ASTM D7653-18

Standard Test Method for Determination of Trace Gaseous Contaminants in Hydrogen Fuel by Fourier Transform Infrared (FTIR) Spectroscopy

SIGNIFICANCE AND USE
5.1 Fuel cell users have implicated trace impurities in feed gases as compromising the performance and lifespan of proton exchange membrane fuel cells (PEMFCs). PEMFCs may be damaged by the presence of some contaminants through poisoning of fuel cell electrode materials; therefore detection of these impurities at low concentrations is critical to fuel cell manufacturers and feed gas suppliers in order to support the facilities and infrastructure required for widespread applicability of fuel cells in transportation and energy production. With field-portable equipment, this test method can be used to quickly analyze hydrogen fuel for impurities at vehicle fueling stations or storage tanks used to supply stationary power plants. This test method can also be used by gas suppliers, customers, and regulatory agencies to certify hydrogen fuel quality.  
5.2 Users include hydrogen producers, gaseous fuel custody transfer stakeholders, fueling stations, fuel cell manufacturers, automotive manufacturers, regulators, and stationary fuel cell power plant operators.
SCOPE
1.1 This test method employs an FTIR gas analysis system for the determination of trace impurities in gaseous hydrogen fuels relative to the hydrogen fuel quality limits described in SAE TIR J2719 (April 2008) or in hydrogen fuel quality standards from other governing bodies. This FTIR method is used to quantify gas phase concentrations of multiple target contaminants in hydrogen fuel either directly at the fueling station or on an extracted sample that is sent to be analyzed elsewhere. Multiple contaminants can be measured simultaneously as long as they are in the gaseous phase and absorb in the infrared wavelength region. The detection limits as well as specific target contaminants for this standard were selected based upon those set forth in SAE TIR J2719.  
1.2 This test method allows the tester to determine which specific contaminants for hydrogen fuel impurities that are in the gaseous phase and are active infrared absorbers which meet or exceed the detection limits set by SAE TIR J2719 for their particular FTIR instrument. Specific target contaminants include, but are not limited to, ammonia, carbon monoxide, carbon dioxide, formaldehyde, formic acid, methane, ethane, ethylene, propane, and water. This test method may be extended to other impurities provided that they are in the gaseous phase or can be vaporized and are active infrared absorbers.  
1.3 This test method is intended for analysis of hydrogen fuels used for fuel cell feed gases or for internal combustion engine fuels. This method may also be extended to the analysis of high purity hydrogen gas used for other applications including industrial applications, provided that target impurities and required limits are also identified.  
1.4 This test method can be used to analyze hydrogen fuel sampled directly at the point-of-use from fueling station nozzles or other feed gas sources. The sampling apparatus includes a pressure regulator and metering valve to provide an appropriate gas stream for direct analysis by the FTIR spectrometer.  
1.5 This test method can also be used to analyze samples captured in storage vessels from point-of-use or other sources. Analysis of the stored samples can be performed either in a mobile laboratory near the sample source or in a standard analytical laboratory.  
1.6 A test plan should be prepared that includes (1) the specific impurity species to be measured, (2) the concentration limits for each impurity species, and (3) the determination of the minimum detectable concentration for each impurity species as measured on the apparatus before testing.  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7.1 Exception—All values are based upon common terms used in the industry of those particular values and when not consistent with SI units, the appropriate...

General Information

• Status: Published
• Publication Date: 30-Nov-2018
• ICS: 71.100.20 - Gases for industrial application
• Technical Committee: D03 - Gaseous Fuels
• Drafting Committee: D03.14 - Hydrogen and Fuel Cells

Relations

• Replaces: ASTM D7653-10 - Standard Test Method for Determination of Trace Gaseous Contaminants in Hydrogen Fuel by Fourier Transform Infrared (FTIR) Spectroscopy
• Effective Date: 01-Dec-2018
• Refers: ASTM D7606-17 - Standard Practice for Sampling of High Pressure Hydrogen and Related Fuel Cell Feed Gases
• Effective Date: 01-Nov-2017
• Refers: ASTM D5287-08(2015) - Standard Practice for Automatic Sampling of Gaseous Fuels (Withdrawn 2024)
• Effective Date: 01-Jun-2015
• Refers: ASTM D6348-12 - Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy
• Effective Date: 01-Feb-2012
• Refers: ASTM D7606-11 - Standard Practice for Sampling of High Pressure Hydrogen and Related Fuel Cell Feed Gases
• Effective Date: 01-Mar-2011
• Refers: ASTM D6348-03(2010) - Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy
• Effective Date: 01-Oct-2010
• Refers: ASTM D5287-08 - Standard Practice for Automatic Sampling of Gaseous Fuels
• Effective Date: 01-Dec-2008
• Refers: ASTM D6348-03 - Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy
• Effective Date: 01-Oct-2003
• Refers: ASTM D6348-98 - Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy
• Effective Date: 10-Dec-1998
• Refers: ASTM D5287-97(2002) - Standard Practice for Automatic Sampling of Gaseous Fuels
• Effective Date: 10-Jun-1997
• Referred By: ASTM D7675-22 - Standard Test Method for Determination of Total Hydrocarbons in Hydrogen by FID-Based Total Hydrocarbon (THC) Analyzer
• Effective Date: 01-Dec-2018

Overview

ASTM D7653-18 establishes a standard test method for determining trace gaseous contaminants in hydrogen fuel using Fourier Transform Infrared (FTIR) Spectroscopy. This method addresses the critical need for hydrogen fuel quality assurance, particularly for proton exchange membrane fuel cells (PEMFCs), which are sensitive to low levels of contaminants. Trace impurities can degrade fuel cell performance and durability or damage sensitive components within hydrogen-powered systems, such as vehicles and stationary power plants. ASTM D7653-18 provides stakeholders-including hydrogen producers, fueling stations, fuel cell and automotive manufacturers, and regulatory agencies-with a reliable means for detecting and quantifying gaseous contaminant levels to verify compliance with industry fuel quality limits.

Key Topics

• Scope of Analysis

  • The method applies to gaseous hydrogen fuels, supporting hydrogen quality standards such as SAE TIR J2719.
  • FTIR Spectroscopy is used to detect multiple contaminants simultaneously if they are in the gaseous phase and absorb in the infrared spectrum.

• Target Contaminants

  • Detects impurities such as ammonia, carbon monoxide, carbon dioxide, formaldehyde, formic acid, methane, ethane, ethylene, propane, water, and others absorbing in the IR region.

• Versatile Sampling

  • Hydrogen samples can be analyzed directly at fueling station nozzles, storage tanks, or after sampling into high-pressure storage vessels.
  • The method is suitable for both field and laboratory settings, using field-portable or stationary equipment.

• Calibration and Test Planning

  • Users must prepare a comprehensive test plan specifying impurity species, concentration limits, and minimum detectable levels for their FTIR instruments.
  • Accurate calibration is crucial, employing certified calibration standards and matrix-matched hydrogen gas.

• Interference Management

  • The method includes procedures for identifying and managing spectral and sampling system interferences, ensuring reliable results.

• SI Units

  • Measurements are reported using SI units, consistent with international standards.

Applications

• Hydrogen Quality Certification

  • Used by gas suppliers, fuel distributors, and quality regulators to certify hydrogen fuel before delivery to end-users or integration into supply chains.

• Support for Fuel Cell Vehicles and Power Systems

  • Ensures hydrogen fuel is free from contaminants that can poison PEMFCs, affecting vehicle performance and service life.
  • Applicable for stationary power plant operations, supporting reliability and uptime.

• Custody Transfer and Compliance

  • Provides a standardized approach for custody transfer scenarios, allowing buyers and sellers of hydrogen fuel to verify and document fuel quality.

• Field and Laboratory Adaptability

  • Suitable for onsite quality checks at refueling stations with field-portable FTIR instruments, as well as comprehensive laboratory analyses for in-depth investigations.

• Industrial Hydrogen Applications

  • Can be extended to high-purity hydrogen used in various industrial processes, provided target impurities and limits are defined.

Related Standards

• ASTM D5287: Practice for Automatic Sampling of Gaseous Fuels
• ASTM D6348: Test Method for Determination of Gaseous Compounds by Extractive Direct Interface FTIR Spectroscopy
• ASTM D7606: Practice for Sampling of High Pressure Hydrogen and Related Fuel Cell Feed Gases
• SAE TIR J2719: Hydrogen Quality Guideline for Fuel Cell Vehicles
• EPA 40 CFR Applications: Provides regulatory context for detection limits and analytical best practices

Practical Value

Adopting ASTM D7653-18 supports the wider adoption and deployment of hydrogen as a clean energy vector, ensuring that hydrogen supply chains meet stringent quality requirements. By using FTIR-based trace contaminant analysis, industry stakeholders can safeguard fuel cell integrity, reduce maintenance costs, comply with international standards, and build confidence in hydrogen-based transportation and energy solutions. This method’s adaptability for use at the point of fuel dispensing or in the laboratory increases its relevance across the hydrogen value chain.

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: D7653 − 18
Standard Test Method for
Determination of Trace Gaseous Contaminants in Hydrogen
Fuel by Fourier Transform Infrared (FTIR) Spectroscopy
This standard is issued under the fixed designation D7653; 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 includes a pressure regulator and metering valve to provide an
appropriate gas stream for direct analysis by the FTIR spec-
1.1 This test method employs an FTIR gas analysis system
trometer.
for the determination of trace impurities in gaseous hydrogen
1.5 This test method can also be used to analyze samples
fuels relative to the hydrogen fuel quality limits described in
captured in storage vessels from point-of-use or other sources.
SAE TIR J2719 (April 2008) or in hydrogen fuel quality
Analysis of the stored samples can be performed either in a
standards from other governing bodies. This FTIR method is
mobile laboratory near the sample source or in a standard
used to quantify gas phase concentrations of multiple target
analytical laboratory.
contaminants in hydrogen fuel either directly at the fueling
station or on an extracted sample that is sent to be analyzed
1.6 A test plan should be prepared that includes (1) the
elsewhere. Multiple contaminants can be measured simultane- specific impurity species to be measured, (2) the concentration
ouslyaslongastheyareinthegaseousphaseandabsorbinthe limits for each impurity species, and (3) the determination of
infrared wavelength region. The detection limits as well as the minimum detectable concentration for each impurity spe-
specific target contaminants for this standard were selected cies as measured on the apparatus before testing.
based upon those set forth in SAE TIR J2719.
1.7 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.2 This test method allows the tester to determine which
standard.
specific contaminants for hydrogen fuel impurities that are in
1.7.1 Exception—All values are based upon common terms
thegaseousphaseandareactiveinfraredabsorberswhichmeet
used in the industry of those particular values and when not
or exceed the detection limits set by SAE TIR J2719 for their
consistent with SI units, the appropriate SI unit will be
particular FTIR instrument. Specific target contaminants
includedinparenthesesafterthecommonvalueusage(4.4,7.8,
include, but are not limited to, ammonia, carbon monoxide,
7.9, 10.5, and 11.6).
carbon dioxide, formaldehyde, formic acid, methane, ethane,
1.8 This standard does not purport to address all of the
ethylene, propane, and water. This test method may be ex-
safety concerns, if any, associated with its use. It is the
tended to other impurities provided that they are in the gaseous
responsibility of the user of this standard to establish appro-
phase or can be vaporized and are active infrared absorbers.
priate safety, health, and environmental practices and deter-
1.3 This test method is intended for analysis of hydrogen
mine the applicability of regulatory limitations prior to use.
fuels used for fuel cell feed gases or for internal combustion
1.9 This international standard was developed in accor-
engine fuels.This method may also be extended to the analysis
dance with internationally recognized principles on standard-
of high purity hydrogen gas used for other applications
ization established in the Decision on Principles for the
including industrial applications, provided that target impuri-
Development of International Standards, Guides and Recom-
ties and required limits are also identified.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.4 This test method can be used to analyze hydrogen fuel
sampled directly at the point-of-use from fueling station
2. Referenced Documents
nozzles or other feed gas sources. The sampling apparatus
2.1 ASTM Standards:
D5287 Practice for Automatic Sampling of Gaseous Fuels
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
Fuels and is the direct responsibility of Subcommittee D03.14 on Hydrogen and
Fuel Cells. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2018. Published February 2019. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2010. Last previous edition approved in 2010 as D7653 – 10. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7653-18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7653 − 18
D6348 Test Method for Determination of Gaseous Com- 3.1.8 dry nitrogen (or dry N ), n—nitrogen gas with a dew
pounds by Extractive Direct Interface Fourier Transform point at or below –60 °C.
Infrared (FTIR) Spectroscopy
3.1.9 dynamic calibration, n—calibration of an analytical
D7606 Practice for Sampling of High Pressure Hydrogen
system using certified calibration gas standards that are diluted
and Related Fuel Cell Feed Gases
to known concentration.
2.2 SAE Document:
3.1.10 FCV, n—Hydrogen fuel cell vehicle.
SAE TIR J2719 Informational Report on the Development
3.1.11 Fourier Transform Infrared (FTIR), n—typically re-
of a Hydrogen Quality Guideline for Fuel Cell Vehicles
fers to a type of infrared spectrometer which incorporates a
2.3 EPA Documents:
Michelson interferometer to modulate the infrared radiation
EPA40 CFR Protection of the Environment,Appendix B to
before probing the sample.
Part 136 Definition and Procedure for the Determination
3.1.11.1 Discussion—The resultant radiation is then mea-
of the Method Detection Limit
sured with an infrared detector and the resulting signal is
EPA40 CFR Protection of the Environment,Appendix B to
decoded using a Fourier transform algorithm to compute the
Part60:PerformanceSpecification15 PerformanceSpeci-
infrared spectrum.
fication for Extractive FTIR Continuous Emissions Moni-
3.1.12 fuel cell grade hydrogen, n—hydrogen satisfying the
toring Systems in Stationary Sources
specifications in SAE TIR J2719.
3. Terminology
3.1.13 gaseous fuel, n—hydrogen gas intended for use as a
fuel cell feed gas or as a fuel for internal combustion engines.
3.1 Definitions of Terms Specific to This Standard:
3.1.1 analytical interference, n—the physical effects of su-
3.1.14 gauge pressure, n—pressure measured above ambi-
perimposing two or more light waves. ent atmospheric pressure; zero gauge pressure is equal to the
ambient atmospheric (barometric) pressure (psig).
3.1.1.1 Discussion—Analytical interferences occur when
3.1.15 path length, n—the distance that the sample gas
two or more compounds have overlapping absorbance bands in
interacts with the infrared radiation.
their infrared spectra.
3.1.2 analytical algorithm, n—the method used to quantify
3.1.16 poisoning, v—process by which catalysts are made
the concentration of the target contaminants and interferences
inoperative due to the activity of substances such as hydrogen
in each FTIR Spectrum.
sulfide or other sulfur substances that can bind to a component
in the catalyst (such as a noble metal like platinum) used in the
3.1.2.1 Discussion—The analytical algorithm should ac-
fuel cell.
count for the analytical interferences by conducting the analy-
3.1.17 proton exchange membrane fuel cells (PEMFCs),
sis in a portion of the infrared spectrum that is the most unique
for that particular compound. n—PEMFC is an electrochemical apparatus that uses an anode
and cathode to convert H and O into electricity.
3.1.3 apodization, n—amathematicaltransformationcarried
2 2
out on data received from an interferometer to reduce the side
3.1.18 purified nitrogen (or purified N ), n—nitrogen gas
lobes of the measured peaks.
that is purified to Ultra-High Purity Grade (99.9995 %) or
equivalent, containing total impurities <1 ppm, specifically:
3.1.3.1 Discussion—This procedure alters the instrument’s
total hydrocarbons (THC) <0.1 ppm, total carbon dioxide +
response function. There are various types of transformation;
carbon monoxide (CO + CO) <0.1 ppm, and water (H O)
2 2
the most common forms are boxcar, triangular, Happ-Genzel,
<0.5 ppm.
and Norton-Beer functions.
3.1.4 background spectrum, n—the spectrum taken in the 3.1.19 purified hydrogen (or purified H ), n—hydrogen gas
absence of absorbing species or sample gas, typically con- that is purified to Research Grade (99.9999 %) or equivalent,
ducted using dry nitrogen or zero air in the gas cell. containing total impurities <1 ppm, specifically: total hydro-
carbons (THC) <0.1 ppm, total carbon dioxide + carbon
3.1.5 classical least squares (CLS), n—common method of
monoxide (CO + CO) <0.1 ppm, and water (H O) <0.5 ppm.
analyzing multicomponent infrared spectra by scaled absor- 2 2
bance subtraction, also referred to as K-Matrix. 3.1.20 qualitative accuracy, n—the ability of an analytical
system to correctly identify compounds without necessarily
3.1.6 constituent, n—component (or compound) found
providing a precise concentration.
within a hydrogen fuel mixture.
3.1.21 quantitative accuracy, n—the ability of an analytical
3.1.7 contaminant, n—impurity that adversely affects the
system to measure the concentration of an identified com-
componentswithinthefuelcellsystemorthehydrogenstorage
pound.
system.
3.1.22 sample interface, n—the entire sampling system
consistingofthesampleprobe,sampletransportline,andother
components necessary to direct effluent to the FTIR gas cell.
Available from SAE International (SAE), 400 Commonwealth Dr.,Warrendale,
PA 15096-0001, http://www.sae.org.
3.1.23 sampling system interference, n—an interference that
Available from United States Environmental Protection Agency (EPA), Ariel
prohibits or prevents delivery of the target contaminants to the
Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http://
www.epa.gov. FTIR gas cell.
D7653 − 18
3.1.23.1 Discussion—Examples of potential sampling sys- reported concentrations for each contaminant. Then, for all of
tem interferences are unwanted moisture condensation within the contaminants that are to be certified, a purified hydrogen
the sampling system, heavy deposition of particulate matter or sample is prepared with a blend of the target contaminants at
aerosols within the sampling system components, or reactive concentrations near the initial estimated detection limits. Sev-
gases. eral measurements are performed on this blended matrix, as
3.1.24 static calibration, n—calibration of an analytical well as several purified hydrogen blanks and then a more
system using standards in a matrix state or manner different accurate detection limit is calculated based upon the standard
than the samples to be analyzed. deviation of the reported concentrations of both the blanks and
blended gas samples.
3.1.25 target contaminant (or target impurity or impurity),
n—a contaminant found in the gaseous fuel that may adversely
4.4 Field measurements of hydrogen fuel are performed
affect or is required to be reported prior to use within the fuel
using direct sampling from high pressure fuel nozzles or other
cell system, hydrogen storage system, or engine used in
highpressurestoragecontainersprovidedthefinalgaspressure
combustion applications.
can be stepped down to 20 psig (139 kPa(g)) without altering
the fuel composition for introduction into the FTIR flow cell.
4. Summary of Test Method
The fuel sampling apparatus and the FTIR measurement
4.1 Test Plan Preparation—The tester should prepare a test
system are flushed with purified nitrogen or hydrogen and then
planthatincludesadescriptionofthefuelsource,requirements
a background reference spectrum is taken. After flushing the
for the sampling interface, list of target contaminant species to
system and taking a background spectrum, a minimum of three
be measured, and measurement requirements for these con-
samples of the purified nitrogen or hydrogen are measured to
taminants.
verify that impurities are not introduced by the sampling
apparatus. Hydrogen fuel is introduced to the sampling appa-
4.2 Calibration—Aset of calibration spectra is prepared for
ratus and at least three different samples are measured to
each hydrogen fuel contaminant to be measured. Typically
determine the impurity concentrations in the fuel.Anew blank
spectraarecollectedatmultipleconcentrationlevelsofasingle
is run through the gas cell between each sample that is run to
contaminantspanningtheexpectedconcentrationrangeforthat
ensure that the system is at an equilibrium state.
contaminantwithinthegaseoussample.Certifiedgasstandards
or permeation tubes are used with a gas blending system as per
4.5 Laboratory measurements of samples collected in the
7.7 to prepare samples of known concentration of the target
field can be performed in a similar manner to thosetakeninthe
contaminant within a purified H matrix gas and spectra are
2 field. Hydrogen fuel is introduced and then collected into three
collected using the FTIR instrument. The impurity
high pressure storage vessels as described in Practices D5287
concentration, measurement path length, gas temperature, and
and D7606.The samples are then transported to the laboratory,
absolute pressure for the calibration sample are stored together
and then the storage vessel is connected to the laboratory
with each spectrum. These calibrations are generally perma-
sampling apparatus. The sampling apparatus is flushed a
nent and transferable between FTIR instruments of similar
minimum of three times with purified nitrogen or hydrogen.
type. Verification of calibrations can be performed before each
Purified hydrogen is then introduced into the FTIR flow cell,
test using a calibrated cylinder that contains one or more of the
andatleastthreesamplesaremeasuredtoverifythatimpurities
target species in a purified H matrix gas, thus it is not
2 are not introduced by the sampling apparatus. The hydrogen
necessary to recalibrate prior to each test.
fuel from the high pressure storage vessel is then introduced to
4.2.1 Calibration Using Surrogate Matrix Gas—The use of
the sampling apparatus, and three samples are measured after
a surrogate matrix gas such as nitrogen (N ) or helium (He) to
2 all of the signals for each of the target contaminants have
create the known target contaminant (or impurity) concentra-
reached an equilibrium value. These samples are used to
tion is not acceptable according to this method. The FTIR
determine the contaminant concentrations in the sampled
spectral line shape of the impurity within a matrix other than
hydrogen fuel. This process is repeated for each of the high
that of H is sensitive to the differences between the matrix in
2 pressure storage vessels collected from the same fuel source.
N or He, resulting in different line shapes for the same
2 While the number listed in the section is for collecting three
impurity concentrations. More detailed studies are needed to
separate samples, that number will be designated by the final
determine the effect of this line shape change on contaminant
governing body overseeing the Hydrogen Fuel testing.
determination. Therefore, use of a surrogate gas is not accept-
able unless the user has studied and determined conditions 5. Significance and Use
under which the measurement precision and accuracy of data
5.1 Fuel cell users have implicated trace impurities in feed
satisfy the users needs and requirements.
gases as compromising the performance and lifespan of proton
4.3 Evaluation of Detection Limits—Detection limits are exchange membrane fuel cells (PEMFCs). PEMFCs may be
first estimated after the calibrations are created by measuring a damaged by the presence of some contaminants through
blank which consists of a purified hydrogen gas sample that poisoning of fuel cell electrode materials; therefore detection
does not contain any of the target contaminants as listed in of these impurities at low concentrations is critical to fuel cell
3.1.19. Several of the blank samples are measured using the manufacturers and feed gas suppliers in order to support the
finalanalyticmethodthatincludesdetectionforallofthetarget facilities and infrastructure required for widespread applicabil-
contaminants and interferents, and then a preliminary detection ity of fuel cells in transportation and energy production. With
limit estimate is made based upon the standard deviation of the field-portable equipment, this test method can be used to
D7653 − 18
quickly analyze hydrogen fuel for impurities at vehicle fueling 7.5 Nitrogen gas purifier to prepare Ultra High Purity grade
stations or storage tanks used to supply stationary power purified nitrogen gas (99.9995 %) from high purity nitrogen
plants. This test method can also be used by gas suppliers, (99.999 %) for zeroing the measurement instrument and purg-
customers, and regulatory agencies to certify hydrogen fuel ing the FTIR optics.
quality.
7.6 Tubing, electropolished TFC 316 stainless steel or other
5.2 Users include hydrogen producers, gaseous fuel custody inert material, of suitable diameter and length.
transfer stakeholders, fueling stations, fuel cell manufacturers,
7.7 Gas Blending Apparatus (See Fig. 1), for diluting
automotive manufacturers, regulators, and stationary fuel cell
calibration gas standards with purified hydrogen in order to
power plant operators.
createstandardsofthetargetcontaminantspeciesatthedesired
concentrations for both creating calibrations and determining
6. Interferences
detection limits. The gas blending apparatus uses mass flow
controllers suitable for the required flow rates with traceable
6.1 Spectral Interferences—Spectral interference occurs
calibrations and 60.5 % accuracy for the flow range to be
when the spectrum of a target contaminant overlaps with the
employed. The mass flow controllers must also be calibrated
spectrum of another component in the sample. The effects of
forusewithH gasandrecertifiedannuallytoassurecontinued
spectral interferences can often be minimized by using appro-
suitable operation. The gas blending apparatus includes a
priate analytical algorithms or by adjusting spectral analysis
temperature-controlledovenforpermeationtubeswhichcanbe
regions to minimize spectral interference.
used to prepare gas standards of liquids or other reactive
6.2 Sampling System Interferences—Sampling system inter-
compounds. The output of the permeation tube oven is con-
ferences occur when target contaminants are retained by the
trolled by a second mass flow controller and a backpressure
sampling system plumbing or components resulting in reduced
regulator to allow for a large range of flow rates through the
concentration of the target contaminants at the measurement
permeation tube oven while maintaining a relatively constant
system. Sampling system interferences can also occur if target
(lower) flow through the FTIR gas cell.
contaminants outgas or desorb from the sampling system
7.8 Apparatus for Measuring Samples Directly from High
plumbing or components, resulting in increased concentrations
Pressure Nozzles (See Fig. 2)—This apparatus is used to
at the measurement system. Care must be taken in the system
sample and analyze gaseous hydrogen fuel directly from high
design to minimize these affects.
pressure fueling nozzles or similar interfaces used in fueling
automotive vehicles and stationary appliances. This apparatus
7. Apparatus
reduces the pressure of the fuel and provides an appropriate
7.1 Fourier Transform Infrared (FTIR) spectrometer with
flow directly to the FTIR measurement system for analysis.
gas cell and detector having sufficient path length and sensi-
The apparatus typically consists of a J2600 receptacle con-
tivity respectively to measure the target contaminants at or
nected to a fueling station J2600 nozzle, an ultra high purity
below the required detection limits. The entire optical path of
check valve, appropriate pressure regulator to reduce the
the spectrometer should be sealed to allow either purging or
pressuretoapproximately20psig(139kPa(g)),andametering
evacuation to prevent interference from ambient water vapor
valve or flow controller to set an appropriate flow rate through
and carbon dioxide in the spectrometer’s optical path. The gas
the FTIR gas cell. The apparatus also includes a means to
sampling cell should also be sealed to prevent leaking inside
introduce purified nitrogen or hydrogen gas as well as calibra-
the spectrometer of the H gas sample to the atmosphere.
tion gases into the gas sampling cell in order to verify the
7.2 The sample delivery lines to the gas sampling cell as
systemzeroorcalibrationintegrity.Highpuritynitrogenisalso
well as out of the cell should be sealed to allow either purging used to purge the FTIR measurement system interferometer
orevacuationtopreventinterferencefromambientwatervapor
and optics.
and carbon dioxide.The sample delivery lines or tubing should
7.9 Apparatus for Measuring Samples from High Pressure
also be leak free and equilibrated with respect to air contami-
Storage Containers (See Fig. 3)—This apparatus is similar to
nants such as water and carbon dioxide.
the direct sampling apparatus except for the interface to the
7.3 Computer and software to control the FTIR spectrom- hydrogen fuel to be measured. Fuel samples are collected in
eter and to collect, process, and store FTIR spectra. It is also
high pressure storage vessels as described in Practices D5287
required for the software to both monitor the temperature and and D7606 using the methodology and apparatus described
pressure of the sample in the gas cell while collecting spectra.
therein. The storage vessel is then connected to the apparatus
Itshouldalsobeabletoautomaticallycorrectfordifferencesin shown in Fig. 3. When ready to measure, the hydrogen fuel
the pressure and temperature recorded for the calibration sample is introduced by opening valve V4 and setting the
samples to those measured in the sample gas. pressure regulator to approximately 20 psig (139 kPa(g)). The
needle valve is used to set the correct flow rate through the
7.4 Hydrogen gas purifier to prepare Research Grade puri-
FTIR gas cell.
fiedhydrogengas(99.9999 %)fromultrahighpurityhydrogen
(99.999 %) for zeroing the measurement instrument, mixing 7.10 Ultra high purity (UHP) nitrogen is required for
calibration standards, and testing the zero response of the purging the FTIR spectrometer and optics assembly. Purge
system. Purifiers that can remove the impurities to less than nitrogen gas should be 99.9995 % pure and have a dew point
1 ppb levels are preferred. at or below –60 ºC. If a lower grade of nitrogen is used, then
D7653 − 18
FIG. 1 Gas Blending Apparatus. Mass Flow Controller (MFC)
FIG. 2 Apparatus for Measuring Samples Directly from High Pressure Nozzles. Line Switching Valve (V), Needle Valve (NV)
aN purifier must be used to remove impurities such as total purifier results in overall stability of the background of the
hydrocarbons, CO, CO , and H O to less then 1 ppm or better instrument so it is recommended to be used even if UHP
2 2
in order to achieve the UHP grade requirement. The use of the nitrogen is used.
D7653 − 18
FIG. 3 Apparatus for Measuring Samples from High Pressure Storage Containers. Line Switching Valve (V), Needle Valve (NV)
7.11 Research Grade purified hydrogen gas (99.9999 % tially combustible gas mixtures do not come in contact with
pure) is required for blending calibration samples and to any ignition sources (for example, infrared source, electronics,
perform baseline measurements (when possible). Purified hy- etc.).
drogen must be run through a H purifier to remove moisture
8.2 Some of the gas mixtures used for calibration are
and other impurities such as total hydrocarbons, CO, and CO ,
potentially harmful or dangerous if not vented properly from
to less than 1 ppb each prior to use with the measurement
the measurement system or sampling apparatus. Review the
system.
Material Safety Data Sheets (MSDS) for all materials and be
7.12 Calibration gas standards prepared in hydrogen for sure to use proper safety precautions.
measurement of calibration spectra and for verification of
sample system integrity. Gas standards should be provided 9. Calibration
with a National Institute of Standards and Technology (NIST)
9.1 Preparation:
traceable certification at or below 62 % accuracy. Multiple
9.1.1 Concentration Range for Calibration Spectra—
target contaminants may be mixed in a single calibration gas
Collect calibration spectra spanning the expected ranges in the
bottle provided that the mixed species are non-reactive, do not
fuel samples for each target contaminant as well as any other
degrade in the presence of the other components, and must not
impurity that may be present in the hydrogen fuel sample
interfere spectrally (in the FTIR regime) with any of the other
which are active in the infrared region. The lowest concentra-
target contaminants in the mixture.
tion should be at or near the contaminant limit defined in the
7.13 Permeation tubes are used to prepare known concen-
test plan. The upper concentration should be high enough to
trations of contaminants that are liquids or reactive com-
prevent the need to extrapolate to higher concentrations.
pounds. Permeation tubes should be provided with a NIST
Typically ten or more calibration points are collected for each
traceable certification at or below 62 % accuracy. A perme-
contaminant (target impurity) species.
ation oven that operates above ambient temperature is required
9.1.2 FTIR Spectrometer Settings—Collect calibration spec-
to be used in order to achieve the accuracy of the permeation
tra with the FTIR gas cell at approximately the same tempera-
tube standards.
ture and pressure as will be used for measuring hydrogen fuel
samples. Due to changes in the ambient field temperatures it is
8. Hazards
best to use elevated gas cell temperatures (>35 °C) to avoid
8.1 Care should be taken to avoid hazards associated with fluctuations or temperature mismatch due to changes in the
bothhighandambientpressurehydrogenleaksinthesampling ambient temperature. Be sure to use the same FTIR spectral
apparatus or measurement system. Redundant safety measures resolution and apodization function for calibrations and mea-
such as hydrogen monitors and nitrogen purged enclosures surements. The gas cell path length is chosen to provide
around the instrument are recommended to ensure that poten- adequate sensitivity while maintaining maximum absorbance
D7653 − 18
unit (AU) values for the quantification region to be at or under overlap within the usable infrared region. Care should be taken
1.0 AU. If necessary, the maximum absorbance requirement toensurethatcontaminantsintheblendsdonotreactwitheach
can be met by choosing analytical regions that exclude strong other.
absorption features. The number of FTIR scans (or measure-
9.3 Collect Calibration Spectra for Species from Perme-
ment time) can be increased to improve detection limits.
ation Tubes:
Record all settings and actual gas cell absolute pressure and
9.3.1 Purge the gas blending apparatus and FTIR gas cell
temperature for each calibration spectrum.
with purified H . Monitor for one or more surrogate contami-
9.1.3 Determine the Number of Gas Cell Volumes Required
nant species (for example, H O which tends to be more sticky)
to Flush the FTIR Gas Cell—The Environmental Protection
using the FTIR to verify that the reported concentrations have
Agency (EPA) recommends 5 cell volumes are adequate to
reached a minimum and stable value such as applying an f-test
fully flush the gas cell of the sample (See EPA 40 CFR
to determine the values are no longer significant. As needed a
Protection of the Environment, Appendix B to Part 60). For a
new background spectrum is acquired.
flow rate of 1 L per min (LPM) and a gas cell volume of
9.3.2 Set the temperature of the permeation tube oven as
200 mL the number of cell volumes would be 1.0 LPM/0.2 L
directed by the permeation tube manufacturer and set the mass
= 5 volumes flushed per 1 min. For a larger cell volume of
flow controllers as required to prepare the desired concentra-
500 mL for the same flow rate you would only achieve
tion.The use of permeation tubes at ambient temperature is not
1.0 LPM⁄0.5 L = 2 volumes flushed per 1 min. Therefore the
acceptable as this will result in excessive variability in perme-
amount of time required to completely flush the gas sample
ation rates due to a lack of fine temperature control. As
fromthegascellisdependantuponthegascellinternalvolume
necessary, the output flow from the permeation oven can be
and the gas sample flow rate. For faster data acquisition a
split using the output mass flow controller and a backpressure
smaller gas sample volume is desired or a faster flow rate can
regulatorinordertopreparelowerconcentrationstandards.For
be used, but that must be balanced by the amount of sample
eachblend,allowthemixturetoflowthroughtheFTIRgascell
that is resident in the gas sample chamber/cylinder that was
purging at the required number of cell volumes as defined in
collected.
9.1.3.
9.1.4 Prior to collecting the calibration spectra verify the
9.3.3 Collect at least three calibration spectra for each
FTIR performance is within acceptable limits following the
contaminant (impurity) concentration.The three spectra can be
instructionsinAnnexA1aswellasthosespecifiedbytheFTIR
used to verify that the calibration gas concentration was not
manufacturer.
changing within 62 %. Record the FTIR settings, gas cell
temperature, gas cell absolute pressure, and gas cell path
9.2 Collect Calibration Spectra for Species in Calibration
length.Also record the permeation tube serial number, concen-
Gas Cylinders:
tration calculation, oven temperature, and flow conditions.
9.2.1 Purge the gas blending apparatus and FTIR gas cell
Repeat this process for each desired concentration for each
with purified H . Monitor for one or more surrogate contami-
contaminant species that requires a permeation tube to be used.
nant species (generally H O is selected) using the FTIR to
9.3.4 Follow Annex A3 for more details on the creation of
verify that the reported concentrations have reached a mini-
the FTIR Reference Spectra.
mum and stable value.As needed a new background spectrum
is acquired.
9.4 Prepare Analytical Methods for Each Impurity Species:
9.2.2 Program the gas blending apparatus to prepare the 9.4.1 For gas impurity analysis the main analytical method
required concentration mixtures while maintaining a relatively used is based upon Classical Least Squares (CLS) algorithms.
constant flow rate to prevent an increase in pressure in the This method requires that each component that might be
FTIR gas cell. For each blend, allow the mixture to flow present in the final gas sample be included in the full analysis
through the FTIR gas cell purging at the required number of method. A calibration method is created for each component
cell volumes as determined in 9.1.3. using the ten or more concentrations that were created with the
gas blending system described above. The analysis region is
9.2.3 Collect at least three calibration spectra for each
chosen to minimize interferences from other components
concentrationblendlevel.Thethreespectracanlaterbeusedto
knowntobepresentinthegassample.Linear,quadratic,cubic,
verify that the calibration gas concentration was wit
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7653 − 10 D7653 − 18
Standard Test Method for
Determination of Trace Gaseous Contaminants in Hydrogen
Fuel by Fourier Transform Infrared (FTIR) Spectroscopy
This standard is issued under the fixed designation D7653; 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
1.1 This test method employs an FTIR gas analysis system for the determination of trace impurities in gaseous hydrogen fuels
relative to the hydrogen fuel quality limits described in SAE TIR J2719 (April 2008) or in hydrogen fuel quality standards from
other governing bodies. This FTIR method is used to quantify gas phase concentrations of multiple target contaminants in
hydrogen fuel either directly at the fueling station or on an extracted sample that is sent to be analyzed elsewhere. Multiple
contaminants can be measured simultaneously as long as they are in the gaseous phase and absorb in the infrared wavelength
region. The detection limits as well as specific target contaminants for this standard were selected based upon those set forth in
SAE TIR J2719.
1.2 This test method allows the tester to determine which specific contaminants for hydrogen fuel impurities that are in the
gaseous phase and are active infrared absorbers which meet or exceed the detection limits set by SAE TIR J2719 for their particular
FTIR instrument. Specific target contaminants include, but are not limited to, ammonia, carbon monoxide, carbon dioxide,
formaldehyde, formic acid, methane, ethane, ethylene, propane, and water. This test method may be extended to other impurities
provided that they are in the gaseous phase or can be vaporized and are active infrared absorbers.
1.3 This test method is intended for analysis of hydrogen fuels used for fuel cell feed gases or for internal combustion engine
fuels. This method may also be extended to the analysis of high purity hydrogen gas used for other applications including industrial
applications, provided that target impurities and required limits are also identified.
1.4 This test method can be used to analyze hydrogen fuel sampled directly at the point-of-use from fueling station nozzles or
other feed gas sources. The sampling apparatus includes a pressure regulator and metering valve to provide an appropriate gas
stream for direct analysis by the FTIR spectrometer.
1.5 This test method can also be used to analyze samples captured in storage vessels from point-of-use or other sources.
Analysis of the stored samples can be performed either in a mobile laboratory near the sample source or in a standard analytical
laboratory.
1.6 A test plan should be prepared that includes (1) the specific impurity species to be measured, (2) the concentration limits
for each impurity species, and (3) the determination of the minimum detectable concentration for each impurity species as
measured on the apparatus before testing.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7.1 Exception—All values are based upon common terms used in the industry of those particular values and when not
consistent with SI units, the appropriate SI unit will be included in parenthesisparentheses after the common value usage.usage
(4.4, 7.8, 7.9, 10.5, and 11.6) ).
1.8 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.
1.8 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
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 Fuel
Cells.
Current edition approved Sept. 1, 2010Dec. 1, 2018. Published March 2011February 2019. Originally approved in 2010. Last previous edition approved in 2010 as
D7653 – 10. DOI: 10.1520/D7653–10.10.1520/D7653-18.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7653 − 18
1.9 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.
2. Referenced Documents
2.1 ASTM Standards:
D5287 Practice for Automatic Sampling of Gaseous Fuels
D6348 Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR)
Spectroscopy
D7606 Practice for Sampling of High Pressure Hydrogen and Related Fuel Cell Feed Gases
2.2 SAE Document:
SAE TIR J2719 Informational Report on the Development of a Hydrogen Quality Guideline for Fuel Cell Vehicles
2.3 EPA DocumentsDocuments:
EPA 40 CFR Protection of the Environment, Appendix B to Part 136 Definition and Procedure for the Determination of the
Method Detection Limit.Limit
EPA 40 CFR Protection of the Environment, Appendix B to partPart 60: Performance Specification 15 Performance Specification
for Extractive FTIR Continuous Emissions Monitoring Systems in Stationary Sources
2.4 Other Document:
“Fourier Transform Infrared Spectrometry” (Second Edition) Peter R. Griffiths and James A. de Haseth, John Wiley and Son,
2007.
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 analytical interference, n—the physical effects of superimposing two or more light waves. Analytical interferences occur
when two or more compounds have overlapping absorbance bands in their infrared spectra.
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 the ASTM website.
Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.
Available from United States Environmental Protection Agency (EPA), Ariel Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http://www.epa.gov.
3.1.1.1 Discussion—
Analytical interferences occur when two or more compounds have overlapping absorbance bands in their infrared spectra.
3.1.2 analytical algorithm, n—the method used to quantify the concentration of the target contaminants and interferences in
each FTIR Spectrum. The analytical algorithm should account for the analytical interferences by conducting the analysis in a
portion of the infrared spectrum that is the most unique for that particular compound.
3.1.2.1 Discussion—
The analytical algorithm should account for the analytical interferences by conducting the analysis in a portion of the infrared
spectrum that is the most unique for that particular compound.
3.1.3 apodization—apodization, n—a mathematical transformation carried out on data received from an interferometer to reduce
the side lobes of the measured peaks. This procedure alters the instrument’s response function. There are various types of
transformation; the most common forms are boxcar, triangular, Happ-Genzel, and Norton-Beer functions.
3.1.3.1 Discussion—
This procedure alters the instrument’s response function. There are various types of transformation; the most common forms are
boxcar, triangular, Happ-Genzel, and Norton-Beer functions.
3.1.4 background spectrum—spectrum, n—the spectrum taken in the absence of absorbing species or sample gas, typically
conducted using dry nitrogen or zero air in the gas cell.
3.1.5 classical least squares (CLS)—(CLS), n—common method of analyzing multicomponent infrared spectra by scaled
absorbance subtraction, also referred to as K-Matrix.
3.1.6 constituent—constituent, n—component (or compound) found within a hydrogen fuel mixture.
3.1.7 contaminant—contaminant, n—impurity that adversely affects the components within the fuel cell system or the hydrogen
storage system.
D7653 − 18
3.1.8 dry nitrogen (or dry N )—), n—nitrogen gas with a dew point at or below -60–60 °C.
3.1.9 dynamic calibration—calibration, n—calibration of an analytical system using certified calibration gas standards that are
diluted to known concentration.
3.1.10 FCV—FCV, n—Hydrogen fuel cell vehicle.
3.1.11 FTIR—Fourier Transform Infrared (FTIR), n—abbreviation for Fourier Transform Infrared. Typically typically refers to
a type of infrared spectrometer which incorporates a Michelson interferometer to modulate the infrared radiation before probing
the sample. The resultant radiation is then measured with an infrared detector and the resulting signal is decoded using a Fourier
transform algorithm to compute the infrared spectrum.
3.1.11.1 Discussion—
The resultant radiation is then measured with an infrared detector and the resulting signal is decoded using a Fourier transform
algorithm to compute the infrared spectrum.
3.1.12 Fuel Cell Grade Hydrogen—fuel cell grade hydrogen, n—hydrogen satisfying the specifications in SAE TIR J2719.
3.1.13 gaseous fuel—fuel, n—hydrogen gas intended for use as a fuel cell feed gas or as a fuel for internal combustion engines.
3.1.14 gauge pressure—pressure, n—pressure measured above ambient atmospheric pressure. Zeropressure; zero gauge
pressure is equal to the ambient atmospheric (barometric) pressure (psig).
3.1.15 path length—length, n—the distance that the sample gas interacts with the infrared radiation.
3.1.16 poisoning—poisoning, v—process by which catalysts are made inoperative due to the activity of substances such as
hydrogen sulfide or other sulfur substances that can bind to a component in the catalyst (such as a noble metal like platinum) used
in the fuel cell.
3.1.17 Proton Exchange Membrane Fuel Cells (PEMFCs)—proton exchange membrane fuel cells (PEMFCs), n—PEMFC is an
electrochemical apparatus that uses an anode and cathode to convert H and O into electricity.
2 2
3.1.18 purified nitrogen (or purified N )—), n—nitrogen gas that is purified to Ultra-High Purity Grade (99.9995 %) or
equivalent, containing total impurities <1 ppm, specifically: total hydrocarbons (THC) <0.1ppm,<0.1 ppm, total carbon dioxide +
carbon monoxide (CO + CO) < 0.1ppm, <0.1 ppm, and water (H O) <0.5ppm.<0.5 ppm.
2 2
3.1.19 purified hydrogen (or purified H )—), n—hydrogen gas that is purified to Research Grade (99.9999 %) or equivalent,
containing total impurities <1 ppm, <1 ppm, specifically: total hydrocarbons (THC) <0.1ppm,<0.1 ppm, total carbon dioxide +
carbon monoxide (CO + CO) < 0.1ppm, <0.1 ppm, and water (H O) <0.5ppm.<0.5 ppm.
2 2
3.1.20 qualitative accuracy—accuracy, n—the ability of an analytical system to correctly identify compounds without
necessarily providing a precise concentration.
3.1.21 quantitative accuracy—accuracy, n—the ability of an analytical system to measure the concentration of an identified
compound.
3.1.22 sample interface—interface, n—the entire sampling system consisting of the sample probe, sample transport line, and
other components necessary to direct effluent to the FTIR gas cell.
3.1.23 sampling system interference—interference, n—an interference that prohibits or prevents delivery of the target
contaminants to the FTIR gas cell. Examples of potential sampling system interferences are unwanted moisture condensation
within the sampling system, heavy deposition of particulate matter or aerosols within the sampling system components, or reactive
gases.
3.1.23.1 Discussion—
Examples of potential sampling system interferences are unwanted moisture condensation within the sampling system, heavy
deposition of particulate matter or aerosols within the sampling system components, or reactive gases.
3.1.24 static calibration—calibration, n—calibration of an analytical system using standards in a matrix state or manner
different than the samples to be analyzed.
3.1.25 target contaminant (or target impurity or impurity)—impurity), n—a contaminant found in the gaseous fuel that may
adversely affect or is required to be reported prior to use within the fuel cell system, hydrogen storage system, or engine used in
combustion applications.
4. Summary of Test Method
4.1 Test Plan Preparation—The tester should prepare a test plan that includes a description of the fuel source, requirements for
the sampling interface, list of target contaminant species to be measured, and measurement requirements for these contaminants.
D7653 − 18
4.2 Calibration—A set of calibration spectra is prepared for each hydrogen fuel contaminant to be measured. Typically spectra
are collected at multiple concentration levels of a single contaminant spanning the expected concentration range for that
contaminant within the gaseous sample. Certified gas standards or permeation tubes are used with a gas blending system as per
7.7 to prepare samples of known concentration of the target contaminant within a purified H matrix gas and spectra are collected
using the FTIR instrument. The impurity concentration, measurement path length, gas temperature, and absolute pressure for the
calibration sample are stored together with each spectrum. These calibrations are generally permanent and transferable between
FTIR instruments of similar type. Verification of calibrations can be performed before each test using a calibrated cylinder that
contains one or more of the target species in a purified H matrix gas, thus it is not necessary to recalibrate prior to each test.
4.2.1 Calibration Using Surrogate Matrix Gas—The use of a surrogate matrix gas such as nitrogen (N ) or helium (He) to create
the known target contaminant (or impurity) concentration is not acceptable according to this method. The FTIR spectral line shape
of the impurity within a matrix other than that of H is sensitive to the differences between the matrix in N or He, resulting in
2 2
different line shapes for the same impurity concentrations. More detailed studies are needed to determine the effect of this line
shape change on contaminant determination. Therefore, use of a surrogate gas is not acceptable unless the user has studied and
determined conditions under which the measurement precision and accuracy of data satisfy the users needs and requirements.
4.3 Evaluation of Detection Limits—Detection limits are first estimated after the calibrations are created by measuring a blank
which consists of a purified hydrogen gas sample that does not contain any of the target contaminants as listed in 3.1.19. Several
of the blank samples are measured using the final analytic method that includes detection for all of the target contaminants and
interferents, and then a preliminary detection limit estimate is made based upon the standard deviation of the reported
concentrations for each contaminant. Then, for all of the contaminants that are to be certified, a purified hydrogen sample is
prepared with a blend of the target contaminants at concentrations near the initial estimated detection limits. Several measurements
are performed on this blended matrix, as well as several purified hydrogen blanks and then a more accurate detection limit is
calculated based upon the standard deviation of the reported concentrations of both the blanks and blended gas samples.
4.4 Field measurements of hydrogen fuel are performed using direct sampling from high pressure fuel nozzles or other high
pressure storage containers provided the final gas pressure can be stepped down to 20 psig (139kPa(g))(139 kPa(g)) without
altering the fuel composition for introduction into the FTIR flow cell. The fuel sampling apparatus and the FTIR measurement
system are flushed with purified nitrogen or hydrogen and then a background reference spectrum is taken. After flushing the system
and taking a background spectrum, a minimum of three samples of the purified nitrogen or hydrogen are measured to verify that
impurities are not introduced by the sampling apparatus. Hydrogen fuel is introduced to the sampling apparatus and at least three
different samples are measured to determine the impurity concentrations in the fuel. A new blank is run through the gas cell
between each sample that is run to ensure that the system is at an equilibrium state.
4.5 Laboratory measurements of samples collected in the field can be performed in a similar manner to those taken in the field.
Hydrogen fuel is introduced and then collected into three a high pressure storage vesselvessels as described in Practices D5287
and D7606. The samples are then transported to the laboratory, and then the storage vessel is connected to the laboratory sampling
apparatus. The sampling apparatus is flushed a minimum of three times with purified nitrogen or hydrogen. Purified hydrogen is
then introduced into the FTIR flow cell, and at least three samples are measured to verify that impurities are not introduced by the
sampling apparatus. The hydrogen fuel from the high pressure storage vessel is then introduced to the sampling apparatus, and
three samples are measured after all of the signals for each of the target contaminants have reached an equilibrium value. These
samples are used to determine the contaminant concentrations in the sampled hydrogen fuel. This process is repeated for each of
the high pressure storage vesselvessels collected from the same fuel source. While the number listed in the section is for collecting
three separate samples, that number will be designated by the final governing body overseeing the Hydrogen Fuel testing.
5. Significance and Use
5.1 Fuel cell users have implicated trace impurities in feed gases as compromising the performance and lifespan of proton
exchange membrane fuel cells (PEMFCs). PEMFCs may be damaged by the presence of some contaminants through poisoning
of fuel cell electrode materialsmaterials; therefore detection of these impurities at low concentrations is critical to fuel cell
manufacturers and feed gas suppliers in order to support the facilities and infrastructure required for widespread applicability of
fuel cells in transportation and energy production. With field-portable equipment, this test method can be used to quickly analyze
hydrogen fuel for impurities at vehicle fueling stations or storage tanks used to supply stationary power plants. This test method
can also be used by gas suppliers, customers, and regulatory agencies to certify hydrogen fuel quality.
5.2 Users include hydrogen producers, gaseous fuel custody transfer stakeholders, fueling stations, fuel cell manufacturers,
automotive manufacturers, regulators, and stationary fuel cell power plant operators.
6. Interferences
6.1 Spectral Interferences—Spectral interference occurs when the spectrum of a target contaminant overlaps with the spectrum
of another component in the sample. The effects of spectral interferences can often be minimized by using appropriate analytical
algorithms or by adjusting spectral analysis regions to minimize spectral interference.
D7653 − 18
FIG. 1 Gas Blending Apparatus. Mass Flow Controller (MFC)
6.2 Sampling System Interferences—Sampling system interferences occur when target contaminants are retained by the
sampling system plumbing or components resulting in reduced concentration of the target contaminants at the measurement
system. Sampling system interferences can also occur if target contaminants outgas or desorb from the sampling system plumbing
or components, resulting in increased concentrations at the measurement system. Care must be taken in the system design to
minimize these affects.
7. Apparatus
7.1 Fourier Transform Infrared (FTIR) spectrometer with gas cell and detector having sufficient path length and sensitivity
respectively to measure the target contaminants at or below the required detection limits. The entire optical path of the spectrometer
should be sealed to allow either purging or evacuation to prevent interference from ambient water vapor and carbon dioxide in the
spectrometer’s optical path. The gas sampling cell should also be sealed to prevent leaking inside the spectrometer of the H gas
sample to the atmosphere.
7.2 The sample delivery lines to the gas sampling cell as well as out of the cell should be sealed to allow either purging or
evacuation to prevent interference from ambient water vapor and carbon dioxide. The sample delivery lines or tubing should also
be leak free and equilibrated with respect to air contaminants such as water and carbon dioxide.
7.3 Computer and software to control the FTIR spectrometer and to collect, process, and store FTIR spectra. It is also required
for the software to both monitor the temperature and pressure of the sample in the gas cell while collecting spectra. It should also
be able to automatically correct for differences in the pressure and temperature recorded for the calibration samples to those
measured in the sample gas.
7.4 Hydrogen gas purifier to prepare Research Grade purified hydrogen gas (99.9999 %) from ultra high purity hydrogen
(99.999 %) for zeroing the measurement instrument, mixing calibration standards, and testing the zero response of the system.
Purifiers that can remove the impurities to less than 1 ppb 1 ppb levels are preferred.
7.5 Nitrogen gas purifier to prepare Ultra High Purity grade purified nitrogen gas (99.9995 %) from high purity nitrogen
(99.999 %) for zeroing the measurement instrument and purging the FTIR optics.
7.6 Tubing, electropolished TFC 316 stainless steel or other inert material, of suitable diameter and length.
7.7 Gas Blending Apparatus (See Fig. 1), for diluting calibration gas standards with purified hydrogen in order to create
standards of the target contaminantscontaminant species at the desired concentrations for both creating calibrations and
determining detection limits. The gas blending apparatus uses mass flow controllers suitable for the required flow rates with
traceable calibrations and 6 0.5 % 60.5 % accuracy for the flow range to be employed. The mass flow controllers must also be
D7653 − 18
FIG. 2 Apparatus for Measuring Samples Directly from High Pressure Nozzles. Line Switching Valve (V), Needle Valve (NV)
calibrated for use with H gas and recertified annually to assure continued suitable operation. The gas blending apparatus includes
a temperature-controlled oven for permeation tubes which can be used to prepare gas standards of liquids or other reactive
compounds. The output of the permeation tube oven is controlled by a second mass flow controller and a backpressure regulator
to allow for a large range of flow rates through the permeation tube oven while maintaining a relatively constant (lower) flow
through the FTIR gas cell.
7.8 Apparatus for Measuring Samples Directly from High Pressure Nozzles (See Fig. 2)—This apparatus is used to sample and
analyze gaseous hydrogen fuel directly from high pressure fueling nozzles or similar interfaces used in fueling automotive vehicles
and stationary appliances. This apparatus reduces the pressure of the fuel and provides an appropriate flow directly to the FTIR
measurement system for analysis. The apparatus typically consists of a J2600 receptacle connected to a fueling station J2600
nozzle, an ultra high purity check valve, appropriate pressure regulator to reduce the pressure to approximately 20 psig
(139kPa(g)), (139 kPa(g)), and a metering valve or flow controller to set an appropriate flow rate through the FTIR gas cell. The
apparatus also includes a means to introduce purified nitrogen or hydrogen gas as well as calibration gases into the gas sampling
cell in order to verify the system zero or calibration integrity. High purity nitrogen is also used to purge the FTIR measurement
system interferometer and optics.
7.9 Apparatus for Measuring Samples from High Pressure Storage Containers (See Fig. 3)—This apparatus is similar to the
direct sampling apparatus except for the interface to the hydrogen fuel to be measured. Fuel samples are collected in high pressure
storage vessels as described in Practices D5287 and D7606 using the methodology and apparatus described therein. The storage
vessel is then connected to the apparatus shown in Fig. 3. When ready to measure, the hydrogen fuel sample is introduced by
opening valve V4 and setting the pressure regulator to approximately 20 psig (139kPa(g)).(139 kPa(g)). The needle valve is used
to set the correct flow rate through the FTIR gas cell.
7.10 Ultra high purity (UHP) nitrogen is required for purging the FTIR spectrometer and optics assembly. Purge nitrogen gas
should be 99.9995 % pure and have a dew point at or below -60–60 ºC. If a lower grade of nitrogen is used, then a N purifier
must be used to remove impurities such as total hydrocarbons, CO, CO , and H O to less then 1 ppm or better in order to achieve
2 2
the UHP grade requirement. The use of the purifier results in overall stability of the background of the instrument so it is
recommended to be used even if UHP nitrogen is used.
7.11 Research Grade purified hydrogen gas (99.9999 % pure) is required for blending calibration samples and to perform
baseline measurements (when possible). Purified hydrogen must be run through a H purifier to remove moisture and other
impurities such as total hydrocarbons, CO, and CO , to less thenthan 1 ppb each prior to use with the measurement system.
7.12 Calibration gas standards prepared in hydrogen for measurement of calibration spectra and for verification of sample
system integrity. Gas standards should be provided with a National Institute of Standards and Technology (NIST) traceable
certification at or below 6 2 % 62 % accuracy. Multiple target contaminants may be mixed in a single calibration gas bottle
D7653 − 18
FIG. 3 Apparatus for Measuring Samples from High Pressure Storage Containers. Line Switching Valve (V), Needle Valve (NV)
provided that the mixed species are non-reactive, do not degrade in the presence of the other components, and must not interfere
spectrally (in the FTIR regime) with any of the other target contaminants in the mixture.
7.13 Permeation tubes are used to prepare known concentrations of contaminants that are liquids or reactive compounds.
Permeation tubes should be provided with a NIST traceable certification at or below 6 2 % 62 % accuracy. A permeation oven
that operates above ambient temperature is required to be used in order to achieve the accuracy of the permeation tube standards.
8. Hazards
8.1 Care should be taken to avoid hazards associated with both high and ambient pressure hydrogen leaks in the sampling
apparatus or measurement system. Redundant safety measures such as hydrogen monitors and nitrogen purged enclosures around
the instrument are recommended to ensure that potentially combustible gas mixtures do not come in contact with any ignition
sources (for example, infrared source, electronics, etc.).
8.2 Some of the gas mixtures used for calibration are potentially harmful or dangerous if not vented properly from the
measurement system or sampling apparatus. Review the Material Safety Data Sheets (MSDS) for all materials and be sure to use
proper safety precautions.
9. Calibration
9.1 Preparation:
9.1.1 Concentration Range for Calibration Spectra—Collect calibration spectra spanning the expected ranges in the fuel
samples for each target contaminant as well as any other impurity that may be present in the hydrogen fuel sample which are active
in the infrared region. The lowest concentration should be at or near the contaminant limit defined in the test plan. The upper
concentration should be high enough to prevent the need to extrapolate to higher concentrations. Typically ten or more calibration
points are collected for each contaminant (target impurity) species.
9.1.2 FTIR Spectrometer Settings—Collect calibration spectra with the FTIR gas cell at approximately the same temperature and
pressure as will be used for measuring hydrogen fuel samples. Due to changes in the ambient field temperatures it is best to use
elevated gas cell temperatures (> 35 (>35 °C) to avoid fluctuations or temperature mismatch due to changes in the ambient
temperature. Be sure to use the same FTIR spectral resolution and apodization function for calibrations and measurements. The
gas cell path length is chosen to provide adequate sensitivity while maintaining maximum absorbance unit (AU) values for the
quantification region to be at or under 1.0 AU. If necessary, the maximum absorbance requirement can be met by choosing
analytical regions that exclude strong absorption features. The number of FTIR scans (or measurement time) can be increased to
improve detection limits. Record all settings and actual gas cell absolute pressure and temperature for each calibration spectrum.
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9.1.3 Determine the Number of Gas Cell Volumes Required to Flush the FTIR Gas Cell—The Environmental Protection Agency
(EPA) recommends 5 cell volumes are adequate to fully flush the gas cell of the sample (See Environmental Protection Agency
40 CFR:EPA 40 CFR Protection of the Environment, Appendix B to partPart 60). For a flow rate of 1 litre 1 L per minutemin
(LPM) and a gas cell volume of 200 ml 200 mL the number of cell volumes would be 1.0 LPM/0.2 L = 5 volumes flushed per
1 min. 1 min. For a larger cell volume of 500 ml 500 mL for the same flow rate you would only achieve 1.0LPM/0.51.0 LPM L
⁄0.5 L = 2 volumes flushed per 1 min. Therefore the amount of time required to completely flush the gas sample from the gas cell
is dependant upon the gas cell internal volume and the gas sample flow rate. For faster data acquisition a smaller gas sample
volume is desired or a faster flow rate can be used, but that must be balanced by the amount of sample that is resident in the gas
sample chamber/cylinder that was collected.
9.1.4 Prior to collecting the calibration spectra verify the FTIR performance is within acceptable limits following the
instructions in Annex A1 as well as those specified by the FTIR manufacturer.
9.2 Collect Calibration Spectra for Species in Calibration Gas Cylinders:
9.2.1 Purge the gas blending apparatus and FTIR gas cell with purified H . Monitor for one or more surrogate contaminant
species (generally H O is selected) using the FTIR to verify that the reported concentrations have reached a minimum and stable
value. As needed a new background spectrum is acquired.
9.2.2 Program the gas blending apparatus to prepare the required concentration mixtures while maintaining a relatively constant
flow rate to prevent an increase in pressure in the FTIR gas cell. For each blend, allow the mixture to flow through the FTIR gas
cell purging at the required number of cell volumes as determined in 9.1.3.
9.2.3 Collect at least three calibration spectra for each concentration blend level. The three spectra can later be used to verify
that the calibration gas concentration was within 6 2 % 62 % of the calibration gas value. Record the FTIR settings, gas cell
temperature, gas cell absolute pressure, and gas cell path length. Repeat this process for each desired concentration for each species
in the calibration gas cylinder.
9.2.4 As desired, a single set of calibration gas blends can be prepared that spans the desired range for all species in the
calibration gas bottle providing that there is no spectral overlap between the target contaminants in the blend. In general it is not
possible or reasonable to combine all of the components into a single standard but a sub set of contaminants that do not have
spectral overlaps can be combined. For example, hydrocarbons,hydrocarbons can be blended with NO, N O, CO, or CO (for
2 2
example, methane and CO or methane and CO ) and have no overlap within the usable infrared region. Care should be taken to
ensure that contaminants in the blends do not react with each other.
9.3 Collect Calibration Spectra for Species from Permeation Tubes:
9.3.1 Purge the gas blending apparatus and FTIR gas cell with purified H2.H . Monitor for one or more surrogate contaminant
species (for example, H O which tends to be more sticky) using the FTIR to verify that the reported concentrations have reached
a minimum and stable value such as applying an f-test to determine the values are no longer significant. As needed a new
background spectrum is acquired.
9.3.2 Set the temperature of the permeation tube oven as directed by the permeation tube manufacturer and set the mass flow
controllers as required to prepare the desired concentration. The use of permeation tubes at ambient temperature is not acceptable
as this will result in excessive variability in permeation rates due to a lack of fine temperature control. As necessary, the output
flow from the permeation oven can be split using the output mass flow controller and a backpressure regulator in order to prepare
lower concentration standards. For each blend, allow the mixture to flow through the FTIR gas cell purging at the required number
of cell volumes as defined in 9.1.3.
9.3.3 Collect at least three calibration spectra for each contaminant (impurity) concentration. The three spectra can be used to
verify that the calibration gas concentration was not changing within 6 2 %. 62 %. Record the FTIR settings, gas cell temperature,
gas cell absolute pressure, and gas cell path length. Also record the permeation tube serial number, concentration calculation, oven
temperature, and flow conditions. Repeat this process for each desired concentration for each contaminant species that requires a
permeation tube to be used.
9.3.4 Follow Annex A3 for more details on the creation of the FTIR Reference Spectra.
9.4 Prepare Analytical Methods for Each Impurity Species:
9.4.1 For gas impurity analysis the main analytical method used is based upon Classical Least Squares (CLS) algorithms. This
method requires that each component that might be present in the final gas sample be included in the full analysis method. A
calibration method is created for each component using the 10ten or more concentrations that were created with the gas blending
system described above. The analysis region is chosen to minimize interferences from other components known to be present in
the gas sample. Linear, quadratic, cubic, quartic, or spline data interpolation functions may be used to fit the concentration range
and reduce the prediction error of the method. For more details on Classical Least Squares see “FourierFourier Transform Infrared
Spectrometry”Spectrometry (Second Edition), in particular page 207. Follow the FTIR manufacturer’s procedure for details in the
creation of the CLS calibration methods.
Griffiths, P. R., and de Haseth, J. A., Fourier Transform Infrared Spectrometry (Second Edition), John Wiley & Sons, 2007.
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9.4.2 In general the largest component peaks are chosen for the target contaminant model analysis region unless severe spectral
interferences are found to be present. Refer to Annex A2 for further details.
9.5 Determine Initial Method Detection Limits:
9.5.1 Configure the FTIR system as it will be used for fuel measurements. Record the number of scans, spectral resolution,
apodization function, gas cell path length, gas cell temperature, and gas cell absolute pressure.
9.5.2 Purge the optical compartment of the FTIR measurement system with purified N to remove air and any other trace
impurities.
9.5.3 Using the gas blending apparatus, begin flowing purified H through the gas cell of the FTIR measurement system
monitoring one or more surrogate contaminant species (for example, H O which tends to be more sticky) until a minimum and
stable value has been reached such as applying an f-test to determine the values are no longer significant. As needed a new
background spectrum is acquired.
9.5.4 Collect spectra from at least seven samples of the purified H gas and compute the concentrations of all target contaminant
species using the final analytical method. Compensate for gas cell pressure and temperature differences from the calibration
conditions as required.
9.5.5 For each target contaminant, compute the mean and standard deviation of the resulting concentrations. Calculate the initial
detection limit using the Student’s t value of 99 % confidence level for the number of samples that were collected, for each target
impurity species. Specifically follow the EPA 40 CFR Part 136 Appendix B for the initial Blank determination.
9.5.5.1 In this standard, a Blank is defined as the purified H (or purified N , if the purified H is not available) gas flowing
2 2 2
through the FTIR gas sample cell then (1) surrogate contaminant species (for example, H O) reaching an equilibrium value, (2)
followed by the collection of a new background, and (3) finally the collection of at least seven analysis values after the new
background has been collected.
9.6 Perform Final Method Detection Limits for Stable/Non-Reactive Species:
9.6.1 Procure a calibration gas standard (Cal Gas Mix) that has a mixture of all stable and non-reactive impurity species at a
concentration of approximately 1 ppm which should be between one to ten times the required detection limits.
9.6.2 Configure the FTIR system as it will be used for fuel measurements. Record the number of scans, spectral resolution,
apodization function, and gas cell path length.
9.6.3 Purge the optical compartment of the FTIR measurement system with purified N to remove air and any other trace
impurities.
9.6.4 Using the gas blending apparatus, begin flowing purified H through the gas cell of the FTIR measurement system
monitoring one or more surrogate contaminant species (for example, H O) until a minimum and stable value has been reached such
as applying an f-test to determine the values are no longer significant. As needed a new background spectrum is acquired.
9.6.5 Connect the Cal Gas Mix to the gas blending apparatus and prepare a blend where all the target impurities are at
concentrations of one to ten times the initial detection limit estimate, for each target component. Flow the Cal Gas Mix into the
gas cell of the FTIR and follow the measurements until the concentrations are stable.
9.6.6 Collect spectra from at least seven samples as well as blanks and compute the concentrations of all target contaminants
using the final analytical method following EPA 40 CFR Part 136 Appendix B. Compensate for gas cell pressure and temperature
differences from the calibration conditions as required.
9.6.7 Collect spectra from at least seven samples from the Cal Gas Mix diluted by a factor of two with high purity H as well
as blanks and compute the concentrations of all target contaminant species using the final analytical method following EPA 40 CFR
Part 136 Appendix B. Compensate for gas cell pressure and temperature differences from the calibration conditions as required.
Use this step to ensure that a lower contaminant concentration will not result in a lower detection limit.
9.6.8 When some of the target contaminants do not produce the same detection limits in both 9.6.6 as well as 9.6.7 then a further
dilution by a factor of four of the Cal Gas Mix with high purity H is required. This will also require further dilution of the blanks
as well. Compute the concentrations of all target contaminants using the final analytical method following EPA 40 CFR Part 136
Appendix B. Compensate for gas cell pressure and temperature differences from the calibration conditions if required. Use this step
to ensure that a lower contaminant concentration will not result in a lower detection limit. If this is still not the case then further
dilution of the Cal Gas Mix will be required until the detection limit no longer changes for that target contaminant.
9.6.9 For each target contaminant, compute the mean and standard deviation of the resulting concentrations. Calculate the final
detection limit using the Student’s t value of 99 % confidence level for each target impurity species using the method described
in EPA 40 CFR Part 136 Appendix B. Use these values as the final Method Detection Limits (MDLs) for this FTIR system and
calibration method.
9.7 Perform Final Test of Detection Limits for Unstable/Reactive Species:
9.7.1 Procure permeation tubes for any species that are too unstable or reactive for calibration gas cylinders. Setup the gas
blending system to prepare a mixture of the flow from the permeation tube with the Cal Gas Mix and purified hydrogen to prepare
a mixture with all impurity species at concentrations of one to ten times the initial detection limit estimate.
9.7.2 Repeat the procedure described in the previous section to determine the final detection limit for the species from the
permeation tube. Repeat for additional unstable or reactive species as required.
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TABLE 1 Comparison of SAE TIR J2719 (April 2008) Requirement Specifications to the Detection Limits of Two Different Detectors
Contaminant SAE J2719 MG2031, MG2031
Detection Limits (ppmv) TE 9μ LN2, 16μ
Contaminant SAE J2719 MG2031, MG2031
Concentration Limits (ppmv) TE 9 μ LN2, 16 μ
Ammonia (NH ) 0.10 0.81 0.02
Carbon Monoxide (CO) 0.20 0.05 0.01
Carbon Monoxide (CO) 0.20 0.05 0.01
Carbon Dioxide (CO ) 2.00 0.05 0.01
Formaldehyde (HCHO) 0.01 0.02 0.02
Formic Acid (HCOOH) 0.20 0.02 0.02
Total HydroCarbons 2.00 . 0.71
(Reported as C1)
Methane 0.10 0.02 0.03
Ethane 0.05 0.05 0.05
Ethylene 0.10 . 0.03
Water (H O) 5.00 0.74 0.12
9.8 Compare Final Test Results of All Contaminants to the Required Detection LimitsLimits:
9.8.1 A sample comparison of results from the method detection limit testing is shown in Table 1 below. . The results were
6 7
obtained using andan MKS MultiGas 2031 FTIR equipped with a 5 metre 5 m pathlength stainless steel gas cell and a 9 micron
thermoelectric cooled detector as well as a 16 micron liquid nitrogen cooled detector. In the case of the 16u16 μ detector all of the
contaminants required by SAE TIR J2719 except for formaldehyde would be detectable whereas with the 9 micron detector system
all but Ammonia and formaldehyde would be detectable.
9.8.2 Different FTIR systems as well as operating conditions can be used to perform the analysis of determining the method
detection limits. The parameters listed in Table 2 were used to successfully meet the measurement requirements as stated in SAE
6 7 6
TIR J2719 listed in Table 1. The results were obtained using an MKS MultiGas 2031 FTIR equipped with the MG2000 analysis
software following the EPA MDL process from EPA 40 CFR Part 136 Appendix B. A stainless steel gas cell equipped with metal
seals and VCR fittings was used to reduce hydrogen leaks from the sampling system.
10. Procedure for Direct Sampling from High Pressure Fuel Sources
10.1 This procedure is used to perform measurements in the field on hydrogen fuel flowing directly from high pressure fuel
nozzles or other high pressure storage containers.
10.2 Assemble the direct sampling apparatus described in Section 7 and couple the hydrogen fuel receptacle to the fuel source
nozzle or other adapter.
10.3 Configure the FTIR system as it will be used for fuel measurements. Record the number of scans, spectral resolution,
apodization function, and gas cell path length, temperature, and pressure.
10.3.1 Purge the optical compartment of the FTIR measurement system with purified N to remove air and any other trace
impurities.
10.3.2 Begin flowing purified H through the gas cell of the FTIR measurement system monitoring one or more surrogate
impurity species (for example, H O) until a minimum and stable value
...