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Transport Research Laboratory

Hydrogen-powered vehicles: review of

type-approval legislation on vehicle

safety Interim report

by C Visvikis, M Pitcher and B Hardy

CPR711

ENTR/05/17.01

CLIENT PROJECT REPORT

Transport Research Laboratory

CLIENT PROJECT REPORT CPR711

Hydrogen-powered vehicles: review of type-approval legislation on vehicle safety

Interim report

by C Visvikis, M Pitcher and B Hardy (TRL)

Prepared for: Project Record: ENTR/05/17.01

Hydrogen-powered vehicles: review of

type-approval legislation on vehicle

safety

Client: European Commission, DG Enterprise and

Industry

Peter Broertjes

Copyright Transport Research Laboratory January 2010

This report has been prepared for the European Commission. The views expressed are

those of the author(s) and not necessarily those of the European Commission.

Name Date

Approved

Project

Manager James Nelson 08/01/2010

Technical

Referee Iain Knight 08/01/2010

Client Project Report

TRL CPR711

When purchased in hard copy, this publication is printed on paper that is FSC (Forest

Stewardship Council) registered and TCF (Totally Chlorine Free) registered.


TRL v CPR711

Contents

Executive summary vii

1 Introduction 1

1.1 Background on hydrogen-powered vehicles 1

1.2 Overview of the legislation for hydrogen-powered vehicles 2 1.2.1 EC type-approval 2 1.2.2 UNECE regulations 2

2 Review of type-approval directives and regulations on vehicle safety 5

2.1 Fuel tanks and rear under-run protection: Directive 70/221/EEC and

UNECE Regulation 34 5 2.1.1 Overview 5 2.1.2 Compatibility with hydrogen-powered vehicles and safety

risks 7 2.1.3 Proposals for amendments 7

2.2 Radio interference (electromagnetic compatibility): Directive

72/245/EEC and UNECE Regulation 10 7 2.2.1 Overview 7 2.2.2 Compatibility with hydrogen-powered vehicles and safety


2.3 Identification of controls, tell-tales and indicators: Directive

78/316/EEC and UNECE Regulation 121 12 2.3.1 Overview 12 2.3.2 Compatibility with hydrogen-powered vehicles and safety


2.4 Frontal impact: Directive 96/79/EC and UNECE Regulation 94 / Side

impact: Directive 96/27/EC and UNECE Regulation 95 14 2.4.1 Overview 14 2.4.2 Compatibility with hydrogen-powered vehicles and safety


2.5 Buses and coaches: Directive 2001/85/EC and UNECE Regulations 66

and 107 17 2.5.1 Overview 17 2.5.2 Compatibility with hydrogen-powered vehicles and safety


3 The use of mixtures of natural gas and hydrogen to power vehicles 21

3.1 The present situation 21

3.2 State-of-the-art 21

3.3 Review of the hydrogen regulation and implementing measures 22

3.4 Proposals for amendments 22

4 Regulating the type-approval of L category vehicles 25

4.1 The present situation 25


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4.2 The state-of-the-art 27

4.3 Review of the hydrogen regulation and implementing measures 27

4.4 Proposals for amendments 29

5 Conclusions 31

Acknowledgements 33

References 33

Appendix A Review of Regulation (EC) No. 79/2009 Annex IV

(Installation of hydrogen components and systems) 35


TRL vii CPR711

Executive summary

Directive 2007/46/EC establishes a framework for the approval of motor vehicles, and of

systems and components intended for such vehicles. Until recently, there were no

specific provisions for hydrogen-powered vehicles within the framework directive.

However, on 4th February 2009, Regulation (EC) No. 79/2009 on the type-approval of

hydrogen-powered vehicles was published in the Official Journal of the European

Communities. The hydrogen regulation amends certain annexes of Directive 2007/46/EC

with the aim of specifying harmonised safety requirements for hydrogen-powered

vehicles.

The hydrogen regulation contains general requirements for the type-approval of

hydrogen systems and components. These are fundamental provisions laid down by the

European Parliament and the Council and adopted through the co-decision procedure.

Detailed test procedures and technical specifications that implement the fundamental

provisions will be laid down in a separate regulation adopted by the European

Commission with the assistance of a regulatory committee. The Commission has

developed a draft regulation (known as the “implementing measures”) with the

assistance of the Hydrogen Working Group. The working group is made up of

representatives of EU Member States, the automotive industry, component

manufacturers and hydrogen associations.

The hydrogen regulation and corresponding implementing measures will set out type-

approval requirements in relation to the safety of hydrogen storage on board the vehicle

(and any components in contact with hydrogen). However, in order to accommodate

fully hydrogen-powered vehicles in the type-approval framework, it will be necessary to

review and possibly amend a number of other separate directives and regulations on

other aspects of vehicle construction.

The Commission awarded a project to TRL to review the type-approval legislation on

vehicle safety for hydrogen-powered vehicles. The objectives of the project are:

To provide technical input to the evaluation of separate type-approval directives

and regulations on vehicle safety with a view to their possible amendment to

accommodate hydrogen-powered vehicles;

To provide technical input to the development of new type-approval requirements

and the evaluation of the issues identified in the hydrogen regulation (EC No.

79/2009).

The review of type-approval directives and regulations on vehicle safety is focussing on

M and N category vehicles. The Commission highlighted six safety directives that may

need to be amended. This interim report presents an initial review of each directive (and

the corresponding UNECE regulation). The main focus was on their compatibility with

hydrogen-powered vehicles, and any safety risks that might result from incompatible

test methods or requirements. Other regulations and standards relating to the topic of

each directive were also reviewed. The aim was to identify examples of the way that

hydrogen-vehicles had been dealt with elsewhere. Finally, the scientific literature was

examined to find robust technical data to support recommendations for amending each

directive.

Two issues are identified in the hydrogen regulation: Firstly, the use of mixtures of

natural gas and hydrogen as a fuel in internal combustion engines, and secondly, the

regulation of hydrogen-powered L category vehicles (i.e. light two, three or four wheel

vehicles). The study is considering whether legislative action on these issues is timely

and what form it might take.

This interim report summarises the work carried out so far and the initial findings. The

remaining work will focus on completing any outstanding analyses. In addition, TRL will

meet a limited number of stakeholders on an individual basis, before presenting the

findings of this interim report at a stakeholder workshop. As mentioned above, the


TRL viii CPR711

intention will be to gain feedback on the proposals and to identify any further topics that

may need to be included.

The review of type-approval directives and regulations on vehicle safety has covered:

fuel tanks, radio interference, identification of controls, frontal impact, side impact and

buses and coaches. This has revealed that:

Hydrogen-powered vehicles should be exempt from fuel tank requirements

because the risks are dealt with by the hydrogen regulation and (draft)

implementing measures.

The radio interference legislation includes performance requirements, but

references international standards for the test methods. Some of the

standards have procedures to deal with electric vehicles (which could be

applied to hydrogen fuel cell vehicles). However, some potential issues were

raised, such as the vehicle load conditions and antenna positions.

Amendments to the frontal and side impact legislation are needed to

accommodate hydrogen-powered vehicles. The amendments will need to

cover:

i. The test procedure including the fuelling conditions for the impact test.

ii. The post-crash requirements including hydrogen leakage limits.

There are no symbols in the legislation that must be used with controls, tell-

tales and indicators for the hydrogen system in a hydrogen-powered vehicle.

Furthermore, no symbols are available in the main international standard.

New symbols will be needed for hydrogen-powered vehicles. However, the

current optical indicator and tell-tale colour meanings set out in the legislation

and the standard are appropriate.

The bus and coach requirements are largely independent of the power train.

However, additional provisions may be needed for the stability and strength of

superstructure tests and for the electrical safety of the driver and passengers.

Internal combustion engines that run on natural gas produce fewer harmful emissions

than petrol engines, but they are less efficient. Adding hydrogen to produce a blended

fuel can increase the efficiency compared with natural gas alone. Further work will be

carried out in this project with a view to providing the Commission with

recommendations on the technical amendments needed to accommodate mixtures of

natural gas and hydrogen in the type-approval legislation. There are several important

issues that need to be resolved. For instance, it is necessary to determine what mixing

ratio is likely to be used. Various different ratios have been examined in the literature. It

might be the case that a standard ratio is used in the future, or that vehicles will be

capable of running on different ratios (within certain limits). The effect of the mixing

ratio on engine performance and emissions needs to taken into account and the safety

implications of each ratio need to be understood. The project will focus on these areas.

Two, three and some four wheel vehicles are not included in the framework directive for

M and N category vehicles (Directive 2007/46/EC). Instead, these are termed L category

vehicles and a different framework directive applies: Directive 2002/24/EC. Currently,

there are no specific provisions for hydrogen-powered L category vehicles in Directive

2002/24/EC or in the separate technical directives. A manufacturer who wishes to place

such a vehicle on the market may face difficulties, therefore, with the present situation.

L category vehicles might be early adopters of hydrogen as a fuel, but it will be essential

to identify any safety risks and to consider how these risks should be mitigated. The

main concern is the safety of hydrogen storage on-board the vehicle (and any

components in contact with hydrogen). Regulation (EC) No. 79/2009 (the hydrogen

regulation) and the draft implementing measures mitigate these concerns for M and N

category vehicles. While it would be inappropriate to include L category vehicles in the


TRL ix CPR711

hydrogen regulation and implementing measures (because they are part of a separate

legislative framework), they might form the basis for new type-approval requirements

for L category vehicles. These issues and their implications will be examined further in

the remainder of the project.


TRL 1 CPR711

1 Introduction

The European Commission (EC) has awarded a project to TRL to review the type-

approval legislation on vehicle safety for hydrogen-powered vehicles. The specific

objectives of the project are:

To provide technical input to the evaluation of separate type-approval directives

and regulations on vehicle safety with a view to their possible amendment to

accommodate hydrogen-powered vehicles;

To provide technical input to the development of new type-approval requirements

and the evaluation of the issues identified in the hydrogen regulation (EC No.

79/2009).

The review of type-approval directives and regulations on vehicle safety is focussing on

M and N category vehicles. The study will consider whether the requirements are

compatible with hydrogen-powered vehicles and the potential safety risks of any

incompatible legislation.

Two issues are identified in the hydrogen regulation: Firstly, the use of mixtures of

natural gas and hydrogen as a fuel in internal combustion engines, and secondly, the

regulation of hydrogen-powered L category vehicles (i.e. light two, three or four wheel

vehicles). The study will consider whether legislative action on these issues is timely and

what form it might take.

This interim report summarises the work carried out so far and the initial findings. The

report has been prepared for the EC, but with the understanding that it will be circulated

among stakeholders. Initial recommendations have been made for amendments that

may be needed to the type-approval legislation on vehicle safety. TRL anticipates that

these initial proposals will generate a great deal of feedback from stakeholders. This is

very much welcome and will be taken into account in the remainder of the research.

The remaining work will focus on completing any outstanding analyses. In addition, TRL

will meet a limited number of stakeholders on an individual basis, before presenting the

findings of this interim report at a stakeholder workshop. As mentioned above, the

intention will be to gain feedback on the proposals and to identify any further topics that

may need to be included.

1.1 Background on hydrogen-powered vehicles

Hydrogen-powered vehicles can be based around an internal combustion engine or a fuel

cell. Hydrogen internal combustion engine vehicles tend to have a limited range and

reduced luggage space compared with conventional vehicles. However, there is

extensive knowledge in engine design and performance and the fundamental technology

is available today. Some internal combustion engines can run on hydrogen as well as on

conventional fuels, or various blends can be used. They are often considered, therefore,

a bridging technology towards the more widespread use of hydrogen. Burning hydrogen

in combustion engines produces nitrous oxides, but these can be up to 90% lower than

petrol engines because the engine can operate in the so-called “lean-burn” mode with an

excess of air (International Energy Agency, 2005). Such engines can achieve an overall

efficiency of 38%, which is 20-25% better than a typical petrol engine (Ahluwalia et al.,

2004).

Hydrogen fuel cell vehicles have an electrical powertrain. Hydrogen (or a hydrogen-rich

fuel) is chemically converted into water, electricity and heat. The process is highly

efficient and there are no harmful emissions at the point of use. Fuel cells are often seen

as a longer term stage in the development of road vehicles. Nevertheless, a number of

major manufacturers have fuel cell cars at the prototype technology demonstration

stage.


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The storage of hydrogen on-board the vehicle represents a technical challenge. In order

to achieve a reasonable energy density it is currently stored as a compressed gas or as a

liquid at very low temperature. Research is also being carried out into solid-state

storage, using absorbers such as hydrides.

1.2 Overview of the legislation for hydrogen-powered vehicles

1.2.1 EC type-approval

European Commission (EC) Whole Vehicle Type-Approval is based around EC directives

and provides for the approval of whole vehicles, in addition to systems and components.

A framework directive lists a number of separate technical directives that the vehicle

must comply with in order to gain type-approval. The framework directive also lists

United Nations Economic Commission for Europe (UNECE) regulations that are

considered to be acceptable alternatives to certain EC directives. The scheme was

introduced in the 1970s through Directive 70/156/EEC and it became mandatory for M1

category vehicles (i.e. passenger cars) in 1998. A recast new framework directive,

2007/46/EC, has since been published and extends the scheme to larger passenger (M2

and M3 category) and goods vehicles (N category).

Until recently, there were no specific provisions for hydrogen-powered vehicles within

the framework directive. This meant that manufacturers were unable to gain type-

approval for their vehicles and may have faced difficulties with the national schemes of

individual member states. However, on 4th February 2009, Regulation (EC) No. 79/2009

on the type-approval of hydrogen-powered vehicles was published. The regulation

amends certain annexes of Directive 2007/46/EC with the aim of establishing

harmonised safety requirements for hydrogen-powered vehicles.

Regulation (EC) No. 79/2009 contains general requirements for the type-approval of

hydrogen systems and components. These are fundamental provisions laid down by the

European Parliament and the Council. Detailed test procedures and technical

specifications that implement the fundamental provisions will be laid down in a separate

regulation adopted by the Commission with the assistance of a regulatory committee.

The Commission has developed a draft regulation (known as the “implementing

measures”) with the assistance of the Hydrogen Working Group. The working group is

made up of representatives of EU Member States, the automotive industry, component

manufacturers and hydrogen associations.

The hydrogen regulation and corresponding implementing measures will set out type-

approval requirements in relation to the safety of hydrogen storage on board the vehicle

(and any components in contact with hydrogen). However, in order to accommodate

fully hydrogen-powered vehicles in the type-approval framework, it will be necessary to

review and possibly amend a number of other separate directives and regulations on

other aspects of vehicle construction.

In 2014, around 50 base directives covering vehicle safety issues will be repealed. Their

requirements will be carried over to Regulation (EC) No. 661/2009 (on the general safety

of motor vehicles) and replaced, where appropriate, with reference to the corresponding

UNECE regulations. This is intended to simplify type-approval legislation in line with the

recommendations contained in the final report of the CARS 21 High Level Group

(European Commission, 2006).

1.2.2 UNECE regulations

UNECE regulations provide for the approval of vehicle systems and separate

components, but not whole vehicles. Many duplicate EC directives, although the EC

directive often lags behind the UNECE regulation. There are no UNECE regulations for

hydrogen systems and components. However, a global technical regulation on hydrogen-


TRL 3 CPR711

powered vehicles is being developed under the auspices of the UNECE. It is being

administered by the World Forum for Harmonisation of Vehicle Regulations (WP 29),

which is a subsidiary body of the UNECE. This has been possible through the 1998 Global

Agreement, which seeks to promote international harmonisation through the

development of global technical regulations. The 1998 Agreement is open to countries

that are not signatories to the 1958 Agreement and hence do not recognise UNECE

regulations. The global technical regulation for hydrogen-powered vehicles specifies both

their safety and their environmental performance. Two subgroups have been formed to

assist in the development of the regulation. A subgroup on safety reports to the Working

Party on Passive Safety (GRSP) and a subgroup on environmental aspects reports to the

Working Party on Pollution and Energy (GRPE).

An informal working group on electric safety (ELSA) has been set up under GRSP to

revise UNECE Regulation 100 (battery electric vehicles). One of the main objectives of

the ELSA is to extend the scope and requirements to all kinds of power train types above

a certain working voltage level. This would include hydrogen-powered fuel cell vehicles.

In addition, a group of interested experts on electric vehicles post-crash provisions

(EVPC) are preparing amendments to UNECE Regulations 94 (frontal impact) and 95

(side impact). Once again, the aim is to extend the scope to all power trains above a

certain voltage.


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2 Review of type-approval directives and regulations

on vehicle safety

The EC highlighted six safety directives that may need to be amended. The following

sections present an initial review of each directive and the corresponding UNECE

regulation, although it is understood that each of the directives will be repealed in 2014

when Regulation (EC) No. 661/2009 (on the general safety of motor vehicles) takes

effect.

For each directive/regulation, the main focus was on their compatibility with hydrogen-

powered vehicles, and any safety risks that might result from incompatible test methods

or requirements. Other regulations and standards relating to the topic of each directive

were also reviewed. The aim was to identify examples of the way that hydrogen-vehicles

had been dealt with elsewhere. Finally, the scientific literature was examined to find

robust technical data to support recommendations for amending the legislation.

2.1 Fuel tanks and rear under-run protection: Directive 70/221/EEC and UNECE Regulation 34

2.1.1 Overview

Directive 70/221/EEC (as amended) comprises two separate parts. The first part relates

to liquid fuel tanks (where the fuel is liquid at ambient temperature conditions). It

outlines a number of general design and installation requirements and assesses the

performance of the tank in a series of tests. For instance, the directive states that the

design of the tank must be such that excess pressure can be compensated for

automatically, by a relief valves (or otherwise). The tank‟s ability to achieve this is

validated by a hydraulic pressure test. Other design requirements include ensuring the

tank and filler system are completely separate from the occupant, luggage and engine

compartments and that fuel leakage is keep to a minimum, including when the vehicle is

inverted (validated by an overturning test). Finally, the installation of the tank in the

vehicle should provide protection against damage caused by a front or rear impact to the

vehicle as well as minimising the risk of fire and avoiding the build up of static electricity.

The types of tests that are carried out depend on the construction of the fuel tank. Metal

fuel tanks are subjected to the following tests:

Hydraulic internal pressure test

The pressure inside a tank, completely filled with a non-flammable liquid (e.g.

water), is increased to double the working pressure (at least 0.3 bar) and maintained

for 1 minute. The tank must not crack or leak during the test, however it may

permanently deform.

Overturning test

Tests are conducted with a tank 90% full and also 30% full of non-flammable liquid

(e.g. water). The tank is rotated 90° in both directions, each time being held for 5

minutes. The tank is then completely inverted and again held for 5 minutes. The fuel

leakage must not exceed 30 g/min during the test.

There are also a series of additional tests that are conducted on fuel tanks made out of

plastic:

Fuel permeability

The tank is filled with fuel to 50% of its capacity and stored at 40°C for eight weeks.

The average loss of fuel must not be more than 20 g per 24 hours of testing time.


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Resistance to fuel

After the fuel permeability test, the tank must still be capable of passing the impact

resistance and mechanical strength tests (described below).

Impact resistance

The tank (filled with a fuel substitute and kept at -40°C) is impacted by a pendulum:

the tank must not leak.

Mechanical strength

This is identical to the hydraulic internal pressure test, but the tank is filled with

water at 53°C, the tank must not crack or leak, but may permanently deform.

Resistance to fire

The tank (50% full of fuel) is heated directly and indirectly by a fire: the tank must

not leak after the test.

Resistance to high temperature

The tank (50% full of water) is stored at a temperature of 95°C for 1 hour, after

which the tank should not leak or be seriously deformed.

Markings on the fuel tank

The tank needs to have marking clearly legible when installed on the vehicle.

The second part of the directive sets requirements to provide rear under-run protection

for large vehicles. It is intended to prevent smaller vehicles from under-running them in

the event of a collision. The rear of the vehicle must provide effective protection, either

by the vehicle bodywork itself or by a specific rear bumper device.

The EC recognises UNECE Regulation 34 (as amended) as an alternative to the fuel tanks

part of Directive 70/221/EEC. The main purpose of the regulation is to prevent fire risks

by establishing design and performance requirements for liquid fuel systems. The

regulation comprises four main parts:

Part 1 Approval of vehicles with regard to their fuel tanks

This part applies to all M and N category vehicles and is practically identical to the

fuel tanks part of Directive 70/221/EEC.

Part 2 Approval of vehicles with regard to the prevention of fire risks in frontal

and/or lateral and/or rear collision

This part applies at the request of the manufacturer to all M and N category vehicles

that are approved to parts 1 and 4 of the regulation. It contains requirements for the

installation of liquid fuel tanks that cover both the fuel installation and the electrical

installation. The fuel installation requirements cover the protection of components

from obstacles on the ground and from abnormal stress brought about by twisting

and bending movements, and vibrations of the vehicle‟s structure. The components

must also remain leak-proof under the various conditions of use of the vehicle. The

electrical installation requirements are intended to protect the wiring insulation from

damage (at points where electrical wires pass through walls or partitions) and from

corrosion.

This part of the regulation also contains frontal, lateral and rear-end impact tests and

associated post-collision leakage requirements. The frontal impact test procedure

comprises a full-width test against a rigid barrier from 48.3 to 53.1 km/h. However,

the test procedure in annex 3 of UNECE Regulation 94 can be used instead. The

lateral impact test is performed according to annex 4 of Regulation 95 (i.e. there is

no test procedure in UNECE Regulation 34). Finally, the rear-end impact test

procedure involves the vehicle being struck by a rigid impacting surface from 35 to

38 km/h. This can take the form of a moving barrier or a pendulum test. In each


TRL 7 CPR711

case, no more than “a slight leakage of liquid in the fuel installation” is permitted,

and if there is a continuous leakage after the collision, it must not exceed 30 g/min.

In addition, the (auxiliary) battery must be kept in position by its securing device.

Part 3 Approval of tanks for liquid fuel as technical units

This part lists the requirements of part 1 of the regulation that must be met when

approving liquid fuel tanks as separate units.

Part 4 Approval of vehicles with regard to the installation of approved tanks

This part lists the requirements of part 1 that must be met when installing an

approved fuel tank.

2.1.2 Compatibility with hydrogen-powered vehicles and safety risks

While some of the design and installation requirements in Directive 70/221/EEC (and

UNECE Regulation 34) are relatively general and could be applied to any type of fuel

tank, it is clear that the performance tests were not designed for a fuel with the

properties of hydrogen. The directive does not consider many of the risks associated with

the use of hydrogen, nor does it take into account the properties of hydrogen in the test

methods. In fact, a number of the tests could be dangerous to persons and property if

they were attempted with a hydrogen container without proper precautions.

Other alternative fuel vehicles are dealt with by separate regulations. For instance,

Liquefied Petroleum Gas (LPG) vehicles and Compressed Natural Gas (CNG) vehicles are

not covered by Directive 70/221/EEC, but must meet the requirements of UNECE

Regulation 67 (LPG) and UNECE Regulation 110 (CNG).

Regulation (EC) No. 79/2009 and the (draft) implementing measures establish

requirements that were developed specifically for hydrogen containers. Similar

requirements are being prepared in the draft global technical regulation on hydrogen. It

appears, therefore, that while Directive 70/221/EEC (Annex 1) and UNECE Regulation 34

are inappropriate for hydrogen-powered vehicles, significant amendment is not

necessary because another regulation will apply that does adequately consider the issues

relevant to hydrogen.

2.1.3 Proposals for amendments

The framework directive, 2007/46/EC, requires a hydrogen-powered vehicle to meet the

requirements of Regulation (EC) No. 79/2009. Hydrogen-powered vehicles should

therefore be exempt from the first part (i.e. Annex 1) of Directive 70/221/EEC (or any

part of UNECE Regulation 34), because the risks are covered by the hydrogen regulation.

The second part of Directive 70/221/EEC (on under-run protection) is still appropriate for

hydrogen-powered vehicles and can be applied without amendment.

2.2 Radio interference (electromagnetic compatibility): Directive 72/245/EEC and UNECE Regulation 10

2.2.1 Overview

Directive 72/245/EEC (as amended) specifies the minimum standards of electromagnetic

compatibility for whole vehicles and for electrical/electronic sub-assemblies (i.e.

components or separate technical units intended to be fitted in vehicles). It includes

requirements regarding the control of radiated emissions from the vehicle, and also the

immunity of the vehicle itself to radiated disturbances. For electrical/electronic sub-

assemblies, conducted emissions and conducted disturbances are assessed. Both

broadband and narrowband emissions and immunity are assessed; narrowband

emissions are primarily those produced by on-board electronic modules.


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Test methods are included in a series of annexes. A CISPR (Comité International Spécial

des Pertubations Radioélectriques; in English, International Special Committee on Radio

Interference) or ISO (International Organisation for Standardisation) standard is

referenced for aspects of the method or for a detailed procedure.

UNECE Regulation 10 (as amended) is equivalent to the directive, and the requirements

are almost identical. Regulation 10 covers vehicle categories L (two or three-wheel

motor vehicles), M (passenger vehicles), N (goods vehicles) and O (trailers), whereas

Directive 72/245/EEC only covers categories M, N and O (category L being covered

within Directive 97/24/EC). Approval to the UNECE regulation is a recognised alternative

to an EC type-approval granted under Directive 72/245/EEC.

Directive 72/245/EEC will be repealed on 1 November 2014 (by Regulation (EC) No.

661/2009). From that date, UNECE Regulation 10 will be the only option for obtaining

EC automotive type-approval for electromagnetic compatibility.

Radiated broadband emissions from vehicles

This test is carried out to measure the broadband emissions generated by electrical or

electronic systems fitted to the vehicle (such as the ignition system or electric motors).

The test method in Directive 72/245/EEC describes the vehicle state during the test and

the test conditions; however, it also notes that the test should be performed according

to CISPR 12:2001 (the fifth edition).

Several revisions and amendments have been made to CISPR 12 since 2001. The first

amendment was made in 2005 and a consolidated version of the standard was

published: CISPR 12:2001+A1:2005. In 2007, a sixth edition was published:

CISPR 12:2007, which has also been amended. It seems that the latest version of the

standard is: CISPR 12:2007+A1:2009. UNECE Regulation 10 uses a later version of

CISPR 12 than the directive (fifth edition, amendment 1, of 2005), but is still not using

the latest edition. Andersen (2009) reports that the sixth edition of CISPR 12 has

removed the broadband / narrowband differentiation. Updating the directive and

regulation to use the sixth edition would therefore require changes beyond just updating

the references to the CISPR document, as both the directive and regulation have

separate broadband and narrowband annexes.

The engine state is probably the most important aspect of the test method (for the

purposes of this study). If the vehicle is equipped with an internal combustion engine,

the engine is operated at 1,500 r/min for a multi-cylinder engine and 2,500 r/min for a

single cylinder engine. If it is equipped with an electric motor, the vehicle is driven on a

dynamometer without a load, or on axle stands, at a constant speed of 40 km/h (or at

maximum speed if less than 40 km/h). These test conditions are set out in

CISPR 12:2001, the version used by the directive. The 2005 amendment (the version

used by the UNECE regulation) adds specific instructions for hybrid vehicles.

Radiated narrowband emissions from vehicles

This test is carried out to measure the narrowband emissions such as those that might

emanate from microprocessor-based systems or other narrowband sources. Once again,

the test method in the directive describes the vehicle state and test conditions. Unless

otherwise stated, the test is performed according to CISPR 12:2001 or to CISPR 25:

2002 (the second edition). The narrowband emissions of a vehicle are measured with the

ignition switched on, but without the engine operating.

UNECE Regulation 10 again refers to the fifth edition, amendment 1, of 2005, of

CISPR 12, but it refers to the same version of CISPR 25 as the directive.

The latest version of CISPR 25 is the third edition, CISPR 25:2008, including

corrigendum 1. As with the sixth edition of CISPR 12, this has had the broadband /

narrowband differentiation removed. Updating the directive and regulation to use the


TRL 9 CPR711

latest editions would therefore require changes beyond just updating the references to

the CISPR documents.

Immunity of vehicles to radiated disturbances

This test is intended to assess the immunity of the vehicle‟s electronic systems. The

vehicle is subjected to electromagnetic fields and monitored during the test. The test is

performed according to ISO 11451-2:2005 (third edition), unless otherwise stated in the

directive. This appears to be the current version of the standard. ISO 11451-2 can be

applied regardless of the vehicle‟s propulsion system (e.g. spark ignition engine, diesel

engine, electric motor). References are also made to ISO 11451-1:2005 (third edition)

for aspects of the test conditions. The latest version of this is ISO 11451-1:2005/Amd

1:2008. In both cases, UNECE Regulation 10 refers to the same edition as the directive.

The vehicle is operated during the test at a steady speed of 50 km/h. The immunity

type-approval limits are probably the most important aspect of this test (for the

purposes of this study). The directive sets the field strength at 30 V/m RMS in over 90%

of the 20 to 2,000 MHz frequency band and a minimum of 25 V/m RMS over the whole

20 to 2,000 MHz frequency band. These figures represent the strength of the

electromagnetic radiation that the vehicle must be capable of withstanding. The vehicle

must demonstrate no degradation in the performance of „immunity-related functions‟.

However, TRL understands that vehicle manufacturers test with much higher field

strengths (typically 80 to 90 V/m). Testing is performed to these higher levels to satisfy

product liability concerns.

Radiated broadband emissions from electrical/electronic sub-assemblies

This test is intended to measure broadband emissions from sub-assemblies which may

be subsequently fitted to vehicles that have passed the whole vehicle test. The test is

performed according to CISPR 25:2002. As noted above, the latest version of this

standard is CISPR 25:2008. UNECE Regulation 10 uses the same edition as the directive.

Radiated narrowband emissions from electrical/electronic sub-assemblies

This test is intended to measure narrowband emissions from sub-assemblies which may

be subsequently fitted to vehicles that have passed the whole vehicle test. The test is

performed according to CISPR 25:2002 in both the directive and the regulation.

Immunity of electric/electronic sub-assemblies to radiated disturbances

This test assesses the immunity of electrical/electronic sub-assemblies. The sub-

assemblies may comply with the requirements of any combination of the following test

methods at the manufacturer‟s discretion (in both the directive and the regulation):

Absorber chamber test according to ISO 11452-2:2004;

TEM cell testing according to ISO 11452-3:2001;

Bulk current injection testing according to ISO 11452-4:2005;

Stripline testing according to ISO 11452-5:2002;

Stripline testing according to the method in the directive.

The sub-assembly is exposed to electromagnetic radiation in the 20 to 2,000 MHz

frequency range at the intervals specified in ISO 11451-1:2005.

Immunity of electrical/electronic sub-assemblies to conducted disturbances

This test is intended to assess the immunity of sub-assemblies to transient disturbances

conducted along supply lines. The directive and the regulation state that certain test


TRL 10 CPR711

pulses must be applied to the sub-assembly according to ISO 7637-2:2004. The pulses

are applied to the supply lines as well as to other connections that may be operationally

connected to the supply lines. ISO 7637-2:2004 specifies bench tests for equipment

fitted to passenger cars and light commercial vehicles equipped with a 12 V electrical

system or to commercial vehicles equipped with a 24 V electrical system. It applies to all

these vehicles irrespective of the propulsion system.

Conducted emissions from electrical/electronic sub-assemblies

This test measures the conducted transient emissions from sub-assemblies to the vehicle

power supply. For both the directive and the regulation, measurements are performed

according to ISO 7637-2:2004 on supply lines as well as on other connections that may

be operationally connected to supply lines.


The current practices for measuring electromagnetic emissions and immunity were

developed for internal combustion engines. However, hydrogen fuel cell vehicles have an

electrical power train. This differs greatly from conventional automotive electrical system

components. The power required by an electrical power train is much higher than the

power demand of the electrical system in conventional vehicles (Guttowski et al., 2003).

Power electronic systems are likely to be the main source of electromagnetic interference

within electrical power trains. In particular, high-speed switching devices could be an

important source of emissions.

Directive 72/245/EEC and UNECE Regulation 10 do not include any specific provisions for

hydrogen-powered vehicles or any vehicles with an electrical power train. However, the

directive and the regulation reference several important CISPR and ISO standards when

describing the test methods. These standards, or parts of them that are referenced,

effectively become part of the legislative test methods. At least one of these standards

(CISPR 12:2001+A1:2005) has been amended to take some account of vehicles with

electrical power trains. In this standard, broadband emission measurements for vehicles

with electrical propulsion are made using a steady-state dynamic test at a constant

speed of 40 km/h. The equivalent test for vehicles with internal combustion engines

would require the engine to be running but not propelling the vehicles.

There are relatively few published studies of the electromagnetic compatibility of

hydrogen-powered vehicles (or vehicles with electrical power trains). Nevertheless, there

is some evidence to suggest that acceleration, deceleration (regenerative braking) and

charging cycles may result in higher electromagnetic emissions (Ruddle, 2002). There

would be significant practical difficulties in making measurements under transient

conditions such as acceleration and deceleration. The current approach seems to offer

greater reliability and consistency. Nevertheless, it may be appropriate at least to

consider these options as possible enhancements of the standards.

UNECE Regulation 10 is equivalent to Directive 72/245/EEC and is practically identical.

However, a different version of CISPR 12 is referenced for the broadband emissions

tests. The directive refers to the fifth edition of the standard (CISPR 12:2001), while the

regulation refers to the fifth edition, including the 2005 amendment

(CISPR 12:2001+A1:2005). The latest version is the sixth edition including a 2009

amendment (CISPR 12:2007+A1:2009).

The directive includes testing for both the immunity of electrical and electronic systems

to transient disturbances and for their emissions. Transient disturbances fall into three

general categories: those generated by electrical and electronic systems on the vehicle,

electrostatic discharges and lightning. A vehicle with an electrical power train is

potentially a source of many transient disturbances, due to the large number of high

power components. There are already a number of electronic systems fitted to vehicles

that control safety critical applications. The transient performance of the vehicle can


TRL 11 CPR711

therefore have a significant effect on vehicle safety (Simmons and Noble, 1996). TRL is

seeking further literature on this subject.


The provisions for the electromagnetic compatibility of vehicles are effectively split

between the legislative documents (Directive 72/245/EEC and UNECE Regulation 10) and

the CISPR and ISO standards. Proposals to amend the provisions might be more

appropriately taken forward through CISPR and ISO, rather than by seeking

amendments to the legislation. Nevertheless, TRL proposes the following areas for

amendment, based on our own analysis and ideas obtained from the literature. In

particular, a number are proposals of, or ideas discussed by Ruddle (2002).

Update the directive and the regulation to refer to the latest versions of the

CISPR and ISO standards, unless there is good reason not to. This would then

make use of any recent changes to CISPR or ISO standards that have specifically

addressed issues concerning vehicles with electrical power trains.

o Rather than continually updating the legislation, the requirement could be

changed to require always the use of the latest version of the standard.

Alternatively, use of the latest version could be optional. However, either

option would carry the risk of changes effectively being made without the

approval of the legislative authorities. Also, it could generate

inconsistencies between the documents. For instance, CISPR 12, sixth

edition, has removed the broadband/narrowband differentiation; this

would require changes to the legislation with its separate broadband and

narrowband annexes, beyond merely updating the references to the CISPR

document.

Consider whether it would be worthwhile to include also testing under

acceleration and regenerative braking. While these conditions may potentially

produce broadband emissions that exceed the steady-state limits, the benefits of

testing to control such emissions may be inadequate to justify the increased costs

of testing. Also, conventional vehicles may also exceed the limits at high engine

speeds, as they are only required to meet the limits at a steady 1,500 r/min

(assuming a multi-cylinder engine); so requiring limits under acceleration for

hydrogen fuel cell vehicles only could be considered to be discriminatory.

Alternatively, conventional vehicles could also be tested under such conditions.

o Higher emissions during acceleration may be caused by the higher power

used or by the higher motor speed, rather than being a direct

consequence of the acceleration. If this is the case it would be more

sensible to use a constant vehicle speed, under load conditions that

simulated acceleration.

Such simulated acceleration would probably be a worst case, so if it

were introduced it should be possible to drop the existing steady

speed requirement.

o However, it might possibly be that varying the power during acceleration

or at the beginning or end of the acceleration phase might be a greater

problem for emissions, if the controller is a significant source.

o As for acceleration, generative braking could potentially be simulated

under constant speed conditions, in this case by powering the vehicle from

the dynamometer.

The antenna in the emissions tests is currently aligned with the centre of the

engine. This is presumably because spark-ignition engines are likely to provide

the principal source of vehicle emissions. However, the electric motor may not be

the principal source of emissions for hydrogen fuel cell vehicles. Consideration


TRL 12 CPR711

should be given to aligning on whichever component is normally the principal

source, or perhaps finding a compromise position.

2.3 Identification of controls, tell-tales and indicators: Directive 78/316/EEC and UNECE Regulation 121

2.3.1 Overview

Drivers must understand and operate a range of controls and instrumentation. There are

the main driving controls and various other buttons and switches that activate

equipment in the vehicle. There are also increasing numbers of information and warning

indicators, particularly with the introduction of active safety systems in recent years.

Directive 78/316/EEC (as amended) describes the symbols to be used for identifying

these controls, tell-tales and indicators. A number of other specifications must be met to

gain approval. These relate to the characteristics of the symbols (such as their colour

and size), or their position.

The directive applies to all M and N category vehicles. The purpose is to harmonise the

symbols used by vehicle manufacturers and hence reduce the risk of drivers being

distracted. For instance, a driver may become distracted from the driving task while

trying to find a control or understand the meaning of a tell-tale or indicator, particularly

in an unfamiliar vehicle. The following definitions are used:

A „control‟ is the hand-operated part of a device that allows the driver to bring

about a change in the state or functioning of a vehicle;

An „indicator‟ is a device which presents information on the functioning or

situation of a system (or part of a system);

A „tell-tale‟ is an optical signal which indicates that a device has been activated, is

functioning correctly or not, or has failed to function at all.

There are 23 controls, tell-tales and indicators that must be identified whenever they are

fitted. The directive includes symbols to be used (which it states are in accordance with

ISO 2575:1982, fourth edition) along with tell-tale colours where applicable. These

mandatory symbols deal with lighting and signalling, visibility and key aspects of the

maintenance, engine and fuel system of vehicles.

There are a further 11 controls, tell-tales and indicators that may be identified whenever

they are fitted, but it is not mandatory. However if they are identified, symbols that

conform to the directive must be used. The symbols for optional controls deal with rear

visibility, security, safety systems, the engine and fuel system. Controls, tell-tales and

indicators that are not listed in the directive can be identified using any other symbol,

provided there is no danger of confusion with those listed in the directive.

The most recent amendment to Directive 78/316/EEC was made in 1994. Since that

time, the Commission has acceded to UNECE Regulation 121 (as amended) on the

location and identification of hand controls, tell-tales and indicators. The regulation

applies to all M category vehicles and also to N1 category vehicles. It lists over 40

controls, tell-tales and indicators and the symbols that must be used to identify them. It

also includes a number of other specifications. These are similar to those in the directive,

but are more comprehensive. For example, the regulation contains specifications relating

to the illumination of controls, which do not appear in the directive.

Many of the symbols are identical to those in the directive, but there are additional

symbols, which typically relate to safety systems and the engine. If a control, tell-tale or

indicator is not listed in the regulation, it recommends that a symbol intended for the

same purpose in ISO 2575:2000 is used. However, a manufacturer may use its own

symbol if no suitable symbol can be found, provided that it does not cause confusion

with any symbol specified in the regulation.


TRL 13 CPR711


There are no symbols in Directive 78/316/EEC or in UNECE Regulation 121 that deal

specifically with a hydrogen system. The directive permits any other symbol to be used

when a control, tell-tale or indicator is not listed, but there can be no possibility of

confusion with a listed symbol. UNECE Regulation 121 takes a slightly different approach

to the directive and recommends that a symbol from ISO 2575:2000 is used (if

available) and that all symbols follow ISO 2575:2000 guidelines.

ISO 2575:2000 has been withdrawn; the current version is ISO 2575:2004, with

amendments 1:2005, 2:2006, 3:2008 and 4:2009. The standard (together with its

amendments) includes thirteen symbols that relate to the fuel system. Many of these are

developed from the traditional fuel symbol (i.e. a fuel pump). For example, there is a

symbol for the fuel type, which comprises the traditional fuel symbol with a label

underneath. Hydrogen is listed as one of the example fuels, but it is unclear whether it

should be written in full, or whether the letter “H” or “H2” could be used. None of the

remaining symbols mention hydrogen specifically, but they could be applied to a

hydrogen vehicle. For example, there are symbols for fuel system failure, fuel shut-off

and fuel pressure. The standard also includes symbols for electric vehicles (for example,

electric motor failure), which could be applicable to hydrogen fuel cell vehicles.

A hydrogen-powered vehicle may use a number of relatively basic controls, tell-tales and

indicators. For example, there will be a hydrogen fuel level indicator and there might

also be a power level indicator. Symbols currently in the legislation, or in the standard,

may need to be amended or new symbols may be needed. A hydrogen vehicle may also

use more complex controls tell-tales and indicators, such as those linked to a critical

safety feature. It is likely that these will be guided by the requirements of Regulation

(EC) No. 79/2009 (the hydrogen regulation) and the draft implementing measures.

Regulation (EC) No. 79/2009 requires that an automatic shut-off valve is fitted on or

within the hydrogen container. The valve must close if there is a malfunction of the

hydrogen system, if an event occurs that results in the leakage of hydrogen, or if the

vehicle is involved in a collision. Although the draft implementing measures do not refer

to a warning system to alert the driver to the activation of the valve, manufacturers may

decide to fit a tell-tale.

The draft implementing measures require that a warning system is fitted to alert the

driver to a failure of the boil-off management system (in a liquid hydrogen vehicle). No

further requirements are made; however, a corresponding symbol may be needed.

Similarly, the implementing measures also require a warning for the driver in the event

of a failure of the electronic vehicle control system.

The draft global technical regulation for hydrogen-powered vehicles must also be

considered. This requires that the driver is warned in the event of hydrogen leakage that

results in concentration levels above a certain threshold. The driver must also be warned

if there is a failure in the detection system. The details of the requirements have not

been finalised yet, but TRL understands that both scenarios will be dealt with by a single

tell-tale. It has been agreed that the colour of the light for the system working correctly

should be green. A malfunction of the detection system should display an amber/orange

light and activation of the emergency shut-off valve should be red. No symbol has been

agreed for the tell-tale at the present time.

In the absence of well-defined symbols for the controls, tell-tales and indicators of a

hydrogen system, there is a risk that each manufacturer might use different symbols in

their vehicles. This could result in a range of symbols in the marketplace, which might be

confusing for consumers. It might also pose a safety risk if, for instance, a driver doesn‟t

recognise a warning or tell-tale that relates to a safety system. There might also be a

risk to emergency services, who may need to understand quickly the meaning of certain

controls, tell-tales and indicators.


TRL 14 CPR711


Directive 78/316/EEC and UNECE Regulation 121 do not include any symbols to identify

the different controls, tell-tales and indicators that will be needed for a hydrogen-

powered vehicle. UNECE Regulation 121 recommends that symbols listed in ISO

2575:2000 are used wherever possible, but a manufacturer may design its own symbols.

There are two possible avenues for amending the type-approval legislation. Firstly, the

legislation could be amended to refer to the latest version of ISO 2575. This is currently

ISO 2575:2004 (seventh edition), including amendments 1:2005, 2:2006, 3:2008 and

4:2009. It is likely that most manufacturers (and their technical services) are already

aware of the latest version of the standard; nevertheless, this would bring the legislation

up-to-date and point all manufacturers towards the latest symbols, such as those for

electric vehicles. TRL understands that ISO 2575:2010 (eighth edition) is under

development and hence it may be worthwhile to wait for this version to be published.

TRL has been unable to determine whether ISO 2575:2010 will include any symbols for a

hydrogen system, but enquiries are being made. In the absence of legislative

requirements, or clear industry standardisation, there is a risk that different symbols will

emerge in the market. With this in mind, a second possible avenue to consider is to

amend the legislation to include the symbols that are needed for hydrogen-powered

vehicles. However, this would require a great deal of industry cooperation, particularly as

the industry standards do not appear to have been amended for hydrogen. Also,

evidence would be needed that any new symbols can be understood by the public before

they are made mandatory.

For certain symbols, such as the hydrogen fuel level, it may be possible to use symbols

already in the directive and regulation, but with modifications. For example, “Hydrogen”

or “H2” could be added somewhere within the current symbol. For other symbols, such

as those that relate to particular features of the hydrogen system, new symbols will be

needed. These symbols must be consistent with the warning requirements in the

hydrogen regulation and draft implementing measures and should also be harmonised

with the draft global technical regulation. The global requirements are still being

developed and every effort should be made to introduce a harmonised global symbol for

hydrogen detection/leakage.

2.4 Frontal impact: Directive 96/79/EC and UNECE Regulation 94 / Side impact: Directive 96/27/EC and UNECE Regulation 95

2.4.1 Overview

Directive 96/79/EC (as amended) and Directive 96/27/EC (as amended) were reviewed

together (along with their corresponding UNECE regulations) because they present

similar challenges for the type-approval of a hydrogen-powered vehicle. Both directives

(and regulations) include dummy and vehicle performance requirements, which are

assessed by means of a full-scale crash test. Directive 96/79/EC and UNECE Regulation

94 (as amended) set the minimum standard for the frontal impact performance of cars

(they apply to M1 vehicles only with a mass less than or equal to 2.5 tonnes). During the

impact test, the car is propelled into an offset, deformable barrier at 56 km/h. The car

overlaps the barrier face by 40%, with first contact with the barrier on the steering

column side. Directive 96/27/EC and UNECE Regulation 95 (as amended) control the

side impact performance of cars and light goods vehicles (they apply to all M1 and N1

vehicles where the reference point of the lowest seat is less than or equal to 700 mm

from the ground). During the test, a mobile deformable barrier is propelled into the side

of the vehicle at 50 km/h. The centre of the barrier is aligned with the reference point on

the driver‟s seat.

The fuel tank is filled with water to 90% of its capacity for both the frontal and the side

impact tests. All other vehicle systems, such as the brakes or the cooling system may be


TRL 15 CPR711

empty. However, the vehicle must reach its unladen kerb weight and hence the mass of

any liquids that are removed must be compensated for. Occupant injury protection is

assessed using instrumented crash test dummies. There are also some important vehicle

performance requirements. Most notably (for the purposes of this study), both directives

(and their corresponding regulations) permit a small leakage from the entire fuel

system, but it must not exceed 5x10-4 kg/s. If the liquid from the fuel system mixes with

liquids from other systems, and the various liquids cannot easily be separated, all the

liquids are taken into account.

In October 2010, a group of interested experts on „Electric Vehicles Post Crash (EVPC)

provisions for regulation‟ was formed. The aim of the group is to derive amendments to

update UNECE Regulations 94 and 95 so that they are appropriate for the assessment of

electric vehicles. The group is formed mainly of experts in electrical safety from the

GRSP informal working group on electrical safety and experts in crash safety from the

GRSP informal working group on frontal impact. The group is focussing on electric

vehicles only, although the proposed amendments aim to extend the scope of the

regulations to power train types above a certain working voltage level. This will include

vehicles with an “electric energy conversion system” such as hydrogen fuel cell vehicles.

Some of the amendments proposed for electric vehicles will be applicable to hydrogen

fuel cell vehicles too. However, the EVPC group is not preparing detailed proposals for

hydrogen-powered vehicles.


The hydrogen regulation and draft implementing measures provide for the safety of

hydrogen storage on-board vehicles. However, full-scale crash testing will also be

important to ensure that mass-produced hydrogen-powered vehicles provide a level of

safety comparable to that of other vehicles. Both the frontal and the side impact tests in

these directives and regulations are generally appropriate for hydrogen-powered

vehicles, but amendments will be required to the test set-up procedures and to the post-

test requirements.

The fuelling condition for the test is a particularly important issue. Hydrogen could pose

a risk to personnel and property in the crash test laboratory, particularly when the

vehicle is equipped with a compressed hydrogen storage system; a fuel substitute will

probably be needed. This would be consistent with the approach currently taken in the

directives and regulations whereby water is used in place of conventional liquid fuels (for

the same reason). The draft global technical regulation on hydrogen requires helium to

be used in place of compressed gaseous hydrogen. Nitrogen is used in place of liquid

hydrogen. The purpose of the crash testing described in the draft global technical

regulation is to demonstrate the integrity of the fuel system. The particular crash tests

that are carried out are those already applied in the respective jurisdictions.

Helium is also used (for compressed gaseous containers) in the Japanese regulation,

Attachment 17, Technical Standard for Fuel Leakage in Collisions. SAE J2578,

Recommended Practice for General Fuel Cell Safety allows hydrogen or helium to be

used and offers different pressure options. Helium or hydrogen can be used at full

service pressure, or hydrogen can be used at low pressure. Certain cylinders (Type IV

composite cylinders) are more vulnerable to impact at low pressure (Hennessey and

Nguyen, 2009). At high pressure, the cylinders are more resistant to deformation and

hence a low pressure option might be a “worst case”. However, the draft global technical

regulation requires gas containers to be filled to a minimum of 90% of the nominal

working pressure.

Testing with low pressure hydrogen might mitigate some of the risks associated with its

use in a crash test and would allow the post-crash electrical output and isolation of the

fuel cell to be monitored (Hennessey and Nguyen, 2009). A fuel cell depends on the flow

of hydrogen through the stack for the electrochemical reaction with oxygen to take place

and generate an electric current. Hennessey and Nguyen (2009) discuss the possible use


TRL 16 CPR711

of a megohmmeter to apply an external voltage to an inactive fuel cell, but also

recognise that testing of such an approach is required. The draft global technical

regulation refers to electrical isolation and the safety and protection against electric

shock (post-crash) in the action plan, but there does not appear to be any requirements

in the text of the regulation for the latest draft (dated January 2010).

Post-crash fuel leakage is another important issue. An appropriate measurement time

and leakage rate is needed to reduce the risks to occupants (and also to emergency

services) following a collision. The draft global technical regulation proposes a limit for

the rate of gas leakage of 118 NL/min (normal litres per minute) within 60 minutes of

the crash test. The amount of gas leakage is determined by measuring the pressure loss

of the compressed gas storage containers. In the case of liquid hydrogen, the storage

system must be “tight, i.e. bubble-free if using a detecting spray”.

SAE J2578 includes guidance on the allowable amount of gas that can escape following a

crash test. This was determined by allowing the same release of energy (on a lower

heating value basis) as FMVSS 301 for gasoline. The allowable amount of hydrogen

resulting from this “equivalent energy” corresponds to an average leak rate of 120 L/min

over the 60 minute period (Scheffler et al., 2009). The Japanese regulations prescribe a

limit of 131 NL/min over 60 minutes.

While there appears to be a general consensus concerning the leakage rate and time

across the different standards mentioned above, Hennessey and Nguyen (2009) pointed

out that the properties of hydrogen are very different from other fuels and may pose a

lesser or greater risk of fire following a crash. Hydrogen dissipates quickly if unconfined,

but has a wide range of flammability. Limits that are based on energy equivalence limits

for other fuels may not be appropriate for hydrogen. Very little published research has

been found so far. However, Maeda et al. (2007) investigated leaks with a flow rate of

131 NL/min (the allowable leakage rate in Japanese regulations) and concluded there

was no significant risk to people.


Ideally, proposals to amend the frontal or side impact directives would draw on the

findings of an experimental study. Very few (if any) vehicles are available on the open

market for purchase and testing and hence it would be difficult to specify and conduct

research tests in the future. The cooperation of manufacturers would be required and it

is likely that the vehicles would be very expensive. Unfortunately, relatively few data are

available in the published literature. Crash tests are sometimes mentioned with respect

to hydrogen-powered vehicles, but the details about the test procedure and post-crash

outcome are not usually presented.

In the absence of experimental data, harmonisation with the draft global technical

regulation seems to be the most sensible approach for the European type-approval

legislation. The crash test procedure would therefore need to be amended to describe

the fuelling conditions for a hydrogen-powered vehicle. In the case of a vehicle that runs

on compressed gas, the container would be filled with helium to 90% of its nominal

working pressure. A liquid hydrogen cylinder would be filled with liquid nitrogen to the

minimum mass equivalent of the maximum quantity of liquid hydrogen that may be

contained in the inner vessel and then the system would be pressurised with gaseous

nitrogen up to typical operating pressure. The post-crash leakage limit and time

proposed in the draft global regulation could also be applied in the directives:

118 NL/min.

The draft global technical regulation is still very much under development and the

content is subject to change. It is important, therefore, to monitor the progress of the

regulation during the remainder of the project before developing detailed proposals for

the European type-approval legislation. In addition, TRL will continue to monitor the

literature and will discuss these initial proposals with stakeholders.


TRL 17 CPR711

2.5 Buses and coaches: Directive 2001/85/EC and UNECE Regulations 66 and 107

2.5.1 Overview

Directive 2001/85/EC applies to passenger vehicles that carry 8 passengers or more

(single deck, double deck, rigid or articulated vehicles of category M2 or M3). It sets out a

series of design requirements for exits, interior arrangements, lighting, handrails and

markings, as well as requirements for the protection against fire. There is also a stability

test for all vehicles and a test of the strength of the superstructure for single deck

vehicles that carry seated passengers. The directive also requires that electrical

equipment is well-insulated and that an isolation switch is provided where the voltage

exceeds 100 V RMS.

Stability Test

The stability test assesses the roll stability of the vehicle. During this test, the vehicle is

tilted in line with the longitudinal axis. The main requirement is that the point at which

overturning occurs must be greater than 28°, when tilted to either side. The tested

vehicle must be equal to its normal running mass and contain masses representing

passengers placed in each passenger seat, or uniformly distributed over the standee

area at the correct centre of gravity. Where a vehicle is equipped to carry luggage on the

roof, a uniformly distributed mass representing the baggage is attached to the roof.

Alternatively, a calculation can be used to verify whether the vehicle would pass the test.

Strength of Superstructure

This part of the directive applies to single deck vehicles that carry seated passengers.

However, if the vehicle has been approved to UNECE Regulation 66, it is said to comply

with the requirements of this test. Four test methods are described to assess the

strength of the superstructure of the vehicle:

Roll-over test on complete vehicle

The whole vehicle, with a correct centre of gravity and mass distribution, is rotated at

no more than 5 deg/s from a platform with a minimum drop of 800 mm onto a

concrete impact area. Fuel, battery acid and other combustible, explosive or

corrosive material may be substituted by other materials as long as the mass

distribution is unaffected.

Roll-over test on a body section(s)

A bodywork section of the vehicle is subjected to the same test as above. The

percentage of total energy absorbed by the bodywork section shall not be less than

the percentage of the total mass of the vehicle as specified by the manufacturer.

Pendulum test on a body section(s)

A rectangular shaped steel pendulum strikes the vehicle body section at a speed

between 3 and 8 m/s. The energy to be applied is a proportion of the energy

declared by the manufacturer to be allocated to each cross-sectional rings included in

that particular bodywork section.

Calculations based on the data obtained from a test on a bodywork section may be

used to demonstrate the acceptability of another bodywork section which is not

identical as long as there are many common structural features.

Verification of strength by calculation

A superstructure or sections of a superstructure may be shown to meet the testing

requirements by calculation. The validity of the calculation method can be established


TRL 18 CPR711

by comparing the results with physical tests, such as a previously tested similar

vehicle.

The vehicle meets the requirements of the test (or calculation) if there is no intrusion

into a defined space in the passenger compartment, and if no part of this space projects

outside the deformed structure. Additional test methods or calculations may be required

if the test method (or calculation) that was used cannot take account of variations in

sections of the roof. These variations might be brought about by, for example, the

installation of an air conditioning system on the roof. If no additional information is

available, the technical service may require that a roll-over test of the complete vehicle

is carried out.

There are two UNECE regulations that are recognised as alternatives to the directive for

EC type-approval: UNECE Regulation 66 (Strength of superstructure of large passenger

vehicles) and UNECE Regulation 107 (General construction of M2 and M3 vehicles). Both

regulations would be needed to gain approval. Regulation 66 (as amended) is based

around the same strength of superstructure test as the directive. Regulation 107 (as

amended) contains the same stability test as the directive and the more general

requirements relating to the construction of vehicles.


The main requirements and tests in Directive 2001/85/EC (and the corresponding UNECE

regulations) are generally unrelated to the vehicle‟s power train. Both the directive and

the regulations should, for the most part, be compatible with hydrogen-powered

vehicles; the main test methods can be carried out irrespective of the type of fuel that

the vehicle uses. For example, there is no specific reference to the fuelling condition in

the stability test method, but the vehicle must be at its “mass in running order” (with

the addition of certain loads to represent passengers, crew and luggage). TRL

understands that the “mass in running order” includes 90% of the fuel capacity. It seems

likely, therefore, that a technical service would simply add an appropriate mass to the

vehicle.

In the case of a hydrogen-powered vehicle, the fuel container is likely to be located on

the roof and may therefore have a greater influence on the stability of the vehicle than a

traditional fuel tank. Furthermore, the level or pressure of hydrogen in a roof-mounted

container might affect the tilting behaviour of the vehicle in the real world. More detailed

test procedures might be needed for hydrogen-powered vehicles.

The strength of superstructure test may have to be performed on a complete vehicle

because a roof-mounted hydrogen system could lead to significant variations in the

sections of the vehicle. The test procedure allows fuel, battery acid and other

combustible, explosive materials to be substituted, provided that the vehicle is

representative of the mass in running order.

Directive 2001/85/EC (and UNECE Regulation 107) also set out provisions for the

protection against fire risks. These include:

The engine compartment

The engine compartment requirements are essentially a series of precautions against

flammable materials coming into contact with fuel or sources of heat. Further analysis is

required to determine whether they are sufficient for a hydrogen-powered vehicle.

Electrical equipment and wiring

These comprise a series of electrical protection measures. They were probably not

developed with a hydrogen-powered vehicle in mind. Nevertheless, some of the

requirements seem appropriate, irrespective of the type of equipment and wiring. For

example, insulation is required, there must be a fuse and circuit breakers and the cables

must be protected from damage. For example, the legislation also states that there must

be a manually-operated isolating switch capable of disconnecting all circuits from the


TRL 19 CPR711

main electrical supply wherever the voltage exceeds 100 V RMS. This could have

implications for a fuel cell vehicle.

UNECE Regulation 100 deals with some (but not all) of these topics in its vehicle

construction requirements, but fire risks are not mentioned explicitly.

Batteries

The directive and the regulation do not say whether the battery requirements relate to

an auxiliary battery only, or whether they would apply to a propulsion battery that forms

part of a fuel cell system. The requirements are quite broad: the batteries must be well-

secured and easily accessible; the battery compartment must be separated from the

driver and passenger compartments and well-ventilated; and the battery terminals must

be protected against short circuit.

Once again, this is similar to the content of UNECE Regulation 100, although the

requirements of the regulation are focussed on the protection against electric shock.


Directive 2001/85/EC (and the corresponding UNECE regulations) can be applied to a

hydrogen-powered vehicle and TRL understands that some vehicles have been approved

already (HyFLEET:CUTE, 2009). The main requirements and performance tests are

unrelated to the type of power train. However, further investigation is needed in the

remainder of the project to understand the fuelling conditions in the stability and

strength of superstructure tests and the fire protection requirements.


TRL 21 CPR711

3 The use of mixtures of natural gas and hydrogen to

power vehicles

3.1 The present situation

Hydrogen-powered vehicles must meet the requirements of Regulation (EC) No.

79/2009. Vehicles that run on compressed natural gas must meet the requirements of

UNECE Regulation 110. Neither of these type-approval regulations includes provisions for

vehicles that use mixtures of natural gas and hydrogen. It is unclear, therefore, how

such a vehicle would gain approval.

The composition of natural gas can vary, depending on its source. These variations can

affect the performance and emissions of an engine. Methane is the main component of

natural gas (typically 88-96%), with a proportion of non-methane alkanes (i.e. ethane,

propane, butane, etc). Other components are nitrogen, carbon dioxide, water, oxygen

and trace amounts of lubricating oil, and sulphur compounds. There may even be small

quantities of hydrogen (i.e. 0.1%).

Gas composition is mentioned in UNECE Regulation 110 with respect to the service

conditions that each cylinder should be capable of withstanding. The regulation states

that each cylinder should be designed to tolerate being filled with natural gas meeting

one of three sets of conditions. The first set of conditions is SAE J1616 (a natural gas

quality standard). The second set of conditions relate to a dry gas (i.e. water vapour

normally limited to less than 32 mg/m3) and include limits for hydrogen of 2% by

volume when the cylinders are manufactured from a steel with an ultimate tensile

strength exceeding 950 MPa. The final set of conditions relates to a wet gas (i.e. water

content greater than above) and limits hydrogen to 0.1%.

The hydrogen regulation (EC No. 79/2009) and the natural gas regulation (UNECE

Regulation 110) include requirements and tests that are appropriate to storage systems

for compressed gaseous fuels. However, each regulation is aimed at the particular

properties of each fuel. This is particularly important for the hydrogen regulation due to

the characteristics of hydrogen and the potential implications for vehicle safety.

3.2 State-of-the-art

Internal combustion engines fuelled with natural gas produce fewer regulated pollutants

and carbon dioxide emissions than petrol engines (Ristovski et al., 2004). However,

some disadvantages have been reported, such as a lower efficiency (Mello et al., 2006).

The addition of small amounts of hydrogen to natural gas (5-30% by volume) has the

potential to overcome this trade-off, thus increasing efficiency and reducing emissions

(Ortenzi et al., 2008). Furthermore, some stakeholders have suggested that the use of

hydrogen in such mixtures might encourage the building of the infrastructure required

for more widespread use of hydrogen in the automotive sector.

There is a substantial body of research on the use of mixtures of natural gas and

hydrogen. The studies tend to be based around experiments using an engine test bed.

The fuels are mixed at various ratios using a gas mixer. However, in real vehicle

applications, it seems more likely that the fuel will be pre-mixed. This would reduce the

complexity of the vehicle by removing the need for separate fuel tanks and mixing

equipment and software.

Mixtures of natural gas and hydrogen have already reached commercialisation. One

example is Hythane®, a blend of 80% natural gas and 20% hydrogen. The Hythane

Corporation intends to deploy the Hythane System, which integrates the technology into

existing natural gas fuelling stations and vehicles, in cities throughout the world

(www.hythane.com). Fuel stations have recently been set up in India in collaboration

with the Indian Oil Company. In the scientific literature, Morrone and Unich (2009)

presented a schematic of a plant layout for hydrogen production in a compressed natural

http://www.hythane.com/


TRL 22 CPR711

gas fuel station. The work was part of a cost analysis to evaluate the economic aspects

of localised medium quantity hydrogen production plants for use in blended fuels. The

gaseous fuel mixture would be stored in tanks and delivered to road vehicles when

required.

The level of hydrogen content in Hythane® and in the experimental blends described in

the literature, mean that natural gas cylinders and engines can be used with relatively

few modifications. However, most of the studies on hydrogen mixtures are based around

combustion analyses that focus on the environmental and performance benefits of the

blended fuel. It appears that the safety implications have not been examined in any

detail. The fuels have very different properties and although natural gas (which is the

major component of the blend) is less reactive than hydrogen, there could be significant

risks.

The NaturalHy project included some work on the safety of natural gas and hydrogen

mixtures, although it was not related directly to vehicle-based applications. NaturalHy

was partially funded by the Commission as an Integrated Project of the Sixth Framework

Programme. The project studied the potential for natural gas pipeline networks to

transport hydrogen from manufacturing sites to hydrogen users. The hydrogen would be

introduced into the pipeline network and mix with the natural gas. The mixture could

then be used directly as a fuel within existing gas-powered equipment, with the benefit

of lower carbon emissions. Alternatively, the hydrogen could be extracted for use in

hydrogen-powered engines or fuel cell applications. The project included a safety work

package that examined the risks of using this existing infrastructure in this new way.

The overall conclusion was that up to 30% by volume of hydrogen could be added to the

natural gas within the current gas infrastructure without adversely affecting the risk to

the public significantly and without any additional mitigation measures (NaturalHy,

2009). However, it is unclear whether this finding is at all relevant to vehicle-based

applications where the hydrogen is stored at high pressure.

3.3 Review of the hydrogen regulation and implementing measures

The hydrogen regulation (EC No. 79/2009) identifies hydrogen mixtures as a potential

transition fuel towards the use of pure hydrogen, to facilitate the introduction of

hydrogen-powered vehicles in member states where the natural gas infrastructure is

good. On that basis, the regulation states that the Commission should develop

requirements for the use of mixtures of hydrogen and natural gas/biomethane.

Particular consideration must be given to the mixing ratio of hydrogen and gas which

takes account of the technical feasibility and environmental benefits.

Based on the analysis conducted so far, it appears that most current blends can be used

in what are essentially natural gas systems and vehicles. Consideration must be given,

therefore, as to the most appropriate approach to take for any future requirements. The

hydrogen regulation and draft implementing measures could be applied to vehicles

intended to run on mixtures, but it may be the case that the requirements are more

stringent than are necessary for a blended fuel. Similarly, the natural gas regulation

(UNECE Regulation 110) could be applied, but it may not address certain properties of

hydrogen, which may be important, even when it is present in relatively small volumes.

Further analysis will be completed in the remainder of the project; although it has been

noted that relatively little published research is available of the safety aspects of

hydrogen mixtures.

3.4 Proposals for amendments

Further work will be carried out with a view to providing the EC with recommendations

on the technical amendments needed to accommodate mixtures of natural gas and

hydrogen. There are several important issues that need to be resolved. For instance, it is

necessary to determine what mixing ratio is likely to be used. Various different ratios


TRL 23 CPR711

have been examined in the literature. It might be the case that a standard ratio is used

in the future, or that vehicles will be capable of running on different ratios (within certain

limits). The effect of the mixing ratio on engine performance and emissions needs to

taken into account and the safety implications of each ratio need to be understood. The

project will focus on these areas.


TRL 25 CPR711

4 Regulating the type-approval of L category vehicles

4.1 The present situation

Two, three and some four wheel vehicles are not included in the framework directive for

M and N category vehicles (Directive 2007/46/EC). Instead, these are termed L category

vehicles and a different framework directive applies: Directive 2002/24/EC. This became

mandatory in May 2003 and draws on a number of separate technical directives in much

the same way as 2007/46/EC does. It applies to light vehicles intended to be used on

the road with a maximum speed greater than 6 km/h. The following system of

classification is used in Directive 2002/24/EC to distinguish between the different types

of L category vehicles:

Category L1e – Two-wheel moped with a maximum speed of 45 km/h and:

o maximum cylinder capacity of 50 cm3 for an internal combustion engine

vehicle, or

o maximum continuous rated power of 4 kW for an electric vehicle.

Category L2e – Three-wheel moped with a maximum speed of 45 km/h and:

o maximum cylinder capacity of 50 cm3 for a spark ignition internal

combustion engine vehicle, or

o maximum net power output of 4 kW for any other internal combustion

engine vehicle, or


Category L3e – Two-wheel motorcycle without a sidecar:

o Cylinder capacity greater than 50 cm3 for an internal combustion engine

vehicle and/or a maximum speed greater than 45 km/h.

Category L4e – Two-wheel motorcycle with a sidecar:



Category L5e – Three-wheel motor tricycle:



Category L6e – Four-wheel light quadricycle:

Maximum unladen mass of 350 kg, not including the mass of batteries in an

electric vehicle, maximum speed of 45 km/h, and

o maximum cylinder capacity of 50 cm3 for a spark ignition internal

combustion engine vehicle, or

o maximum net power output of 4 kW for any other internal combustion

engine vehicle, or


The technical requirements of a three-wheel moped (category L2e) apply unless

specified differently in a particular directive.

Category L7e – Four-wheel quadricycle:

Maximum unladen mass of 400 kg (550 kg for a goods vehicle), not including the

mass of the batteries in an electric vehicle, and a maximum net power of 15 kW.

The technical requirements of a motor tricycle (category L5e) apply unless

specified differently in a particular directive.


TRL 26 CPR711

It is interesting to note that provisions are made for electric vehicles in Directive

2002/24/EC. For instance, electric vehicles are included in the descriptions of mopeds

(categories L1e and L2e) and quadricycles (categories L6e and L7e). This may reflect the

growing use of electric powertrains in these vehicles. Electric vehicles are not included in

the definitions of motorcycles (categories L3e and L4e) or motor tricycles (category L5e).

Currently, there are no specific provisions for hydrogen-powered L category vehicles in

Directive 2002/24/EC. A manufacturer who wishes to place such a vehicle on the market

may face difficulties with the present situation. It is likely that the vehicle will be

considered outside the scope of 2002/24/EC, because of the exemption clause set out in

Article 16.3. The exemption relates to vehicles that incorporate new technologies which

cannot, due to their nature, comply with the separate technical directives. A hydrogen-

powered L category vehicle might fit into this category. This is because the directives

were written for vehicles with internal combustion engines or for battery electric

vehicles. The use of hydrogen may result in additional risks, which are not considered by

2002/24/EC.

Although a hydrogen-powered category L vehicle could be exempt (for the reasons

described above), the framework directive does allow vehicles featuring new

technologies to obtain type-approval. However, it is necessary to demonstrate to the

relevant authority, a level of safety and environmental protection that is equivalent to

that in the technical directives. This could prove very challenging technically both for the

manufacturer and for the relevant authority.

With the current arrangement, the relevant authority in each member state would have

to derive the appropriate tests required to demonstrate an equivalent level of safety

and/or address any additional risks in order to approve the vehicle in their territory.

However, it is likely that their national legislation will also not provide for hydrogen-

powered vehicles. Some member states could choose to effectively ban the vehicle (in

the absence of an appropriate testing regime), while others may approve it on an

individual vehicle basis, if it was intended to be made in very low numbers. Such an

approval could be invalid in other member states.

Robinson et al. (2009) examined the costs and benefits of a series of policy options for L

category vehicles. These included options to accommodate hydrogen-powered L category

vehicles. Three scenarios were considered: no change; legislation at European Union

level; legislation at national level. Unfortunately, insufficient data were available to

complete a full cost-benefit analysis. Nevertheless, Robinson judged that legislation at

European Union level would be likely to deliver both economic and environmental

benefits. However, stakeholders provided a mixed response. Some favoured European

legislation because it would establish uniform requirements. However, others were

concerned that regulatory activity could stifle innovation and delay the conversion of

these vehicles to hydrogen.

The Commission carried out a public consultation on the proposals for L category

vehicles and published the results on-line (European Commission, 2009). Forty-one

stakeholders took part in the consultation. They were asked whether EU legislation on

hydrogen-powered L category vehicles is needed. Twenty-nine percent were favourable

or relatively favourable towards EU legislation, while 20% were not favourable. Fifty-one

percent did not reply to the question. The unfavourable responses tended to come from

the motorcycle industry. The typical view was that EU legislation is not needed since

vehicles could be individually type-approved at national level or subject to an exemption

from 2002/24/EC. While ad-hoc authorisation at national level could be more flexible,

TRL‟s view is that it could lead to problems. For instance, if a vehicle obtains national or

single type-approval in one member state, it is not guaranteed that the vehicle will be

authorised in other member states. In fact, member states may even establish different

requirements, potentially resulting in a fragmented internal market, with costly and

complicated approval procedures.


TRL 27 CPR711

4.2 The state-of-the-art

One of the challenges for hydrogen-powered vehicles is to deliver the range and

performance that consumers have come to expect from their motor vehicles. Although

there are clear efficiency and environmental benefits of hydrogen (depending on the way

it is produced), it has a lower energy density than conventional fuels, even when it is

compressed. However, L category vehicles are lighter and need less energy than larger

vehicles. Introducing hydrogen for these vehicles might, therefore, be less demanding.

The main developments have been in two-wheel vehicles and have focussed on fuel cells

rather than hydrogen internal combustion engines. Typically, a hybrid system is used

that combines the fuel cell with a battery. The main advantage of this arrangement is

that the size (and hence cost) of the fuel cell can be reduced (Lin 2000). In many

applications, the average speed is relatively low and hence a reduced power fuel cell

stack can meet the power requirements of the vehicle (Mirzaei et al., 2007).

Some important studies have been carried out in Europe, with the support of the

Commission. For instance, the FRESCO project was partially funded by the Commission

under the Fifth Framework Programme. The project demonstrated the technical

feasibility of fuel cell propulsion for scooters. A dedicated fuel cell system was developed

and integrated in a mass-produced Piaggio scooter. The scooter was capable of a top

speed of 45 mph with a range of 75 miles (Fuel Cells Bulletin, 2006). The fuel cell stack

produced 6 kW of electric power and was combined with a 45 Wh supercapacitor, with

regenerative braking to boost overall efficiency. The on-board hydrogen supply

comprised a 525 bar tank with a carbon-reinforced liner. However, the vehicle was

driven on a test circuit only: no attempt was made to gain type-approval. Unfortunately,

the vehicle did not progress beyond the FRESCO project. Instead, Piaggio has

concentrated on hybrid vehicles that combine a conventionally-fuelled combustion

engine with a small battery.

The HYCHAIN MINI-TRANS project is a more recent Integrated Project of the Sixth

Framework Programme (www.hychain.org). The project is deploying several fleets of

innovative fuel cell vehicles in four regions of Europe (in France, Spain, Germany and

Italy). The vehicles include scooters, tricycles, small utility vehicles, minibuses and

wheelchairs. The project comprises two phases: 2006 – 2007 was spent manufacturing

the vehicles and developing the infrastructure and in 2008 – 2010, the vehicles will be

tested under real world conditions. The scooter runs on a hydrogen-fuelled hybrid

system with a 2 kW fuel cell stack. The hydrogen is stored at 700 bar in an

exchangeable cartridge. Participants in the project have reported difficulties with the

current regulatory situation with respect to L category vehicles and the implications for

the deployment of fleets in Europe (Barth, 2006).

Powered two-wheel vehicles can play an important role in urban transportation. They are

particularly popular in Asian cities. Attempts to tackle increasing air and sound pollution

from these vehicles have included the development of fuel cell vehicles. These

developments are interesting because they do not always employ the most conventional

methods of hydrogen storage in vehicles (i.e. compressed gaseous or liquid hydrogen).

For example, Lin (2000) presented a conceptual fuel cell scooter design with compact

metal hydride storage. A battery hybrid system was developed, which allowed a smaller

fuel cell to be used and energy to be stored through regenerative braking. Samsung

Engineering developed and pilot-tested a fuel cell scooter that used hydrogen storage

technology based on a solution of sodium borohydride (Fuel Cells Bulletin, 2005). Mirzaei

et al. (2007) described the modelling and optimisation of a hybrid fuel cell system for a

motorcycle based on more conventional compressed hydrogen storage.

4.3 Review of the hydrogen regulation and implementing measures

L category vehicles might be early adopters of hydrogen as a fuel, but it will be essential

to identify any safety risks and to consider how these risks should be mitigated. The

http://www.hychain.org/


TRL 28 CPR711

main concern is the safety of hydrogen storage on-board the vehicle (and any

components in contact with hydrogen). Regulation (EC) No. 79/2009 (the hydrogen

regulation) and the draft implementing measures mitigate these concerns for M and N

category vehicles. While it would be inappropriate to include L category vehicles in the

hydrogen regulation and implementing measures (because they are part of a separate

legislative framework), they might form the basis for new type-approval requirements

for L category vehicles.

The requirements of the hydrogen regulation are set out in a series of Articles. In some

cases, the Article references a separate Annex. The key technical Articles are:

Article 5: General requirements for hydrogen components and systems;

Article 6: Requirements for hydrogen containers designed to use liquid hydrogen;

Article 7: Requirements for hydrogen components, other than containers,

designed to use liquid hydrogen;

Article 8: Requirements for hydrogen containers designed to use compressed

(gaseous) hydrogen;

Article 9: Requirements for hydrogen components, other than containers,

designed to use compressed (gaseous) hydrogen;

Article 10: General requirements for the installation of hydrogen components and

systems.

The main elements of the hydrogen regulation are relevant for L category vehicles. The

requirements for hydrogen components and systems (i.e. Articles 5 to 9) could be

adopted relatively easily. However, the requirements for the installation of hydrogen

components and systems (Article 10) might need to be amended for certain L category

vehicles.

A similar judgement was made in a white paper prepared during the HYCHAIN project.

This concluded that many of the provisions and specifications in the hydrogen regulation

are independent of vehicle type and could therefore be applied to hydrogen-powered

L category vehicles without amendment (HYCHAIN, 2007). However, some potentially

vehicle-specific requirements were found in Annex VI of the hydrogen regulation. This

Annex is referenced by Article 10 and sets out general requirements for the installation

of hydrogen components and systems. There are 16 requirements and these are

reviewed in full in Appendix A. The list below highlights the requirements that may need

to be amended for L category vehicles:

1. The hydrogen system must be installed in such a way that it is protected against

damage. It must be isolated from heat sources in the vehicle.

While this requirement is appropriate for L category vehicles, it might be challenging

for certain categories. For instance, the frame and bodywork of a typical two-wheel

vehicle is unlikely to provide the same level of protection as the chassis and

bodywork of a three or four wheel vehicle.

2. The hydrogen container may only be removed for replacement with another

hydrogen container, for the purpose of refuelling or for maintenance. In the case

of an internal combustion engine, the container must not be installed in the

engine compartment of the vehicle.

This requirement is generally independent of vehicle type or category. However,

some L category vehicles, such as two or three wheel vehicles, may not have a

clearly defined engine compartment. This requirement would need to be reworded to

reflect the layout of two and three wheel L category vehicles.

5. The hydrogen container must be mounted and fixed so that the specified

accelerations can be absorbed without damage to the safety related parts when

the hydrogen containers are full.


TRL 29 CPR711

The draft implementing measures set out specific accelerations according to (M and

N) vehicle category. The provisions do not apply if the vehicle is approved according

to the front and side impact directives. L category vehicles are lighter than M and N

category vehicles and might be subjected to higher accelerations, although their

impact scenarios are also likely to be different. It may be necessary to specify

acceleration levels according to each L category.

11. The venting or heating system for the passenger compartment and places where

leakage or accumulation of hydrogen is possible must be designed so that

hydrogen is not drawn into the vehicle.

Some L category vehicles do not have a passenger compartment. It could be argued,

therefore, that these vehicles are not exposed to the risks associated with the

accumulation of hydrogen in an enclosed space. Nevertheless, it may be necessary to

reword this requirement for L category vehicles.

13. The passenger compartment of the vehicle must be separated from the hydrogen

system in order to avoid accumulation of hydrogen. It must be ensured that any

fuel leaking from the container or its accessories does not escape to the

passenger compartment of the vehicle.

As discussed above, some L category vehicles do not have passenger compartments;

however, hydrogen accumulation may not be a problem in these vehicles.

14. Hydrogen components that could leak hydrogen within the passenger or luggage

compartment or other non-ventilated compartment must be enclosed by a gas-

tight housing or by an equivalent solution as specified in the implementing

measures.

As above, some L category vehicles do not have passenger or luggage

compartments.

16. Labels or other means of identification must be used to indicate to rescue

services that the vehicle is powered by hydrogen and that liquid or compressed

(gaseous) hydrogen is used.

This requirement is independent of category and could be applied to L category

vehicles. However, there may be issues to consider regarding the size and placement

of such labels for smaller L category vehicles.

The analysis completed so far has focussed on Regulation (EC) No. 79/2009 (the

hydrogen regulation). These fundamental provisions could be adopted for L category

vehicles relatively easily. However, some adjustments would be needed to take account

of the particular features of L category vehicles, especially those with two or three

wheels. A similar analysis of the draft implementing measures will be made during the

remainder of the project. In addition, stakeholders will be contacted with a view to

establishing a working group to discuss requirements for the type-approval of hydrogen-

powered L category vehicles.

4.4 Proposals for amendments

Further work will be carried out on L category vehicles in the remainder of the project.

The aim of this section of the interim report was twofold: firstly, to present initial

suggestions for areas in the legislation for L category vehicles that may need to be

amended for hydrogen; and secondly, to provide a basis for further discussions with

stakeholders.

Some hydrogen-powered L category vehicles will be produced in very low numbers.

Individual approval at member state level may be appropriate for these vehicles.

However, some vehicles have the potential for mass production and Europe-wide sale.

Manufacturers need a European regulatory framework in place to provide uniform safety

and environmental requirements and prevent the need for multiple approvals in separate


TRL 30 CPR711

countries. Such a framework could include provisions for vehicles produced in low

numbers only and should, therefore, not inhibit the development of new vehicles by

increasing the cost of approval unduly.

The framework directive for L category vehicles (Directive 2002/24/EC) would need to be

amended to accommodate hydrogen-powered vehicles. Potential amendments include

specific mention of hydrogen within the articles of the directive, such as within the

descriptions of each L category. In the case of fuel cell vehicles, consideration is needed

as to the implications of the current situation whereby electric vehicles are not included

in the definition of certain categories.

It may also be necessary to add new technical requirements for hydrogen storage. The

hydrogen regulation and draft implementing measures are being examined in this study

with a view to the Commission introducing requirements relating to hydrogen in the

type-approval framework for L category vehicles. However, the hydrogen regulation and

implementing measures are part of the type-approval framework for M and N category

vehicles. While the requirements may largely be appropriate for L category vehicles it

would be inappropriate to simply amend these acts to include L category vehicles.

Nevertheless, they could form the basis for new requirements.

A new regulation for hydrogen-powered L category vehicles could be developed and

referred to in the framework directive for L category vehicles. It is likely that the new

regulation would be very similar to the present hydrogen regulation for M and N category

vehicles. Another approach might be to amend the technical directive for fuel tanks

(Directive 97/24/EC). This could either include detailed requirements for hydrogen-

powered vehicles or a series of references to the hydrogen regulation and implementing

measures. These issues and their implications will be examined further in the remainder

of the project.


TRL 31 CPR711

5 Conclusions

1. TRL has performed the first part of a project for the European Commission to review

the type-approval legislation on vehicle safety for hydrogen-powered vehicles. An

initial review has been completed and the findings are summarised below. The next

part of the project will involve liaison with stakeholders, including a workshop, to

present the findings of the work to date for comment. Following this, the review will

be completed and recommendations made for necessary legislative action; in

particular amendments for current legislation.

2. The review focussed on the type-approval legislation for vehicle safety and on two

issues identified in the hydrogen regulation (EC No. 79/2009).

The safety legislation covered: fuel tanks, radio interference, identification of

controls, frontal impact, side impact and buses and coaches.

The issues identified in the hydrogen regulation covered: the use of mixtures

of natural gas and hydrogen as a fuel in internal combustion engines and the

regulation of hydrogen-powered L category vehicles.

3. The review of safety legislation revealed that:

Hydrogen-powered vehicles should be exempt from fuel tank requirements

because the risks are dealt with by the hydrogen regulation and (draft)

implementing measures.

The radio interference legislation includes performance requirements, but

references international standards for the test methods. Some of the

standards have procedures to deal with electric vehicles (which could be

applied to hydrogen fuel cell vehicles). However, some potential issues were

raised, such as the vehicle load conditions and antenna positions.

Amendments to the frontal and side impact legislation are needed to

accommodate hydrogen-powered vehicles. The amendments will need to

cover:

i. The test procedure including the fuelling conditions for the impact test.

ii. The post-crash requirements including hydrogen leakage limits.

There are no symbols in the legislation that must be used with controls, tell-

tales and indicators for the hydrogen system in a hydrogen-powered vehicle.

Furthermore, no symbols are available in the main international standard.

New symbols will be needed for hydrogen-powered vehicles. However, the

current optical indicator and tell-tale colour meanings set out in the legislation

and the standard are appropriate.

The bus and coach requirements are largely independent of the power train.

However, additional provisions may be needed for the stability and strength of

superstructure tests and for the electrical safety of the driver and passengers.

4. The review of issues identified in the hydrogen regulation revealed that:

Fuel mixtures of natural gas and hydrogen typically contain between 5% and

30% hydrogen by volume. With such blends, the fuel could be used in what

are essentially natural gas systems and vehicles. However, the legislation for

natural gas systems may not deal with certain properties of hydrogen, which

may be important, even when it is present in relatively small volumes.

The framework directive L category vehicles (Directive 2002/24/EC) would

need to be amended to accommodate hydrogen-powered vehicles. It may also

be necessary to develop new technical requirements for hydrogen storage on

L category vehicles: the hydrogen regulation and implementing measures are

generally appropriate for L category vehicles, but they are part of the type-


TRL 32 CPR711

approval framework for M and N category vehicles. It would be inappropriate

to simply amend these acts to include L category vehicles, but they could

form the basis for new requirements.


TRL 33 CPR711

Acknowledgements

The work described in this report was carried out in the Vehicle Safety Group of the

Transport Research Laboratory. The authors are grateful to Iain Knight who carried out

the technical review and auditing of this report.

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TRL 34 CPR711

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TRL 35 CPR711

Appendix A Review of Regulation (EC) No. 79/2009

Annex IV (Installation of hydrogen components and systems)


damage. It must be isolated from heat sources in the vehicle.

While this requirement is appropriate for L category vehicles, it might be challenging

for certain categories. For instance, the frame and bodywork of a typical two-wheel

vehicle is unlikely to provide the same level of protection as the chassis and

bodywork of a three or four wheel vehicle.

2. The hydrogen container may only be removed for replacement with another

hydrogen container, for the purpose of refuelling or for maintenance. In the case of

an internal combustion engine, the container must not be installed in the engine

compartment of the vehicle.

This requirement is generally independent of vehicle type or category. However,

some L category vehicles, such as two or three wheel vehicles, may not have a

clearly defined engine compartment. This requirement would need to be reworded to

reflect the layout of two and three wheel L category vehicles.

3. Measures must be taken to prevent misfuelling (sic) of the vehicle and hydrogen

leakage during refuelling and to make sure that the removal of a removable

hydrogen storage system is done safely.

This requirement is not vehicle-specific and could be applied to L category vehicles.

4. The refuelling connection or receptacle must be secured against maladjustment and

protected from dirt and water. The refuelling connection or receptacle must be

integrated with a non-return valve or a valve with the same function. If the refuelling

connection is not mounted directly on the container, the refuelling line must be

secured by a non-return valve or a valve with the same function which is mounted

directly on the container.


vehicles.

5. The hydrogen container must be mounted and fixed so that the specified

accelerations can be absorbed without damage to the safety related parts when the

hydrogen containers are full.

The draft implementing measures set out specific accelerations according to (M and

N) vehicle category. The provisions do not apply if the vehicle is approved according

to the front and side impact directives. L category vehicles are lighter than M and N

category vehicles and might be subjected to higher accelerations, although their

impact scenarios are also likely to be different. It may be necessary to specify

acceleration levels according to each L category.

6. The hydrogen fuel supply lines must be secured with an automatic shut-off valve

mounted directly on or within the container. The valve shall close if a malfunction of

the hydrogen system so requires or any other event that results in the leakage of

hydrogen occurs.


vehicles.

7. In the event of an accident, the automatic shut-off valve mounted directly on or

within the container shall interrupt the flow of gas from the container.


TRL 36 CPR711


vehicles.

8. Hydrogen components, including any protective materials that form part of such

components, must not project beyond the outline of the vehicle or protective

structure. This does not apply to a hydrogen component which is adequately

protected and no part of which is located outside this protective structure.


vehicles.


damage so far as is reasonably practicable, such as damage due to moving vehicle

components, impact, grit, the loading or unloading of the vehicle or the shifting of

loads.


vehicles. However, it may be more challenging for certain L category vehicles.

10. Hydrogen components must not be located near the exhaust of an internal

combustion engine or other heat source, unless such components are adequately

shielded against heat.


vehicles.

11. The venting or heating system for the passenger compartment and places where

leakage or accumulation of hydrogen is possible must be designed so that hydrogen

is not drawn into the vehicle.

Some L category vehicles do not have a passenger compartment. It could be argued,

therefore, that these vehicles are not exposed to the risks associated with the

accumulation of hydrogen in an enclosed space. Nevertheless, it may be necessary to

reword this requirement for L category vehicles.

12. In the event of an accident, it must be ensured so far as is reasonably practicable

that the pressure relief device and the associated venting system remain capable of

functioning. The venting system of the pressure relief device must be adequately

protected against dirt and water.


vehicles.

13. The passenger compartment of the vehicle must be separated from the hydrogen

system in order to avoid accumulation of hydrogen. It must be ensured that any fuel

leaking from the container or its accessories does not escape to the passenger

compartment of the vehicle.

As discussed above, some L category vehicles do not have passenger compartments;

however, hydrogen accumulation may not be a problem in these vehicles.

14. Hydrogen components that could leak hydrogen within the passenger or luggage

compartment or other non-ventilated compartment must be enclosed by a gas-tight

housing or by an equivalent solution as specified in the implementing measures.

As above, some L category vehicles do not have passenger or luggage

compartments.

15. Electrically operated devices containing hydrogen must be insulated in such a manner

that no current passes through hydrogen containing parts in order to prevent electric

sparks in the case of a fracture.


vehicles.


TRL 37 CPR711

16. Labels or other means of identification must be used to indicate to rescue services

that the vehicle is powered by hydrogen and that liquid or compressed (gaseous)

hydrogen is used.


vehicles. However, there may be issues to consider regarding the size and placement

of such labels for smaller L category vehicles.

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