[Code of Federal Regulations]
[Title 40, Volume 18]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR92.114]

[Page 433-442]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 92--CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES--
Table of Contents
 
                       Subpart B--Test Procedures
 
Sec. 92.114  Exhaust gas and particulate sampling and analytical system.

    (a) General. (1) During emission testing, the engine exhaust is 
routed through an exhaust duct connected to, or otherwise adjacent to 
the outlet of the locomotive exhaust system. Emission samples are 
collected as specified in paragraphs (b) and (c) of this section. 
Exhaust duct requirements are specified in paragraph (d) of this 
section.
    (2) The systems described in this section are appropriate for use 
with locomotives or engines employing a single exhaust.
    (i) For testing where the locomotive or engine has multiple exhausts 
all exhaust streams shall be combined into a single stream prior to 
sampling, except as allowed by paragraph (a)(2)(ii) of this section.
    (ii) For locomotive testing where the locomotive has multiple 
exhaust stacks, proportional samples may be collected from each exhaust 
outlet instead of ducting the exhaust stacks together, provided that the 
CO2 concentrations in each exhaust stream are shown (either 
prior to testing or during testing) to be within 5 percent of each other 
for each test mode.
    (3) All vents, including analyzer vents, bypass flow, and pressure 
relief vents of regulators, should be vented in such a manner to avoid 
endangering personnel in the immediate area.
    (4) Additional components, not specified here, such as instruments, 
valves, solenoids, pumps, switches, and so forth, may be employed to 
provide additional information and coordinate the functions of the 
component systems, provided that their use is consistent with good 
engineering practice. Any variation from the specifications in this 
subpart including performance specifications and emission detection 
methods may be used only with prior approval by the Administrator.
    (b) Raw exhaust sampling for gaseous emissions. (1)(i) An example of 
the type of sampling and analytical system which is to be used for 
gaseous emissions testing under this subpart is shown in Figure B114-1 
of this section. All components or parts of components that are wetted 
by the sample or corrosive calibration gases shall be either chemically 
cleaned stainless steel or other inert material, for example, 
polytetrafluoroethylene resin. The use of ``gauge savers'' or 
``protectors'' with nonreactive diaphragms to reduce dead volumes is 
permitted. Additional components such as instruments, valves, solenoids, 
pumps, switches, etc. may be employed to provide additional information 
and coordinate the functions of the component systems.

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    (ii) System components list. The following is a list of components 
shown in Figure B114-1 of this section by numeric identifier.
    (A) Filters. Glass fiber filter paper is permitted for the fine 
particulate filters (F1, F2, and F3). Optional filter F4 is a coarse 
filter for large particulates. Filters F3 and F4 are heated filters
    (B) Flowmeters. Flowmeters FL1 and FL2 indicate sample flow rates 
through the CO and CO2 analyzers. Flowmeters FL3, FL4, FL5, 
and FL6 indicate bypass flow rates.
    (C) Gauges. Downstream gauges are required for any system used for 
testing under this subpart. Upstream gauges may be required under this 
subpart. Upstream gauges G1 and G2 measure the input to the CO and 
CO2 analyzers. Downstream gauges G3 and G4 measure the exit 
pressure of the CO and CO2 analyzers. If the normal operating 
range of the downstream gauges is less than 3 inches of water, then the 
downstream gauges must be capable of reading both pressure and vacuum. 
Gauges G3 and G4 are not necessary if the analyzers are vented directly 
to atmospheric pressure.
    (D) Pressure gauges. P1 is a bypass pressure gauge; P2, P3, P4, and 
P5 are for sample or span pressure at inlet to flow control valves.
    (E) Water traps. Water traps WT1 and WT2 to remove water from the 
sample. A water trap performing the function of WT1 is required for any 
system used for testing under this subpart. Chemical dryers are not an 
acceptable method of removing the water. Water removal by condensation 
is acceptable. If water is removed by condensation, the sample gas 
temperature or sample dew point must be monitored either within the 
water trap or downstream; it may not exceed 45  deg.F (7  deg.C). Means 
other than condensation may be used only with prior approval from the 
Administrator.
    (F) Regulators. R1, R3, R4, and R6 are line pressure regulators to 
control span pressure at inlet to flow control valves; R2 and R5 are 
back pressure regulators to control sample pressure at inlet to flow 
control valves.
    (G) Valves. V1, V7, V8, and V14 are selector valves to select zero 
or calibration gases; V2 are optional heated selector valves to purge 
the sample probe, perform leak checks, or to perform hang-up checks; V3 
and V5 are selector valves to select sample or span gases; V4, V6, and 
V15 are flow control valves; V9 and V13--heated selector valve to select 
sample or span gases; V10 and V12--heated flow control valves; V11--
Selector valve to select NOX or bypass mode in the 
chemiluminescence analyzer; V16--heated selector valve to perform leak 
checks.
    (H) Pump. Sample transfer pump to transport sample to analyzers.
    (I) Temperature sensor. A temperature sensor (T1) to measure the 
NO2 to NO converter temperature is required for any system 
used for testing under this subpart.
    (J) Dryer. Dryers D1 and D2 to remove the water from the bypass 
flows to prevent condensation in flowmeters FL3, FL4, and FL6.
    (2) The following requirements must be incorporated in each gaseous 
sampling system used for testing under this subpart:
    (i) The exhaust is analyzed for gaseous emissions using analyzers 
meeting the specifications of Sec. 92.109, and all analyzers must obtain 
the sample to be analyzed from the same sample probe, and internally 
split to the different analyzers.
    (ii) Sample transfer lines must be heated as specified in paragraph 
(b)(4) of this section.
    (iii) Carbon monoxide and carbon dioxide measurements must be made 
on a dry basis. Specific requirements for the means of drying the sample 
can be found in paragraph (b)(1)(ii)(E) of this section.
    (iv) All NDIR analyzers must have a pressure gauge immediately 
downstream of the analyzer. The gauge tap must be within 2 inches of the 
analyzer exit port. Gauge specifications can be found in paragraph 
(b)(1)(ii)(C) of this section.
    (v) All bypass and analyzer flows exiting the analysis system must 
be measured. Capillary flows such as in HFID and CL analyzers are 
excluded. For each NDIR analyzer with a flow meter located upstream of 
the analyzer, an upstream pressure gauge must be used. The gauge tap 
must be

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within 2 inches of the analyzer entrance port.
    (vi) Calibration or span gases for the NOX measurement 
system must pass through the NO2 to NO converter.
    (vii) The temperature of the NO2 to NO converter must be 
displayed continuously.
    (3) Gaseous sample probe. (i) The gaseous emissions sample probe 
shall be a straight, closed end, stainless steel, multi-hole probe. The 
inside diameter shall not be greater than the inside diameter of the 
sample line by more than 0.01 inches (0.03 cm). The wall thickness of 
the probe shall not be greater than 0.04 inches (0.10 cm). The fitting 
that attaches the probe to the exhaust duct shall be as small as 
practical in order to minimize heat loss from the probe.
    (ii) The gaseous emissions sample probe shall have a minimum of 
three holes in each 3 inch segment of length of the probe. The spacing 
of the radial planes for each hole in the probe must be such that they 
cover approximately equal cross-sectional areas of the exhaust duct. The 
angular spacing of the holes must be approximately equal. The angular 
spacing of any two holes in one plane may not be 180 
deg.20 deg. (see section view C-C of Figure B114-2 of this 
section). The holes should be sized such that each has approximately the 
same flow. If only three holes are used in each 3 inch segment of probe 
length, they may not all be in the same radial plane.
    (iii) The sample probe shall be so located in the center of the 
exhaust duct to minimize stratification, with respect to both 
concentration and velocity, present in the exhaust stream. The probe 
shall be located between two feet and five feet downstream of the 
locomotive exhaust outlet (or nearest practical equivalent during engine 
testing), and at least 1 foot upstream of the outlet of the exhaust duct 
to the atmosphere.
    (iv) If the exhaust duct is circular in cross section, the sample 
probe should extend approximately radially across the exhaust duct, and 
approximately through the center of the duct. The sample probe must 
extend across at least 80 percent of the diameter of the duct.
    (v) If the exhaust duct is not circular in cross section, the sample 
probe should extend across the exhaust duct approximately parallel to 
the longest sides of the duct, or along the longest axis of the duct 
which is not a diagonal, and through the approximate center of the duct. 
The sample probe must extend across at least 80 percent of the longest 
axis of the duct which is not a diagonal, and be approximately parallel 
to the longest sides of the duct.
    (vi) Other sample probe designs and/or locations may be used only if 
demonstrated (to the Administrator's satisfaction) to provides a more 
representative sample.
    (4) Sample transfer line(s). (i) The maximum inside diameter of the 
gaseous emissions sample line shall not exceed 0.52 inches (1.32 cm).
    (ii) If valve V2 is used, the sample probe must connect directly to 
valve V2. The location of optional valve V2 may not be greater than 4 
feet (1.22 m) from the exhaust duct.
    (iii) The sample transport system from the engine exhaust duct to 
the HC analyzer and the NOX analyzer must be heated as is 
indicated in Figure B114-1 of this section.
    (A) For diesel fueled and biodiesel fueled locomotives and engines, 
the wall temperature of the HC sample line must be maintained at 375 
 20  deg.F (191  11  deg.C). An exception is 
made for the first 4 feet (122 cm) of sample line from the exhaust duct. 
The upper temperature tolerance for this 4 foot section is waived and 
only the minimum temperature specification applies.
    (B) For locomotives and engines using fuels other than diesel or 
biodiesel, the heated components in the HC sample path shall be 
maintained at a temperature approved by the Administrator, not exceeding 
446  deg.F (230  deg.C).
    (C) For all fuels, wall temperature of the NOX sample 
line must be maintained between 140  deg.F (60  deg.C) and 446  deg.F 
(230  deg.C). An exception is made for the first 4 feet (122 cm) of 
sample line from the exhaust duct. The upper temperature tolerance for 
this 4 foot section is waived and only the minimum temperature 
specification applies.
    (D) For each component (pump, sample line section, filters, etc.) in 
the heated portion of the sampling system

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that has a separate source of power or heating element, use engineering 
judgment to locate the coolest portion of that component and monitor the 
temperature at that location. If several components are within an oven, 
then only the surface temperature of the component with the largest 
thermal mass and the oven temperature need be measured.
    (c) Particulate emissions. (1)(i) Schematic drawing. An example of a 
sampling system which may be used for particulate emissions testing 
under this subpart is shown in Figure B114-3 of this section. All 
components or parts of components that are wetted by the samples gases 
upstream of the filter shall be either chemically cleaned stainless 
steel or other inert material, for example, polytetrafluoroethylene 
resin. The use of ``gauge savers'' or ``protectors'' with nonreactive 
diaphragms to reduce dead volumes is permitted. Additional components 
such as instruments, valves, solenoids, pumps, switches, etc. may be 
employed to provide additional information and coordinate the functions 
of the component systems.
    (ii) The following requirements must be incorporated in each system 
used for testing under this subpart:
    (A) All particulate filters must obtain the sample from the same 
sample probe located within the exhaust gas extension with internal 
split to the different filters.
    (B) The wall temperature of the sample transport system from the 
probe to the dilution tunnel (excluding the first 4 feet of the 
particulate transfer tube) must be maintained at 375  deg.F to 395 
deg.F (191  deg.C to 202  deg.C).
    (2) Particulate raw sample probe. (i) The sample probe for the raw 
exhaust shall be a straight, closed end, stainless steel, multi-hole 
probe of approximately 1.25 inch (3.2 cm) diameter. The inside diameter 
shall not be greater than the inside diameter of the sample line by more 
than 0.1 inches (0.3 cm). The wall thickness of the probe shall not be 
greater than 0.06 inches (0.15 cm). The fitting that attaches the probe 
to the exhaust duct shall be as small as practical in order to minimize 
heat loss from the probe.
    (ii) All sample collection holes in the probe shall be located so as 
to face away from the direction of flow of the exhaust stream or at most 
be tangential to the flow of the exhaust stream past the probe (see 
Figure B114-4 of this section). Five holes shall be located in each 
radial plane along the length of the probe in which sample holes are 
placed. The spacing of the radial planes for each set of holes in the 
probe must be such that they cover approximately equal cross-sectional 
areas of the exhaust duct. For rectangular ducts, this means that the 
sample hole-planes must be equidistant from each other. For circular 
ducts, this means that the distance between the sample hole-planes must 
be decreased with increasing distance from the center of the duct (see 
Figure B114-4 of this section).

    (Note: Particulate concentrations are expected to vary to some 
extent as a function of the distance to the duct wall; thus each set of 
sample holes collects a sample that is representative of a cross-
sectional disk at that approximate distance from the wall.)


The spacing between sets of sample holes along the length of the probe 
shall be no more than 4 inches (10 cm). The holes should be sized such 
that each has approximately the same flow.
    (iii)(A) The particulate sample probe shall be located in the 
exhaust duct on an axis which is directly downstream of, and parallel to 
the axis of the gaseous sample probe. The distance between the probes 
shall be between 3 inches (7.6 cm) and 6 inches (15.2 cm). Greater 
spacing is allowed for engine testing, where spacing of 3 inches (7.6 
cm) to 6 inches (15.2 cm) is not practical.
    (B) If the exhaust duct is circular in cross section, the sample 
probe should extend approximately radially across the exhaust duct, and 
approximately through the center of the duct. The sample probe must 
extend across at least 80 percent of the diameter of the duct.
    (C) If the exhaust duct is not circular in cross section, the sample 
probe should extend across the exhaust duct approximately parallel to 
the longest sides of the duct, or along the longest

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axis of the duct which is not a diagonal, and through the approximate 
center of the duct. The sample probe must extend across at least 80 
percent of the longest axis of the duct which is not a diagonal, and be 
approximately parallel to the longest sides of the duct.
    (3) Particulate sample transfer line. (i) The maximum inside 
diameter of the particulate emissions sample line shall be approximately 
2.5 inches (6.4 cm).
    (ii) The sample transfer line shall be heated to maintain a wall 
temperature above 375  deg.F.
    (4) Dilution tunnel. The flow capacity of the blower moving the 
mixture of sample and air through the tunnel must be sufficient to 
maintain the diluted sample stream at a temperature of 125  deg.F (51.7 
deg.C) or less, at the sampling zone in the dilution tunnel and at the 
sample filter. A single measurement of diluted exhaust temperature is 
required. The temperature shall also be maintained as required to 
prevent condensation at any point in the dilution tunnel. A small 
negative pressure is to be maintained in the dilution tunnel by 
throttling at the source of the dilution air, and adjusted as necessary, 
sufficient to draw sample through the probe and sample transfer line. 
Direct sampling of the particulate material may take place (Figure B114-
3 of this section) at this point.
    (i)(A) The dilution tunnel shall be:
    (1) Small enough in diameter to cause turbulent flow (Reynolds 
Number greater than 4000) and of sufficient length to cause complete 
mixing of the exhaust and dilution air;
    (2) 4 inches (10 cm) minimum inside diameter;
    (3) Constructed of electrically conductive material which does not 
react with the exhaust components; and
    (4) Electrically grounded.
    (B) The temperature of the diluted exhaust stream inside of the 
dilution tunnel shall be sufficient to prevent water condensation.
    (C) The engine exhaust shall be directed downstream at the point 
where it is introduced into the dilution tunnel.
    (ii) Dilution air:
    (A) Shall be at a temperature of 68  deg.F (20  deg.C) or greater.
    (B) May be filtered at the dilution air inlet.
    (C) May be sampled to determine background particulate levels, which 
can then be subtracted from the values measured in the exhaust stream.
    (D) Shall be sampled to determine the background concentration of 
CO2.
    (iii) Dilute sample probe and collection system.
    (A) The particulate sample probe in the dilution tunnel shall be:
    (1) Installed facing upstream at a point where the dilution air and 
exhaust are well mixed (i.e., on the tunnel centerline, approximately 10 
tunnel diameters downstream of the point where the exhaust enters the 
dilution tunnel).
    (2) Sufficiently distant (radially) from other sampling probes so as 
to be free from the influence of wakes or eddies produced by the other 
probes.
    (3) 0.5 in. (1.3 cm) minimum inside diameter.
    (4) The distance from the sampling tip to the filter holder shall 
not be more than 40 inches (102 cm).
    (5) Designed to minimize the deposition of particulate during 
transfer (i.e., bends should be as gradual as possible, protrusions (due 
to sensors, etc.) should be smooth and not sudden, etc.).
    (B) The gas meters or flow instrumentation shall be located 
sufficiently distant from the tunnel so that the inlet gas temperature 
remains constant (5  deg.F (2.8  deg.C)). 
Alternately, the temperature of the sample may be monitored at the gas 
meter, and the measured volume corrected to standard conditions.
    (C) Particulate sampling filters. (1) Fluorocarbon-coated glass 
fiber filters or fluorocarbon-based (membrane) filters are required.
    (2) Particulate filters must have a diameter to maintain the average 
face velocity of the sample across the filter between 35 and 80 cm/s.
    (3) The dilute exhaust will be simultaneously sampled by a pair of 
filters (one primary and one back-up filter) during each phase of the 
test. The back-up filter shall be located no more than 4 inches (10 cm) 
downstream of the primary filter. The primary and back-up filters shall 
not be in contact with each other.

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    (4) The recommended target loading on a primary 70-mm filter (60 mm 
diameter stain area) is 1.3 milligrams. Equivalent loadings (0.5 mg/1075 
mm2 stain area) shall be used as target loadings when other 
filter sizes are used.
    (D) Diluted CO2 sample collection system. (1) The 
concentrations of CO2 in the dilution air and diluted exhaust 
are determined by pumping a sample into a sample bag (made of a 
nonreactive material) or directly to the analyzer, as shown in Figure 
B114-3 of this section.
    (2) The sample probe for the diluted exhaust shall be installed 
facing upstream at a point where the dilution air and exhaust are well 
mixed (i.e., on the tunnel centerline, approximately 10 tunnel diameters 
downstream of the point where the exhaust enters the dilution tunnel). 
It shall also be sufficiently distant (radially) from other sampling 
probes so as to be free from the influence of any wakes or eddies 
produced by the other probes.
    (iv) Other sample flow handling and/or measurement systems may be 
used if shown to yield equivalent results and if approved in advance by 
the Administrator. (See Appendix IV of this part for guidance.)
    (d) Exhaust system. The exhaust system shall meet the following 
requirements:
    (1) For locomotive testing, the engine exhaust shall be routed 
through an exhaust duct with dimensions equal to or slightly larger than 
the dimensions of the locomotive exhaust outlet. The exhaust duct shall 
be designed so as to not significantly affect exhaust backpressure.
    (2) For engine testing, either a locomotive-type or a facility-type 
exhaust system (or a combination system) may be used. The exhaust 
backpressure for engine testing shall be set between 90 and 100 percent 
of the maximum backpressure that will result with the exhaust systems of 
the locomotives in which the engine will be used. The facility-type 
exhaust system shall meet the following requirements:
    (i) It must be composed of smooth ducting made of typical in-use 
steel or stainless steel.
    (ii) If an aftertreatment system is employed, the distance from the 
exhaust manifold flange(s), or turbocharger outlet to any exhaust 
aftertreatment device shall be the same as in the locomotive 
configuration unless the manufacturer is able to demonstrate equivalent 
performance at another location.
    (iii) If the exhaust system ducting from the exit of the engine 
exhaust manifold or turbocharger outlet to smoke meter exceeds 12 feet 
(3.7 m) in length, then all ducting shall be insulated consistent with 
good engineering practice.
    (iv) For engines designed for more than one exhaust outlet to the 
atmosphere, a specially fabricated collection duct may be used. The 
collection duct should be located downstream of the in-locomotive exits 
to the atmosphere. Any potential increase in backpressure due to the use 
of a single exhaust instead of multiple exhausts may be compensated for 
by using larger than standard exhaust system components in the 
construction of the collection duct.
    (e) Dilute exhaust sampling for gaseous and particulate emissions. 
(1) Dilution of the exhaust prior to sampling is allowed for gaseous 
emissions. The equipment and methods used for dilution, sampling and 
analysis shall comply with the requirements of subpart N of part 86 of 
this chapter, with the following exceptions and additional requirements:
    (i) Proportional sampling and heat exchangers are not required;
    (ii) Larger minimum dimensions for the dilution tunnel(s) shall be 
specified by the Administrator;
    (iii) Other modifications may be made with written approval from the 
Administrator.
    (2) Dilution of only a portion of the exhaust is allowed, provided 
that:
    (i) The fraction of the total exhaust that is diluted is determined 
for systems that determine mass emission rates (g/hr) from the total 
volume of the diluted sample; or
    (ii) The ratio of raw sample volume to diluted sample volume is 
determined for systems that determine mass emission rates (g/hr) from 
measured fuel flow rates.

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