replace
or repair the system; otherwise, the system can be used.
10.3.3 Temperature Measurement Apparatus. Check the calibration of
the Temperature Measurement Apparatus, using the procedures outlined in
Section 10.3 of Method 2, at temperatures of 0, 100, and 150 [deg]C (32,
212, and 302 [deg]F). If the calibration is off by more than 5 [deg]C (9
[deg]F) at any of the temperatures,

[[Page 370]]

repair or replace the apparatus; otherwise, the apparatus can be used.
10.4 Periodic Performance Checks. Repeat the procedures outlined in
Section 10.3 no more than 12 months after the initial performance
checks. If the above systems pass the performance checks (i.e., if no
repair or replacement of any component is necessary), continue with the
performance checks on a 12-month interval basis. However, if any of the
above systems fail the performance checks, repair or replace the
system(s) that failed, and conduct the periodic performance checks on a
3-month interval basis, until sufficient information (to the
satisfaction of the Administrator) is obtained to establish a modified
performance check schedule and calculation procedure.

Note: If any of the above systems fails the 12-month periodic
performance checks, the data for the past year need not be recalculated.

11.0 Analytical Procedures

Same as Section 11.0 of either Method 13A or Method 13B.

12.0 Data Analysis and Calculations

Same as Section 12.0 of either Method 13A or Method 13B, as
applicable, with the following additions and exceptions:
12.1 Nomenclature.

A=Roof monitor open area, m\2\ (ft\2\).
Bws=Water vapor in the gas stream, portion by volume.
Cs=Average fluoride concentration in roof monitor air, mg F/
dscm (gr/dscf).
Dd=Diameter of duct at sampling location, m (ft).
Dn=Diameter of a roof monitor manifold nozzle, m (ft).
F=Emission Rate multiplication factor, dimensionless.
Ft=Total fluoride mass collected during a particular sub-run
(from Equation 13A-1 of Method 13A or Equation 13B-1 of Method 13B), mg
F^- (gr F^-).
Md=Mole fraction of dry gas, dimensionless.
Prm=Pressure in the roof monitor; equal to barometric
pressure for this application.
Qsd=Average volumetric flow from roof monitor at standard
conditions on a dry basis, m\3\/min.
Trm=Average roof monitor temperature (from Section 8.2),
[deg]C ( [deg]F).
Vd=Desired velocity in duct at sampling location, m/sec.
Vm=Anticipated average velocity (from Section 8.1.1) in
sampling duct, m/sec.
Vmt=Arithmetic mean roof monitor effluent gas velocity, m/
sec.
Vs=Actual average velocity in the sampling duct (from
Equation 2-9 of Method 2 and data obtained from Method 13A or 13B), m/
sec.

12.2 Isokinetic Sampling Check.
12.2.1 Calculate the arithmetic mean of the roof monitor effluent
gas velocity readings (vm) as measured by the anemometer in
the section of the roof monitor containing the sampling manifold. If two
or more sub-runs have been performed, the average velocity for each sub-
run may be calculated separately.
12.2.2 Calculate the expected average velocity (vd) in
the duct, corresponding to each value of vm obtained under
Section 12.2.1, using Equation 14-1.
[GRAPHIC] [TIFF OMITTED] TR17OC00.252

Where:

8=number of required manifold nozzles.
60=sec/min.

12.2.3 Calculate the actual average velocity (vs) in the
sampling duct for each run or sub-run according to Equation 2-9 of
Method 2, using data obtained during sampling (Section 8.0 of Method
13A).
12.2.4 Express each vs value from Section 12.2.3 as a percentage of
the corresponding vd value from Section 12.2.2.
12.2.4.1 If vs is less than or equal to 120 percent of
vd, the results are acceptable (note that in cases where the
above calculations have been performed for each sub-run, the results are
acceptable if the average percentage for all sub-runs is less than or
equal to 120 percent).
12.2.4.2 If vs is more than 120 percent of vd,
multiply the reported emission rate by the following factor:
[GRAPHIC] [TIFF OMITTED] TR17OC00.253

12.3 Average Velocity of Roof Monitor Effluent Gas. Calculate the
arithmetic mean roof monitor effluent gas velocity (vmt)
using all the velocity or volumetric flow readings from Section 8.1.2.
12.4 Average Temperature of Roof Monitor Effluent Gas. Calculate the
arithmetic mean roof monitor effluent gas temperature (Tm)
using all the temperature readings recorded in Section 8.2.
12.5 Concentration of Fluorides in Roof Monitor Effluent Gas.
12.5.1 If a single sampling train was used throughout the run,
calculate the average fluoride concentration for the roof monitor using
Equation 13A-2 of Method 13A.
12.5.2 If two or more sampling trains were used (i.e., one per sub-
run), calculate the average fluoride concentration for the run using
Equation 14-3:

[[Page 371]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.254

Where:

n=Total number of sub-runs.
12.6 Mole Fraction of Dry Gas.
[GRAPHIC] [TIFF OMITTED] TR17OC00.255

12.7 Average Volumetric Flow Rate of Roof Monitor Effluent Gas.
Calculate the arithmetic mean volumetric flow rate of the roof monitor
effluent gases using Equation 14-5.
[GRAPHIC] [TIFF OMITTED] TR17OC00.256

Where:

K1=0.3858 K/mm Hg for metric units,
=17.64 [deg]R/in. Hg for English units.

13.0 Method Performance [Reserved]

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

Same as Section 16.0 of either Method 13A or Method 13B, as
applicable, with the addition of the following:

1. Shigehara, R.T. A Guideline for Evaluating Compliance Test
Results (Isokinetic Sampling Rate Criterion). U.S. Environmental
Protection Agency, Emission Measurement Branch, Research Triangle Park,
NC. August 1977.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

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[GRAPHIC] [TIFF OMITTED] TR17OC00.257

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[GRAPHIC] [TIFF OMITTED] TR17OC00.258

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[GRAPHIC] [TIFF OMITTED] TR17OC00.259

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[GRAPHIC] [TIFF OMITTED] TR17OC00.260

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[GRAPHIC] [TIFF OMITTED] TR17OC00.261

Method 14A--Determination of Total Fluoride Emissions from Selected
Sources at Primary Aluminum Production Facilities

Note: This method does not include all 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 methods: Method 5, Methods 13A and 13B, and
Method 14 of this appendix.

1.0 Scope and Application
1.1 Analytes.

[[Page 377]]

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Total fluorides................. None assigned..... Not determined.
Includes hydrogen fluoride...... 007664-39-3....... Not determined.
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of total fluorides (TF) emissions from sources specified in the
applicable regulation. This method was developed by consensus with the
Aluminum Association and the U.S. Environmental Protection Agency (EPA).
2.0 Summary of Method
2.1 Total fluorides, in the form of solid and gaseous fluorides, are
withdrawn from the ascending air stream inside of an aluminum reduction
potroom and, prior to exiting the potroom roof monitor, into a specific
cassette arrangement. The cassettes are connected by tubing to
flowmeters and a manifold system that allows for the equal distribution
of volume pulled through each cassette, and finally to a dry gas meter.
The cassettes have a specific internal arrangement of one unaltered
cellulose filter and support pad in the first section of the cassette
for solid fluoride retention and two cellulose filters with support pads
that are impregnated with sodium formate for the chemical absorption of
gaseous fluorides in the following two sections of the cassette. A
minimum of eight cassettes shall be used for a potline and shall be
strategically located at equal intervals across the potroom roof so as
to encompass a minimum of 8 percent of the total length of the potroom.
A greater number of cassettes may be used should the regulated facility
choose to do so. The mass flow rate of pollutants is determined with
anemometers and temperature sensing devices located immediately below
the opening of the roof monitor and spaced evenly within the cassette
group.
3.0 Definitions
3.1 Cassette. A segmented, styrene acrylonitrile cassette
configuration with three separate segments and a base, for the purpose
of this method, to capture and retain fluoride from potroom gases.
3.2 Cassette arrangement. The cassettes, tubing, manifold system,
flowmeters, dry gas meter, and any other related equipment associated
with the actual extraction of the sample gas stream.
3.3 Cassette group. That section of the potroom roof monitor where a
distinct group of cassettes is located.
3.4 Potline. A single, discrete group of electrolytic reduction
cells electrically connected in series, in which alumina is reduced to
form aluminum.
3.5 Potroom. A building unit that houses a group of electrolytic
reduction cells in which aluminum is produced.
3.6 Potroom group. An uncontrolled potroom, a potroom that is
controlled individually, or a group of potrooms or potroom segments
ducted to a common primary control system.
3.7 Primary control system. The equipment used to capture the gases
and particulate matter generated during the reduction process and the
emission control device(s) used to remove pollutants prior to discharge
of the cleaned gas to the atmosphere.
3.8 Roof monitor. That portion of the roof of a potroom building
where gases, not captured at the cell, exit from the potroom.
3.9 Total fluorides (TF). Elemental fluorine and all fluoride
compounds as measured by Methods 13A or 13B of this appendix or by an
approved alternative method.
4.0 Interferences and Known Limitations
4.1 There are two principal categories of limitations that must be
addressed when using this method. The first category is sampling bias
and the second is analytical bias. Biases in sampling can occur when
there is an insufficient number of cassettes located along the roof
monitor of a potroom or if the distribution of those cassettes is
spatially unequal. Known sampling biases also can occur when there are
leaks within the cassette arrangement and if anemometers and temperature
devices are not providing accurate data. Applicable instruments must be
properly calibrated to avoid sampling bias. Analytical biases can occur
when instrumentation is not calibrated or fails calibration and the
instrument is used out of proper calibration. Additionally, biases can
occur in the laboratory if fusion crucibles retain residual fluorides
over lengthy periods of use. This condition could result in falsely
elevated fluoride values. Maintaining a clean work environment in the
laboratory is crucial to producing accurate values.
4.2 Biases during sampling can be avoided by properly spacing the
appropriate number of cassettes along the roof monitor, conducting leak
checks of the cassette arrangement, calibrating the dry gas meter every
30 days, verifying the accuracy of individual flowmeters (so that there
is no more than 5 percent difference in the volume pulled between any
two flowmeters), and calibrating or replacing anemometers and
temperature sensing devices as necessary to maintain true data
generation.
4.3 Analytical biases can be avoided by calibrating instruments
according to the manufacturer's specifications prior to conducting any
analyses, by performing internal and external audits of up to 10 percent
of all samples analyzed, and by rotating individual crucibles as the
``blank'' crucible to detect any potential residual fluoride carry-over
to samples. Should any contamination be discovered in the blank
crucible, the crucible shall be thoroughly cleaned to remove any
detected residual fluorides and a ``blank'' analysis conducted again to
evaluate the effectiveness of the cleaning. The crucible

[[Page 378]]

shall remain in service as long as no detectable residual fluorides are
present.
5.0 Safety
5.1 This method may involve the handling of hazardous materials in
the analytical phase. This method does not purport to address all of the
potential safety hazards associated with its use. It is the
responsibility of the user to establish appropriate safety and health
practices and determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burn as thermal burn.
5.3 Sodium Hydroxide (NaOH). Causes severe damage to eyes and skin.
Inhalation causes irritation to nose, throat, and lungs. Reacts
exothermically with limited amounts of water.
5.4 Perchloric Acid (HClO4). Corrosive to eyes, skin,
nose, and throat. Provide ventilation to limit exposure. Very strong
oxidizer. Keep separate from water and oxidizable materials to prevent
vigorous evolution of heat, spontaneous combustion, or explosion. Heat
solutions containing HClO4 only in hoods specifically designed for
HClO4.
6.0 Equipment and Supplies
6.1 Sampling.
6.1.1 Cassette arrangement. The cassette itself is a three-piece,
styrene acrylonitrile cassette unit (a Gelman Sciences product), 37
millimeter (mm), with plastic connectors. In the first section (the
intake section), an untreated Gelman Sciences 37 mm, 0.8 micrometer
([micro]m) DM-800 metricel membrane filter and cellulose support pad, or
equivalent, is situated. In the second and third segments of the
cassette there is placed one each of Gelman Sciences 37 mm, 5 [micro]m
GLA-5000 low-ash PVC filter with a cellulose support pad or equivalent
product. Each of these two filters and support pads shall have been
immersed in a solution of 10 percent sodium formate (volume/volume in an
ethyl alcohol solution). The impregnated pads shall be placed in the
cassette segments while still wet and heated at 50 [deg]C (122 [deg]F)
until the pad is completely dry. It is important to check for a proper
fit of the filter and support pad to the cassette segment to ensure that
there are no areas where gases could bypass the filter. Once all of the
cassette segments have been prepared, the cassette shall be assembled
and a plastic plug shall be inserted into the exhaust hole of the
cassette. Prior to placing the cassette into service, the space between
each segment shall be taped with an appropriately durable tape to
prevent the infiltration of gases through the points of connection, and
an aluminum nozzle shall be inserted into the intake hole of the
cassette. The aluminum nozzle shall have a short section of tubing
placed over the opening of the nozzle, with the tubing plugged to
prevent dust from entering the nozzle and to prepare the nozzle for the
cassette arrangement leak check. An alternate nozzle type can be used if
historical results or scientific demonstration of applicability can be
shown.
6.1.2 Anemometers and temperature sensing devices. To calculate the
mass flow rate of TF from the roof monitor under standard conditions,
anemometers that meet the specifications in section 2.1.1 in Method 14
of this appendix or an equivalent device yielding equivalent information
shall be used. A recording mechanism capable of accurately recording the
exit gas temperature at least every 2 hours shall be used.
6.1.3 Barometer. To correct the volumetric flow from the potline
roof monitor to standard conditions, a mercury (Hg), aneroid, or other
barometer capable of measuring atmospheric pressure to within 2.5 mm
[0.1 inch (in)] Hg shall be used.

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

6.2 Sample recovery.
6.2.1 Hot plate.
6.2.2 Muffle furnace.
6.2.3 Nickel crucible.
6.2.4 Stirring rod. Teflon.
6.2.5 Volumetric flask. 50-milliliter (ml).
6.2.6 Plastic vial. 50-ml.
6.3 Analysis.
6.3.1 Primary analytical method. An automated analyzer having the
following components or equivalent: a multichannel proportioning pump,
multiposition sampler, voltage stabilizer, colorimeter, instrument
recording device, microdistillation apparatus, flexible
Teflon^[reg] heating bath, vacuum pump, pulse suppressers and
an air flow system.
6.3.2 Secondary analytical method. Specific Ion Electrode (SIE).
7.0 Reagents and Standards
7.1 Water. Deionized distilled to conform to ASTM Specification D
1193-77, Type 3 (incorporated by reference in Sec. 60.17(a)(22) of this
part). The KMnO4 test for oxidizable organic matter may be
omitted when high concentrations of organic matter are not expected to
be present.
7.2 Calcium oxide.
7.3 Sodium hydroxide (NaOH). Pellets.

[[Page 379]]

7.4 Perchloric acid (HClO4). Mix 1:1 with water. Sulfuric
acid (H2SO4) may be used in place of
HClO4.
7.5 Audit samples. The audit samples discussed in section 9.1 shall
be prepared from reagent grade, water soluble stock reagents, or
purchased as an aqueous solution from a commercial supplier. If the
audit stock solution is purchased from a commercial supplier, the
standard solution must be accompanied by a certificate of analysis or an
equivalent proof of fluoride concentration.
8.0 Sample Collection and Analysis
8.1 Preparing cassette arrangement for sampling. The cassettes are
initially connected to flexible tubing. The tubing is connected to
flowmeters and a manifold system. The manifold system is connected to a
dry gas meter (Research Appliance Company model 201009 or equivalent).
The length of tubing is managed by pneumatically or electrically
operated hoists located in the roof monitor, and the travel of the
tubing is controlled by encasing the tubing in aluminum conduit. The
tubing is lowered for cassette insertion by operating a control box at
floor level. Once the cassette has been securely inserted into the
tubing and the leak check performed, the tubing and cassette are raised
to the roof monitor level using the floor level control box.
Arrangements similar to the one described are acceptable if the
scientific sample collection principles are followed.
8.2 Test run sampling period. A test run shall comprise a minimum of
a 24-hour sampling event encompassing at least eight cassettes per
potline (or four cassettes per potroom group). Monthly compliance shall
be based on three test runs during the month. Test runs of greater than
24 hours are allowed; however, three such runs shall be conducted during
the month.
8.3 Leak-check procedures.
8.3.1 Pretest leak check. A pretest leak-check is recommended;
however, it is not required. To perform a pretest leak-check after the
cassettes have been inserted into the tubing, isolate the cassette to be
leak-checked by turning the valves on the manifold to stop all flows to
the other sampling points connected to the manifold and meter. The
cassette, with the plugged tubing section securing the intake of the
nozzle, is subjected to the highest vacuum expected during the run. If
no leaks are detected, the tubing plug can be briefly removed as the dry
gas meter is rapidly turned off.
8.3.2 Post-test leak check. A leak check is required at the
conclusion of each test run for each cassette. The leak check shall be
performed in accordance with the procedure outlined in section 8.3.1 of
this method except that it shall be performed at a vacuum greater than
the maximum vacuum reached during the test run. If the leakage rate is
found to be no greater than 4 percent of the average sampling rate, the
results are acceptable. If the leakage rate is greater than 4 percent of
the average sampling rate, either record the leakage rate and correct
the sampling volume as discussed in section 12.4 of this method or void
the test run if the minimum number of cassettes were used. If the number
of cassettes used was greater than the minimum required, discard the
leaking cassette and use the remaining cassettes for the emission
determination.
8.3.3 Anemometers and temperature sensing device placement. Install
the recording mechanism to record the exit gas temperature. Anemometers
shall be installed as required in section 6.1.2 of Method 14 of this
appendix, except replace the word ``manifold'' with ``cassette group''
in section 6.1.2.3. These two different instruments shall be located
near each other along the roof monitor. See conceptual configurations in
Figures 14A-1, 14A-2, and 14A-3 of this method. Fewer temperature
devices than anemometers may be used if at least one temperature device
is located within the span of the cassette group. Other anemometer
location siting scenarios may be acceptable as long as the exit velocity
of the roof monitor gases is representative of the entire section of the
potline being sampled.
8.4 Sampling. The actual sample run shall begin with the removal of
the tubing and plug from the cassette nozzle. Each cassette is then
raised to the roof monitor area, the dry gas meter is turned on, and the
flowmeters are set to the calibration point, which allows an equal
volume of sampled gas to enter each cassette. The dry gas meter shall be
set to a range suitable for the specific potroom type being sampled that
will yield valid data known from previous experience or a range
determined by the use of the calculation in section 12 of this method.
Parameters related to the test run that shall be recorded, either during
the test run or after the test run if recording devices are used,
include: anemometer data, roof monitor exit gas temperature, dry gas
meter temperature, dry gas meter volume, and barometric pressure. At the
conclusion of the test run, the cassettes shall be lowered, the dry gas
meter turned off, and the volume registered on the dry gas meter
recorded. The post-test leak check procedures described in section 8.3.2
of this method shall be performed. All data relevant to the test shall
be recorded on a field data sheet and maintained on file.
8.5 Sample recovery.
8.5.1 The cassettes shall be brought to the laboratory with the
intake nozzle contents protected with the section of plugged tubing
previously described. The exterior of cassettes shall carefully be wiped
free of any dust or debris, making sure that any falling dust or debris
does not present a potential laboratory contamination problem.

[[Page 380]]

8.5.2 Carefully remove all tape from the cassettes and remove the
initial filter, support pad, and all loose solids from the first
(intake) section of the cassette. Fold the filter and support pad
several times and, along with all loose solids removed from the interior
of the first section of the cassette, place them into a nickel crucible.
Using water, wash the interior of the nozzle into the same nickel
crucible. Add 0.1 gram (g) [0.1 milligram (mg)] of
calcium oxide and a sufficient amount of water to make a loose slurry.
Mix the contents of the crucible thoroughly with a Teflon'' stirring
rod. After rinsing any adhering residue from the stirring rod back into
the crucible, place the crucible on a hot plate or in a muffle furnace
until all liquid is evaporated and allow the mixture to gradually char
for 1 hour.
8.5.3 Transfer the crucible to a cold muffle furnace and ash at 600
[deg]C (1,112 [deg]F). Remove the crucible after the ashing phase and,
after the crucible cools, add 3.0 g (0.1 g) of
NaOH pellets. Place this mixture in a muffle furnace at 600 [deg]C
(1,112 [deg]F) for 3 minutes. Remove the crucible and roll the melt so
as to reach all of the ash with the molten NaOH. Let the melt cool to
room temperature. Add 10 to 15 ml of water to the crucible and place it
on a hot plate at a low temperature setting until the melt is soft or
suspended. Transfer the contents of the crucible to a 50-ml volumetric
flask. Rinse the crucible with 20 ml of 1:1 perchloric acid or 20 ml of
1:1 sulfuric acid in two (2) 10 ml portions. Pour the acid rinse slowly
into the volumetric flask and swirl the flask after each addition. Cool
to room temperature. The product of this procedure is particulate
fluorides.
8.5.4 Gaseous fluorides can be isolated for analysis by folding the
gaseous fluoride filters and support pads to approximately \1/4\ of
their original size and placing them in a 50-ml plastic vial. To the
vial add exactly 10 ml of water and leach the sample for a minimum of 1
hour. The leachate from this process yields the gaseous fluorides for
analysis.
9.0 Quality Control
9.1 Laboratory auditing. Laboratory audits of specific and known
concentrations of fluoride shall be submitted to the laboratory with
each group of samples submitted for analysis. An auditor shall prepare
and present the audit samples as a ``blind'' evaluation of laboratory
performance with each group of samples submitted to the laboratory. The
audits shall be prepared to represent concentrations of fluoride that
could be expected to be in the low, medium and high range of actual
results. Average recoveries of all three audits must equal 90 to 110
percent for acceptable results; otherwise, the laboratory must
investigate procedures and instruments for potential problems.

Note: The analytical procedure allows for the analysis of individual
or combined filters and pads from the cassettes provided that equal
volumes (10 percent) are sampled through each
cassette.

10.0 Calibrations
10.1 Equipment evaluations. To ensure the integrity of this method,
periodic calibrations and equipment replacements are necessary.
10.1.1 Metering system. At 30-day intervals the metering system
shall be calibrated. Connect the metering system inlet to the outlet of
a wet test meter that is accurate to 1 percent. Refer to Figure 5-4 of
Method 5 of this appendix. The wet-test meter shall have a capacity of
30 liters/revolution [1 cubic foot (ft\3\)/revolution]. A spirometer of
400 liters (14 ft\3\) or more capacity, or equivalent, may be used for
calibration; however, a wet-test meter is usually more practical. The
wet-test meter shall be periodically tested with a spirometer or a
liquid displacement meter to ensure the accuracy. Spirometers or wet-
test meters of other sizes may be used, provided that the specified
accuracies of the procedure are maintained. Run the metering system pump
for about 15 min. with the orifice manometer indicating a median reading
as expected in field use to allow the pump to warm up and to thoroughly
wet the interior of the wet-test meter. Then, at each of a minimum of
three orifice manometer settings, pass an exact quantity of gas through
the wet-test meter and record the volume indicated by the dry gas meter.
Also record the barometric pressure, the temperatures of the wet test
meter, the inlet temperatures of the dry gas meter, and the temperatures
of the outlet of the dry gas meter. Record all calibration data on a
form similar to the one shown in Figure 5-5 of Method 5 of this appendix
and calculate Y, the dry gas meter calibration factor, and [Delta]H@,
the orifice calibration factor at each orifice setting. Allowable
tolerances for Y and [Delta]H@ are given in Figure 5-6 of Method 5 of
this appendix.
10.1.2 Estimating volumes for initial test runs. For a facility's
initial test runs, the regulated facility must have a target or desired
volume of gases to be sampled and a target range of volumes to use
during the calibration of the dry gas meter. Use Equations 14A-1 and
14A-2 in section 12 of this method to derive the target dry gas meter
volume (Fv) for these purposes.
10.1.3 Calibration of anemometers and temperature sensing devices.
If the standard anemometers in Method 14 of this appendix are used, the
calibration and integrity evaluations in sections 10.3.1.1 through
10.3.1.3 of Method 14 of this appendix shall be used as well as the
recording device described in section 2.1.3 of Method 14. The
calibrations or complete change-outs of anemometers shall take place at
a minimum of once per year. The temperature sensing and recording
devices shall be calibrated according to the manufacturer's
specifications.

[[Page 381]]

10.1.4 Calibration of flowmeters. The calibration of flowmeters is
necessary to ensure that an equal volume of sampled gas is entering each
of the individual cassettes and that no large differences, which could
possibly bias the sample, exist between the cassettes.
10.1.4.1 Variable area, 65 mm flowmeters or equivalent shall be
used. These flowmeters can be mounted on a common base for convenience.
These flowmeters shall be calibrated by attaching a prepared cassette,
complete with filters and pads, to the flowmeter and then to the system
manifold. This manifold is an aluminum cylinder with valved inlets for
connections to the flowmeters/cassettes and one outlet to a dry gas
meter. The connection is then made to the wet-test meter and finally to
a dry gas meter. All connections are made with tubing.
10.1.4.2 Turn the dry gas meter on for 15 min. in preparation for
the calibration. Turn the dry gas meter off and plug the intake hole of
the cassette. Turn the dry gas meter back on to evaluate the entire
system for leaks. If the dry gas meter shows a leakage rate of less than
0.02 ft³/min at 10 in. of Hg vacuum as noted on the dry gas
meter, the system is acceptable to further calibration.
10.1.4.3 With the dry gas meter turned on and the flow indicator
ball at a selected flow rate, record the exact amount of gas pulled
through the flowmeter by taking measurements from the wet test meter
after exactly 10 min. Record the room temperature and barometric
pressure. Conduct this test for all flowmeters in the system with all
flowmeters set at the same indicator ball reading. When all flowmeters
have gone through the procedure above, correct the volume pulled through
each flowmeter to standard conditions. The acceptable difference between
the highest and lowest flowmeter rate is 5 percent. Should one or more
flowmeters be outside of the acceptable limit of 5 percent, repeat the
calibration procedure at a lower or higher indicator ball reading until
all flowmeters show no more than 5 percent difference among them.
10.1.4.4 This flowmeter calibration shall be conducted at least once
per year.
10.1.5 Miscellaneous equipment calibrations. Miscellaneous equipment
used such as an automatic recorder/ printer used to measure dry gas
meter temperatures shall be calibrated according to the manufacturer's
specifications in order to maintain the accuracy of the equipment.
11.0 Analytical Procedure
11.1 The preferred primary analytical determination of the
individual isolated samples or the combined particulate and gaseous
samples shall be performed by an automated methodology. The analytical
method for this technology shall be based on the manufacturer's
instructions for equipment operation and shall also include the analysis
of five standards with concentrations in the expected range of the
actual samples. The results of the analysis of the five standards shall
have a coefficient of correlation of at least 0.99. A check standard
shall be analyzed as the last sample of the group to determine if
instrument drift has occurred. The acceptable result for the check
standard is 95 to 105 percent of the standard's true value.
11.2 The secondary analytical method shall be by specific ion
electrode if the samples are distilled or if a TISAB IV buffer is used
to eliminate aluminum interferences. Five standards with concentrations
in the expected range of the actual samples shall be analyzed, and a
coefficient of correlation of at least 0.99 is the minimum acceptable
limit for linearity. An exception for this limit for linearity is a
condition when low-level standards in the range of 0.01 to 0.48 [micro]g
fluoride/ml are analyzed. In this situation, a minimum coefficient of
correlation of 0.97 is required. TISAB II shall be used for low-level
analyses.
12.0 Data Analysis and Calculations
12.1 Carry out calculations, retaining at least one extra decimal
point beyond that of the acquired data. Round off values after the final
calculation. Other forms of calculations may be used as long as they
give equivalent results.
12.2 Estimating volumes for initial test runs.
[GRAPHIC] [TIFF OMITTED] TR07OC97.000

Where

Fv=Desired volume of dry gas to be sampled, ft\3\.
Fd=Desired or analytically optimum mass of TF per cassette,
micrograms of TF per cassette ([micro]g/cassette).
X=Number of cassettes used.
Fe=Typical concentration of TF in emissions to be sampled,
[micro]g/ft \3\, calculated from Equation 14A-2.

[[Page 382]]

[GRAPHIC] [TIFF OMITTED] TR07OC97.001

Where

Re=Typical emission rate from the facility, pounds of TF per
ton (lb/ton) of aluminum.
Rp=Typical production rate of the facility, tons of aluminum
per minute (ton/min).
Vr=Typical exit velocity of the roof monitor gases, feet per
minute (ft/min).
Ar=Open area of the roof monitor, square feet
(ft²).

12.2.1 Example calculation. Assume that the typical emission rate
(Re) is 1.0 lb TF/ton of aluminum, the typical roof vent gas
exit velocity (Vr) is 250 ft/min, the typical production rate
(Rp) is 0.10 ton/min, the known open area for the roof
monitor (Ar) is 8,700 ft², and the desired
(analytically optimum) mass of TF per cassette is 1,500 [micro]g. First
calculate the concentration of TF per cassette (Fe) in
[micro]g/ft³ using Equation 14A-2. Then calculate the desired
volume of gas to be sampled (Fv) using Equation 14A-1.
[GRAPHIC] [TIFF OMITTED] TR07OC97.002

[GRAPHIC] [TIFF OMITTED] TR07OC97.003

This is a total of 575.40 ft³ for eight cassettes or
71.925 ft³/cassette.
12.3 Calculations of TF emissions from field and laboratory data
that would yield a production related emission rate can be calculated as
follows:
12.3.1 Obtain a standard cubic feet (scf) value for the volume
pulled through the dry gas meter for all cassettes by using the field
and calibration data and Equation 5-1 of Method 5 of this appendix.
12.3.2 Derive the average quantity of TF per cassette (in [micro]g
TF/cassette) by adding all laboratory data for all cassettes and
dividing this value by the total number of cassettes used. Divide this
average TF value by the corrected dry gas meter volume for each
cassette; this value then becomes TFstd ([micro]g/
ft³).
12.3.3 Calculate the production-based emission rate (Re)
in lb/ton using Equation 14A-5.
[GRAPHIC] [TIFF OMITTED] TR07OC97.004

12.3.4 As an example calculation, assume eight cassettes located in
a potline were used to sample for 72 hours during the run. The analysis
of all eight cassettes yielded a total of 3,000 [micro]g of TF. The dry
gas meter volume was corrected to yield a total of 75 scf per cassette,
which yields a value for TFstd of 3,000/75=5 [micro]g/
ft³. The open area of the roof monitor for the potline
(Ar) is 17,400 ft². The exit velocity of the roof
monitor gases (Vr) is 250 ft/min. The production rate of
aluminum over the previous 720 hours was 5,000 tons, which is 6.94 tons/
hr or 0.116 ton/min (Rp). Substituting these values into
Equation 14A-5 yields:

[[Page 383]]

[GRAPHIC] [TIFF OMITTED] TR07OC97.005

12.4 Corrections to volumes due to leakage. Should the post-test
leak check leakage rate exceed 4 percent as described in section 8.3.2
of this method, correct the volume as detailed in Case I in section 6.3
of Method 5 of this appendix.
[GRAPHIC] [TIFF OMITTED] TR07OC97.020

[[Page 384]]

[GRAPHIC] [TIFF OMITTED] TR07OC97.021

[[Page 385]]

[GRAPHIC] [TIFF OMITTED] TR07OC97.022

[[Page 386]]

Method 15--Determination of Hydrogen Sulfide, Carbonyl Sulfide, and
Carbon Disulfide Emissions From Stationary Sources

Note: This method is not inclusive with respect to 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 have a thorough
knowledge of gas chromatography techniques.

1.0 Scope and Application

1.1 Analytes.

------------------------------------------------------------------------
Sensitivity (See Sec
Analyte CAS No. 13.2)
------------------------------------------------------------------------
Carbon disulfide [CS2]......... 75-15-0 0.5 ppmv
Carbonyl sulfide [COS]......... 463-58-1 0.5 ppmv
Hydrogen sulfide [H2S]......... 7783-06-4 0.5 ppmv
------------------------------------------------------------------------

1.2 Applicability.
1.2.1 This method applies to the determination of emissions of
reduced sulfur compounds from tail gas control units of sulfur recovery
plants, H2S in fuel gas for fuel gas combustion devices, and
where specified in other applicable subparts of the regulations.
1.2.2 The method described below uses the principle of gas
chromatographic (GC) separation and flame photometric detection (FPD).
Since there are many systems or sets of operating conditions that
represent useable methods for determining sulfur emissions, all systems
which employ this principle, but differ only in details of equipment and
operation, may be used as alternative methods, provided that the
calibration precision and sample-line loss criteria are met.
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 A gas sample is extracted from the emission source and diluted
with clean dry air (if necessary). An aliquot of the diluted sample is
then analyzed for CS2, COS, and H2S by GC/FPD.

3.0 Definitions [Reserved]

4.0 Interferences

4.1 Moisture Condensation. Moisture condensation in the sample
delivery system, the analytical column, or the FPD burner block can
cause losses or interferences. This potential is eliminated by heating
the probe, filter box, and connections, and by maintaining the
SO2 scrubber in an ice water bath. Moisture is removed in the
SO2 scrubber and heating the sample beyond this point is not
necessary provided the ambient temperature is above 0 [deg]C (32
[deg]F). Alternatively, moisture may be eliminated by heating the sample
line, and by conditioning the sample with dry dilution air to lower its
dew point below the operating temperature of the GC/FPD analytical
system prior to analysis.
4.2 Carbon Monoxide (CO) and Carbon Dioxide (CO2). CO and
CO2 have substantial desensitizing effects on the FPD even
after 9:1 dilution. (Acceptable systems must demonstrate that they have
eliminated this interference by some procedure such as eluting CO and
CO2 before any of the sulfur compounds to be measured.)
Compliance with this requirement can be demonstrated by submitting
chromatograms of calibration gases with and without CO2 in
the diluent gas. The CO2 level should be approximately 10
percent for the case with CO2 present. The two chromatograms
should show agreement within the precision limits of Section 13.3.
4.3 Elemental Sulfur. The condensation of sulfur vapor in the
sampling system can lead to blockage of the particulate filter. This
problem can be minimized by observing the filter for buildup and
changing as needed.
4.4 Sulfur Dioxide (SO2). SO2 is not a
specific interferent but may be present in such large amounts that it
cannot be effectively separated from the other compounds of interest.
The SO2 scrubber described in Section 6.1.3 will effectively
remove SO2 from the sample.
4.5 Alkali Mist. Alkali mist in the emissions of some control
devices may cause a rapid increase in the SO2 scrubber pH,
resulting in low sample recoveries. Replacing the SO2
scrubber contents after each run will minimize the chances of
interference in these cases.

5.0 Safety

[[Page 387]]

6.0 Equipment and Supplies

6.1 Sample Collection. See Figure 15-1. The sampling train component
parts are discussed in the following sections:
6.1.1 Probe. The probe shall be made of Teflon or Teflon-lined
stainless steel and heated to prevent moisture condensation. It shall be
designed to allow calibration gas to enter the probe at or near the
sample point entry. Any portion of the probe that contacts the stack gas
must be heated to prevent moisture condensation. The probe described in
Section 6.1.1 of Method 16A having a nozzle directed away from the gas
stream is recommended for sources having particulate or mist emissions.
Where very high stack temperatures prohibit the use of Teflon probe
components, glass or quartz-lined probes may serve as substitutes.
6.1.2 Particulate Filter. 50-mm Teflon filter holder and a 1- to 2-
micron porosity Teflon filter (available through Savillex Corporation,
5325 Highway 101, Minnetonka, Minnesota 55343). The filter holder must
be maintained in a hot box at a temperature of at least 120 [deg]C (248
[deg]F).
6.1.3 SO2 Scrubber. Three 300-ml Teflon segment impingers
connected in series with flexible, thick-walled, Teflon tubing.
(Impinger parts and tubing available through Savillex.) The first two
impingers contain 100 ml of citrate buffer, and the third impinger is
initially dry. The tip of the tube inserted into the solution should be
constricted to less than 3-mm (\1/8\-in.) ID and should be immersed to a
depth of at least 50 cm (2 in.). Immerse the impingers in an ice water
bath and maintain near 0 [deg]C. The scrubber solution will normally
last for a 3-hour run before needing replacement. This will depend upon
the effects of moisture and particulate matter on the solution strength
and pH. Connections between the probe, particulate filter, and
SO2 scrubber shall be made of Teflon and as short in length
as possible. All portions of the probe, particulate filter, and
connections prior to the SO2 scrubber (or alternative point
of moisture removal) shall be maintained at a temperature of at least
120 [deg]C (248 [deg]F).
6.1.4 Sample Line. Teflon, no greater than 13-mm (\1/2\-in.) ID.
Alternative materials, such as virgin Nylon, may be used provided the
line-loss test is acceptable.
6.1.5 Sample Pump. The sample pump shall be a leakless Teflon-coated
diaphragm type or equivalent.
6.2 Analysis. The following items are needed for sample analysis:
6.2.1 Dilution System. The dilution system must be constructed such
that all sample contacts are made of Teflon, glass, or stainless steel.
It must be capable of approximately a 9:1 dilution of the sample.
6.2.2 Gas Chromatograph (see Figure 15-2). The gas chromatograph
must have at least the following components:
6.2.2.1 Oven. Capable of maintaining the separation column at the
proper operating temperature 1 [deg]C.
6.2.2.2 Temperature Gauge. To monitor column oven, detector, and
exhaust temperature 1 [deg]C.
6.2.2.3 Flow System. Gas metering system to measure sample, fuel,
combustion gas, and carrier gas flows.
6.2.2.4 Flame Photometric Detector.
6.2.2.4.1 Electrometer. Capable of full scale amplification of
linear ranges of 10^-9 to 10^-4 amperes full scale.
6.2.2.4.2 Power Supply. Capable of delivering up to 750 volts.
6.2.2.5 Recorder. Compatible with the output voltage range of the
electrometer.
6.2.2.6 Rotary Gas Valves. Multiport Teflon-lined valves equipped
with sample loop. Sample loop volumes shall be chosen to provide the
needed analytical range. Teflon tubing and fittings shall be used
throughout to present an inert surface for sample gas. The GC shall be
calibrated with the sample loop used for sample analysis.
6.2.2.7 GC Columns. The column system must be demonstrated to be
capable of resolving three major reduced sulfur compounds:
H2S, COS, and CS2. To demonstrate that adequate
resolution has been achieved, a chromatogram of a calibration gas
containing all three reduced sulfur compounds in the concentration range
of the applicable standard must be submitted. Adequate resolution will
be defined as base line separation of adjacent peaks when the amplifier
attenuation is set so that the smaller peak is at least 50 percent of
full scale. Base line separation is defined as a return to zero (5 percent) in the interval between peaks. Systems not
meeting this criteria may be considered alternate methods subject to the
approval of the Administrator.
6.3 Calibration System (See Figure 15-3). The calibration system
must contain the following components:
6.3.1 Flow System. To measure air flow over permeation tubes within
2 percent. Each flowmeter shall be calibrated after each complete test
series with a wet-test meter. If the flow measuring device differs from
the wet-test meter by more than 5 percent, the completed test shall be
discarded. Alternatively, use the flow data that will yield the lowest
flow measurement. Calibration with a wet-test meter before a test is
optional. Flow over the permeation device may also be determined using a
soap bubble flowmeter.
6.3.2 Constant Temperature Bath. Device capable of maintaining the
permeation tubes at the calibration temperature within 0.1 [deg]C.

[[Page 388]]

6.3.3 Temperature Sensor. Thermometer or equivalent to monitor bath
temperature within 0.1 [deg]C.

7.0 Reagents and Standards

7.1 Fuel. Hydrogen gas (H2). Prepurified grade or better.
7.2 Combustion Gas. Oxygen (O2) or air, research purity
or better.
7.3 Carrier Gas. Prepurified grade or better.
7.4 Diluent. Air containing less than 0.5 ppmv total sulfur
compounds and less than 10 ppmv each of moisture and total hydrocarbons.
7.5 Calibration Gases.
7.5.1 Permeation Devices. One each of H2S, COS, and
CS2, gravimetrically calibrated and certified at some
convenient operating temperature. These tubes consist of hermetically
sealed FEP Teflon tubing in which a liquified gaseous substance is
enclosed. The enclosed gas permeates through the tubing wall at a
constant rate. When the temperature is constant, calibration gases
covering a wide range of known concentrations can be generated by
varying and accurately measuring the flow rate of diluent gas passing
over the tubes. These calibration gases are used to calibrate the GC/FPD
system and the dilution system.
7.5.2 Cylinder Gases. Cylinder gases may be used as alternatives to
permeation devices. The gases must be traceable to a primary standard
(such as permeation tubes) and not used beyond the certification
expiration date.
7.6 Citrate Buffer. Dissolve 300 g of potassium citrate and 41 g of
anhydrous citric acid in 1 liter of water. Alternatively, 284 g of
sodium citrate may be substituted for the potassium citrate. Adjust the
pH to between 5.4 and 5.6 with potassium citrate or citric acid, as
required.
8.0 Sample Collection, Preservation, Transport, and Storage
8.1 Pretest Procedures. After the complete measurement system has
been set up at the site and deemed to be operational, the following
procedures should be completed before sampling is initiated. These
procedures are not required, but would be helpful in preventing any
problem which might occur later to invalidate the entire test.
8.1.1 Leak-Check. Appropriate leak-check procedures should be
employed to verify the integrity of all components, sample lines, and
connections. The following procedure is suggested: For components
upstream of the sample pump, attach the probe end of the sample line to
a manometer or vacuum gauge, start the pump and pull a vacuum greater
than 50 mm (2 in.) Hg, close off the pump outlet, and then stop the pump
and ascertain that there is no leak for 1 minute. For components after
the pump, apply a slight positive pressure and check for leaks by
applying a liquid (detergent in water, for example) at each joint.
Bubbling indicates the presence of a leak. As an alternative to the
initial leak-test, the sample line loss test described in Section 8.3.1
may be performed to verify the integrity of components.
8.1.2 System Performance. Since the complete system is calibrated at
the beginning and end of each day of testing, the precise calibration of
each component is not critical. However, these components should be
verified to operate properly. This verification can be performed by
observing the response of flowmeters or of the GC output to changes in
flow rates or calibration gas concentrations, respectively, and
ascertaining the response to be within predicted limits. If any
component or the complete system fails to respond in a normal and
predictable manner, the source of the discrepancy should be identified
and corrected before proceeding.
8.2 Sample Collection and Analysis
8.2.1 After performing the calibration procedures outlined in
Section 10.0, insert the sampling probe into the test port ensuring that
no dilution air enters the stack through the port. Begin sampling and
dilute the sample approximately 9:1 using the dilution system. Note that
the precise dilution factor is the one determined in Section 10.4.
Condition the entire system with sample for a minimum of 15 minutes
before beginning the analysis. Inject aliquots of the sample into the
GC/FPD analyzer for analysis. Determine the concentration of each
reduced sulfur compound directly from the calibration curves or from the
equation for the least-squares line.
8.2.2 If reductions in sample concentrations are observed during a
sample run that cannot be explained by process conditions, the sampling
must be interrupted to determine if the probe or filter is clogged with
particulate matter. If either is found to be clogged, the test must be
stopped and the results up to that point discarded. Testing may resume
after cleaning or replacing the probe and filter. After each run, the
probe and filter shall be inspected and, if necessary, replaced.
8.2.3 A sample run is composed of 16 individual analyses (injects)
performed over a period of not less than 3 hours or more than 6 hours.
8.3 Post-Test Procedures.
8.3.1 Sample Line Loss. A known concentration of H2S at
the level of the applicable standard, 20 percent,
must be introduced into the sampling system at the opening of the probe
in sufficient quantities to ensure that there is an excess of sample
which must be vented to the atmosphere. The sample must be transported
through the entire sampling system to the measurement system in the same
manner as the emission samples.

[[Page 389]]

The resulting measured concentration is compared to the known value to
determine the sampling system loss. For sampling losses greater than 20
percent, the previous sample run is not valid. Sampling losses of 0-20
percent must be corrected by dividing the resulting sample concentration
by the fraction of recovery. The known gas sample may be calibration gas
as described in Section 7.5. Alternatively, cylinder gas containing
H2S mixed in nitrogen and verified according to Section 7.1.4
of Method 16A may be used. The optional pretest procedures provide a
good guideline for determining if there are leaks in the sampling
system.
8.3.2 Determination of Calibration Drift. After each run, or after a
series of runs made within a 24-hour period, perform a partial
recalibration using the procedures in Section 10.0. Only H2S
(or other permeant) need be used to recalibrate the GC/FPD analysis
system and the dilution system. Compare the calibration curves obtained
after the runs to the calibration curves obtained under Section 10.3.
The calibration drift should not exceed the limits set forth in Section
13.4. If the drift exceeds this limit, the intervening run or runs
should be considered invalid. As an option, the calibration data set
which gives the highest sample values may be chosen by the tester.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.3.1......................... Sample line loss Ensures that
check. uncorrected negative
bias introduced by
sample loss is no
greater than 20
percent, and
provides for
correction of bias
of 20 percent or
less.
8.3.2......................... Calibration drift Ensures that bias
test. introduced by drift
in the measurement
system output during
the run is no
greater than 5
percent.
10.0.......................... Analytical Ensures precision of
calibration. analytical results
within 5 percent.
------------------------------------------------------------------------

10.0 Calibration and Standardization

Prior to any sampling run, calibrate the system using the following
procedures. (If more than one run is performed during any 24-hour
period, a calibration need not be performed prior to the second and any
subsequent runs. However, the calibration drift must be determined as
prescribed in Section 8.3.2 after the last run is made within the 24-
hour period.)

Note: This section outlines steps to be followed for use of the GC/
FPD and the dilution system. The calibration procedure does not include
detailed instructions because the operation of these systems is complex,
and it requires an understanding of the individual system being used.
Each system should include a written operating manual describing in
detail the operating procedures associated with each component in the
measurement system. In addition, the operator should be familiar with
the operating principles of the components, particularly the GC/FPD. The
references in Section 16.0 are recommended for review for this purpose.

10.1 Calibration Gas Permeation Tube Preparation.
10.1.1 Insert the permeation tubes into the tube chamber. Check the
bath temperature to assure agreement with the calibration temperature of
the tubes within 0.1 [deg]C. Allow 24 hours for the tubes to
equilibrate. Alternatively, equilibration may be verified by injecting
samples of calibration gas at 1-hour intervals. The permeation tubes can
be assumed to have reached equilibrium when consecutive hourly samples
agree within 5 percent of their mean.
10.1.2 Vary the amount of air flowing over the tubes to produce the
desired concentrations for calibrating the analytical and dilution
systems. The air flow across the tubes must at all times exceed the flow
requirement of the analytical systems. The concentration in ppmv
generated by a tube containing a specific permeant can be calculated
using Equation 15-1 in Section 12.2.
10.2 Calibration of Analytical System. Generate a series of three or
more known concentrations spanning the linear range of the FPD
(approximately 0.5 to 10 ppmv for a 1-ml sample) for each of the three
major sulfur compounds. Bypassing the dilution system, inject these
standards into the GC/FPD and monitor the responses until three
consecutive injections for each concentration agree within 5 percent of
their mean. Failure to attain this precision indicates a problem in the
calibration or analytical system. Any such problem must be identified
and corrected before proceeding.
10.3 Calibration Curves. Plot the GC/FPD response in current
(amperes) versus their causative concentrations in ppmv on log-log
coordinate graph paper for each sulfur compound. Alternatively, a least-
squares equation may be generated from the calibration data using
concentrations versus the appropriate instrument response units.
10.4 Calibration of Dilution System. Generate a known concentration
of H2S using the permeation tube system. Adjust the flow rate
of diluent air for the first dilution stage

[[Page 390]]

so that the desired level of dilution is approximated. Inject the
diluted calibration gas into the GC/FPD system until the results of
three consecutive injections for each dilution agree within 5 percent of
their mean. Failure to attain this precision in this step is an
indication of a problem in the dilution system. Any such problem must be
identified and corrected before proceeding. Using the calibration data
for H2S (developed under Section 10.3), determine the diluted
calibration gas concentration in ppmv. Then calculate the dilution
factor as the ratio of the calibration gas concentration before dilution
to the diluted calibration gas concentration determined under this
section. Repeat this procedure for each stage of dilution required.
Alternatively, the GC/FPD system may be calibrated by generating a
series of three or more concentrations of each sulfur compound and
diluting these samples before injecting them into the GC/FPD system.
These data will then serve as the calibration data for the unknown
samples and a separate determination of the dilution factor will not be
necessary. However, the precision requirements are still applicable.

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.

C=Concentration of permeant produced, ppmv.
COS=Carbonyl sulfide concentration, ppmv.
CS2=Carbon disulfide concentration, ppmv.
d=Dilution factor, dimensionless.
H2S=Hydrogen sulfide concentration, ppmv.
K=24.04 L/g mole. (Gas constant at 20 [deg]C and 760 mm Hg)
L=Flow rate, L/min, of air over permeant 20 [deg]C, 760 mm Hg.
M=Molecular weight of the permeant, g/g-mole.
N=Number of analyses performed.
Pr=Permeation rate of the tube, [micro]g/min.

12.2 Permeant Concentration. Calculate the concentration generated
by a tube containing a specific permeant (see Section 10.1) using the
following equation:
[GRAPHIC] [TIFF OMITTED] TR17OC00.262

12.3 Calculation of SO2 Equivalent. SO2
equivalent will be determined for each analysis made by summing the
concentrations of each reduced sulfur compound resolved during the given
analysis. The SO2 equivalent is expressed as SO2
in ppmv.
[GRAPHIC] [TIFF OMITTED] TR17OC00.263

12.4 Average SO2 Equivalent. This is determined using the
following equation. Systems that do not remove moisture from the sample
but condition the gas to prevent condensation must correct the average
SO2 equivalent for the fraction of water vapor present. This
is not done under applications where the emission standard is not
specified on a dry basis.
[GRAPHIC] [TIFF OMITTED] TR17OC00.264

Where:

Avg SO2 equivalent=Average SO2 equivalent in ppmv,
dry basis.
Average SO2 equivalent i=SO2 in ppmv as
determined by Equation 15-2.

13.0 Method Performance

13.1 Range. Coupled with a GC system using a 1-ml sample size, the
maximum limit of the FPD for each sulfur compound is approximately 10
ppmv. It may be necessary to

[[Page 391]]

dilute samples from sulfur recovery plants a hundredfold (99:1),
resulting in an upper limit of about 1000 ppmv for each compound.
13.2 Sensitivity. The minimum detectable concentration of the FPD is
also dependent on sample size and would be about 0.5 ppmv for a 1-ml
sample.
13.3 Calibration Precision. A series of three consecutive injections
of the same calibration gas, at any dilution, shall produce results
which do not vary by more than 5 percent from the mean of the three
injections.
13.4 Calibration Drift. The calibration drift determined from the
mean of three injections made at the beginning and end of any run or
series of runs within a 24-hour period shall not exceed 5 percent.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References.

1. O'Keeffe, A.E., and G.C. Ortman. ``Primary Standards for Trace
Gas Analysis.'' Anal. Chem. 38,760. 1966.
2. Stevens, R.K., A.E. O'Keeffe, and G.C. Ortman. ``Absolute
Calibration of a Flame Photometric Detector to Volatile Sulfur Compounds
at Sub-Part-Per-Million Levels.'' Environmental Science and Technology
3:7. July 1969.
3. Mulik, J.D., R.K. Stevens, and R. Baumgardner. ``An Analytical
System Designed to Measure Multiple Malodorous Compounds Related to
Kraft Mill Activities.'' Presented at the 12th Conference on Methods in
Air Pollution and Industrial Hygiene Studies, University of Southern
California, Los Angeles, CA, April 6-8, 1971.
4. Devonald, R.H., R.S. Serenius, and A.D. McIntyre. ``Evaluation of
the Flame Photometric Detector for Analysis of Sulfur Compounds.'' Pulp
and Paper Magazine of Canada, 73,3. March 1972.
5. Grimley, K.W., W.S. Smith, and R.M. Martin. ``The Use of a
Dynamic Dilution System in the Conditioning of Stack Gases for Automated
Analysis by a Mobile Sampling Van.'' Presented at the 63rd Annual APCA
Meeting in St. Louis, MO. June 14-19, 1970.
6. General Reference. Standard Methods of Chemical Analysis Volume
III-A and III-B: Instrumental Analysis. Sixth Edition. Van Nostrand
Reinhold Co.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

[[Page 392]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.265

[[Page 393]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.266

[[Page 394]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.267

Method 15A--Determination of Total Reduced Sulfur Emissions From Sulfur
Recovery Plants in Petroleum Refineries

1.0 Scope and Application

1.1 Analytes.

[[Page 395]]

------------------------------------------------------------------------
Analyte CAS No. Sensitivity
------------------------------------------------------------------------
Reduced sulfur compounds...... None assigned... Not determined.
------------------------------------------------------------------------

1.2 Applicability. This method is applicable for the determination
of emissions of reduced sulfur compounds from sulfur recovery plants
where the emissions are in a reducing atmosphere, such as in Stretford
units.
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 An integrated gas sample is extracted from the stack, and
combustion air is added to the oxygen (O2)-deficient gas at a
known rate. The reduced sulfur compounds [including carbon disulfide
(CS2), carbonyl sulfide (COS), and hydrogen sulfide
(H2S)] are thermally oxidized to sulfur dioxide
(SO2), which is then collected in hydrogen peroxide as
sulfate ion and analyzed according to the Method 6 barium-thorin
titration procedure.

3.0 Definitions [Reserved]

4.0 Interferences

4.1 Reduced sulfur compounds, other than CS2, COS, and
H2S, that are present in the emissions will also be oxidized
to SO2, causing a positive bias relative to emission
standards that limit only the three compounds listed above. For example,
thiophene has been identified in emissions from a Stretford unit and
produced a positive bias of 30 percent in the Method 15A result.
However, these biases may not affect the outcome of the test at units
where emissions are low relative to the standard.
4.2 Calcium and aluminum have been shown to interfere in the Method
6 titration procedure. Since these metals have been identified in
particulate matter emissions from Stretford units, a Teflon filter is
required to minimize this interference.
4.3 Dilution of the hydrogen peroxide (H2O2)
absorbing solution can potentially reduce collection efficiency, causing
a negative bias. When used to sample emissions containing 7 percent
moisture or less, the midget impingers have sufficient volume to contain
the condensate collected during sampling. Dilution of the
H2O2 does not affect the collection of
SO2. At higher moisture contents, the potassium citrate-
citric acid buffer system used with Method 16A should be used to collect
the condensate.

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.
5.2 Corrosive reagents. The following reagents are hazardous.
Personal protective equipment and safe procedures are useful in
preventing chemical splashes. If contact occurs, immediately flush with
copious amounts of water for at least 15 minutes. Remove clothing under
shower and decontaminate. Treat residual chemical burns as thermal
burns.
5.2.1 Hydrogen Peroxide (H2O2). Irritating to
eyes, skin, nose, and lungs.
5.2.2 Sodium Hydroxide (NaOH). Causes severe damage to eyes and
skin. Inhalation causes irritation to nose, throat, and lungs. Reacts
exothermically with limited amounts of water.
5.2.3 Sulfuric Acid (H2SO4). Rapidly
destructive to body tissue. Will cause third degree burns. Eye damage
may result in blindness. Inhalation may be fatal from spasm of the
larynx, usually within 30 minutes. May cause lung tissue damage with
edema. 3 mg/m\3\ will cause lung damage in uninitiated. 1 mg/m\3\ for 8
hours will cause lung damage or, in higher concentrations, death.
Provide ventilation to limit inhalation. Reacts violently with metals
and organics.

6.0 Equipment and Supplies

6.1 Sample Collection. The sampling train used in performing this
method is shown in Figure 15A-1, and component parts are discussed
below. Modifications to this sampling train are acceptable provided that
the system performance check is met.
6.1.1 Probe. 6.4-mm (\1/4\-in.) OD Teflon tubing sequentially
wrapped with heat-resistant fiber strips, a rubberized heating tape
(with a plug at one end), and heat-resistant adhesive tape. A flexible
thermocouple or some other suitable temperature-measuring device shall
be placed between the Teflon tubing and the fiber strips so that the
temperature can be monitored. The probe should be sheathed in stainless
steel to provide in-stack rigidity. A series of bored-out stainless
steel fittings placed at the front of the sheath will prevent flue gas
from entering between the probe and sheath. The sampling probe is
depicted in Figure 15A-2.
6.1.2 Particulate Filter. A 50-mm Teflon filter holder and a 1- to
2-mm porosity Teflon filter (available through Savillex Corporation,
5325 Highway 101, Minnetonka, Minnesota 55345). The filter holder must
be

[[Page 396]]

maintained in a hot box at a temperature high enough to prevent
condensation.
6.1.3 Combustion Air Delivery System. As shown in the schematic
diagram in Figure 15A-3. The rate meter should be selected to measure an
air flow rate of 0.5 liter/min (0.02 ft\3\/min).
6.1.4 Combustion Tube. Quartz glass tubing with an expanded
combustion chamber 2.54 cm (1 in.) in diameter and at least 30.5 cm (12
in.) long. The tube ends should have an outside diameter of 0.6 cm (\1/
4\ in.) and be at least 15.3 cm (6 in.) long. This length is necessary
to maintain the quartz-glass connector near ambient temperature and
thereby avoid leaks. Alternatively, the outlet may be constructed with a
90 degree glass elbow and socket that would fit directly onto the inlet
of the first peroxide impinger.
6.1.5 Furnace. Of sufficient size to enclose the combustion tube.
The furnace must have a temperature regulator capable of maintaining the
temperature at 1100 50 [deg]C (2,012 90 [deg]F). The furnace operating temperature must be
checked with a thermocouple to ensure accuracy. Lindberg furnaces have
been found to be satisfactory.
6.1.6 Peroxide Impingers, Stopcock Grease, Temperature Sensor,
Drying Tube, Valve, Pump, and Barometer. Same as in Method 6, Sections
6.1.1.2, 6.1.1.4, 6.1.1.5, 6.1.1.6, 6.1.1.7, 6.1.1.8, and 6.1.2,
respectively, except that the midget bubbler of Method 6, Section
6.1.1.2 is not required.
6.1.7 Vacuum Gauge and Rate Meter. At least 760 mm Hg (30 in. Hg)
gauge and rotameter, or equivalent, capable of measuring flow rate to
5 percent of the selected flow rate and calibrated
as in Section 10.2.
6.1.8 Volume Meter. Dry gas meter capable of measuring the sample
volume under the particular sampling conditions with an accuracy of 2
percent.
6.1.9 U-tube manometer. To measure the pressure at the exit of the
combustion gas dry gas meter.
6.2 Sample Recovery and Analysis. Same as Method 6, Sections 6.2 and
6.3, except a 10-ml buret with 0.05-ml graduations is required for
titrant volumes of less than 10.0 ml, and the spectrophotometer is not
needed.

7.0 Reagents and Standards

Note: Unless otherwise indicated, all reagents must conform to the
specifications established by the Committee on Analytical Reagents of
the American Chemical Society. When such specifications are not
available, the best available grade shall be used.

7.1 Sample Collection. The following reagents and standards are
required for sample analysis:
7.1.1 Water. Same as Method 6, Section 7.1.1.
7.1.2 Hydrogen Peroxide (H2O2), 3 Percent by
Volume. Same as Method 6, Section 7.1.3 (40 ml is needed per sample).
7.1.3 Recovery Check Gas. Carbonyl sulfide in nitrogen [100 parts
per million by volume (ppmv) or greater, if necessary] in an aluminum
cylinder. Concentration certified by the manufacturer with an accuracy
of 2 percent or better, or verified by gas
chromatography where the instrument is calibrated with a COS permeation
tube.
7.1.4 Combustion Gas. Air, contained in a gas cylinder equipped with
a two-stage regulator. The gas shall contain less than 50 ppb of reduced
sulfur compounds and less than 10 ppm total hydrocarbons.
7.2 Sample Recovery and Analysis. Same as Method 6, Sections 7.2 and
7.3.

8.0 Sample Collection, Preservation, Storage, and Transport

8.1 Preparation of Sampling Train. For the Method 6 part of the
train, measure 20 ml of 3 percent H2O2 into the
first and second midget impingers. Leave the third midget impinger empty
and add silica gel to the fourth impinger. Alternatively, a silica gel
drying tube may be used in place of the fourth impinger. Place crushed
ice and water around all impingers. Maintain the oxidation furnace at
1100 50 [deg]C (2,012 90
[deg]F) to ensure 100 percent oxidation of COS. Maintain the probe and
filter temperatures at a high enough level (no visible condensation) to
prevent moisture condensation and monitor the temperatures with a
thermocouple.
8.2 Leak-Check Procedure. Assemble the sampling train and leak-check
as described in Method 6, Section 8.2. Include the combustion air
delivery system from the needle valve forward in the leak-check.
8.3 Sample Collection. Adjust the pressure on the second stage of
the regulator on the combustion air cylinder to 10 psig. Adjust the
combustion air flow rate to 0.5 0.05 L/min (1.1
0.1 ft\3\/hr) before injecting combustion air into
the sampling train. Then inject combustion air into the sampling train,
start the sample pump, and open the stack sample gas valve. Carry out
these three operations within 15 to 30 seconds to avoid pressurizing the
sampling train. Adjust the total sample flow rate to 2.0 0.2 L/min (4.2 0.4 ft\3\/hr).
These flow rates produce an O2 concentration of 5.0 percent
in the stack gas, which must be maintained constantly to allow oxidation
of reduced sulfur compounds to SO2. Adjust these flow rates
during sampling as necessary. Monitor and record the combustion air
manometer reading at regular intervals during the sampling period.
Sample for 1 or 3 hours. At the end of sampling, turn off the sample
pump and combustion air simultaneously (within 30 seconds of each
other). All other procedures are the same as in Method 6, Section 8.3,
except that the sampling train should not be purged. After collecting
the

[[Page 397]]

sample, remove the probe from the stack and conduct a leak-check
according to the procedures outlined in Section 8.2 of Method 6
(mandatory). After each 3-hour test run (or after three 1-hour samples),
conduct one system performance check (see Section 8.5). After this
system performance check and before the next test run, it is recommended
that the probe be rinsed and brushed and the filter replaced.

Note: In Method 15, a test run is composed of 16 individual analyses
(injects) performed over a period of not less than 3 hours or more than
6 hours. For Method 15A to be consistent with Method 15, the following
may be used to obtain a test run: (1) Collect three 60-minute samples or
(2) collect one 3-hour sample. (Three test runs constitute a test.)

8.4 Sample Recovery. Recover the hydrogen peroxide-containing
impingers as detailed in Method 6, Section 8.4.
8.5 System Performance Check.
8.5.1 A system performance check is done (1) to validate the
sampling train components and procedure (before testing, optional) and
(2) to validate a test run (after a run, mandatory). Perform a check in
the field before testing consisting of at least two samples (optional),
and perform an additional check after each 3-hour run or after three 1-
hour samples (mandatory).
8.5.2 The checks involve sampling a known concentration of COS and
comparing the analyzed concentration with the known concentration. Mix
the recovery gas with N2 as shown in Figure 15A-4 if dilution
is required. Adjust the flow rates to generate a COS concentration in
the range of the stack gas or within 20 percent of the applicable
standard at a total flow rate of at least 2.5 L/min (5.3 ft\3\/hr). Use
Equation 15A-4 (see Section 12.5) to calculate the concentration of
recovery gas generated. Calibrate the flow rate from both sources with a
soap bubble flow tube so that the diluted concentration of COS can be
accurately calculated. Collect 30-minute samples, and analyze in the
same manner as the emission samples. Collect the samples through the
probe of the sampling train using a manifold or some other suitable
device that will ensure extraction of a representative sample.
8.5.3 The recovery check must be performed in the field before
replacing the particulate filter and before cleaning the probe. A sample
recovery of 100 20 percent must be obtained for
the data to be valid and should be reported with the emission data, but
should not be used to correct the data. However, if the performance
check results do not affect the compliance or noncompliance status of
the affected facility, the Administrator may decide to accept the
results of the compliance test. Use Equation 15A-5 (see Section 12.6) to
calculate the recovery efficiency.

9.0 Quality Control

------------------------------------------------------------------------
Quality control
Section measure Effect
------------------------------------------------------------------------
8.5........................... System Ensures validity of
performance sampling train
check. components and
analytical
procedure.
8.2, 10.0..................... Sampling Ensures accurate
equipment leak- measurement of stack
check and gas flow rate,
calibration. sample volume
10.0.......................... Barium standard Ensures precision of
solution normality
standardization. determination.
11.1.......................... Replicate Ensures precision of
titrations. titration
determinations.
11.2.......................... Audit sample Evaluates analyst's
analysis. technique and
standards
preparation.
------------------------------------------------------------------------

10.0 Calibration and Standardization

10.1 Metering System, Temperature Sensors, Barometer, and Barium
Perchlorate Solution. Same as Method 6, Sections 10.1, 10.2, 10.4, and
10.5, respectively.
10.2 Rate Meter. Calibrate with a bubble flow tube.

11.0 Analytical Procedure

11.1 Sample Loss Check and Sample Analysis. Same as Method 6,
Sections 11.1 and 11.2.
11.2 Audit Sample Analysis. Same as Method 6, Section 11.3.

12.0 Data Analysis and Calculations

In the calculations, retain at least one extra decimal figure beyond
that of the acquired data. Round off figures after final calculations.
12.1 Nomenclature.

CCOS=Concentration of COS recovery gas, ppm.
CRG(act)=Actual concentration of recovery check gas (after
dilution), ppm.
CRG(m)=Measured concentration of recovery check gas
generated, ppm.
CRS=Concentration of reduced sulfur compounds as
SO2, dry basis, corrected to standard conditions, ppm.
N=Normality of barium perchlorate titrant, milliequivalents/ml.
Pbar=Barometric pressure at exit orifice of the dry gas
meter, mm Hg.
Pstd=Standard absolute pressure, 760 mm Hg.
QCOS=Flow rate of COS recovery gas, liters/min.
QN=Flow rate of diluent N2, liters/min.
R=Recovery efficiency for the system performance check, percent.

[[Page 398]]

Tm=Average dry gas meter absolute temperature, [deg]K.
Tstd=Standard absolute temperature, 293 [deg]K.
Va=Volume of sample aliquot titrated, ml.
Vms=Dry gas volume as measured by the sample train dry gas
meter, liters.
Vmc=Dry gas volume as measured by the combustion air dry gas
meter, liters.
Vms(std)=Dry gas volume measured by the sample train dry gas
meter, corrected to standard conditions, liters.
Vmc(std)=Dry gas volume measured by the combustion air dry
gas meter, corrected to standard conditions, liters.
Vsoln=Total volume of solution in which the sulfur dioxide
sample is contained, 100 ml.
Vt=Volume of barium perchlorate titrant used for the sample
(average of replicate titrations), ml.
Vtb=Volume of barium perchlorate titrant used for the blank,
ml.
Y=Calibration factor for sampling train dry gas meter.
Yc=Calibration factor for combustion air dry gas meter.
32.03=Equivalent weight of sulfur dioxide, mg/meq.
[GRAPHIC] [TIFF OMITTED] TR17OC00.411

12.2 Dry Sample Gas Volume, Corrected to Standard Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.268

Where:

K1=0.3855 [deg]K/mm Hg for metric units,
=17.65 [deg]R/in. Hg for English units.

12.3 Combustion Air Gas Volume, corrected to Standard Conditions.
[GRAPHIC] [TIFF OMITTED] TR17OC00.269

Note: Correct Pbar for the average pressure of the
manometer during the sampling period.

12.4 Concentration of reduced sulfur compounds as ppm
SO2.
[GRAPHIC] [TIFF OMITTED] TR17OC00.270

Where:

[[Page 399]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.271

12.5 Concentration of Generated Recovery Gas.
[GRAPHIC] [TIFF OMITTED] TR17OC00.272

12.6 Recovery Efficiency for the System Performance Check.
[GRAPHIC] [TIFF OMITTED] TR17OC00.273

13.0 Method Performance

13.1 Analytical Range. The lower detectable limit is 0.1 ppmv when
sampling at 2 lpm for 3 hours or 0.3 ppmv when sampling at 2 lpm for 1
hour. The upper concentration limit of the method exceeds concentrations
of reduced sulfur compounds generally encountered in sulfur recovery
plants.
13.2 Precision. Relative standard deviations of 2.8 and 6.9 percent
have been obtained when sampling a stream with a reduced sulfur compound
concentration of 41 ppmv as SO2 for 1 and 3 hours,
respectively.
13.3 Bias. No analytical bias has been identified. However, results
obtained with this method are likely to contain a positive bias relative
to emission regulations due to the presence of nonregulated sulfur
compounds (that are present in petroleum) in the emissions. The
magnitude of this bias varies accordingly, and has not been quantified.

14.0 Pollution Prevention [Reserved]

15.0 Waste Management [Reserved]

16.0 References

1. American Society for Testing and Materials Annual Book of ASTM
Standards. Part 31: Water, Atmospheric Analysis. Philadelphia,
Pennsylvania. 1974. pp. 40-42.
2. Blosser, R.O., H.S. Oglesby, and A.K. Jain. A Study of Alternate
SO2 Scrubber Designs Used for TRS Monitoring. National
Council of the Paper Industry for Air and Stream Improvement, Inc., New
York, New York. Special Report 77-05. July 1977.
3. Curtis, F., and G.D. McAlister. Development and Evaluation of an
Oxidation/Method 6 TRS Emission Sampling Procedure. Emission Measurement
Branch, Emission Standards and Engineering Division, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina. February
1980.
4. Gellman, I. A Laboratory and Field Study of Reduced Sulfur
Sampling and Monitoring Systems. National Council of the Paper Industry
for Air and Stream Improvement, Inc., New York, New York. Atmospheric
Quality Improvement Technical Bulletin No. 81. October 1975.
5. Margeson, J.H., et al. A Manual Method for TRS Determination.
Journal of Air Pollution Control Association. 35:1280-1286. December
1985.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

[[Page 400]]

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[[Page 401]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.275

[[Page 402]]

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[[Page 403]]

[GRAPHIC] [TIFF OMITTED] TR17OC00.277

[36 FR 24877, Dec. 23, 1971]

Editorial Note: For Federal Register citations affecting part 60,
appendix A-5, see the List of CFR Sections Affected, which appears in
the Finding Aids section of the printed volume and on GPO Access.