[Code of Federal Regulations]
[Title 40, Volume 31]
[Revised as of July 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1065.145]
[Page 691-694]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents
Subpart B_Equipment Specifications
Sec. 1065.145 Gaseous and PM probes, transfer lines, and sampling
system components.
(a) Continuous and batch sampling. Determine the total mass of each
constituent with continuous or batch sampling, as described in Sec.
1065.15(c)(2). Both types of sampling systems have probes, transfer
lines, and other sampling system components that are described in this
section.
(b) Gaseous and PM sample probes. A probe is the first fitting in a
sampling system. It protrudes into a raw or diluted exhaust stream to
extract a sample, such that its inside and outside surfaces are in
contact with the exhaust. A sample is transported out of a probe into a
transfer line, as described in paragraph (c) of this section. The
following provisions apply to probes:
(1) Probe design and construction. Use sample probes with inside
surfaces of 300 series stainless steel or, for raw exhaust sampling, use
a nonreactive material capable of withstanding raw exhaust temperatures.
Locate sample probes where constituents are mixed to their mean sample
concentration. Take into account the mixing of any crankcase emissions
that may be routed into the raw exhaust. Locate each probe to minimize
interference with the flow to other probes. We recommend that all probes
remain free from influences of boundary layers, wakes, and eddies--
especially near the outlet of a raw-exhaust tailpipe where unintended
dilution might occur. Make sure that purging or back-flushing of a probe
does not influence another probe during testing. You may use a single
probe to extract a sample of more than one constituent as long as the
probe meets all the specifications for each constituent.
(2) Gaseous sample probes. Use either single-port or multi-port
probes for sampling gaseous emissions. You may orient these probes in
any direction relative to the raw or diluted exhaust flow. For some
probes, you must control sample temperatures, as follows:
(i) For probes that extract NOX from diluted exhaust,
control the probe's wall temperature to prevent aqueous condensation.
(ii) For probes that extract hydrocarbons for NMHC or NMHCE analysis
from the diluted exhaust of compression-ignition engines, 2-stroke
spark-ignition engines, or 4-stroke spark-ignition engines below 19 kW,
maintain a probe wall temperature tolerance of (191 11) [deg]C.
[[Page 692]]
(3) PM sample probes. Use PM probes with a single opening at the
end. Orient PM probes to face directly upstream. If you shield a PM
probe's opening with a PM pre-classifier such as a hat, you may not use
the preclassifier we specify in paragraph (d)(4)(i) of this section. We
recommend sizing the inside diameter of PM probes to approximate
isokinetic sampling at the expected mean flow rate.
(c) Transfer lines. You may use transfer lines to transport an
extracted sample from a probe to an analyzer, storage medium, or
dilution system. Minimize the length of all transfer lines by locating
analyzers, storage media, and dilution systems as close to probes as
practical. We recommend that you minimize the number of bends in
transfer lines and that you maximize the radius of any unavoidable bend.
Avoid using 90[deg] elbows, tees, and cross-fittings in transfer lines.
Where such connections and fittings are necessary, take steps, using
good engineering judgment, to ensure that you meet the temperature
tolerances in this paragraph (c). This may involve measuring temperature
at various locations within transfer lines and fittings. You may use a
single transfer line to transport a sample of more than one constituent,
as long as the transfer line meets all the specifications for each
constituent. The following construction and temperature tolerances apply
to transfer lines:
(1) Gaseous samples. Use transfer lines with inside surfaces of 300
series stainless steel, PTFE, Viton \TM\, or any other material that you
demonstrate has better properties for emission sampling. For raw exhaust
sampling, use a non-reactive material capable of withstanding raw
exhaust temperatures. You may use in-line filters if they do not react
with exhaust constituents and if the filter and its housing meet the
same temperature requirements as the transfer lines, as follows:
(i) For NOX transfer lines upstream of either an
NO2-to-NO converter that meets the specifications of Sec.
1065.378 or a chiller that meets the specifications of Sec. 1065.376,
maintain a sample temperature that prevents aqueous condensation.
(ii) For THC transfer lines for testing compression-ignition
engines, 2-stroke spark-ignition engines, or 4-stroke spark-ignition
engines below 19 kW, maintain a wall temperature tolerance throughout
the entire line of (191 11) [deg]C. If you sample
from raw exhaust, you may connect an unheated, insulated transfer line
directly to a probe. Design the length and insulation of the transfer
line to cool the highest expected raw exhaust temperature to no lower
than 191 [deg]C, as measured at the transfer line's outlet.
(2) PM samples. We recommend heated transfer lines or a heated
enclosure to minimize temperature differences between transfer lines and
exhaust constituents. Use transfer lines that are inert with respect to
PM and are electrically conductive on the inside surfaces. We recommend
using PM transfer lines made of 300 series stainless steel. Electrically
ground the inside surface of PM transfer lines.
(d) Optional sample-conditioning components for gaseous sampling.
You may use the following sample-conditioning components to prepare
gaseous samples for analysis, as long you do not install or use them in
a way that adversely affects your ability to show that your engines
comply with all applicable gaseous emission standards.
(1) NO2-to-NO converter. You may use an NO2-
to-NO converter that meets the efficiency-performance check specified in
Sec. 1065.378 at any point upstream of a NOX analyzer,
sample bag, or other storage medium.
(2) Sample dryer. You may use either type of sample dryer described
in this paragraph (d)(2) to decrease the effects of water on gaseous
emission measurements. You may not use a chemical dryer, or used dryers
upstream of PM sample filters.
(i) Osmotic-membrane. You may use an osmotic-membrane dryer upstream
of any gaseous analyzer or storage medium, as long as it meets the
temperature specifications in paragraph (c)(1) of this section. Because
osmotic-membrane dryers may deteriorate after prolonged exposure to
certain exhaust constituents, consult with the membrane manufacturer
regarding your application before incorporating an osmotic-membrane
dryer. Monitor the
[[Page 693]]
dewpoint, Tdew, and absolute pressure, ptotal, downstream of an osmotic-
membrane dryer. You may use continuously recorded values of Tdew and
ptotal in the amount of water calculations specified in Sec. 1065.645.
If you do not continuously record these values, you may use their peak
values observed during a test or their alarm setpoints as constant
values in the calculations specified in Sec. 1065.645. You may also use
a nominal ptotal, which you may estimate as the dryer's lowest absolute
pressure expected during testing.
(ii) Thermal chiller. You may use a thermal chiller upstream of some
gas analyzers and storage media. You may not use a thermal chiller
upstream of a THC measurement system for compression-ignition engines,
2-stroke spark-ignition engines, or 4-stroke spark-ignition engines
below 19 kW. If you use a thermal chiller upstream of an NO2-
to-NO converter or in a sampling system without an NO2-to-NO
converter, the chiller must meet the NO2 loss-performance
check specified in Sec. 1065.376. Monitor the dewpoint, Tdew, and
absolute pressure, ptotal, downstream of a thermal chiller. You may use
continuously recorded values of Tdew and ptotal in the emission
calculations specified in Sec. 1065.650. If you do not continuously
record these values, you may use their peak values observed during a
test or their high alarm setpoints as constant values in the amount of
water calculations specified in Sec. 1065.645. You may also use a
nominal ptotal, which you may estimate as the dryer's lowest absolute
pressure expected during testing. If it is valid to assume the degree of
saturation in the thermal chiller, you may calculate Tdew based on the
known chiller efficiency and continuous monitoring of chiller
temperature, Tchiller. If you do not continuously record values of
Tchiller, you may use its peak value observed during a test, or its
alarm setpoint, as a constant value to determine a constant amount of
water according to Sec. 1065.645. If it is valid to assume that
Tchiller is equal to Tdew, you may use Tchiller in lieu of Tdew
according to Sec. 1065.645. If we ask for it, you must show by
engineering analysis or by data the validity of any assumptions allowed
by this paragraph (d)(2)(ii).
(3) Sample pumps. You may use sample pumps upstream of an analyzer
or storage medium for any gas. Use sample pumps with inside surfaces of
300 series stainless steel, PTFE, or any other material that you
demonstrate has better properties for emission sampling. For some sample
pumps, you must control temperatures, as follows:
(i) If you use a NOX sample pump upstream of either an
NO2-to-NO converter that meets Sec. 1065.378 or a chiller
that meets Sec. 1065.376, it must be heated to prevent aqueous
condensation.
(ii) For testing compression-ignition engines, 2-stroke spark-
ignition engines, or 4-stroke compression ignition engines below 19 kW,
if you use a THC sample pump upstream of a THC analyzer or storage
medium, its inner surfaces must be heated to a tolerance of (191 11) [deg]C.
(e) Optional sample-conditioning components for PM sampling. You may
use the following sample-conditioning components to prepare PM samples
for analysis, as long you do not install or use them in a way that
adversely affects your ability to show that your engines comply with the
applicable PM emission standards. You may condition PM samples to
minimize positive and negative biases to PM results, as follows:
(1) PM preclassifier. You may use a PM preclassifier to remove
large-diameter particles. The PM preclassifier may be either an inertial
impactor or a cyclonic separator. It must be constructed of 300 series
stainless steel. The preclassifier must be rated to remove at least 50%
of PM at an aerodynamic diameter of 10 [micro]m and no more than 1% of
PM at an aerodynamic diameter of 1 [micro]m over the range of flow rates
for which you use it. Follow the preclassifier manufacturer's
instructions for any periodic servicing that may be necessary to prevent
a buildup of PM. Install the preclassifier in the dilution system
downstream of the last dilution stage. Configure the preclassifier
outlet with a means of bypassing any PM sample media so the
preclassifier flow may be stabilized before starting a test. Locate PM
sample media within 50 cm downstream of the preclassifier's exit. You
may not use this preclassifier if you use a PM probe
[[Page 694]]
that already has a preclassifier. For example, if you use a hat-shaped
preclassifier that is located immediately upstream of the probe in such
a way that it forces the sample flow to change direction before entering
the probe, you may not use any other preclassifier in your PM sampling
system.
(2) Other components. You may request to use other PM conditioning
components upstream of a PM preclassifier, such as components that
condition humidity or remove gaseous-phase hydrocarbons from the diluted
exhaust stream. You may use such components only if we approve them
under Sec. 1065.10.