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ECE/TRANS/180/Add.13
July 19, 2013
GLOBAL REGISTRY
Created on November 18, 2004, Pursuant to Article 6 of the
AGREEMENT CONCERNING THE ESTABLISHING OF GLOBAL TECHNICAL
REGULATIONS FOR WHEELED VEHICLES, EQUIPMENT AND PARTS WHICH
CAN BE FITTED AND/OR BE USED ON WHEELED VEHICLES
(ECE/TRANS/132 and Corr.1)
DONE AT GENEVA ON JUNE 25, 1998
Addendum 13:
GLOBAL TECHNICAL REGULATION NO. 13
GLOBAL TECHNICAL REGULATION ON HYDROGEN AND FUEL CELL VEHICLES
(ESTABLISHED IN THE GLOBAL REGISTRY ON JUNE 27, 2013)

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G. Optional Requirements: Vehicles with Liquefied Hydrogen Storage Systems/Rationale
1. Background Information for Liquefied Hydrogen Storage Systems
2. Rationale for Liquefied Hydrogen Storage System Design Qualification
Requirements of Paragraph 7.2.
3. Rationale for Vehicle Fuel System Design Qualification Requirements (LH )
4. Rationale for Test Procedures for LHSSs
5. Rationale for Paragraph 7.5. (Test Procedure for Post-crash Concentration
Measurement for Vehicles with Liquefied Hydrogen Storage Systems (LHSSs))
H. National Provisions for Material Compatibility (Including Hydrogen Embrittlement) and
Conformity of Production
1. Material Compatibility and Hydrogen Embrittlement
2. National Requirements Complimentary to GTR Requirements
I. Topics for the Next Phase in Developing the GTR for Hydrogen-fuelled Vehicles
J. Existing Regulations, Directives, and International Standards
1. Vehicle Fuel System Integrity
2. Storage System
3. Electric Safety
K. Benefits and Costs
II.
TEXT OF THE REGULATION
1. Purpose
2. Scope
3. Definitions
4. Applicability of Requirements
5.
Performance Requirements
5.1.
Compressed Hydrogen Storage System
5.2.
Vehicle Fuel System
5.3.
Electrical Safety
6.
Test Conditions and Procedures
6.1.
Compliance Tests for Fuel System Integrity
6.2.
Test Procedures for Compressed Hydrogen Storage
6.3.
Test Procedures for Electrical Safety

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GLOBAL TECHNICAL REGULATION NO. 13
I. STATEMENT OF TECHNICAL RATIONALE AND JUSTIFICATION
A. INTRODUCTION
1. In the ongoing debate over the need to identify new sources of energy and to reduce
greenhouse gas emissions, companies around the world have explored the use of various
alternative fuels, including compressed natural gas, liquefied propane gas and hydrogen.
Hydrogen has emerged as one of the most promising alternatives due to its vehicle
emissions being virtually zero. In the late 1990s, the European community allocated
resources to study the issue under its European integrated hydrogen project (EIHP) and
forwarded the results, two proposals for compressed gaseous and liquefied hydrogen, to the
UNECE secretariat. The follow-up project, EIHP2, initiated discussions about the possibility
of a global technical regulation for hydrogen fuelled vehicles. A few years later, the United
States of America outlined a vision for a global initiative, the international partnership for the
hydrogen economy, and invited china, japan, the Russian federation, the European Union
and many other countries to participate in this effort.
2. For decades scientists, researchers and economists have pointed to hydrogen, in both
compressed gaseous and liquid forms, as a possible alternative to gasoline and diesel as a
vehicle fuel. Ensuring the safe use of hydrogen as a fuel is a critical element in successful
transitioning to a global hydrogen economy. By their nature, all fuels present an inherent
degree of danger due to their energy content. The safe use of hydrogen, particularly in the
compressed gaseous form, lies in preventing catastrophic failures involving a combination of
fuel, air and ignition sources as well as pressure and electrical hazards.
3. Governments have identified the development of regulations and standards as one of the
key requirements for commercialization of hydrogen-fuelled vehicles. Regulations and
standards will help overcome technological barriers to commercialization, facilitate
manufacturers’ investment in building hydrogen-fuelled vehicles and facilitate public
acceptance by providing a systematic and accurate means of assessing and communicating
the risk associated with the use of hydrogen vehicles, be it to the general public, consumer,
emergency response personnel or the insurance industry.
4. The development of this United Nations global technical regulation (GTR) for Hydrogen and
Fuel Cell Vehicles occurred within the World Forum for Harmonisation of Vehicle
Regulations (WP.29) of the Inland Transport Committee (ITC) of UNECE. The goals of this
global technical regulation (GTR) are to develop and establish a GTR for hydrogen-fuelled
vehicles that:
(i)
(ii)
attains or exceeds the equivalent levels of safety of those for conventional gasoline
fuelled vehicles; and
is performance-based and does not restrict future technologies.

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8. The GTR will consist of the following key elements:
(a)
Component and subsystem level requirements (non-crash test based):
Evaluate the non-crash requirements by reviewing analyses and evaluations
conducted to justify the requirements. Add and subtract requirements or amend test
procedures as necessary, based on existing evaluations or on quick evaluations that
could be conducted by Contracting Parties and participants. Avoid design specific
requirements to the extent possible and do not include provisions that are not
technically justified. The main areas of focus are:
(i)
(ii)
(iii)
Performance requirements for hydrogen storage systems, high pressure
closures, pressure relief devices, and fuel lines;
Electrical isolation, safety and protection against electric shock (in use);
Performance and other requirements for subsystem integration in the vehicle.
(b)
Vehicle-level requirements:
Examine the risks posed by the different types of fuel systems in different crash
modes. Review and evaluate analyses and crash tests conducted to examine the
risks and identify appropriate mitigating measures for hydrogen fuelled vehicles. The
main areas of focus are as follows:
(i)
(ii)
In-use and post-crash limits on hydrogen releases. Post-crash leakage limits
apply following execution of crash tests (front, side and rear) that are specified
in national requirements for crash safety testing in each jurisdiction;
In-use and post-crash requirements for electrical isolation and protection
against electric shock. Post-crash electrical safety criteria apply following
execution of crash tests (front, side and rear) that are specified in national
requirements for crash safety testing in each jurisdiction.
C. DESCRIPTION OF TYPICAL HYDROGEN-FUELLED FUEL CELL VEHICLES (HFCVs)
1. Vehicle Description
9. Hydrogen fuelled vehicles can use either internal combustion engine (ICEs) or fuel
cells to provide power; however, hydrogen-fuelled vehicles are typically powered by
fuel cell power systems. Hydrogen-fuelled fuel cell vehicles (HFCVs) have an electric
drivetrain powered by a fuel cell that generates electric power electrochemically using
hydrogen. In general, HFCVs are equipped with other advanced technologies that
increase efficiency, such as regenerative braking systems that capture the kinetic
energy lost during braking and store it in a battery or ultra-capacitors. While the
various HFCVs are likely to differ in the details of the systems and hardware/software
implementations, the following major systems are common to most HFCVs:
(a)
(b)
Hydrogen fuelling system;
Hydrogen storage system;

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12. A typical arrangement of componentry of a hydrogen fuelled vehicle with compressed
hydrogen storage and powered by a fuel cell is shown in Figure 2.
2. Hydrogen Fuelling System
Figure 2
Example of a Hydrogen Fuel Cell Vehicle
13. Either liquefied or compressed gas may be supplied to the vehicle at a fuelling
station, depending on the type of hydrogen storage system in the vehicle. At present,
hydrogen is most commonly dispensed to vehicles as a compressed gas that is
dispensed at pressures up to 125% of the nominal working pressure (NWP) of the
vehicle to compensate for transient heating from adiabatic compression during
fuelling.
14. Regardless of the state of the hydrogen, the vehicles are fuelled through a special
fuelling nozzle on the fuel dispenser at the fuelling station that connects with the
fuelling receptacle on the vehicle to provide a "closed system" transfer of hydrogen to
the vehicle. The fuelling receptacle on the vehicle contains a check valve (or other
device) that prevents leakage of hydrogen out of the vehicle when the fuelling nozzle
is disconnected.
3. Hydrogen Storage System
15. The hydrogen storage system consists of all components that form the primary high
pressure boundary for containment of stored hydrogen. The key functions of the
hydrogen storage system are to receive hydrogen during fuelling, contain the
hydrogen until needed, and then release the hydrogen to the fuel cell system for use
in powering the vehicle. At present, the most common method of storing and
delivering hydrogen fuel on-board is in compressed gas form. Hydrogen can also be
stored as liquid (at cryogenic conditions). Each of these types of hydrogen storage
systems are described in the following sections.

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18. The hydrogen storage containers store the compressed hydrogen gas. A hydrogen
storage system may contain more than one container depending on the amount that
needs to be stored and the physical constraints of the particular vehicle. Hydrogen
fuel has a low energy density per unit volume. To overcome this limitation,
compressed hydrogen storage containers store the hydrogen at very high pressures.
On current development vehicles (prior to 2011), hydrogen has typically been stored
at a nominal working pressure of 35MPa or 70MPa, with maximum fuelling pressures
of 125% of nominal working pressure (43.8MPa or 87.5MPa respectively). During the
normal "fast fill" fuelling process, the pressure inside the container(s) may rise to 25%
above the nominal working pressure as adiabatic compression of the gas causes
heating within the containers. As the temperature in the container cools after fuelling,
the pressure is reduced. By definition, the settled pressure of the system will be equal
to the nominal working pressure when the container is at 15°C. Different pressures
(that are higher or lower or in between current selections) are possible in the future as
commercialisation proceeds.
19. Containers are currently constructed from composite materials in order to meet the
challenge of high pressure containment of hydrogen at a weight that is acceptable for
vehicular applications. Most high pressure hydrogen storage containers used in fuel
cell vehicles consist of two layers: an inner liner that prevents gas
leakage/permeation (usually made of metal or thermoplastic polymer), and an outer
layer that provides structural integrity (usually made of metal or thermoset
esin-impregnated fibre-reinforced composite wrapped over the gas-sealing inner
liner).
20. During fuelling, hydrogen enters the storage system through a check valve. The
check valve prevents back-flow of hydrogen into the fuelling line.
21. An automated hydrogen shut-off valve prevents the out-flow of stored hydrogen when
the vehicle is not operating or when a fault is detected that requires isolation of the
hydrogen storage system.
22. In the event of a fire, thermally activated pressure relief devices (TPRDs) provide a
controlled release of the gas from the compressed hydrogen storage containers
before the high temperatures in the fire weaken the containers and cause a
hazardous rupture. TPRDs are designed to vent the entire contents of the container
rapidly. They do not reseat or allow re-pressurisation of the container. Storage
containers and TPRDs that have been subjected to a fire are expected to be removed
from service and destroyed.
(b)
Liquefied Hydrogen Storage System
23. Since on-road vehicle experience with liquefied hydrogen storage systems is limited
and constrained to demonstration fleets, safety requirements have not been
comprehensively evaluated nor have test procedures been widely examined for
feasibility and relevance to known failure conditions. Therefore optional requirements
and test procedures for vehicles with liquefied hydrogen storage systems are
presented in section G of this preamble and Paragraph 7. of the text of the regulation,
respectively, for consideration by Contracting Parties for possible adoption into their
individual regulations. It is expected that these requirements will be considered as
requirements in a future GTR that applies to vehicles with liquefied hydrogen storage
systems.

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6. Electric Propulsion and Power Management System
30. The electric power generated by the fuel cell system is used to drive electric motors
that propel the vehicle. As illustrated in Figure 2, many passenger fuel cell vehicles
are front wheel drive with the electric drive motor and drive-train located in the
"engine compartment" mounted transversely over the front axle; however, other
configurations and rear-wheel drive are also viable options. Larger Sport Utility
Vehicle-type fuel cell vehicles may be all-wheel drive with electric motors on the front
and rear axles or with compact motors at each wheel.
31. The "throttle position" is used by the drive motor controller(s) to determine the amount
of power to be sent to the drive wheels. Many fuel cell vehicles use batteries or ultracapacitors
to supplement the output of the fuel cells. These vehicles may also
recapture energy during stopping through regenerative braking, which recharges the
batteries or ultra-capacitors and thereby maximises efficiency.
32. The drive motors may be either DC or AC. If the drive motors are AC, the drive motor
controller shall convert the DC power from the fuel cells, batteries, and
ultra-capacitors to AC. Conversely, if the vehicle has regenerative braking, the drive
motor controller shall convert the AC power generated in the drive motor back to DC
so that the energy can be stored in the batteries or ultra-capacitors.
D. RATIONALE FOR SCOPE, DEFINITIONS AND APPLICABILITY
1. Rationale for Paragraph 2 (Scope)
33. This GTR applies to hydrogen storage systems having nominal working pressures
(NWP) of 70MPa or less, with an associated maximum fuelling pressure of 125% of
the nominal working pressure. Systems with NWP up to 70MPa include storage
systems currently expected to be of commercial interest for vehicle applications. In
the future, if there is interest in qualifying systems to higher nominal working
pressures, the test procedures for qualification will be re-examined.
34. This GTR applies to fuel storage systems securely attached within a vehicle for usage
throughout the service life of the vehicle. It does not apply to storage systems
intended to be exchanged in vehicle fuelling. This GTR does not apply to vehicles
with storage systems using chemical bonding of hydrogen; it applies to vehicles with
storage by physical containment of gaseous or liquid hydrogen.
35. The hydrogen fuelling infrastructure established prior to 2010 applies to fuelling of
vehicles up to 70MPa NWP. This GTR does not address the requirements for the
fuelling station or the fuelling station/vehicle interface.
36. This GTR provides requirements for fuel system integrity in vehicle crash conditions,
but does not specify vehicle crash conditions. Contracting Parties to the
1998 Agreement are expected to execute crash conditions as specified in their
national regulations.

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E. RATIONALE FOR PARAGRAPH 5. (PERFORMANCE REQUIREMENTS)
1. Compressed Hydrogen Storage System Test Requirements and Safety Needs
42. The containment of the hydrogen within the compressed hydrogen storage system is
essential to successfully isolate the hydrogen from the surroundings and
down-stream systems. The storage system is defined to include all closure surfaces
that provide primary containment of high-pressure hydrogen storage. The definition
provides for future advances in design, materials and constructions that are expected
to provide improvements in weight, volume, conformability and other attributes.
43. Performance test requirements for all compressed hydrogen storage systems in on
road vehicle service are specified in Paragraph 5.1. The performance-based
requirements address documented on-road stress factors and usages to assure
robust qualification for vehicle service. The qualification tests were developed to
demonstrate capability to perform critical functions throughout service including
fuelling/defueling, parking under extreme conditions, and performance in fires without
compromising the safe containment of the hydrogen within the storage system. These
criteria apply to qualification of storage systems for use in new vehicle production.
44. Conformity of Production with Storage Systems Subjected to Formal Design
Qualification Testing:
Manufacturers shall ensure that all production units comply with the requirements of
performance verification testing in Paragraph 5.1.2. In addition, manufacturers are
expected to monitor the reliability, durability and residual strength of representative
production units throughout service life.
45. Organisation of Requirements:
Paragraph 5.1. design qualification requirements for on-road service include:
5.1.1. Verification tests for baseline metrics;
5.1.2. Verification test for performance durability (hydraulic sequential tests);
5.1.3. Verification test for expected on-road performance (pneumatic sequential
tests);
5.1.4. Verification test for service-terminating performance;
46. Paragraph 5.1.1. establishes metrics used in the remainder of the performance
verification tests and in production quality control. Paragraphs. 5.1.2. and 5.1.3. are
the qualification tests that verify that the system can perform basic functions of
fuelling, defueling and parking under extreme on-road conditions without leak or
rupture throughout the specified service life. Paragraph 5.1.4. provides confirmation
that the system performs safely under the service-terminating condition of fire.

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(b) Second example: an overriding requirement for initial burst pressure (>225%
NWP for carbon fibre composite containers and >350% NWP for glass fibre
composite containers) has been used previously in some places for lower
pressure CNG containers. The basis for this type of burst pressure requirement
for new (unused) containers was examined. A credible quantitative, data-driven
basis for historical requirements linked to demands of on-road service was not
identified. Instead, modern engineering methods of identifying stressful
conditions of service from decades of experience with real-world usage and
designing qualification tests to replicate and compound extremes of those
conditions were used to force systems to demonstrate capability to function
and survive a lifetime’s exposure. However, a risk factor that could be identified
as not already addressed by other test requirements and for which a burst
pressure test would be relevant was the demonstration of capability to resist
burst from over-pressurisation by a fuelling station through-out service life. The
more stringent test condition applies to containers at the "end-of-life" (as
simulated by extreme test conditions) rather than new (unused) containers.
Therefore, a residual (end-of-life) requirement of exposure (without burst) to
180% NWP for 4min was adopted based on the demonstrated equivalence of
the probability for failure after 4min at 180% NWP to failure after 10h at 150%
NWP (based on time to failure data for "worst-case" glass composite strands).
Maximum fuelling station over-pressurisation is taken as 150% NWP.
Experiments on highly insulated containers have shown cool down from
compressive heating lasting on the order of 10h. An additional requirement
corresponding to minimum burst pressure of 200% NWP for new, unused
containers has been under consideration as a screen for minimum new
containers capability with potential to complete the durability test sequence
requiring burst pressure above 180% NWP considering <±10% variability in
new containers strength. The historical minimum, 225% NWP has been
adopted in this document as a conservative placeholder without a quantitative
data-driven basis but instead using previous history in some Contracting
Parties with the expectation that additional consideration and data/analyses will
be available to support the 225% NWP value or for reconsideration of the
minimum new containers burst requirement.

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(iii)
verify that requirements are met for the minimum burst pressure and number of
pressure cycles before leak.
51. The baseline initial burst pressure requirements differ from the "end-of-life" burst
pressure requirements that conclude the test sequences in Paragraphs 5.1.2. and
5.1.3. The baseline burst pressure pertains to a new, unused container and the
"end-of-life" burst pressure pertains to a container that has completed a series of
performance tests (Paragraphs 5.1.2. or 5.1.3.) that replicate conditions of worst-case
usage and environmental exposure in a full service life. Since fatigue accumulates
over usage and exposure conditions, it is expected that the "end-of-life" burst
pressure (i.e. burst strength) could be lower than that of a new and unexposed
container.
(i)
Rationale for Paragraph 5.1.1.1. Baseline Initial Burst Pressure
52. Paragraph 5.1.1.1. establishes the midpoint initial burst pressure (BP ) and verifies
that initial burst pressures of systems in the qualification batch are within the range
BP ±10%. BP is used as a reference point in performance verification
(Paragraphs 5.1.2.8. and 5.1.3.5.) and verification of consistency within the
qualification batch. Paragraph 5.1.1.1. verifies that BP is greater than or equal to
225% NWP or 350% NWP (for glass fibre composites), values tentatively selected
without data-driven derivation but instead based on historical usage and applied here
as placeholders with the expectation that data or analysis will be available for
reconsideration of the topic in Phase 2 of the development of this GTR. For example,
a 200% minimum initial burst pressure requirement can be supported by the
data-driven performance-linked justification that a greater-than 180% NWP
end-of-service burst requirement (linked to capability to survive the maximum fuelling
station over-pressurisation) combined with a 20% lifetime decline (maximum allowed)
from median initial burst strength is equivalent to a requirement for a median initial
burst strength of 225% NWP, which corresponds to a minimum burst strength of
200% NWP for the maximum allowed 10% variability in initial strength. The interval
between Phase I and Phase II provides opportunity for development of new data or
analysis pertaining to a 225% NWP (or another per cent NWP) minimum prior to
resolution of the topic in Phase 2.
53. In addition to being a performance requirement, it is expected that satisfaction of this
requirement will provide assurance to the testing facility of container stability before
the qualification testing specified in Paragraphs 5.1.2., 5.1.3. and 5.1.4. is
undertaken.
(ii)
Rationale for Paragraph 5.1.1.2. Baseline Initial Pressure Cycle Life
54. The requirement specifies that three (3) randomly selected new containers are to be
hydraulically pressure cycled to 125% NWP without rupture for 22,000 cycles or until
leak occurs. Leak may not occur within a specified number of pressure cycles
(number of Cycles). The specification of number of cycles within the range
5,500 – 11,000 is the responsibility of individual Contracting Parties. That is, the
number of pressure cycles in which no leakage may occur, number of cycles, cannot
be greater than 11,000, and it could be set by the Contracting Party at a lower
number but not lower than 5,500 cycles for 15 years' service life. The rationale for the
numerical values used in this specification follows:

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(a)
(b)
(c)
(d)
Vehicle fleet odometer data (including taxis): Sierra Research Report
No. SR2004-09-04 for the California Air Resource Board (2004) reported on
vehicle lifetime distance travelled by scrapped California vehicles, which all
showed lifetime distances travelled below 560,000 km (350,000mi). Based on
these figures and 320 – 480km (200 – 300mi) driven per full fuelling, the
maximum number of lifetime empty-to-full fuellings can be estimated as
1,200 – 1,800;
Vehicle fleet odometer data (including taxis): Transport Canada reported that
required emissions testing in British Columbia, Canada, in 2009 showed the
5 most extreme usage vehicles had odometer readings in the
800,000 – 1,000,000km (500,000 – 600,000mi) range. Using the reported
model year for each of these vehicles, this corresponds to less than 300 full
fuellings per year, or less than 1 full fuelling per day. Based on these figures
and 320 – 480km (200 – 300mi) driven per full fuelling, the maximum number
of empty-to-full fuellings can be estimated as 1,650 – 3,100;
Taxi usage (Shifts/Day and Days/Week) data: The New York City (NYC)
taxicab fact book (Schaller Consulting, 2006) reports extreme usage of 320km
(200mi) in a shift and a maximum service life of 5 years. Less than 10% of
vehicles remain in service as long as 5 years. The average mileage per year is
72,000 for vehicles operating 2 shifts per day and 7 days per week. There is no
record of any vehicle remaining in high usage throughout the full 5 year service
life. However, if a vehicle were projected to have fuelled as often as
1.5 – 2 times per day and to have remained in service for the maximum 5 year
New York City (NYC) taxi service life, the maximum number of fuellings during
the taxi service life would be 2,750 – 3,600;
Taxi usage (Shifts/Day and Days/Week) data: Transport Canada reported a
survey of taxis operating in Toronto and Ottawa that showed common high
usage of 20h per day, 7 days per week with daily driving distances of
540 – 720km (335 – 450mi). Vehicle odometer readings were not reported. In
the extreme worst-case, it might be projected that if a vehicle could remain at
this high level of usage for 7 years (the maximum reported taxi service life);
then a maximum extreme driving distance of 1,400,000 – 1,900,000km
(870,000 – 1,200,000mi) is projected. Based on 320 – 480km (200 – 300mi)
driven per full fuelling, the projected full-usage 15 year number of full fuellings
could be 2,900 – 6,000. Consistent with these extreme usage projections, the
minimum number of full pressure hydraulic qualification test cycles for
hydrogen storage systems is set at 5,500. The upper limit on the number of
full-fill pressure cycles is set at 11,000, which corresponds to a vehicle that
remains in the high usage service of 2 full fuellings per day for an entire service
life of 15 years (expected lifetime vehicle mileage of 3.5 – 5.3 million km
(2.2 – 3.3 million miles)).
59. In establishing number of cycles, it was recognised that practical designs of some
storage system designs (such as composite wrap systems with metal liner interiors)
might not qualify for service at 70MPa NWP if number of cycles is greater than 5,500.
In establishing cycles, it was recognised that if number of cycles is specified at 5,500,
some Contracting Parties may require usage constraints to assure actual fuellings do
not exceed number of cycles.

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(d) Severe usage: exposure to chemicals in the on-road environment
(Paragraph 5.1.2.4.)
(i)
(ii)
(iii)
(iv)
Fluids include fluids used on vehicles (battery acid and washer fluid),
chemicals used on or near roadways (fertiliser nitrates and lye), and
fluids used in fuelling stations (methanol and gasoline);
The primary historical cause of rupture of high pressure vehicle
containers (CNG containers), other than fire and physical damage, has
been stress corrosion rupture – rupture occurring after a combination of
exposure to corrosive chemicals and pressurisation;
Stress corrosion rupture of on-road glass-composite wrapped containers
exposed to battery acid was replicated by the proposed test protocol;
other chemicals were added to the test protocol once the generic risk of
chemical exposure was recognised;
Penetration of coatings from impacts and expected on-road wear can
degrade the function of protective coatings – recognised as a
contributing risk factor for stress corrosion cracking (rupture); capability
to manage that risk is therefore required.
(e)
Extreme number of fuellings/defueling's
Rationale for number of cycles greater than 5,500 and less than 11,000 is
provided in Paragraphs 58-59 Section E.1.(a).(ii).b of the preamble.
(f) Extreme pressure conditions for fuelling/de-fuelling cycles (Paragraph 5.1.2.4.)
(i)
(ii)
(iii)
Fuelling station over-pressurisation constrained by fuelling station
requirements to less than or equal to 150% NWP. (This requirement for
fuelling stations shall be established within local codes and/or
regulations for fuelling stations.);
Field data on the frequency of failures of high pressure fuelling stations
involving activation of pressure relief controls is not available.
Experience with CNG vehicles suggests overpressure by fuelling
stations has not contributed significant risk for container rupture;
Assurance of capability to sustain multiple occurrences of over
pressurisation due to fuelling station failure is provided by
the requirement to demonstrate absence of leak in 10 exposures
to 150% NWP fuelling followed by long-term leak-free parking and
subsequent fuelling/de-fuelling.

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(ii)
(iii)
The testing is performed at +85°C because some composites exhibit a
temperature-dependent fatigue rate (potentially associated with resin
oxidation) (J. Composite Materials 11, 79 (1977)). A temperature
of +85°C is selected as the maximum potential exposure because
under-hood maximum temperatures of +82°C have been measured
within a dark-coloured vehicle parked outside on asphalt in direct
sunlight in 50°C ambient conditions. Also, a compressed gas container,
painted black, with no cover, in the box of a black pickup truck in direct
sunlight in 49°C had maximum/average measured container skin surface
temperatures of 87°C (189°F)/70°C (159°F);
On-road experience with CNG containers – there have not been reports
of any on-road stress rupture without exposure to corrosives (stress
corrosion cracking) or design anomaly (hoop wrap tensioned for liner
compression without autofrettage). Paragraph 5.1.2. testing that includes
chemical exposure test and 1,000h of static full pressure exposure
simulates these failure conditions.
(i) Residual proof pressure (Paragraph 5.1.2.7.)
(i)
(ii)
(iii)
Fuelling station over-pressurisation constrained by fuelling station
requirements to less than or equal to 150% NWP. (This requirement for
fuelling stations shall be established within local codes/regulations for
fuelling stations);
Laboratory data on static stress rupture used to define equivalent
probability of stress rupture of composite strands after 4min at 180%
NWP as after 10h at 150% NWP as the worst case (SAE Technical
Report 2009-01-0012). Fuelling stations are expected to provide overpressure
protection up to 150% NWP;
Testing at "end-of-life" provides assurance to sustain fuelling station
failure throughout service.
(j) Residual strength burst (Paragraph 5.1.2.8.)
Requirement for a less than 20% decline in burst pressure after 1,000h static
pressure exposure is linked (in the Society of Automotive Engineers (SAE)
Technical Report 2009-01-0012) to assurance that requirement has allowance
for ±10% manufacturing variability in assurance of 25 years of rupture
resistance at 100% NWP.
(k)
Rationale for not including a boss torque test requirement:
Note: That damage to containers caused by maintenance errors is not
included because maintenance errors, such as applying excessive
torque to the boss, are addressed by maintenance training procedures
and tools and fail safe designs. Similarly, damage to containers caused
by malicious and intentional tampering is not included.

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(ii)
Number of fuelling/defueling cycles
a. The number of full fuellings required to demonstrate capability for
leak-free performance in expected service is taken to be 500.
i. Expected vehicle lifetime range is taken to be 250,000km
(155,000mi);
Source:
Figure 4
Vehicle Age vs. Average Odometer
Sierra Research Report No. SR2004-09-04, titled "Review
of the August 2004 Proposed CARB Regulations to Control
Greenhouse Gas Emissions from Motor Vehicles: Cost
Effectiveness for the Vehicle Owner or Operator," and dated
September 22, 2004.
ii.
Expected vehicle range per full fuelling is taken to be
greater than or equal to 500km (300mi) (based on
2006-2007 market data of high volume passenger vehicle
manufacturers in Europe, Japan and North America);
iii. 500 cycles = 250,000mi/500mi-per-cycle
~150,000mi/300mi-per-cycle;
iv.
Some vehicles may have shorter driving ranges per full
fuelling, and may achieve more than 500 full fuellings if no
partial fuellings occur in the vehicle life. Demonstrated
capability to perform without leak in 500 full fuellings is
intended to establish fundamental suitability for on-road
service leakage is subject to secondary mitigation by
detection and vehicle shutdown before safety risk develops;

---

vi.
Test experience:
70MPa hydrogen storage systems that passed Natural Gas
Vehicle (NGV2) test requirements have failed during the
test conditions of Paragraph 5.1.3. in failure modes that
would be expected to occur in on-road service. The
Powertech report (McDougal, M., "SAE J2579 Validation
Testing Program Powertech Final Report", National
Renewable Energy Laboratory Report No. SR-5600-49867
(www.nrel.gov/docs/fy11osti/49867.pdf) cites two failures of
systems with containers that have qualified for service:
metal-lined composite container valve leak and in-container
solenoid leak, polymer-lined composite container leak due
to liner failure. The polymer-lined composite container
failure by leakage was on a container that was qualified to
American National Standard Association and Canadian
Standards Association (ANSI/CSA) NGV2 modified for
hydrogen. The metal-lined composite failure of the container
valve was on a valve qualified to EIHP rev12b. Report
conclusion: "The test sequences in SAE TIR J2579 have
shown that containers with no known failures in service
either met the requirements of the tests, or fail for reasons
that are understood and are representative of future service
conditions."
(iii)
Fuelling conditions
a. SAE J2601 establishes fuelling protocol – 3min is fastest
empty-to-full fuelling (comparable to typical gasoline fuelling;
existing in installed state-of-art hydrogen fuelling stations); fuel
temperature for 70MPa fast fuelling is ~-40°C;
b. Expected maximum thermal shock conditions are for a system
equilibrated at an environmental temperature of ~50°C subjected
to -40°C fuel, and for a system equilibrated at -40°C subjected to
indoor private fuelling at approximately +20°C;
c. Fuelling stresses are interspersed with parking stresses.

---

(iv)
(v)
(vi)
For ease of compliance testing, however, the discharge
requirement has been specified in terms of storage system
permeation instead of vehicle-level (iii) permeation as a means of
compliance is consistent with the proposals developed by the EU
NoE HySafe. In this case, the permeation limit measured at 55°C
and 115% NWP is 46ml/h/L-water-capacity of the storage system.
If the total water capacity of the vehicle storage system is less
greater than 330L and the garage size is no smaller than 50m ,
then the 46ml/h/L-water capacity requirement results in a
steady-state hydrogen concentration of no more than 1%.
(An upper limit per storage system of 46ml/h/L (per container
volume capacity) × 330L (system volume capacity)/60min/hr =
253ml/min per storage system, which comparable to that derived
from the alternative approach 150ml/min × 50/30.4 = 247ml/min
(scaling factor R = 1.645), which results in a 1% concentration).
This permeation specification has been adopted under the
assumption that storage capacity ~330L is not expected for the
vehicles within the scope of this GTR, so garages less than 50m
can be accommodated;
The maximum pressure of a fully filled container at 55°C is
115% NWP (equivalent state of charge to 125% NWP at 85°C and
100% NWP at 15°C);
A localised leak test is to be conducted to ensure that external
leakage cannot sustain a flame that could weaken materials and
subsequently cause loss of containment. Per Technical Report
2008-01-0726 ("Flame Quenching Limits of Hydrogen Leaks"), the
lowest flow of H that can support a flame is 0.028mg/sec per from
a typical compression fitting and the lowest leak possible from a
miniature burner configuration is 0.005mg/sec. Since the miniature
burner configuration is considered a conservative "worst case",
the maximum leakage criterion is selected as 0.005mg/sec;
(vii) Parking provides opportunity for hydrogen saturation of
interlaminate layers, wrap/liner interface, liner materials, junctures,
O-rings, and joinings – fuelling stresses are applied with and
without exposure to hydrogen saturation. Hydrogen saturation is
marked by permeation reaching steady-state rate;
(viii) By requiring qualification under the worst credible case conditions
of raised temperature, pressure cycling and equilibration with
hydrogen, the permeation verification removes uncertainty about
permeation/temperature dependence, and long term deterioration
with time and usage.
(d) Residual proof pressure (Paragraph 5.1.3.4.)
(i)
Fuelling station over-pressurisation is constrained by fuelling
station requirements to pressurise at less than 150% NWP. (This
requirement for fuelling stations shall be established within local
codes/regulations for fuelling stations.);

---

65. A comprehensive examination of CNG container in-service failures during the past
decade (SAE Technical Paper 2011-01-0251 (Scheffler, McClory et al., "Establishing
Localised Fire Test Methods and Progressing Safety Standards for FCVs and
Hydrogen Vehicles")) showed that the majority of fire incidents occurred on storage
systems that did not utilise properly designed pressure relief devices (PRDs), and the
remainder resulted when PRDs did not respond to protect the container due to the
lack of adequate heat exposure on the PRDs even though the localised fire was able
to degrade the container wall and eventually cause the storage container to burst.
The localised fire exposure has not been addressed in previous regulations or
industry standards. The fire test method in Paragraph 6.2.5. addresses both localised
and engulfing fires.
66. The fire test conditions of Paragraph 6.2.5. were based on vehicle-level tests by the
Japanese Automobile Research Institute (JARI) and US manufacturers. A summary
of data is found in paper SAE Technical Paper 2011-01-0251. Key findings are as
follows:
(a)
About 40% of the vehicle laboratory fires investigated resulted in conditions
that could be categorised as a localised fire since the data indicates that a
composite compressed gas container could have been locally degraded before
conventional PRDs on end bosses (away from the local fire exposure) would
have activated.
Note: A temperature of 300°C was selected as the temperature where the
localised fire condition could start as thermal gravimetric analysis
(TGA) indicates that container materials begin to degrade rapidly at this
temperature);
(b)
(c)
(d)
While vehicle laboratory fires often lasted 30-60min, the period of localised fire
degradation on the storage containers lasted less than 10min;
The average of the maximum temperature during the localised fire period was
less than 570°C with peak temperatures reaching approximately between
600°C and 880°C in some cases;
The rise in peak temperature near the end of the localised fire period often
signalled the transition to an engulfing fire condition.
67. Based upon the above findings, the temperature profile in Paragraph 6.2.5. was
adopted. The selection of 600°C as the minimum temperature for the localised fire
hold period ensures that the average temperature and time of localised fire test
exposure are consistent with test data. Thermocouples located 25mm ± 10mm from
the outside surface of the test article are used to control the heat input and confirm
that the required temperature profile is met. In order to improve the response and
controllability of the fire during testing (as well as reproducibility of results), the use of
Liquefied Petroleum Gas (LPG) and wind guards are specified. Experience indicates
the controllability of the LPG fire will be approximately ±100°C in outdoor situations,
producing peak temperatures that also agree favourably with test results.

---

(i)
Rationale for TPRD Qualification Requirements
71. The qualification requirements verify that the device, once activated, will fully vent the
contents of the fuel container even at the end of the service life when the device has
been exposed to fuelling/defueling pressure and temperature changes and
environmental exposures. The adequacy of flow rate for a given application is verified
by the hydrogen storage system fire test requirements (Paragraph 5.1.4.).
(ii)
Rationale for Check Valve Qualification Requirements
72. These requirements are not intended to prevent the design and construction of
components (e.g. components having multiple functions) that are not specifically
prescribed in this standard, provided that such alternatives have been considered in
testing the components. In considering alternative designs or construction, the
materials or methods used shall be evaluated by the testing facility to ensure
equivalent performance and reasonable concepts of safety to that prescribed by this
standard. In that case, the number of samples and order of applicable tests shall be
mutually agreed upon by the manufacturer and the testing agency. Unless otherwise
specified, all tests shall be conducted using hydrogen gas that complies with
SAE J2719 (Information report on the development of a hydrogen quality guideline for
fuel cell vehicles), or ISO 14687-2 (Hydrogen fuel-product specification). The total
number of operational cycles shall be 11,000 (fuelling cycles) for the check valve
and 50,000 (duty cycles) for the automatic shut-off valve.
73. Fuel flow shut-off by an automatic shut-off valve mounted on a compressed hydrogen
storage container shall be fail-safe. The term "fail safe" refers to a device that reverts
to a safe mode or a safe complete shutdown for all reasonable failure modes.
74. The electrical tests for the automatic shut-off valve mounted on the compressed
hydrogen storage containers (Paragraph 6.2.6.2.7.) provide assurance of
performance with:
(i)
(ii)
over temperature caused by an overvoltage condition; and
potential failure of the insulation between the component’s power conductor
and the component casing.
The purpose of the pre-cooled hydrogen exposure test (Paragraph 6.2.6.2.10.) is to
verify that all components in the flow path from the receptacle to the container that
are exposed to precooled hydrogen during fuelling can continue to operate safely.

---

79. In order to ensure that the exhaust discharge from the vehicle is non-hazardous, a
performance-based tests is designed to demonstrate that the discharge is nonignitable.
The 3s rolling-average accommodates extremely short, non-hazardous
transients up to 8% without ignition. Tests of flowing discharges have shown that
flame propagation from the ignition source readily occurs above 10% hydrogen, but
does not propagate below 8% hydrogen (SAE Technical Report 2007-01-437, Corfu
et al., "Development of Safety Criteria for Potentially Flammable Discharges from
Hydrogen Fuel Cell Vehicles"). By limiting the hydrogen content of any instantaneous
peak to 8%, the hazard to people near the point of discharge is controlled even if an
ignition source is present. The time period of the rolling-average is determined to
ensure that the space around the vehicle remains non-hazardous as the hydrogen
from exhaust diffuses into the surroundings; this is the case of an idling vehicle in a
closed garage. In order to readily gain acceptance for this situation by building
officials and safety experts, it should be recognised that government/municipal
building codes and internationally-recognised standards such as International
Electrotechnical Commission (IEC) 60079 require that the space be less than 25%
LFL (or 1% hydrogen) by volume. The time limit for the rolling-average was
determined by assuming an extremely high hydrogen discharge rate that is equivalent
to the input to a 100kW fuel cell stack. The time was then calculated for this hydrogen
discharge to fill the nominal space occupied by a passenger vehicle
(4.6m × 2.6m × 2.6m) to 25% LFL. The resultant time limit was conservatively
estimated to be 8s for a "rolling average", demonstrating that the 3s rolling average
used in this document is appropriate and accommodates variations in garage and
engine size. The standard ISO instrumentation requirement is a factor of 6-10 less
than the measured value. Therefore, during the test procedure according to
Paragraph 6.1.4., the 3s rolling average requires a sensor response (90% of reading)
and recording rate of less than 300ms.
(iv)
Rationale for Paragraph 5.2.1.4. Protection Against Flammable Conditions:
80. Single Failure Conditions. Dangerous situations can occur if unintended leakage of
hydrogen reaches flammable concentrations.
(a)
(b)
Any single failure downstream of the main hydrogen shut off valve shall not
result in any level of hydrogen concentration in air anywhere in the passenger
compartment;
Protection against the occurrence of hydrogen in air in the enclosed or semi
enclosed spaces within the vehicle that contain unprotected ignition sources is
important.
(i)
(ii)
Vehicles may achieve this objective by design (for example, where
spaces are vented to prevent increasing hydrogen concentrations);
The vehicle achieves this objective by detection of hydrogen
concentrations in air of 2% ± 1.0% or greater, then the warning shall be
provided. If the hydrogen concentration exceeds 3% ± 1.0% by volume
in air in the enclosed or semi enclosed spaces of the vehicle, the main
shutoff valve shall be closed to isolate the storage system.

---

(viii) Recommended Features for Design of a Hydrogen Fuel System
84. As any performance-based technical regulation cannot include testing requirements
for every possible scenario, this section is to provide manufacturers a list of items that
they should consider during the design of hydrogen fuelling systems with the intention
to reduce hydrogen leaks and provide a safe product:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
The hydrogen fuel system should function in a safe and proper manner and be
designed to minimise the potential for hydrogen leaks, (e.g. minimise line
connections to the extent possible);
The hydrogen fuel system should reliably withstand the chemical, electrical,
mechanical and thermal service conditions that may be found during normal
vehicle operation;
The materials used should be compatible with gaseous or liquid hydrogen, as
appropriate;
The hydrogen fuel system should be installed such that it is protected against
damage under normal operating conditions;
Rigid fuel lines should be secured such that they shall not be subjected to
critical vibration or other stresses;
The hydrogen fuel system should protect against excess flow in the event of a
failure downstream;
No component of the hydrogen fuel system, including any protective materials
that form part of such components, should project beyond the outline of the
vehicle or protective structure.
(b)
Post Crash Requirements
(i)
Rationale for Paragraph 5.2.2.1. Post-crash Test Leakage Limit
85. Allowable post-crash leakage in Federal Motor Vehicle Safety Standard (FMVSS) 301
(for the United States of America) and Regulation Nos. 94 and 95 are within 6% of
each other for the 60min period after the crash. Since the values are quite similar, the
value in Regulation No. 94 of 30g/min was selected as a basis for the calculations to
establish the post-crash allowable hydrogen leakage for this GTR.
86. The criterion for post-crash hydrogen leakage is based on allowing an equivalent
release of combustion energy as permitted by gasoline vehicles. Using a lower
heating value of 120MJ/kg for hydrogen and 42.7MJ/kg for gasoline based on the
US DOE Transportation Data Book, the equivalent allowable leakage of hydrogen can
be determined as follows:
42.7MJ/kg
W
H
= 30g/min gasoline leakage ×
= 10.7g/min hydrogen leakage
120MJ/kg
For vehicles with either compressed hydrogen storage systems or liquefied hydrogen
storage systems. The total allowable loss of hydrogen is therefore 642g for the 60min
period following the crash.

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93. A sustained electric shock from AC at 120V, 60Hz is an especially dangerous source
of ventricular fibrillation f because it usually exceeds the let-goo threshold, while not
delivering enough initial energy to propel the person away fromm the source. . However,
the
potential seriousness of the shock
depends on paths through the body that the
currents take.
94. If the voltage is i less than 200V, then the human skin is the main contributor to the
impedance of the t body in the case of a macro-shock the passing of current between
two
contact points on the skin. The characteristics of o the skin are non-linear however.
If the voltage is above 450–600V, then
dielectric breakdown b of the skin occurs. The
protection offered by the skin is lowered by perspiration, andd this is accelerated if
electricity causes muscless to contract above thee let-go threshold for a sustained
period of time.
(b)
In-Use Requirements
95. "In-Use Requirements" aree the specifications whichh have to bee consideredd when the
fuel cell vehiclee is engineered. These have to be fulfilled to avoid any electric hazard
to passengers of an electricc vehicle.
96. The requirements are focusing on the electric power train operating on high voltage
as well as the high voltage components and systems which are galvanically
connected.
97. To
avoid electrical hazardss it is requested that live parts p (= conductive pat(s) intended
to be electrically energised in normal use) are protected againstt direct contact.
98. Protection against direct contact inside the passenger compartment has to be
checked by using a standardised Test Wire (IPXXD).
Figure 5
Standardised Test Wire W

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106. After the impact of the vehicle the following three measures demonstrate that the
systems are safe. It means that the remaining "electricity level" of the high voltage
systems are no longer dangerous to the passengers of the vehicle.
(a)
Absence of high Voltage
After the impact the voltage is equal or less than 30VAC or 60VDC
(b)
Isolation Resistance
Isolation resistance measured against the electrical chassis is a physical
dimension describing which maximum current is not dangerous to the human
being.
After the impact for AC systems measured against the electrical chassis the
minimum isolation resistance has to be 500Ω/V and for DC systems 100Ω/V.
The isolation resistance requirements of 100Ω/V for DC or 500Ω/V for AC allow
maximum body currents of 10mA and 2mA respectively.
(c)
Physical protection
After the impact it should not be possible to touch live parts after the crash,
tested with the standardised Test Finger. Furthermore protection against
indirect contact has also been fulfilled.
By decision of the Contracting Parties of the 1998 Agreement a fourth measure
is allowed
(d)
Low Energy
After the impact the energy of the system has to be below 2.0 Joules.
F. RATIONALE FOR STORAGE AND FUEL SYSTEM TEST PROCEDURES
107. Test procedures in Paragraph 6. replicate on-road conditions for performance
requirements specified in Paragraph 5. Most test procedures derive from test
procedures specified in historical national regulations and/or industry standards.
1. Rationale for Storage and Fuel System Integrity Tests
(a)
Rationale for Paragraph 6.1.1. Test Procedure for Post-crash Leak Test Procedure for
Compressed Hydrogen Storage Systems
108. The post-crash leak test is organised as follows:
6.1.1.1. Test procedure when the test gas is hydrogen
6.1.1.2. Test procedure when the test gas is helium

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112. Based on the above relationship, it is possible to determine that the ratio of the volumetric
flow (and therefore the ratio gas concentration by volume) between helium test gas and
hydrogen is approximately 75% for the same leak passages from the storage system. Thus,
the post-crash hydrogen leakage can be determined by
where
V = V /0.75
V
is the post-crash helium leakage (NL/min).
(b)
Rationale for Paragraph 6.1.2. (Test Procedure for Post-crash Concentration Test in
Enclosed Spaces for Vehicles with Compressed Hydrogen Storage Systems)
113. The test may be conducted by measuring hydrogen or by measuring the corresponding
depression in oxygen content. Sensors are to be located at significant locations in the
passenger, luggage, and cargo compartments. Since the test is conducted in parallel with
the post-crash leak test of the storage system and therefore will extend for at least 60
minutes, there is no need to provide margin on the criteria to manage dilution zones as
there is sufficient time for the hydrogen to diffuse throughout the compartment.
114. In the case where the vehicle is not crashed with hydrogen and a leak test is conducted with
compressed helium, it is necessary to define a criteria for the helium content that is
equivalent to 4% hydrogen by volume. Recognizing that the content of hydrogen or helium
in the compartment (by volume) is proportional to the volumetric flow of the respective
releases, it is possible to determine the allowable helium content by volume, X , from the
equation developed in Paragraphs 108. to 112. of the preamble by multiplying the hydrogen
concentration criteria by 0.75. The criteria for helium concentration is therefore as follows:
X = 4% H by volume × 0.75 = 3.0% by volume.
The criteria for helium concentration is therefore 3% by volume in the passenger, luggage,
and cargo compartments if the crash test of a vehicle with a compressed storage system is
conducted with compressed helium instead of compressed hydrogen.
115. An example of hydrogen concentration measurement locations can be found in the
document "Examples of hydrogen concentration measurement points for testing" (OICA
report to SGS-3 based on Japanese Regulation Attachment 100).
2. Rationale for Paragraph 6.2. (Test procedures for compressed hydrogen storage
systems)
116. Most test procedures for hydrogen storage systems derive from test procedures specified in
historical national regulations and/or industry standards. Key differences are the execution
of tests in sequence (as opposed to historical execution of tests in parallel, each on a
separate new container), and slowing of the filling rate in burst testing to correspond to
in-service fuelling rates. In addition, hold times at burst pressure test points have been
extended to 4min. These changes are designed to reduce the sensitivity of initial burst
measurements to the fuelling rate and to evaluate capability to sustain pressure. An
evaluation of the sufficiency and stringency of requirements in this GTR document
compared to historical EU requirements is given in Transport Research Laboratory Project
Report RPN1742 "Hydrogen-Powered Vehicles: A Comparison of the European Legislation
and the draft UNECE global technical regulation" by C. Visvikis.

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(b)
A Typical Liquefied Hydrogen Storage System (LHSS)) is Shown Figure 7
120. Actual systems will differ in the type, number, configuration, andd arrangement of the
functional constituents. Ultimately, the boundaries of the LHSS L are defined by the interfaces
which can isolate the
stored liquefied (and/or
gaseous) hydrogen fromm the remainder of the
fuel system and the environment.
. All components located within this boundary are
subject to
the requirements defined in this Section while
components outside thee boundary are subject
to general requirements in Section 4. For example, thee typical LHSS shown in
Figure 7
consists of the following regulatory elements:
(a)
(b)
(c)
(d)
(e)
Liquefied hydrogen storagee container(s);
Shut off devices(s);
A boil-off system;
Pressure Relief Devices (PRDs);
The interconnecting piping (if any) and fittings between the above components.
Figure 7
Typical Liquefied Storagee System
(c)
During Fuelling, Liquefied Hydrogen Flows from the Fuelling System to the Storage
Container(S)
121. Hydrogen
gas from the LHSS returns to the filling stationn during the fill process so that the
liquefied hydrogen can flow into liquefied hydrogen storage s container(s) without over
pressurizing the system. Two shut-offs are provided on both b the liquefied hydrogen fill and
hydrogen
fill return line to preventt leakage in the event of single failures.

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(i) Rationale for Proof Pressure Requirement in Paragraphs 7.2.1.1. and 7.4.1.1.
130. By design of the container and specification of the pressure limits during regular operation
and during fault management (as demonstrated in Paragraphs 7.4.2.2. and 7.4.2.3.), the
pressure in the inner container could rise to 110% of the Maximum Allowable Working
Pressure (MAWP) during fault management by the primary pressure relief device and no
higher than 150% of MAWP even in "worst case" fault management situations where the
primary relief device has failed and the secondary pressure relief device is required to
activate and protect the system. The purpose of the proof test to 130% MAWP is to
demonstrate that the inner container stays below its yield strength at that pressure.
(ii) Rationale for Baseline Initial Burst Pressure Requirement Paragraphs 7.2.1.2. and 7.4.1.2.
131. By design (and as demonstrated in Paragraph 5.2.3.3.), the pressure may rise up to 150%
of the MAWP when the secondary (backup) pressure relief device(s) may be required to
activate. The burst test is intended to demonstrate margin against burst during this "worst
case" situation. The pressure test levels of either the Maximum Allowable Working Pressure
(in MPa) plus 0.1MPa multiplied by 3.25, or the MAWP (in MPa) plus 0.1MPa multiplied by
1.5 and multiplied by Rm/Rp (where Rm is ultimate tensile strength and Rp is minimum yield
strength of the container material), are common values to provide such margin for metallic
liners.
132. Additionally, the high burst test values (when combined with proper selection of materials
demonstrate that the stress levels are acceptably low such that cycle fatigue issues are
unlikely for metallic containers that have supporting design calculations. In the case of
non-metallic containers, an additional test is required in Paragraph 7.4.1.2. to demonstrate
this capability as the calculation procedures have not yet been standardised for these
materials.
(b) Rationale for Verification for Expected on-road Performance Paragraph 7.2.2.
(i) Rationale for Boil-off requirement Paragraphs 7.2.2.1. and 7.4.2.1.
133. During normal operation the boil-off management system shall limit the pressure below
MAWP. The most critical condition for the boil-off management system is a parking period
after a refuelling to maximum filling level in a liquefied hydrogen storage system with a
limited cool-down period of a maximum of 48h.
(ii) Rationale for Hydrogen Leak Requirement Paragraphs 7.2.2.2. and 7.4.2.2.
134. The hydrogen discharge test shall be conducted during boil-off of the liquid storage system.
Manufacturers will typically elect to react all (or most) of the hydrogen that leaves the
container, but, in order to have a hydrogen discharge criteria that is comparable to the
values used for Compressed Hydrogen Storage Systems, it should count any hydrogen that
leaves the vehicle boil-off systems with other leakage, if any, to determine the total
hydrogen discharge from the vehicles.

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(d)
Rationale for Verification of LHSS Components: Pressure Relief Device(s) and Shut
off Valves Paragraph 7.2.4.
(i) Rationale for Pressure Relief Device Qualification Requirements (LHSS) Paragraph 7.2.4.1.
141. The qualification requirements verify that the design shall be such that the device(s) will limit
the pressure of the fuel container to the specified values even at the end of the service life
when the device has been exposed to fuelling/de-fuelling pressure and temperature
changes and environmental exposures. The adequacy of flow rate for a given application is
verified by the hydrogen storage system bonfire test and vacuum loss test requirements
(Paragraphs 7.2.3. and 7.4.3.).
(ii) Rationale for shut-off valve qualification requirements (LHSS) Paragraph 7.2.4.2.
142. These requirements are not intended to prevent the design and construction of components
(e.g. components having multiple functions) that are not specifically prescribed in this
standard, provided that such alternatives have been considered in testing the components.
In considering alternative designs or construction, the materials or methods used shall be
evaluated by the testing facility to ensure equivalent performance and reasonable concepts
of safety to that prescribed by this standard. In that case, the number of samples and order
of applicable tests shall be mutually agreed upon by the manufacturer and the testing
agency. Unless otherwise specified, all tests shall be conducted using pressurised gas such
as air or nitrogen containing at least 10% helium (see EC Reg. 406/2010 p.52 4.1.1.). The
total number of operational cycles shall be 20,000 (duty cycles) for the automatic shut-off
valves.
143. Fuel flow shut-off by an automatic shut-off valve mounted on a liquid hydrogen storage
container shall be fail safe. The term "fail safe" shall refer to a device’s ability to revert to a
safe mode or a safe complete shutdown for all reasonable failure modes.
144. The electrical tests for the automatic shut-off valve mounted on the liquid hydrogen storage
containers provide assurance of performance with:
(i)
(ii)
over temperature caused by an overvoltage condition, and:
potential failure of the insulation between the component’s power conductor and the
component casing.
3. Rationale for Vehicle Fuel System Design Qualification Requirements (LH )
145. This section specifies requirements for the integrity of the hydrogen fuel delivery system,
which includes the liquefied hydrogen storage system, piping, joints, and components in
which hydrogen is present. These requirements are in addition to requirements specified in
Paragraph 5.2., all of which apply to vehicles with liquefied hydrogen storage systems with
the exception of Paragraph 2.1.1. The fuelling receptacle label shall designate liquid
hydrogen as the fuel type. Test procedures are given in Paragraph 7.5.
4. Rationale for Test Procedures for LHSSs
146. Rationale for test procedures is included within rationale for performance requirements in
sections G.2.(a) and G.2.(b) of the preamble.

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150. If the bubble test is not possible or desired, an overall leakage test may be conducted to
produce a more objective result. In this case, the leakage criteria is the same as that
developed for vehicles with compressed hydrogen storage systems. Specifically, the
allowable hydrogen leakage from the LHSS is 118NL/min or 10.7g/min. The state of flow
leaking from the LHSS may be gaseous, liquid, or a two-phase mixture of both. The leakage
is expected to be in the gaseous state as the piping and shutoff valves downstream of the
container are more vulnerable to crash damage than the highly insulated, double-walled
LHSS container. None-the-less, the post-crash tests prescribed in this document can detect
very small leak sites and thus demonstrate the acceptability even if the leakage in the liquid
state. It is not necessary to address the possibility of a two-phase leak as the flow rate will
be less than that what can occur in the liquid state.
151. The post-crash leak test in Paragraph 7.5.1.2.1. is conducted with pressurised helium.
Conduct of this test not only confirms that LHSS leakage is acceptable but also allows the
post-crash helium concentration test as described in Paragraphs 113. to 115.
Section F.1.(b) of the preamble to be performed at the same time. The helium leak test is
conducted at room temperature with the LHSS pressurised with helium to normal operating
pressure. The pressure level should be below the activation pressure of the pressure
regulators and the PRDs. It is expected that the helium test pressure can be conducted at
approximately 80% of the MAWP.
Leakage of hydrogen in the liquid state of an operating system is given by:
where
W = C × A × (2 × ρ × ∆P ) Equation A.7.5.1-1
W
C
A
ρ
∆P
is the mass flow,
is the discharge coefficient,
is the area of the hole,
is the density, and
is the pressure drop between the operating system and atmosphere.
This equation is for incompressible fluids such as fluids in the liquid state.
Use of this equation is very conservative for this situation as a portion of the fluid often
flashes (that is, changes to a gaseous state) as the fluid passes through the leakage hole,
causing a reduction in density and therefore a reduction in the mass flow.
The leakage of helium gas during the leak test is given by:
where
W = C × C × A × (ρ × P ) Equation A.7.5.1-2
C and A are as defined above,
ρ and P are the upstream (stagnation) fluid density and pressure in the LHSS.

---

where
∂P /∂t is the change in pressure during the helium pressure test. Since the change in mass
within the LHSS (∂M /∂t) is equal to the helium mass flow during the test period (W ),
Equation 5 for W can be substituted into Equation 7.
After rearranging terms, the equation becomes
where
∂P /P = R × T/V × (W /P ) × ∂t = (W /M ) × ∂t Equation A.7.5.1-8
M is the initial mass of helium in the LHSS for the pressure test.
Integrating the above differential equation results in expressions for the allowable pressure
at the end of the helium leak test and the corresponding allowable pressure loss over the
test period. The expressions are:
and
where
P = P × exp (-W /M × t ) Equation A.7.5.1-9
∆P = P × (1 - exp (-W /M × t )) Equation A.7.5.1-10
t
is the period of the test.
153. Use of the above equations can be best illustrated by providing an example for a typical
passenger vehicle with a 100l (L) volume LHSS. Per ground rule, the basic safety
parameters are established to be the same as that for the compressed hydrogen storage
System. Specifically, the period of the leak test is 60min and the average H leakage shall
be equivalent to 10.7g/min. Using these parameters for the example yields the following:
Post-crash test period (t ) = 60min
Allowable Liquid H Leakage (W )
MAWP
Selected Helium Test Pressure (P )
below Pressure Regulator Setpoints
= 10.7g/min
= 118NL/min of gas after flashing
= 6atm (gauge)
= 7atm (absolute)
= 5.8atm (absolute)
Ratio of specific heat (k) for helium = 1.66
C for helium
Helium density at initial test pressure
Density of liquefied hydrogen
= 0.725 from Equation A.7.5.1-3
= 0.956g/l
= 71.0g/l

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H. NATIONAL PROVISIONS FOR MATERIAL COMPATIBILITY (INCLUDING HYDROGEN
EMBRITTLEMENT) AND CONFORMITY OF PRODUCTION
1. Material Compatibility and Hydrogen Embrittlement
156. The SGS subgroup recognised the importance of requirements for material compatibility
and hydrogen embrittlement and started the work in these items. Compliance with material
qualification requirements ensures that manufacturers consistently use materials that are
appropriately qualified for hydrogen storage service and that meet the design specifications
of the manufacturers. However, due to time constraint and other policy and technical issues,
agreement was not reached during Phase 1. Therefore, the SGS working group
recommended that Contracting Parties continue using their national provisions on material
compatibility and hydrogen embrittlement and recommended that requirements for these
topics be deferred to Phase 2 of the GTR activity.
2. National Requirements Complimentary to GTR Requirements
157. The qualification performance requirements (Paragraph 5.) provide qualification
requirements for on-road service for hydrogen storage systems. The goal of harmonisation
of requirements as embodied in the United Nations Global Technical Regulations provides
the opportunity to develop vehicles that can be deployed throughout Contracting Parties to
achieve uniformity of compliance, and thereby, deployment globally. Therefore, Type
Approval requirements are not expected beyond requirements that address conformity of
production and associated verification of material properties (including requirements for
material acceptability with respect to hydrogen embrittlement).
I. TOPICS FOR THE NEXT PHASE IN DEVELOPING THE GTR FOR HYDROGEN-FUELLED
VEHICLES
158. Since hydrogen fuelled vehicles and fuel cell technologies are in early stages of
development of commercial deployment, it is expected that revisions to these requirements
may be suggested by an extended time of on-road experience and technical evaluations. It
is further expected that with additional experience or additional time for fuller technical
consideration, the requirements presented as optional requirements in this document (LHSS
Section G of the preamble) could be adopted as requirements with appropriate
modifications.
Focus topics for Phase 2 are expected to include:
(a)
(b)
(c)
(d)
(e)
(f)
Potential scope revision to address additional vehicle Classes;
Potential harmonisation of crash test specifications;
Requirements for material compatibility and hydrogen embrittlement;
Requirements for the fuelling receptacle;
Evaluation of performance-based test for long-term stress rupture proposed in
Phase 1;
Consideration of research results reported after completion of Phase 1 – specifically
research related to electrical safety, hydrogen storage systems, and post-crash
safety;

---

J. EXISTING REGULATIONS, DIRECTIVES, AND INTERNATIONAL STANDARDS
1. Vehicle Fuel System Integrity
(a)
National Regulations and Directives
(a)
European Union – Regulation 79/2009 – Type-approval of Hydrogen-powered Motor
Vehicles;
(b) European Union – Regulation 406/2010 – Implementing EC Regulation 79/2009;
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
Japan – Safety Regulation Article 17 and Attachment 17 – Technical Standard for
Fuel Leakage in Collision;
Japan – Attachment 100 – Technical Standard for Fuel Systems of Motor Vehicle
Fuelled by Compressed Hydrogen Gas;
Canada – Motor Vehicle Safety Standard (CMVSS) 301.1 – Fuel System Integrity;
Canada – Motor Vehicle Safety Standard (CMVSS) 301.2 – CNG Vehicles;
Korea – Motor Vehicle Safety Standard, Article 91 – Fuel System Integrity;
United States – Federal Motor Vehicle Safety Standard (FMVSS) No. 301 – Fuel
System Integrity;
United States – FMVSS No. 303 – CNG Vehicles;
China – GB/T 24548-2009 Fuel Cell Electric Vehicles – Terminology;
China – GB/T 24549-2009 Fuel Cell Electric Vehicles – Safety Requirements;
China – GB/T 24554-2009 Fuel Cell Engine – Performance – Test Methods.
(b)
National and International Standards.
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
ISO 17268 – Compressed Hydrogen Surface Vehicle Refuelling Connection Devices;
ISO 23273-1 – Fuel Cell Road Vehicles – Safety Specifications – Part 1: Vehicle
Functional Safety;
ISO 23273-2 – Fuel Cell Road Vehicles – Safety Specifications – Part 2: Protection
Against Hydrogen Hazards for Vehicles Fuelled with Compressed Hydrogen;
ISO 14687-2 – Hydrogen Fuel – Product Specification – Part 2: Proton Exchange
Membrane (PEM) Fuel Cell Applications for Road Vehicles;
SAE J2578 – General Fuel Cell Vehicle Safety;
SAE J2600 – Compressed Hydrogen Surface Vehicle Fuelling Connection Devices;
SAE J2601 – Fuelling Protocols for Light Duty Gaseous Hydrogen Surface Vehicles;
SAE J2799 – Hydrogen Quality Guideline for Fuel Cell Vehicles.

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3. Electric Safety
(a)
National Regulations and Directives:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
Canada – CMVSS 305 – Electric Powered Vehicles: Electrolyte Spillage and
Electrical Shock Protection;
ECE – Regulation 100 – Uniform Provisions Concerning the Approval of Battery
Electric Vehicles with Regard to Specific Requirements for the Construction and
Functional Safety;
Japan – Attachment 101 – Technical Standard for Protection of Occupants against
High Voltage in Fuel Cell Vehicles;
Japan – Attachment 110 – Technical Standard for Protection of Occupants against
High Voltage in Electric Vehicles and Hybrid Electric Vehicles;
Japan – Attachment 111 – Technical Standard for Protection of Occupants against
High Voltage after Collision in Electric Vehicles and Hybrid Electric Vehicles;
Korea – Motor Vehicle Safety Standard, Article 18-2 – High Voltage System;
Korea – Motor Vehicle Safety Standard, Article 91-4 – Electrolyte Spillage and
Electric Shock Protection;
United States – FMVSS 305 – Electric-Powered Vehicles: Electrolyte Spillage and
Electrical Shock Protection.
(b)
National and International Industry Sandards:
(a)
(b)
(c)
ISO 23273-3 – Fuel Cell Road Vehicles – Safety Specifications – Part 3: Protection of
Persons Against Electric Shock;
SAE J1766 – Electric and Hybrid Electric Vehicle Battery Systems Crash Integrity
Testing;
SAE J2578 – General Fuel Cell Vehicle Safety.
K. BENEFITS AND COSTS
159. At this time, the GTR does not attempt to quantify costs and benefits for this first stage.
While the goal of the GTR is to enable increased market penetration of HFCVs, the resulting
rates and degrees of penetration are not currently known or estimatable. Therefore, a
quantitative cost-benefit analysis was not possible.
160. Some costs are anticipated from greater market penetration of HFCVs. For example,
building the infrastructure required to make HFCVs a viable alternative to conventional
vehicles will entail significant investment costs for the private and public sectors, depending
on the country. Especially in the early years of HFCV sales, individual purchasers of HFCVs
are also likely to face greater costs than purchasers of conventional gasoline or diesel
vehicles, the same goes for manufacturers of new HFCVs (However, costs incurred by
HFCV purchasers and manufacturers would essentially be voluntary, as market choice
would not be affected).

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3.2. "Automatic disconnect" is a device that, when triggered, conductively separates the
electrical energy sources from the rest of the high voltage circuit of the electrical power
train.
3.3. "Burst-disc" is the non-reclosing operating part of a pressure relief device which, when
installed in the device, is designed to burst at a predetermined pressure to permit the
discharge of compressed hydrogen.
3.4. "Check valve" is a non-return valve that prevents reverse flow in the vehicle fuel line.
3.5. "Concentration of hydrogen" is the percentage of the hydrogen moles (or molecules)
within the mixture of hydrogen and air (Equivalent to the partial volume of hydrogen gas).
3.6. "Container" (for hydrogen storage) is the component within the hydrogen storage
system that stores the primary volume of hydrogen fuel.
3.7. "Conductive connection" is the connection using contactors to an external power
supply when the rechargeable energy storage system (REESS) is charged.
3.8. "Coupling system" for charging the rechargeable energy storage system (REESS) is
the electrical circuit used for charging the REESS from an external electric power supply
including the vehicle inlet.
3.9. "Date of removal from service" is the date (month and year) specified for removal from
service.
3.10. "Date of manufacture" (of a compressed hydrogen container) is the date (month and
year) of the proof pressure test carried out during manufacture.
3.11. "Direct contact" indicates the contact of persons with high voltage live parts.
3.12. "Enclosed or semi-enclosed spaces" indicates the special volumes within the vehicle
(or the vehicle outline across openings) that are external to the hydrogen system
(storage system, fuel cell system and fuel flow management system) and its housings (if
any) where hydrogen may accumulate (and thereby pose a hazard), as it may occur in
the passenger compartment, luggage compartment, cargo compartment and space
under the hood.
3.13. "Enclosure" is the part enclosing the internal units and providing protection against any
direct contact.
3.14. "Electric energy conversion system" is a system (e.g. fuel cell) that generates and
provides electrical power for vehicle propulsion.
3.15. "Electric power train" is the electrical circuit which may include the traction motor(s),
and may also include the REESS, the electrical power conversion system, the electronic
converters, the traction motors, the associated wiring harness and connectors and the
coupling system for charging the REESS.
3.16. "Electrical chassis" is a set of conductive parts electrically linked together, whose
electrical potential is taken as reference.
3.17. "Electrical circuit" is an assembly of connected high voltage live parts that is designed
to be electrically energised in normal operation.

---

3.33. "Liquefied hydrogen storage system" indicates liquefied hydrogen storage
container(s) PRDs, shut off device, a boil-off system and the interconnection piping (if
any) and fittings between the above components.
3.34. "Lower flammability limit (LFL)" is the lowest concentration of fuel at which a gaseous
fuel mixture is flammable at normal temperature and pressure. The lower flammability
limit for hydrogen gas in air is 4% by volume (Paragraph 83 of the Preamble).
3.35. "Maximum allowable working pressure (MAWP)" is the highest gauge pressure to
which a pressure container or storage system is permitted to operate under normal
operating conditions.
3.36. "Maximum fuelling pressure (MFP)" is the maximum pressure applied to compressed
system during fuelling. The maximum fuelling pressure is 125% of the Nominal Working
Pressure.
3.37. "Nominal working pressure (NWP)" is the gauge pressure that characterises typical
operation of a system. For compressed hydrogen gas containers, NWP is the settled
pressure of compressed gas in fully fuelled container or storage system at a uniform
temperature of 15°C.
3.38. "On-board isolation resistance monitoring system" is the device that monitors
isolation resistance between the high voltage buses and the electrical chassis.
3.39. "Open type traction battery" is a type of battery requiring liquid and generating
hydrogen gas that is released into the atmosphere.
3.40. "Passenger compartment (for electric safety assessment)" is the space for occupant
accommodation, bounded by the roof, floor, side walls, doors, outside glazing, front
bulkhead and rear bulkhead – or rear gate -, as well as by the electrical barriers and
enclosures provided for protecting the occupants from direct contact with live parts.
3.41. "Pressure relief device (PRD)" is a device that, when activated under specified
performance conditions, is used to release hydrogen from a pressurised system and
thereby prevent failure of the system.
3.42. "Pressure relief valve" is a pressure relief device that opens at a preset pressure level
and can re-close.
3.43. "Protection degree IPXXB" indicates protection from contact with high voltage live
parts provided by either an electrical barrier or an enclosure; it is tested using a Jointed
Test Finger (IPXXB), as described in Paragraph 6.3.3.
3.44. "Protection degree IPXXD" indicates protection from contact with high voltage live
parts provided by either an electrical barrier or an enclosure and tested using a Test
Wire (IPXXD), as described in Paragraph 6.3.3.
3.45. "Rechargeable energy storage system (REESS)" is the rechargeable energy storage
system that provides electric energy for electrical propulsion.
3.46. "Rupture and burst" both mean to come apart suddenly and violently, break open or fly
into pieces due to the force of internal pressure.

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5.
Performance requirements
5.1. Compressed Hydrogen Storage System
This section specifiess the requirements for the
integrity of the compressed hydrogen storage
system. The hydrogen storage system consists of the high pressure storage container and
primary closure devices for openings into the high pressure storage container. Figure 1
shows a typical compressed hydrogen storage system consisting of a pressurised container,
three closure devices
and their fittings. The closure devices include:
(a)
(b)
(c)
A TPRD;
A check valve that t preventss reverse flow
to the fill line; and
An
automatic shut-off valve that can close to prevent flow fromm the container to the
fuel cell or ICE
engine. Anyy shut-off valve, and TPRD that form the primary closure of
flow
from the storage container shall be
mounted directly d on or r within each container.
At least one component with a check valve function shall be mounted directly on or
within each container.
Figure 1
Typical Compressed Hydrogen Storage System
All new compressed hydrogen storage systems produced for on-road vehicle
service shall have a NWP of 70MPa
or less andd a service life of 15 years or less,
and be capable of satisfying the requirements off Paragraph 5.1.
The hydrogen storage systemm shall meet the performance test requirements specified in
this paragraph. The qualification requirements for on-road service are:

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5.1.1. Verification Tests for Baseline Metrics
5.1.1.1. Baseline Initial Burst Pressure
Three (3) new containers randomly selected from the design qualification batch of at
least 10 containers, are hydraulically pressurised until burst (Paragraph 6.2.2.1. test
procedure). The manufacturer shall supply documentation (measurements and
statistical analyses) that establish the midpoint burst pressure of new storage
containers, BP .
All containers tested shall have a burst pressure within ±10% of BP and greater than
or equal to a minimum BPmin of 225% NWP.
In addition, containers having glass-fibre composite as a primary constituent to have
a minimum burst pressure greater than 350% NWP.
5.1.1.2. Baseline Initial Pressure Cycle Life
Three (3) new containers randomly selected from the design qualification batch are
hydraulically pressure cycled at 20 (±5)°C to 125% NWP without rupture for 22,000
cycles or until a leak occurs (Paragraph 6.2.2.2. test procedure). Leakage shall not
occur within a number of Cycles, where the number of Cycles is set individually by
each Contracting Party at 5,500, 7,500 or 11,000 cycles for a 15 year service life.
5.1.2. Verification Tests for Performance Durability (Hydraulic Sequential Tests)
If all three pressure cycle life measurements made in Paragraph 5.1.1.2. are greater
than 11,000 cycles, or if they are all within ±25% of each other, then only one (1)
container is tested in Paragraph 5.1.2. Otherwise, three (3) containers are tested in
Paragraph 5.1.2.
A hydrogen storage container shall not leak during the following sequence of tests,
which are applied in series to a single system and which are illustrated in Figure 2. At
least one system randomly selected from the design qualification batch shall be
tested to demonstrate the performance capability. Specifics of applicable test
procedures for the hydrogen storage system are provided in Paragraph 6.2.3.

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5.1.2.6. Extreme Temperature Pressure Cycling.
The storage container is pressure cycled at ≤-40°CC to 80% NWP for 20% number of
Cycles and at ≥+85°C andd 95% relative humidity to t 125% NWP for 20% number of
Cycles (Paragraph 6.2.2.2. test procedure).
5.1.2.7. Hydraulic Residual Pressure Test.
The storage container is pressurised
(Paragraph 6.2.3.1. test procedure).
to 180% NWP N and held 4min without burst
5.1.2.8. Residual Burstt Strength Test
The storage container undergoes a hydraulic burst test to verify that the burst
pressure is at least 80% of the baseline initial burst pressuree (BP ) determined in
Paragraph 5.1. .1.1. (Paragraph 6.2.2.1. test procedure).
5.1.3. Verification Test for Expected on-road Performance
e (Pneumaticc Sequential Tests)
A hydrogen storage system shall not leak duringg the following sequencee of tests,
which are illustrated in Figure 3. Specifics of applicable test procedures for the
hydrogen storage system are provided in Paragraphh 6.
Figure 3
Verification
Test for Expected on-road 150% NWP for 30s (Paragraph 6.2.3.1. test procedure).
A storage container that has undergone a prooff pressure test in manufacture is
Performance (Pneumatic/Hydraulic)
5.1.3.1. Proof Pressuree Test
A system is pressurised too
exempt from this test.

---

5.1.4. Verification Test for Service Terminating Performance in Fire
This section describes the fire test with compressed hydrogen as the test gas.
Containers tested with hydrogen gas shall be accepted by all Contracting Parties.
However, Contracting Parties under the 1998 Agreement may choose to use
compressed air as an alternative test gas for certification of a container for use only
within their countries or regions.
A hydrogen storage system is pressurised to NWP and exposed to fire
(Paragraph 6.2.5.1. test procedure). A temperature-activated pressure relief device
shall release the contained gases in a controlled manner without rupture.
5.1.5. Verification Test for Performance Durability of Primary Closures
Manufacturers shall maintain records that confirm that closures that isolate the high
pressure hydrogen storage system (the TPRD(s), check valve(s) and shut-off valve(s)
shown in Figure 1) comply with the requirements described in the remainder of this
Section.
The entire storage system does not have to be re-qualified (Paragraph 5.1.) if these
closure components (components in Figure 1 excluding the storage container) are
exchanged for equivalent closure components having comparable function, fittings,
materials, strength and dimensions, and qualified for performance using the same
qualification tests as the original components. However, a change in TPRD hardware,
its position of installation or venting lines requires re-qualification with fire testing
according to Paragraph 5.1.4.
5.1.5.1. TPRD Qualification Requirements
Design qualification testing shall be conducted on finished pressure relief devices
which are representative of normal production. The TPRD shall meet the following
performance qualification requirements:
(a) Pressure cycling test (Paragraph 6.2.6.1.1.);
(b) Accelerated life test (Paragraph 6.2.6.1.2.);
(c) Temperature cycling test (Paragraph 6.2.6.1.3.);
(d) Salt corrosion resistance test (Paragraph 6.2.6.1.4.);
(e) Vehicle environment test (Paragraph 6.2.6.1.5.);
(f) Stress corrosion cracking test (Paragraph 6.2.6.1.6.);
(g) Drop and vibration test (Paragraph 6.2.6.1.7.);
(h) Leak test (Paragraph 6.2.6.1.8.);
(i) Bench top activation test (Paragraph 6.2.6.1.9.);
(j) Flow rate test (Paragraph 6.2.6.1.10.).

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5.2.1.1.2. Fuelling receptacle label A label shall be affixed close to the fuelling receptacle; for
instance inside a refilling hatch, showing the following information: fuel type, NWP,
date of removal from service of containers.
5.2.1.1.3. The fuelling receptacle shall be mounted on the vehicle to ensure positive locking of
the fuelling nozzle. The receptacle shall be protected from tampering and the ingress
of dirt and water (e.g. installed in a compartment which can be locked). Test
procedure is by visual inspection.
5.2.1.1.4. The fuelling receptacle shall not be mounted within the external energy absorbing
elements of the vehicle (e.g. bumper) and shall not be installed in the passenger
compartment, luggage compartment and other places where hydrogen gas could
accumulate and where ventilation is not sufficient. Test procedure is by visual
inspection.
5.2.1.2. Over-pressure Protection for the Low Pressure System (Paragraph 6.1.6. Test
Procedure)
The hydrogen system downstream of a pressure regulator shall be protected against
overpressure due to the possible failure of the pressure regulator. The set pressure of
the overpressure protection device shall be lower than or equal to the maximum
allowable working pressure for the appropriate section of the hydrogen system.
5.2.1.3. Hydrogen Discharge Systems
5.2.1.3.1. Pressure Relief Systems (Paragraph 6.1.6. Test Procedure)
(a)
(b)
Storage system TPRDs. The outlet of the vent line, if present, for hydrogen gas
discharge from TPRD(s) of the storage system shall be protected by a cap;
Storage system TPRDs. The hydrogen gas discharge from TPRD(s) of the
storage system shall not be directed:
(i)
(ii)
(iii)
(iv)
Into enclosed or semi-enclosed spaces;
Into or towards any vehicle wheel housing;
Towards hydrogen gas containers;
Forward from the vehicle, or horizontally (parallel to road) from the back
or sides of the vehicle.
(c)
Other pressure relief devices (such as a burst disk) may be used outside the
hydrogen storage system. The hydrogen gas discharge from other pressure
relief devices shall not be directed:
(i)
(ii)
(iii)
(iv)
Towards exposed electrical terminals, exposed electrical switches or
other ignition sources;
Into or towards the vehicle passenger or cargo compartments;
Into or towards any vehicle wheel housing;
Towards hydrogen gas containers.

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5.2.2. Post-crash Fuel System Integrity
5.2.2.1. Fuel Leakage Limit
The volumetric flow of hydrogen gas leakage shall not exceed an average of 118NL
per minute for 60min after the crash (Paragraph 6.1.1. test procedures).
5.2.2.2. Concentration Limit in Enclosed Spaces
Hydrogen gas leakage shall not result in a hydrogen concentration in the air greater
than 3 ± 1.0% by volume in the passenger, luggage and cargo compartments
(Paragraph 6.1.2. test procedures). The requirement is satisfied if it is confirmed that
the shut-off valve of the storage system has closed within 5s of the crash and no
leakage from the storage system.
5.2.2.3. Container Displacement
The storage container(s) shall remain attached to the vehicle at a minimum of one
attachment point.
5.3. Electrical Safety
5.3.1. Electrical Safety Requirements – In-use
5.3.1.1. General
Paragraph 5.3.1. applies to the electric power train of fuel cell vehicles equipped with
one or more traction motor(s) operated by electric power and not permanently
connected to the grid, as well as their high voltage components and systems which
are conductively connected to the high voltage bus of the electric power train.
5.3.1.2. Requirements for Protection Against Electric Shock
5.3.1.2.1. Protection Against Electric Shock
These electrical safety requirements apply to high voltage buses under conditions
where they are not connected to external high voltage power supplies.
5.3.1.2.2. Protection Against Direct Contact
The protection against direct contact with live parts shall comply with
Paragraphs 5.3.1.2.2.1. and 5.3.1.2.2.2. These protections (solid insulator, electrical
protection barrier, enclosure, etc.) shall not be opened, disassembled or removed
without the use of tools.
5.3.1.2.2.1. For protection of live parts inside the passenger compartment or luggage
compartment, the protection degree IPXXD shall be provided.
5.3.1.2.2.2. For protection of live parts in areas other than the passenger compartment or luggage
compartment, the protection degree IPXXB shall be satisfied.

---

5.3.1.2.3. Protection Against Indirect Contact
5.3.1.2.3.1. For protection against electric shock which could arise from indirect contact, the
exposed conductive parts, such as the conductive electrical protection barrier and
enclosure, shall be conductively connected and secured to the electrical chassis with
electrical wire or ground cable, by welding, or by connection using bolts, etc. so that
no dangerous potentials are produced.
5.3.1.2.3.2. The resistance between all exposed conductive parts and the electrical chassis shall
be lower than 0.1ohm when there is current flow of at least 0.2A. Demonstrated by
using one of the test procedures described in Paragraph 6.3.4.
This requirement is satisfied if the galvanic connection has been established by
welding. In case of doubts a measurement shall be made.
5.3.1.2.3.3. In the case of motor vehicles which are connected to the grounded external electric
power supply through the conductive connection, a device to enable the conductive
connection of the electrical chassis to the earth ground shall be provided.
The device shall enable connection to the earth ground before exterior voltage is
applied to the vehicle and retain the connection until after the exterior voltage is
removed from the vehicle.
Compliance to this requirement may be demonstrated either by using the connector
specified by the car manufacturer, or by analysis (e.g. visual inspection, drawings
etc.).
5.3.1.2.4. Isolation Resistance Monitoring System
5.3.1.2.4.1. In fuel cell vehicles, DC high voltage buses shall have an on-board isolation
resistance monitoring system together with a warning to the driver if the isolation
resistance drops below the minimum required value of 100ohms/V. The function of
the on-board isolation resistance monitoring system shall be confirmed as described
in Paragraph 6.3.2.
The isolation resistance between the high voltage bus of the coupling system for
charging the REESS, which is not energised in conditions other than that during the
charging of the REESS, and the electrical chassis need not to be monitored.
5.3.1.2.4.2. Electric Power Train Consisting of Separate DC or AC Buses
If AC high voltage buses and DC high voltage buses are conductively isolated from
each other, isolation resistance between the high voltage bus and the electrical
chassis shall have a minimum value of 100ohms/V of the working voltage for DC
buses, and a minimum value of 500ohms/V of the working voltage for AC buses.
The measurement shall be conducted according to Paragraph 6.3.1.

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5.3.2. Electric Safety Requirements – Post-crash
5.3.2.1. General
Fuel cell vehicles equipped with electric power train shall comply with the
requirements of Paragraphs 5.3.2.2. to 5.3.2.4. This can be met by a separate impact
test provided that the electrical components do not influence the occupant protection
performance of the vehicle type as defined in the impact regulation. In case of this
condition the requirements of Paragraph 5.3.2.2. to 5.3.2.4. shall be checked in
accordance with the methods set out in Paragraph 6.3.5.
5.3.2.2. Protection Against Electric Shock
After the impact at least one of the three criteria specified in Paragraphs 5.3.2.2.1. to
5.3.2.2.3. shall be met.
If the vehicle has an automatic disconnect function, or device(s) that conductively
divide the electric power train circuit during driving condition, at least one of the
following criteria shall apply to the disconnected circuit or to each divided circuit
individually after the disconnect function is activated. However criteria defined in
Paragraph 5.3.2.2.2. shall not apply if more than a single potential of a part of the
high voltage bus is not protected under the conditions of protection degree IPXXB.
In the case that the test is performed under the condition that part(s) of the high
voltage system are not energised, the protection against electric shock shall be
proved by either Paragraph 5.3.2.2.2. or Paragraph 5.3.2.2.3. for the relevant part(s).
5.3.2.2.1. Absence of High Voltage
The voltages Vb, V1 and V2 of the high voltage buses shall be equal or less than
30VAC or 60Vdc within 60s after the impact as specified in Paragraph 6.3.5. and
Paragraph 6.3.5.2.2.
5.3.2.2.2. Isolation Resistance
The criteria specified in the Paragraphs 5.3.2.2.2.1. and 5.3.2.2.2.2. below shall be
met.
The measurement shall be conducted in accordance with Paragraph 6.3.5.2.3. of
Paragraph 6.3.5.
5.3.2.2.2.1. Electrical Power Train Consisting of Separate DC and AC Buses
If the AC high voltage buses and the DC high voltage buses are conductively isolated
from each other, isolation resistance between the high voltage bus and the electrical
chassis (Ri, as defined in Paragraph 6.3.5.2.3.) shall have a minimum value of
100Ω/V of the working voltage for DC buses, and a minimum value of 500Ω/V of the
working voltage for AC buses.

---

6. Test Conditions and Procedures
6.1. Compliance Tests for Fuel System Integrity
6.1.1. Post-crash Compressed Hydrogen Storage System Leak Test
The crash tests used to evaluate post-crash hydrogen leakage are those already
applied in the jurisdictions of each contracting party.
Prior to conducting the crash test, instrumentation is installed in the hydrogen storage
system to perform the required pressure and temperature measurements if the
standard vehicle does not already have instrumentation with the required accuracy.
The storage system is then purged, if necessary, following manufacturer directions to
remove impurities from the container before filling the storage system with
compressed hydrogen or helium gas. Since the storage system pressure varies with
temperature, the targeted fill pressure is a function of the temperature. The target
pressure shall be determined from the following equation:
where
P = NWP × (273 + T )/288
NWP
T
P
is the nominal working pressure (MPa),
is the ambient temperature to which the storage system is expected to settle,
and
is the targeted fill pressure after the temperature settles.
The container is filled to a minimum of 95% of the targeted fill pressure and allowed to
settle (stabilise) prior to conducting the crash test.
The main stop valve and shut-off valves for hydrogen gas, located in the downstream
hydrogen gas piping, are kept open immediately prior to the impact.
6.1.1.1. Post-crash Leak Test – Compressed Hydrogen Storage System Filled with
Compressed Hydrogen
The hydrogen gas pressure, P (MPa), and temperature, T (°C), is measured
immediately before the impact and then at a time interval, ∆t (min), after the impact.
The time interval, ∆t, starts when the vehicle comes to rest after the impact and
continues for at least 60 minutes. The time interval, ∆t, is increased if necessary in
order to accommodate measurement accuracy for a storage system with a large
volume operating up to 70MPa; in that case, ∆t can be calculated from the following
equation:
where
∆t = V × NWP/1,000 × ((-0.027 × NWP +4) × R - 0.21) -1.7 × R
R =
P /NWP,
P
is the pressure range of the pressure sensor (MPa),
NWP
is the Nominal Working Pressure (MPa),
V
is the volume of the compressed hydrogen storage system (L), and
∆t
is the time interval (min).

---

6.1.1.2. Post-crash Leak Test – Compressed Hydrogen Storage System Filled with
Compressed Helium
The helium gas pressure, P (MPa), and temperature T (°C), are measured
immediately before the impact and then at a predetermined time interval after the
impact. The time interval, ∆t, starts when the vehicle comes to rest after the impact
and continues for at least 60min.
The time interval, ∆t, shall be increased if necessary in order to accommodate
measurement accuracy for a storage system with a large volume operating up to
70MPa; in that case, ∆t can be calculated from the following equation:
where
∆t = V × NWP/1,000 × ((-0.028 × NWP +5.5) × R - 0.3) - 2.6 × R
R = P /NWP, P is the pressure range of the pressure sensor (MPa),
NWP is the Nominal Working Pressure (MPa),
is the volume of the compressed storage system (L), and
∆t is the time interval (min).
If the value of ∆t is less than 60min, ∆t is set to 60min.
The initial mass of hydrogen in the storage system is calculated as follows:
P ’ = P × 288/(273 + T )
ρ ’ = –0.0043 × (P ’) + 1.53 × P ’ + 1.49
M = ρ ’ × V
The final mass of hydrogen in the storage system at the end of the time interval, ∆t, is
calculated as follows:
where
P ’ = P × 288/(273 + T )
ρ ’ = –0.0043 × (P ’) + 1.53 × P ’ + 1.49
M = ρ ’ × V
P
T
is the measured final pressure (MPa) at the end of the time interval, and
is the measured final temperature (°C).
The average helium flow rate over the time interval is therefore
where
V = (M -M )/∆t × 22.41/4.003 × (P /P )
V s the average volumetric flow rate (NL/min) over the time interval and the term
P /P is used to compensate for differences between the measured initial
pressure (P ) and the targeted fill pressure (P ).

---

6.1.3. Compliance Test for Single Failure Conditions
Either test procedure of Paragraph 6.1.3.1. or Paragraph 6.1.3.2. shall be executed:
6.1.3.1. Test Procedure for Vehicle Equipped with Hydrogen Gas Leakage Detectors
6.1.3.1.1. Test Condition
6.1.3.1.1.1 Test Vehicle:
6.1.3.1.1.2. Test Gas:
The propulsion system of the test vehicle is started, warmed up to its normal
operating temperature, and left operating for the test duration. If the vehicle is not a
fuel cell vehicle, it is warmed up and kept idling. If the test vehicle has a system to
stop idling automatically, measures are taken so as to prevent the engine from
stopping.
Two mixtures of air and hydrogen gas: 2 ± 1.0% concentration (or less) of hydrogen
in the air to verify function of the warning, and 3 ± 1.0% concentration (or less) of
hydrogen in the air to verify function of the shut-down. The proper concentrations are
selected based on the recommendation (or the detector specification) by the
manufacturer.
6.1.3.1.2. Test Method
6.1.3.1.2.1. Preparation for the Test:
The test is conducted without any influence of wind.
(a)
(b)
A test gas induction hose is attached to the hydrogen gas leakage detector;
The hydrogen leak detector is enclosed with a cover to make gas stay around
hydrogen leak detector.
6.1.3.1.2.2. Execution of the Test
(a)
(b)
(c)
Test gas is blown to the hydrogen gas leakage detector;
Proper function of the warning system is confirmed when tested with the gas to
verify function of the warning;
The main shut-off valve is confirmed to be closed when tested with the gas to
verify function of the shut-down. For example, the monitoring of the electric
power to the shut-off valve or of the sound of the shut-off valve activation may
be used to confirm the operation of the main shut-off valve of the hydrogen
supply.

---

6.1.4. Compliance Test for the Vehicle Exhaust System
6.1.4.1. The power system of the test vehicle (e.g. fuel cell stack or engine) is warmed up to
its normal operating temperature.
6.1.4.2. The measuring device is warmed up before use to its normal operating temperature.
6.1.4.3. The measuring section of the measuring device is placed on the centre line of the
exhaust gas flow within 100mm from the exhaust gas outlet external to the vehicle.
6.1.4.4. The exhaust hydrogen concentration is continuously measured during the following
steps:
(a)
(b)
(c)
The power system is shut down;
Upon completion of the shut-down process, the power system is immediately
started;
After a lapse of one minute, the power system is turned off and measurement
continues until the power system shut-down procedure is completed.
6.1.4.5. The measurement device shall have a measurement response time of less than
300ms.
6.1.5. Compliance Test for Fuel Line Leakage
6.1.5.1. The power system of the test vehicle (e.g. fuel cell stack or engine) is warmed up and
operating at its normal operating temperature with the operating pressure applied to
fuel lines.
6.1.5.2. Hydrogen leakage is evaluated at accessible sections of the fuel lines from the
high-pressure section to the fuel cell stack (or the engine), using a gas detector or
leak detecting liquid, such as soap solution.
6.1.5.3. Hydrogen leak detection is performed primarily at joints.
6.1.5.4. When a gas leak detector is used, detection is performed by operating the leak
detector for at least 10s at locations as close to fuel lines as possible.
6.1.5.5. When a leak detecting liquid is used, hydrogen gas leak detection is performed
immediately after applying the liquid. In addition, visual checks are performed a few
minutes after the application of liquid in order to check for bubbles caused by trace
leaks.
6.1.6. Installation Verification
The system is visually inspected for compliance.

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6.2.3. Test Procedures for Performance Durability (Requirement of Paragraph 5.1.2.)
6.2.3.1. Proof Pressure Test
The system is pressurised smoothly and continually with a non-corrosive hydraulic
fluid until the target test pressure level is reached and then held for the specified time.
6.2.3.2. Drop (Impact) Test (Unpressurised)
The storage container is drop tested at ambient temperature without internal
pressurisation or attached valves. The surface onto which the containers are dropped
shall be a smooth, horizontal concrete pad or other flooring type with equivalent
hardness.
(a)
The orientation of the container being dropped (per requirement of
Paragraph 5.1.2.2.) is determined as follows: One or more additional
container(s) shall be dropped in each of the orientations described below. The
drop orientations may be executed with a single container or as many as four
containers may be used to accomplish the four drop orientations.
(i)
(ii)
(iii)
(iv)
Dropped once from a horizontal position with the bottom 1.8m above the
surface onto which it is dropped;
Dropped once onto the end of the container from a vertical position with
the ported end upward with a potential energy of not less than 488J, with
the height of the lower end no greater than 1.8m;
Dropped once onto the end of the container from a vertical position with
the ported end downward with a potential energy of not less than 488J,
with the height of the lower end no greater than 1.8m. If the container is
symmetrical (identical ported ends), this drop orientation is not required;
Dropped once at a 45° angle from the vertical orientation with a ported
end downward with its centre of gravity 1.8m above the ground.
However, if the bottom is closer to the ground than 0.6m, the drop angle
shall be changed to maintain a minimum height of 0.6m and a centre of
gravity of 1.8m above the ground.

---

6.2.3.3. Surface damage test (unpressurised)
The test proceeds in the following sequence:
(a)
Surface flaw generation: Two longitudinal saw s cuts aree made on the t bottom
outer surface of the unpressurised horizontal storagee container along the
cylindrical zone close to but not
in the shoulder area. The first cut is at least
1.25mm deep and 25mm long toward the valve end of the container. The
second cut is at least 0.75mm deep and 200mm long toward the end of the
container opposite the valve;
(b)
Pendulum impacts: The upper section of the horizontal storage container is
divided into i five distinct (not overlapping) areas 100mm in diameter each (see
Figure 6). After 12h preconditioning at -40°CC in an environmental chamber, the
centre of each of the five areas
sustains the impact of a pendulum
having a
pyramid with equilateral faces and square base, b the summit and edges being
rounded to a radius of 3mm. The centre of impact of the pendulum
coincides
with the centre of gravity of the pyramid. The energy of the pendulum at the
moment of impact with each of the five marked areas onn the container is 30J.
The container is secured in place during pendulum p impacts and not under
pressure.
Figure 6
Side View of Tank
6.2.3.4. Chemical Exposure and Ambient Temperature Pressure Cyclingg Test
Each of the 5 areas of the unpressurised container preconditioned by pendulum
impact (Paragraph 6.4.2.5.2.) is exposed to one of five f solutions:
(a)
19% (by
volume) sulphuric acid in water (battery acid);
(b)
25% (by
weight) sodium hydroxide in water;
(c)
5% (by volume) methanol in gasoline (fluids in fuelling stations);
(d)
28% (by
weight) ammonium nitrate in water ( urea solution); and
(e)
50% (by
volume) methyl alcohol in water (windshield washer fluid).

---

6.2.4.2. Gas Permeation Test (Pneumatic)
A storage system is fully filled with hydrogen gas at 115% NWP (full fill density
equivalent to 100% NWP at +15°C is 113% NWP at +55°C) and held at ≥+55°C in a
sealed container until steady-state permeation or 30h, whichever is longer. The total
steady-state discharge rate due to leakage and permeation from the storage system
is measured.
6.2.4.3. Localised Gas Leak Test (Pneumatic)
A bubble test may be used to fulfil this requirement. The following procedure is used
when conducting the bubble test:
(a)
The exhaust of the shutoff valve (and other internal connections to hydrogen
systems) shall be capped for this test (as the test is focused at external
leakage).
At the discretion of the tester, the test article may be immersed in the leak-test
fluid or leak-test fluid applied to the test article when resting in open air.
Bubbles can vary greatly in size, depending on conditions. The tester estimates
the gas leakage based on the size and rate of bubble formation.
(b)
Note: For a localised rate of 0.005mg/s (3.6Nml/min), the resultant allowable
rate of bubble generation is about 2,030 bubbles per minute for a
typical bubble size of 1.5mm in diameter. Even if much larger bubbles
are formed, the leak should be readily detectable. For an unusually
large bubble size of 6mm in diameter, the allowable bubble rate would
be approximately 32 bubbles per minute.
6.2.5. Test Procedures for Service Terminating Performance In Fire (Paragraph 5.1.4.)
6.2.5.1. Fire Test
The hydrogen container assembly consists of the compressed hydrogen storage
system with additional relevant features, including the venting system (such as the
vent line and vent line covering) and any shielding affixed directly to the container
(such as thermal wraps of the container(s) and/or coverings/barriers over the
TPRD(s)).
Either one of the following two methods are used to identify the position of the system
over the initial (localised) fire source:
6.2.5.1.1. Method 1: Qualification for a Generic (Non-specific) Vehicle Installation
If a vehicle installation configuration is not specified (and the qualification of the
system is not limited to a specific vehicle installation configuration) then the localised
fire exposure area is the area on the test article farthest from the TPRD(s). The test
article, as specified above, only includes thermal shielding or other mitigation devices
affixed directly to the container that are used in all vehicle applications. Venting
system(s) (such as the vent line and vent line covering) and/or coverings/barriers over
the TPRD(s) are included in the container assembly if they are anticipated for use in
any application. If a system is tested without representative components, retesting of
that system is required if a vehicle application specifies the use of these type of
components.

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(f)
As shown in Figure 7 the temperature of the thermocouples in the localised fire
area has
increased continuously
to at least 300°C 3 withinn 1min of ignition, to at
least 600°C within 3min of ignition, and a temperaturee of at leastt 600°C is
maintained for the next 7min. The temperature in the localised fire area shall
not exceed 900°C during this period. Compliance to thee thermal requirements
begins 1min after entering the period with minimum and maximum limits and is
based on
a 1min rolling average of each thermocouple in n the region of interest.
(Note: The temperature outside the region of the initial fire source is not
specified during these initial 10min from the time of ignition.)
Figure 7
Temperaturee Profile of Fire F Test
Engulfing Portion of the Fire Test
Within the next 2min interval, the temperature along the entire surface of the test
article shall be increased too at least 800°C and the fire source is extended to t produce
a uniform temperature along the entire length up too 1.65m and the entire width of the
test article (engulfing fire) ). The minimum temperature is held at 800°C, and the
maximum
temperature
shall
not exceed 1,100°C.
Compliance
to
thermal
requirements
begins 1minn after entering the period with constant minimum and
maximum limits
and is based on a 1min
rolling average of each thermocouple.
The test article
is held at temperature (engulfing fire condition) until the system vents
through the TPRD and thee pressure falls to less than 1MPa. . The venting shall be
continuous (without interruption), and
the storage system shall not rupture. An
additional release throughh leakage (not including release through the TPRD) that
results in a flame with length greater than 0.5m beyond the perimeter of the applied
flame shall not occur.

---

Documenting of the Fire Test
The arrangement of the fire is recorded in sufficient detail to ensure the rate of heat
input to the test article is reproducible. The results include the elapsed time from
ignition of the fire to the start of venting through the TPRD(s), and the maximum
pressure and time of evacuation until a pressure of less than 1MPa is reached.
Thermocouple temperatures and container pressure are recorded at intervals of every
10s or less during the test. Any failure to maintain specified minimum temperature
requirements based on the 1min rolling averages invalidates the test result. Any
failure to maintain specified maximum temperature requirements based on the 1min
rolling averages invalidates the test result only if the test article failed during the test.
6.2.5.2. Engulfing Fire Test:
The test unit is the compressed hydrogen storage system. The storage system is
filled with compressed hydrogen gas at 100% NWP. The container is positioned
horizontally with the container bottom approximately 100mm above the fire source.
Metallic shielding is used to prevent direct flame impingement on container valves,
fittings, and/or pressure relief devices. The metallic shielding is not in direct contact
with the specified fire protection system (pressure relief devices or container valve).
A uniform fire source of 1.65m length provides direct flame impingement on the
container surface across its entire diameter. The test shall continue until the container
fully vents (until the container pressure falls below 0.7MPa (100psi)). Any failure or
inconsistency of the fire source during a test shall invalidate the result.
Flame temperatures shall be monitored by at least three thermocouples suspended in
the flame approximately 25mm below the bottom of the container. Thermocouples
may be attached to steel cubes up to 25mm on a side. Thermocouple temperature
and the container pressure shall be recorded every 30s during the test.
Within five minutes after the fire is ignited, an average flame temperature of not less
than 590°C (as determined by the average of the two thermocouples recording the
highest temperatures over a 60s interval) is attained and maintained for the duration
of the test.
If the container is less than 1.65m in length, the centre of the container shall be
positioned over the centre of the fire source. If the container is greater than 1.65m in
length, then if the container is fitted with a pressure relief device at one end, the fire
source shall commence at the opposite end of the container. If the container is
greater than 1.65m in length and is fitted with pressure relief devices at both ends, or
at more than one location along the length of the container, the centre of the fire
source shall be centred midway between the pressure relief devices that are
separated by the greatest horizontal distance.
The container shall vent through a pressure relief device without bursting.

---

6.2.6.1.4. Salt Corrosion Resistance Test
Two TPRD units are tested. Any non-permanent outlet caps are removed. Each
TPRD unit is installed in a test fixture in accordance with the manufacturer’s
recommended procedure so that external exposure is consistent with realistic
installation. Each unit is exposed for 500h to a salt spray (fog) test as specified in
ASTM B117 (Standard Practice for Operating Salt Spray (Fog) Apparatus) except that
in the test of one unit, the pH of the salt solution shall be adjusted to 4.0 ± 0.2 by the
addition of sulphuric acid and nitric acid in a 2:1 ratio, and in the test of the other unit,
the pH of the salt solution shall be adjusted to 10.0 ± 0.2 by the addition of sodium
hydroxide. The temperature within the fog chamber is maintained at 30-35°C).
Following these tests, each pressure relief device shall comply with the requirements
of the leak test (Paragraph 6.2.6.1.8.), Flow Rate Test (Paragraph 6.2.6.1.10.) and
bench top activation test (Paragraph 6.2.6.1.9.).
6.2.6.1.5. Vehicle Environment Test
Resistance to degradation by external exposure to automotive fluids is determined by
the following test:
(a)
The inlet and outlet connections of the TPRD are connected or capped in
accordance with the manufacturers installation instructions. The external
surfaces of the TPRD are exposed for 24h at 20 (±5)°C to each of the following
fluids:
(i) Sulphuric acid – 19% solution by volume in water;
(ii) Sodium hydroxide – 25% solution by weight in water;
(iii) Ammonium nitrate – 28% by weight in water; and
(iv)
Windshield washer fluid (50% by volume methyl alcohol and water).
The fluids are replenished as needed to ensure complete exposure for the
duration of the test. A distinct test is performed with each of the fluids. One
component may be used for exposure to all of the fluids in sequence.
(b)
(c)
After exposure to each fluid, the component is wiped off and rinsed with water;
The component shall not show signs of physical degradation that could impair
the function of the component, specifically: cracking, softening, or swelling.
Cosmetic changes such as pitting or staining are not failures. At the conclusion
of all exposures, the unit(s) shall comply with the requirements of the Leak Test
(Paragraph 6.2.6.1.8.), Flow Rate Test (Paragraph 6.2.6.1.10.) and Bench Top
Activation test (Paragraph 6.2.6.1.9.).

---

Additional units undergo leak testing as specified in other tests in Paragraph 6.2.6.1.
with uninterrupted exposure at the temperature specified in those tests.
At all specified test temperatures, the unit is conditioned for one minute by immersion
in a temperature controlled fluid (or equivalent method). If no bubbles are observed
for the specified time period, the sample passes the test. If bubbles are detected, the
leak rate is measured by an appropriate method. The total hydrogen leak rate shall be
less than 10Nml/hr.
6.2.6.1.9. Bench Top Activation Test
Two new TPRD units are tested without being subjected to other design qualification
tests in order to establish a baseline time for activation. Additional pre-tested units
(pre-tested according to Paragraph 6.2.6.1.1., 6.2.6.1.3., 6.2.6.1.4., 6.2.6.1.5. or
6.2.6.1.7.) undergo bench top activation testing as specified in other tests in
Paragraph 6.2.6.1.
(a)
(b)
(c)
(d)
(e)
The test setup consists of either an oven or chimney which is capable of
controlling air temperature and flow to achieve 600 (±10)°C in the air
surrounding the TPRD. The TPRD unit is not exposed directly to flame. The
TPRD unit is mounted in a fixture according to the manufacturer’s installation
instructions; the test configuration is to be documented;
A thermocouple is placed in the oven or chimney to monitor the temperature.
The temperature remains within the acceptable range for two minutes prior to
running the test;
The pressurised TPRD unit is inserted into the oven or chimney, and the time
for the device to activate is recorded. Prior to insertion into the oven or
chimney, one new (not pre-tested) TPRD unit is pressurised to no more than
25% NWP (the pre-tested); TPRD units are pressurised to no more than 25%
NWP; and one new (not pre-tested) TPRD unit is pressurised to 100% NWP;
TPRD units previously subjected to other tests in Paragraph 6.2.6.1. shall
activate within a period no more than two minutes longer than the baseline
activation time of the new TPRD unit that was pressurised to up to 25% NWP;
The difference in the activation time of the two TPRD units that had not
undergone previous testing shall be no more than 2min.

---

6.2.6.2.2. Leak Test
One unit that has not undergone previous testing is tested at ambient, high and low
temperatures without being subjected to other design qualification tests. The three
temperature test conditions are:
(a)
(b)
(c)
Ambient temperature: condition the unit at 20 (± 5)°C; test at 5% NWP
(+0/-2MPa) and 150% NWP (+2/-0 MPa) ;
High temperature: condition the unit at 85°C or higher ; test at 5% NWP
(+0/-2MPa) and 150% NWP (+2/-0MPa) ;
Low temperature: condition the unit at -40°C or lower; test at 5% NWP
(+0/-2MPa) and 100% NWP (+2/-0MPa).
Additional units undergo leak testing as specified in other tests in Paragraph 6.2.6.2.
with uninterrupted exposure at the temperatures specified in those tests.
The outlet opening is plugged with the appropriate mating connection and pressurised
hydrogen is applied to the inlet. At all specified test temperatures, the unit is
conditioned for one minute by immersion in a temperature controlled fluid (or
equivalent method). If no bubbles are observed for the specified time period, the
sample passes the test. If bubbles are detected, the leak rate is measured by an
appropriate method. The leak rate shall not exceed 10Nml/hr of hydrogen gas.
6.2.6.2.3. Extreme Temperature Pressure Cycling Test
(a)
The total number of operational cycles is 11,000 for the check valve and
50,000 for the shut-off valve. The valve unit are installed in a test fixture
corresponding to the manufacturer’s specifications for installation. The
operation of the unit is continuously repeated using hydrogen gas at all
specified pressures.
An operational cycle shall be defined as follows:
(i)
(ii)
A check valve is connected to a test fixture and 100% NWP (+2/-0MPa)
is applied in six step pulses to the check valve inlet with the outlet
closed. The pressure is then vented from the check valve inlet. The
pressure is lowered on the check valve outlet side to less than 60%
NWP prior to the next cycle;
A shut-off valve is connected to a test fixture and pressure is applied
continuously to the both the inlet and outlet sides.
An operational cycle consists of one full operation and reset.

---

6.2.6.2.5. Vehicle Environment Test
Resistance to degradation by exposure to automotive fluids is determined by the
following test.
(a)
The inlet and outlet connections of the valve unit are connected or capped in
accordance with the manufacturers installation instructions. The external
surfaces of the valve unit are exposed for 24h at 20 (±5)°C to each of the
following fluids:
(i) Sulphuric acid –19% solution by volume in water;
(ii) Sodium hydroxide – 25% solution by weight in water;
(iii) Ammonium nitrate – 28% by weight in water; and
(iv)
Windshield washer fluid (50% by volume methyl alcohol and water).
The fluids are replenished as needed to ensure complete exposure for the
duration of the test. A distinct test is performed with each of the fluids. One
component may be used for exposure to all of the fluids in sequence.
(b)
(c)
After exposure to each chemical, the component is wiped off and rinsed with
water;
The component shall not show signs of physical degradation that could impair
the function of the component, specifically: cracking, softening, or swelling.
Cosmetic changes such as pitting or staining are not failures. At the conclusion
of all exposures, the unit(s) shall comply with the requirements of the ambient
temperature leakage test (Paragraph 6.2.6.2.2.) and hydrostatic strength test
(Paragraph 6.2.6.2.1.).

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6.2.6.2.8. Vibration Test
The valve unit is pressurised to its 100% NWP (+2/-0MPa) with hydrogen, sealed at
both ends, and vibrated for 30min along each of the three orthogonal axes (vertical,
lateral and longitudinal) at the most severe resonant frequencies. The most severe
resonant frequencies are determined by acceleration of 1.5g with a sweep time of
10min within a sinusoidal frequency range of 10 to 40Hz. If the resonance frequency
is not found in this range the test is conducted at 40Hz. Following this test, each
sample shall not show visible exterior damage that indicates that the performance of
the part is compromised. At the completion of the test, the unit shall comply with the
requirements of the ambient temperature leak test specified in Paragraph 6.2.6.2.2.
6.2.6.2.9. Stress Corrosion Cracking Test
For the valve units containing components made of a copper-based alloy (e.g. brass),
one valve unit is tested. The valve unit is disassembled, all copper based alloy
components are degreased and then the valve unit is reassembled before it is
continuously exposed for ten days to a moist ammonia-air mixture maintained in a
glass chamber having a glass cover.
Aqueous ammonia having a specific gravity of 0.94 is maintained at the bottom of the
glass chamber below the sample at a concentration of at least 20ml per litre of
chamber volume. The sample is positioned 35 (±5)mm above the aqueous ammonia
solution and supported in an inert tray. The moist ammonia-air mixture is maintained
at atmospheric pressure at 35 (±5)ºC. Copper-based alloy components shall not
exhibit cracking or delaminating due to this test.
6.2.6.2.10. Pre-cooled Hydrogen Exposure Test
The valve unit is subjected to pre-cooled hydrogen gas at -40 ºC or lower at a flow
rate of 30g/s at external temperature of 20 (±5) ºC for a minimum of three minutes.
The unit is de-pressurised and re-pressurised after a two minute hold period. This test
is repeated ten times. This test procedure is then repeated for an additional ten
cycles, except that the hold period is increased to 15mins. The unit shall then comply
with the requirements of the ambient temperature leak test specified in
Paragraph 6.2.6.2.2.

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6.3.1.2.2.
6.3.1.2.2.1.
Measurement Method Using the Vehicle’s Own REESS as DC Voltage Source
Test Vehiclee Conditionss
The high voltage-bus is energised by the vehicle’s own REESS and/ /or energy
conversion system and the voltage level of the REESS and/or energy conversion
system throughout the test shall be at least the nominal operating voltage as
specified by
the vehicle manufacturer.
6.3.1.2.2.2.
Measurement Instrument
The voltmeter used in this test shall measuree DC valuess and has an internal
resistance of at least 10MΩ.
6.3.1.2.2.3.
6.3.1.2.2.3.1.
Measurement Method
First Step
The voltage
is measured as shown
in Figure 9 and the high voltage Bus voltage
(Vb) is recorded. Vb shall be equal to or greater than the nominal operating
voltage of the REESSS and/or energy conversion systemm as specified by the
vehicle manufacturer.
Figure
8
Measurement of
Vb, V1, V2

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If V2 is greater than V1, , a standard known resistance (Ro) iss inserted between the
positive side of the highh voltage bus and the electrical chassis. With Ro
installed,
the voltage
(V2’) between the positive side of o the high voltage bus
and the
electrical chassis is measured (see Figure 10). The electrical isolation (Ri) is
calculated according to the formula shown below. This electrical isolation value (in
ohms) is divided by the nominal operating voltage of thee high voltage bus (in
volts). The electrical isolation (Ri) is calculated according a to the following
formula:
Ri = Ro × (Vb/V2’ - Vb/V2) or Ri = Ro R × Vb × (1/V2’ - 1/V2)
The resulting Ri, which is the electrical isolationn resistance value (in Ω), , is divided
by the working voltage of the high voltage bus inn volts (V).
Ri Ω/V = Ri Ω/Workingg voltage
Figure 10
Measurement off V2
6.3.1.2.2.3.5.
Fifth Step
The electrical isolation value Ri (in
ohms) divided by the working voltage of the
high voltage
bus (in volts) results in the isolation resistance (in ohms/V).
Note 1: The standardd known resistance Roo (in ohms) is the value of the
minimum required isolation resistance (in ohms/V) multiplied by the
working voltage of the vehicle plus/ /minus 20% (in volts). Ro is not
equired to bee precisely this value since the equations are valid for any
Ro; however, a Ro value in this range should provide good resolution for
the voltage measurements).

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Table 3
Access Probes for the Tests for Protectionn of
Persons Against Access to Hazardous Parts

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6.3.4. Test Method for Measuringg Electric Resistance
Test method using a resistance tester.
The resistancee tester is connected to the measuring points (typically, electrical
chassis and electro conductive enclosure/electrical protection barrier) ) and the
resistance is measured using a resistance tester that meets the specification that
follows;
Resistance tester: Measurement current at least 0.2A
Resolution 0.01Ω or less
The resistancee R shall be less than 0.1ohm.
Test method using DC power supply, voltmeter andd ammeter.
Example of the
test methodd using DC power supply, voltmeter and ammeter is shown
below.
Figure 12
Connection to Barrier/Enclosure
Test Proceduree
The DC power supply, voltmeter and ammeter are connected too the measuring points
(Typically, electrical chassis and electro conductive enclosure/electrical
protection
barrier).
The voltage off the DC power supply
more than 0.2A.
is adjusted so that the
current flow
becomes
The current "I" and the voltage "V" are measured.
The resistancee "R" is calculated according to the following formula:
R = V/I
The resistancee R shall be less than 0.1ohm.

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6.3.5.2. Test Procedures for the Protection of the Occupants of Vehicles Operating on
Electrical Power from High Voltage and Electrolyte Spillage
This section describes test procedures to demonstrate compliance with the
electrical safety requirements of Paragraph 5.3.2.
Before the vehicle impact test conducted, the high voltage bus voltage (Vb)
(see Figure 13) is measured and recorded to confirm that it is within the operating
voltage of the vehicle as specified by the vehicle manufacturer.
6.3.5.2.1. Test Setup and Equipment
If a high voltage disconnect function is used, measurements are taken from both
sides of the device performing the disconnect function.
However, if the high voltage disconnect is integral to the REESS or the energy
conversion system and the high-voltage bus of the REESS or the energy
conversion system is protected according to protection degree IPXXB following
the impact test, measurements may only be taken between the device performing
the disconnect function and electrical loads.
The voltmeter used in this test measures DC values and have an internal
resistance of at least 10MΩ.
6.3.5.2.2. The following instructions may be used if voltage is measured.
After the impact test, determine the high voltage bus voltages (Vb, V1, V2)
(see Figure 13).
The voltage measurement is made not earlier than 5s, but not later than 60s after
the impact.
This procedure is not applicable if the test is performed under the condition where
the electric power train is not energised.
Figure 13
Measurement of Vb, V1, V2

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7. Vehicles with a Liquefied Hydrogen Storage System (LHSSs)
7.1. LHSS Optional Requirements
As described in Paragraph 23. and 118. of the preamble, individual Contracting
Parties may elect to adopt the GTR with or without the LHSS requirements in
Paragraph 7.
Paragraph 7. is organised as follows:
Paragraph 7.2. LHSS design qualification requirements
Paragraph 7.3. LHSS fuel system integrity
Paragraph 7.4. Test procedures for LHSS design qualification
Paragraph 7.5. Test procedures for LHSS fuel system integrity
7.2. LHSS Design Qualification Requirements
This Section specifies the requirements for the integrity of a liquefied hydrogen
storage system.
The hydrogen storage system qualifies for the performance test requirements
specified in this Section. All liquefied hydrogen storage systems produced for on-road
vehicle service shall be capable of satisfying requirements of Paragraph 7.2.
The manufacturer shall specify a maximum allowable working pressure (MAWP) for
the inner container.
The test elements within these performance requirements are summarised in Table 4.
These criteria apply to qualification of storage systems for use in new vehicle
production. They do not apply to re-qualification of any single produced system for
use beyond its expected useful service or re-qualification after a potentially significant
damaging event.

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7.2.1.3. Baseline Pressure Cycle Life
When using metallic containers and/or metallic vacuum jackets, the manufacturer
shall either provide a calculation in order to demonstrate that the container is
designed according to current regional legislation or accepted standards (e.g. in US
the ASME Boiler and Pressure Vessel Code, in Europe EN 1251-1 and EN 1251-2
and in all other countries an applicable regulation for the design of metallic pressure
containers), or define and perform suitable tests (including Paragraph 7.4.1.3.) that
prove the same level of safety compared to a design supported by calculation
according to accepted standards.
For non-metallic containers and/or vacuum jackets, in addition to Paragraph 7.4.1.3.
testing, suitable tests shall be designed by the manufacturer to prove the same level
of safety compared to a metallic container.
7.2.2. Verification for Expected On-road Performance
7.2.2.1. Boil-off
7.2.2.2. Leak
The boil-off test is performed on a liquefied hydrogen storage system equipped with
all components as described in Paragraph G.1.(b). of the preamble (Figure 7 in
section G of the preamble). The test is performed on a system filled with liquid
hydrogen per the test procedure in Paragraph 7.4.2.1. and shall demonstrate that the
boil-off system limits the pressure in the inner storage container to below the
maximum allowable working pressure.
After the boil-off test in Paragraph 7.2.2.1., the system is kept at boil-off pressure and
the total discharge rate due to leakage shall be measured per the test procedure in
Paragraph 7.4.2.2. The maximum allowable discharge from the hydrogen storage
system is R × 150Nml/min where R = (Vwidth+1) × (Vheight+0.5) × (Vlength+1)/30.4
and Vwidth, Vheight, Vlength are the vehicle width, height, length (m), respectively.
7.2.2.3. Vacuum Loss
The vacuum loss test is performed on a liquefied hydrogen storage system equipped
with all components as described in Paragraph G.1.(b). of the preamble (Figure 7 of
the preamble). The test is performed on a system filled with liquid hydrogen per the
test procedure in Paragraph 7.4.2.3. and shall demonstrate that both primary and
secondary pressure relief devices limit the pressure to the values specified in
Paragraph 7.4.2.3. in case vacuum pressure is lost.

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(e)
(f)
(g)
(h)
Resistance to dry-heat test (Paragraph 7.4.4.6. test procedure);
Ozone ageing test (Paragraph 7.4.4.7. test procedure);
Temperature cycle test (Paragraph 7.4.4.8. test procedure);
Flex line cycle test (Paragraph 7.4.4.9. test procedure).
7.2.5. Labelling
A label shall be permanently affixed on each container with at least the following
information: Name of the Manufacturer, Serial Number, Date of Manufacture, MAWP,
Type of Fuel. Any label affixed to the container in compliance with this section shall
remain in place. Contracting parties may specify additional labelling requirements.
7.3. LHSS Fuel System Integrity
This section specifies requirements for the integrity of the hydrogen fuel delivery
system, which includes the liquefied hydrogen storage system, piping, joints, and
components in which hydrogen is present. These requirements are in addition to
requirements specified in Paragraph 5.2., all of which apply to vehicles with liquefied
hydrogen storage systems with the exception of Paragraph 5.2.1.1. The fuelling
receptacle label shall designate liquid hydrogen as the fuel type. Test procedures are
given in Paragraph 7.5.
7.3.1. Flammable materials used in the vehicle shall be protected from liquefied air that may
condense on elements of the fuel system.
7.3.2. The insulation of the components shall prevent liquefaction of the air in contact with
the outer surfaces, unless a system is provided for collecting and vaporizing the
liquefied air. The materials of the components nearby shall be compatible with an
atmosphere enriched with oxygen.

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7.4.1.2. Baseline Initial Burst Pressure
The test is conducted according to the following procedure:
(a)
(b)
(c)
(d)
(e)
The test is conducted on the inner container at ambient temperature;
The test is conducted hydraulically with water or a water/glycol mixture;
The pressure is increased at a constant rate, not exceeding 0.5MPa/min until
burst or leakage of the container occurs;
When MAWP is reached there is a wait period of at least ten minutes at
constant pressure, during which time the deformation of the container can be
checked;
The pressure is recorded or written during the entire test.
For steel inner containers, the test is passed successfully if at least one of the two
passing criteria described in Paragraph 5.2.1.2. is fulfilled. For inner containers made
out of an aluminium alloy or other material, a passing criterion shall be defined which
guarantees at least the same level of safety compared to steel inner containers.
7.4.1.3. Baseline Pressure Cycle Life
Containers and/or vacuum jackets are pressure cycled with a number of cycles at
least three times the number of possible full pressure cycles (from the lowest to
highest operating pressure) for an expected on-road performance. The number of
pressure cycles is defined by the manufacturer under consideration of operating
pressure range, size of the storage and, respectively, maximum number of refuellings
and maximum number of pressure cycles under extreme usage and storage
conditions. Pressure cycling is conducted between atmospheric pressure and MAWP
at liquid nitrogen temperatures, e.g. by filling the container with liquid nitrogen to
certain level and alternately pressurising and depressurising it with (pre-cooled)
gaseous nitrogen or helium.

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The pressure of the inner container and the vacuum jacket is recorded or written
during the entire test. The opening pressure of the first safety device is recorded or
written. The first part of test is passed if the following requirements are fulfilled:
(a)
(b)
(c)
The first pressure relief device opens below or at MAWP and limit the pressure
to not more than 110% of the MAWP;
The first pressure relief device does not open at pressure above MAWP;
The secondary pressure relief device does not open during the entire test.
After passing the first part, the test shall be repeated subsequently to regeneration of
the vacuum and cool-down of the container as described above.
(a)
(b)
(c)
(d)
(e)
The vacuum is re-generated to a value specified by the manufacturer. The
vacuum shall be maintained at least 24h. The vacuum pump may stay
connected until the time directly before the start of the vacuum loss;
The second part of the vacuum loss test is conducted with a completely
cooled-down container (according to the procedure in Paragraph 7.4.2.1.);
The container is filled to the specified maximum filling level;
The line downstream the first safety relief device is blocked and the vacuum
enclosure is flooded with air at an even rate to atmospheric pressure;
The test is terminated when the second pressure relief device does not open
any more.
The pressure of the inner container and the vacuum jacket is recorded or written
during the entire test. For steel containers the second part of the test is passed if the
second pressure relief device does not open below 110% of the set pressure of the
first safety relief device and limits the pressure in the container to a maximum 136%
of the MAWP if a safety valve is used, or, 150% of the MAWP if a burst disk is used
as the second safety relief device. For other container materials, an equivalent level
of safety shall be demonstrated.
7.4.3. Verification Test for Service-terminating Performance Due to Fire
The tested liquefied hydrogen storage system shall be representative of the design
and the manufacturing of the type to be homologated. Its manufacturing shall be
completely finished and it shall be mounted with all its equipment.
The first part of the test is conducted according to the following procedure:
(a) The bonfire test is conducted with a completely cooled-down container (according
to the procedure in Paragraph 7.4.2.1.);
(b)
(c)
The container contained during the previous 24h a volume of liquid hydrogen at
least equal to half of the water volume of the inner container;
The container is filled with liquid hydrogen so that the quantity of liquid
hydrogen measured by the mass measurement system is half of the maximum
allowed quantity that may be contained in the inner container;

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7.4.4.1. Pressure Test
A hydrogen containing component shall withstand without any visible evidence of leak
or deformation a test pressure of 150% MAWP with the outlets of the high pressure
part plugged. The pressure shall subsequently be increased from 150% to 300%
MAWP. The component shall not show any visible evidence of rupture or cracks.
The pressure supply system shall be equipped with a positive shut-off valve and a
pressure gauge having a pressure range of not less than 150% and no more than
200% of the test pressure; the accuracy of the gauge shall be 1% of the pressure
range.
For components requiring a leakage test, this test shall be performed prior to the
pressure test.
7.4.4.2. External Leakage Test
A component shall be free from leakage through stem or body seals or other joints,
and shall not show evidence of porosity in casting when tested as described in
Paragraph 7.4.4.3.3. at any gas pressure between zero and its MAWP.
The test shall be performed on the same equipment at the following conditions:
(a)
(b)
(c)
At ambient temperature;
At the minimum operating temperature or at liquid nitrogen temperature after
sufficient conditioning time at this temperature to ensure thermal stability;
At the maximum operating temperature after sufficient conditioning time at this
temperature to ensure thermal stability.
During this test, the equipment under test shall be connected to a source of gas
pressure. A positive shut-off valve and a pressure gauge having a pressure range of
not less than 150% and not more than 200% of the test pressure shall be installed in
the pressure supply piping; the accuracy of the gauge shall be 1% of the pressure
range. The pressure gauge shall be installed between the positive shut-off valve and
the sample under test.
Throughout the test, the sample shall be tested for leakage, with a surface active
agent without formation of bubbles or measured with a leakage rate less than
216Nml/hour.
7.4.4.3. Endurance Test
7.4.4.3.1. A component shall be capable of conforming to the applicable leakage test
requirements of Paragraph 7.4.4.2. and 7.4.4.9., after being subjected to
20,000 operation cycles.
7.4.4.3.2. The appropriate tests for external leakage and seat leakage, as described in
Paragraph 7.4.4.2. and 7.4.4.9. shall be carried out immediately following the
endurance test.

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7.4.4.7. Ozone Ageing Test
The test shall be in compliance with ISO 1431-1. The test piece, which shall be
stressed to 20% elongation, shall be exposed to air at +40°C with an ozone
concentration of 50 parts per hundred million during 120h.
No cracking of the test piece is allowed.
7.4.4.8. Temperature Cycle Test
A non-metallic part containing hydrogen shall comply with the leakage tests referred
to in Paragraph 7.4.4.2. and 7.4.4.9. after having been submitted to a 96h
temperature cycle from the minimum operating temperature up to the maximum
operating temperature with a cycle time of 120mins, under MAWP.
7.4.4.9. Flex Line Cycle Test
Any flexible fuel line shall be capable of conforming to the applicable leakage test
requirements referred to in Paragraph 7.4.4.2., after being subjected to
6,000 pressure cycles.
The pressure shall change from atmospheric pressure to the MAWP of the container
within less than five seconds, and after a time of at least five seconds, shall decrease
to atmospheric pressure within less than five seconds.
The appropriate test for external leakage, as referred to in Paragraph 7.4.4.2., shall
be carried out immediately following the endurance test.
7.5. Test Procedures for LHSS Fuel System Integrity
7.5.1. Post-crash Leak Test for the Liquefied Hydrogen Storage Systems
Prior to the vehicle crash test, the following steps are taken to prepare the liquefied
hydrogen storage system (LHSS):
(a)
If the vehicle does not already have the following capabilities as part of the
standard vehicle, and tests in Paragraph 6.1.1. are to be performed; the
following shall be installed before the test:
(i)
(ii)
(iii)
LHSS pressure sensor. The pressure sensor shall have a full scale of
reading of at least 150% of MAWP, an accuracy of at least 1% of full
scale, and capable of reading values of at least 10kPa;
LHSS temperature sensor. The temperature sensor shall be capable of
measuring cryogenic temperatures expected before crash. The sensor is
located on an outlet, as near as possible to the container;
Fill and drain ports. The ability to add and remove both liquefied and
gaseous contents of the LHSS before and after the crash test shall be
provided.

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Prior to the test the manufacturer shall provide a list of all possible leaking parts of the
LHSS. Possible leaking parts are:
(a)
(b)
(c)
(d)
(e)
Any connectors between pipes and between pipes and the container;
Any welding of pipes and components downstream the container;
Valves;
Flexible lines;
Sensors.
Prior to the leak test overpressure in the LHSS should be released to atmospheric
pressure and afterwards the LHSS should be pressurised with helium to at least the
operating pressure but well below the normal pressure control setting (so the
pressure regulators do not activate during the test period). The test is passed if the
total leakage amount (i.e. the sum of all detected leakage points) is less than
216Nml/hr.
7.5.1.2. Alternative post-crash tests for the liquefied hydrogen storage systems. Both tests of
Paragraph 7.5.1.2.1. and 7.5.1.2.2. are conducted under the test procedure of
Paragraph 7.5.1.2.
7.5.1.2.1. Alternative Post-crash Leak Test
Following confirmation that the pressure control and/or safety relief valves are still
functional, the following test may be conducted to measure the post-crash leakage.
The concentration test in Paragraph 6.1.1.1. shall be conducted in parallel for the
60min test period if the hydrogen concentration has not already been directly
measured following the vehicle crash.
The container shall be vented to atmospheric pressure and the liquefied contents of
the container shall be removed and the container shall be heated up to ambient
temperature. The heat-up could be done, e.g. by purging the container sufficient
times with warm nitrogen or increasing the vacuum pressure.
If the pressure control set point is less than 90% of the MAWP, the pressure control
shall be disabled so that it does not activate and vent gas during the leak test.
The container shall then be purged with helium by either:
(a)
(b)
Flowing at least 5 volumes through the container; or
Pressurising and de-pressurising the container the LHSS at least 5 times.

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