[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: 40CFR1065.170]
[Page 694-696]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents
Subpart B_Equipment Specifications
Sec. 1065.170 Batch sampling for gaseous and PM constituents.
Batch sampling involves collecting and storing emissions for later
analysis. Examples of batch sampling include collecting and storing
gaseous emissions in a bag and collecting and storing PM on a filter.
You may use batch sampling to store emissions that have been diluted at
least once in some way, such as with CVS, PFD, or BMD. You may use
batch-sampling to store undiluted emissions only if we approve it as an
alternate procedure under Sec. 1065.10.
(a) Sampling methods. For batch sampling, extract the sample at a
rate proportional to the exhaust flow. If you extract from a constant-
volume flow rate, sample at a constant-volume flow rate. If you extract
from a varying flow rate, vary the sample rate in proportion to the
varying flow rate. Validate proportional sampling after an emission test
as described in Sec. 1065.545. Use storage media that do not change
measured emission levels (either up or down). For example, do not use
sample bags for storing emissions if the bags are permeable with respect
to emissions or if they off-gas emissions. As another example, do not
use PM filters that irreversibly absorb or adsorb gases.
(b) Gaseous sample storage media. Store gas volumes in sufficiently
clean containers that minimally off-gas or allow permeation of gases.
Use good engineering judgment to determine acceptable thresholds of
storage media cleanliness and permeation. To clean a container, you may
repeatedly purge and evacuate a container and you may heat it. Use a
flexible container (such as a bag) within a temperature-controlled
environment, or use a temperature controlled rigid container that is
initially evacuated or has a volume that can be displaced, such as a
piston and cylinder arrangement. Use containers meeting the
specifications in the following table, noting that you may request to
use other container materials under Sec. 1065.10:
Table 1 of Sec. 1065.170--Gaseous Batch Sampling Container Materials
------------------------------------------------------------------------
Engines
-----------------------------------------
Compression-ignition,
Emissions two-stroke spark All other
ignition, 4-stroke engines
spark-ignition <19 kW
------------------------------------------------------------------------
CO, CO2, O2, CH4, C2H6, C3H8, Tedlar\TM\, \2\ Tedlar\TM\, \2\
NO, NO2 \1\. Kynar\TM\, \2\ Kynar\TM\, \2\
Teflon\TM\, \3\ or Teflon\TM\, \3\
300 series stainless or 300 series
steel \3\. stainless steel
\3\
THC, NMHC..................... Teflon\TM\ \4\ or 300 Tedlar\TM\, \2\
series stainless Kynar\TM\, \2\
steel \4\. Teflon\TM\, \3\
or 300 series
stainless steel
\3\
------------------------------------------------------------------------
\1\ As long as you prevent aqueous condensation in storage container.
\2\ Up to 40 [deg]C.
\3\ Up to 202 [deg]C.
\4\ At (191 11) [deg]C.
[[Page 695]]
(c) PM sample media. Apply the following methods for sampling
particulate emissions:
(1) If you use filter-based sampling media to extract and store PM
for measurement, your procedure must meet the following specifications:
(i) If you expect that a filter's total surface concentration of PM
will exceed 0.473 mm/mm\2\ for a given test interval, you may use filter
media with a minimum initial collection efficiency of 98%; otherwise you
must use a filter media with a minimum initial collection efficiency of
99.7%. Collection efficiency must be measured as described in ASTM D
2986-95a (incorporated by reference in Sec. 1065.1010), though you may
rely on the sample-media manufacturer's measurements reflected in their
product ratings to show that you meet applicable requirements.
(ii) The filter must be circular, with an overall diameter of 46.50
0.6 mm and an exposed diameter of at least 38 mm.
See the cassette specifications in paragraph (c)(1)(vi) of this section.
(iii) We highly recommend that you use a pure PTFE filter material
that does not have any flow-through support bonded to the back and has
an overall thickness of 40 20 [micro]m. An inert
polymer ring may be bonded to the periphery of the filter material for
support and for sealing between the filter cassette parts. We consider
Polymethylpentene (PMP) and PTFE inert materials for a support ring, but
other inert materials may be used. See the cassette specifications in
paragraph (c)(1)(v) of this section. We allow the use of PTFE-coated
glass fiber filter material, as long as this filter media selection does
not affect your ability to demonstrate compliance with the applicable
standards, which we base on a pure PTFE filter material. Note that we
will use pure PTFE filter material for compliance testing, and we may
require you to use pure PTFE filter material for any compliance testing
we require, such as for selective enforcement audits.
(iv) You may request to use other filter materials or sizes under
the provisions of Sec. 1065.10.
(v) To minimize turbulent deposition and to deposit PM evenly on a
filter, use a 12.5[deg] (from center) divergent cone angle to transition
from the transfer-line inside diameter to the exposed diameter of the
filter face. Use 300 series stainless steel for this transition.
(vi) Maintain sample velocity at the filter face at or below 100 cm/
s, where filter face velocity is the measured volumetric flow rate of
the sample at the pressure and temperature upstream of the filter face,
divided by the filter's exposed area.
(vii) Use a clean cassette designed to the specifications of Figure
1 of Sec. 1065.170 and made of any of the following materials:
Delrin\TM\, 300 series stainless steel, polycarbonate, acrylonitrile-
butadiene-styrene (ABS) resin, or conductive polypropylene. We recommend
that you keep filter cassettes clean by periodically washing or wiping
them with a compatible solvent applied using a lint-free cloth.
Depending upon your cassette material, ethanol
(C2H5OH) might be an acceptable solvent. Your
cleaning frequency will depend on your engine's PM and HC emissions.
(viii) If you store filters in cassettes in an automatic PM sampler,
cover or seal individual filter cassettes after sampling to prevent
communication of semi-volatile matter from one filter to another.
(2) You may use other PM sample media that we approve under Sec.
1065.10, including non-filtering techniques. For example, you might
deposit PM on an inert substrate that collects PM using electrostatic,
thermophoresis, inertia, diffusion, or some other deposition mechanism,
as approved.
[[Page 696]]
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