ASTM D7634-10(2017)

Standard Test Method for Visualizing Particulate Sizes and Morphology of Particles Contained in Hydrogen Fuel by Microscopy

SIGNIFICANCE AND USE
5.1 Low temperature fuel cells such as proton exchange membrane fuel cells (PEMFCs) require high purity hydrogen for maximum material performance and lifetime. The particulates in hydrogen used in FCVs and hydrogen powered internal combustion vehicles may adversely affect pneumatic control components, such as valves or other critical system components. The visualization of the size and morphology of particles is an important tool for determining particle origin as well as for devising particle formation reduction strategies.
SCOPE
1.1 This test method is primarily intended for visualizing and measuring the sizes and morphology of particulates in hydrogen used as a fuel for fuel cell or internal combustion engine powered vehicles. This test method describes procedures required to obtain size and morphology data of known quality. This test method can be applied to other gaseous samples requiring determination of particulate sizes and morphology provided the user’s data quality objectives are satisfied.  
1.2 Mention of trade names in standard does not constitute endorsement or recommendation. Other manufacturers of equipment, software or equipment models can be used.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2017
• ICS: 27.075 - Hydrogen technologies
• Technical Committee: D03 - Gaseous Fuels
• Drafting Committee: D03.14 - Hydrogen and Fuel Cells

Relations

• Refers: ASTM D7650-10 - Standard Test Method for Test Method for Sampling of Particulate Matter in High Pressure Hydrogen used as a Gaseous Fuel with an In-Stream Filter
• Effective Date: 01-Jul-2010

Overview

ASTM D7634-10(2017), titled Standard Test Method for Visualizing Particulate Sizes and Morphology of Particles Contained in Hydrogen Fuel by Microscopy, establishes procedures for the visualization and measurement of particulate matter in hydrogen gas fuel. Developed by ASTM, this international standard is crucial for evaluating hydrogen fuel quality, particularly for fuel cell vehicles (FCVs) and hydrogen-powered internal combustion engines. Clean, contaminant-free hydrogen is essential for maximizing the performance and lifespan of low temperature fuel cells, such as proton exchange membrane fuel cells (PEMFCs). This standard outlines a microscopy-based approach to assess the size distribution and morphology of particles, supporting both quality control and failure analysis activities in hydrogen fuel supply chains.

Key Topics

• Purpose: Ensures accurate visualization and measurement of particle sizes and morphologies in hydrogen fuel, supporting data quality objectives for various applications.
• Microscopy Requirements: Details the use of advanced microscopy systems-including reflectance and transmittance illumination, built-in polarization, and digital imaging-for precise particle analysis.
• Contamination Control: Recommends cleanroom practices, HEPA filters, and proper handling techniques to avoid external contamination that could compromise sample integrity.
• Test Procedures: Describes the selection and use of specific filters (e.g., PTFE membrane disc filters), filter conditioning, and the application of appropriate magnification and lighting to identify and document particles.
• Reporting: Specifies how to record particle size, morphology, images, pinholes, and overlapping or clustered particles within the final analysis, using calibrated digital tools and standardized metrics.
• Precision and Repeatability: Covers the expectations for consistency in measurement results, including factors affecting accuracy and the importance of repeatable procedures and inter-laboratory comparisons.

Applications

The ASTM D7634-10(2017) standard has a wide range of practical applications in the hydrogen energy sector:

• Fuel Cell Vehicles (FCVs): Assures hydrogen quality by detecting particulates that could damage sensitive fuel cell components, valves, and pneumatic controls, thereby supporting operational reliability.
• Hydrogen Infrastructure: Enables hydrogen fueling stations and distributors to routinely monitor and control particulate contamination in their supply, mitigating wear-related failures.
• Research and Development: Provides laboratories, manufacturers, and system integrators with standardized methodology for evaluating and improving hydrogen purification and delivery processes.
• Regulatory Compliance: Helps meet the requirements set by international guidelines such as SAE TIR J2719 and ISO TS 14687-2 for hydrogen fuel quality, particularly with reference to particulate contamination.
• Broader Gaseous Fuels: While focused on hydrogen, the testing approach can be adapted for other gaseous fuels, provided similar data quality targets are upheld.

Related Standards

Adherence to ASTM D7634-10(2017) can be enhanced through the use of related standards and guidelines, including:

• ASTM D7650: Practice for Sampling of Particulate Matter in High Pressure Gaseous Fuels with an In-Stream Filter
• ASTM D7651: Test Method for Gravimetric Measurement of Particulate Concentration of Hydrogen Fuel
• SAE TIR J2719: Hydrogen Quality Guideline for Fuel Cell Vehicles
• ISO TS 14687-2: Hydrogen Fuel - Product Specification - PEM Fuel Cell Applications
• ISO/TR 15916: Basic Consideration for Safety of Hydrogen Systems

These documents collectively support consistent, high-quality analysis and control of particulates in hydrogen fuels, ensuring safe and effective use in transportation and energy applications.

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Keywords: ASTM D7634, hydrogen fuel, particulate analysis, microscopy, fuel cell vehicle, hydrogen quality, PEMFC, standard test method, particulate size, hydrogen contamination.

Standards Content (Sample)

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 [e-mail]. 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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