ASTM D7634-10(2017)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7634 − 10 (Reapproved 2017)
Standard Test Method for
Visualizing Particulate Sizes and Morphology of Particles
Contained in Hydrogen Fuel by Microscopy
This standard is issued under the fixed designation D7634; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 SAE Standards:
SAE TIR J2719 Hydrogen Quality Guideline for Fuel Cell
1.1 This test method is primarily intended for visualizing
Vehicles, April 2008
and measuring the sizes and morphology of particulates in
SAE J6000 Compressed Hydrogen Surface Vehicle Refuel-
hydrogen used as a fuel for fuel cell or internal combustion
ing Connection Devices
engine powered vehicles. This test method describes proce-
dures required to obtain size and morphology data of known
3. Terminology
quality. This test method can be applied to other gaseous
3.1 Definitions of Terms Specific to This Standard:
samples requiring determination of particulate sizes and mor-
3.1.1 constituent—component (or compound) found within
phology provided the user’s data quality objectives are satis-
a hydrogen fuel mixture
fied.
3.1.2 contaminant—impurity that adversely affects the com-
1.2 Mention of trade names in standard does not constitute
ponents within the fuel cell system or the hydrogen storage
endorsement or recommendation. Other manufacturers of
system
equipment, software or equipment models can be used.
3.1.3 fuel cell grade hydrogen—hydrogen satisfying the
1.3 The values stated in SI units are to be regarded as
specifications in SAE TIR J2719.
standard. No other units of measurement are included in this
3.1.4 gaseous fuel—material to be tested, as sampled, with-
standard.
out change of composition by drying or otherwise.
1.4 This standard does not purport to address all of the
3.1.5 HEPA Filter—A high efficiency particulate air filter
safety concerns, if any, associated with its use. It is the
which, by definition, removes at least 99.97% of airborne
responsibility of the user of this standard to establish appro-
particles 0.3μm in diameter.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.1.6 SAE TIR J2719—Information Report on the develop-
1.5 This international standard was developed in accor-
ment of a hydrogen quality guideline for fuel cell vehicles
dance with internationally recognized principles on standard-
3.2 Acronyms:
ization established in the Decision on Principles for the
3.2.1 FCV—Fuel Cell Vehicle
Development of International Standards, Guides and Recom-
3.2.2 PSA—Particulate sampling adapter for sampling par-
mendations issued by the World Trade Organization Technical
ticulate in hydrogen fuel
Barriers to Trade (TBT) Committee.
3.2.3 HQSA—Hydrogen quality sampling adapter for sam-
2. Referenced Documents
pling gaseous hydrogen fuel
2.1 ASTM Standards:
3.2.4 SAE—Society of Automotive Engineers International
D7650 Practice for Sampling of Particulate Matter in High
3.2.5 PEM—Polymer Electrolyte Membrane, also called
Pressure Gaseous Fuels with an In-Stream Filter
Proton Exchange Membrane
3.2.6 PEMFC—proton exchange membrane fuel cells
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous
Fuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen and
4. Summary of Test Method
Fuel Cells.
Current edition approved April 1, 2017. Published April 2017. Originally
4.1 This procedure is for visualizing and measuring, by
approved in 2010. Last previous edition approved in 2010 as D7634-10. DOI:
microscopy, the sizes and morphology of particulates after
10.1520/D7634–10R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,
the ASTM website. PA 15096-0001, http://www.sae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7634 − 10 (2017)
collection of particulates contained within hydrogen fuel at 8. Reagents and Materials
fueling station dispenser nozzles (Test Method D7650, SAE
8.1 Filter—A 47 mm diameter polytetrafluoroethylene filter
J2600) or other gaseous fuel delivery system dispenser inter-
(PTFE Membrane Disc Filters) is used. An example of a
faces. Every precaution should be taken to avoid contamination
suitable filter is a Pall TF-200 47mm 0.2 μm (P/N 66143) with
of particulates onto the filter coming from the PSA, the
a pore size of 0.2 μm. One side of this type filter is composed
analytical system, ambient air, filter handling or other environ-
of polytetrafluoroethylene (PTFE) and the reverse side is
mental sources.
composed of polypropylene. Installed in the filter holder, the
PTFE side should face the hydrogen fuel stream. The polypro-
5. Significance and Use
pylene side of the filter is generally shinier than the PTFE side,
5.1 Low temperature fuel cells such as proton exchange
which is dull when viewed under a bright light. When
membrane fuel cells (PEMFCs) require high purity hydrogen
examining, visualizing, handling, and weighing filters, the side
for maximum material performance and lifetime. The particu-
facing the gas stream and collecting particulates must always
lates in hydrogen used in FCVs and hydrogen powered internal
face up. Before visualizing a filter by microscopy, examine it
combustion vehicles may adversely affect pneumatic control
carefully to ensure the filter is not damaged and record the
components, such as valves or other critical system compo-
condition and appearance of the filter. Filters are always stored
nents. The visualization of the size and morphology of particles
in a small particulate free plastic container in a mini clean room
is an important tool for determining particle origin as well as
(7.2) when not in use.
for devising particle formation reduction strategies.
9. Test Specimens and Test Units
6. Interferences
9.1 Test specimens—Particulate.
6.1 Particulate matter originating in the environment or
equipment will interfere with the determinations. Every pre-
9.2 Test units—μm.
caution should be taken to avoid contamination of particulates
onto the filter coming from the analytical system, ambient air,
10. Preparation of Apparatus
filter handling, or other environmental sources.
10.1 Microscope—The microscope, when not in use, must
6.2 The potential effect of body moisture or oils contacting
be covered with particulate free plastic and remain in a
the filters is minimized by using powder-free gloves while
Horizontal Flow Hood (7.3) fitted with a HEPA Filter. The
handling filters outside the glove box.
surface of the hood must be cleaned using a HEPA filter fitted
vacuum (7.6) before visualization activity and the flow in the
7. Apparatus
hood is turned on at least an hour before this activity.
7.1 Microscope—A microscopy system is necessary to have
reflectance and transmittance illuminations, built-in polariza-
11. Conditioning
tion system and a digital camera with an USB connection to a
11.1 Filter Conditioning—New filters are stored in their
computer. The microscope is covered with a plastic cover when
original packaging and the filters ready for visualization are
not in use and placed on a table top inside a horizontal flow
stored in a mini-clean room as described in 7.2.
hood containing a HEPA filter (7.3).
7.2 Mini-Clean Room—A small clean room with HEPA
12. Procedure
filter should be used to store unused TFE-flourocarbon filters,
12.1 Always clean horizontal flow hood HEPA filter air inlet
filter holders, and sampled filters at atmospheric moisture less
surfaces using a HEPA Vacuum before handling filters.
than 30%.
12.2 Clean the surface area around microscope with a HEPA
7.3 HEPA Filter Fitted Horizontal Flow Hood—A flow
vacuum before performing visualizations.
hood that blows filtered air through a HEPA filter horizontally.
12.3 Remove the plastic microscope covering inside the
This eliminates or reduces environmental particulates that can
interfere with microscope visualization. The air velocity mea- HEPA filter fitted horizontal flow hood. Place a Vaneometers
(7.4) on one side of the microscope and an electronic air
sured by Vaneometer (7.4) should be over 80 ft/minute (1.46
km/hour); otherwise, an electronic air velocity meter (7.5) velocity meter (7.5) on the other side to ensure the air linear
should alarm the operator. velocity is greater than 80ft/min.
7.4 Vaneometer—This metering device is used to measure 12.4 Transfer filters stored in a pla
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