Guidance

LPG (liquefied petroleum gas) vehicles

Published 1 March 2010

For a vehicle to be used on the public roads in Great Britain it must comply with insurance, licensing (tax) and registration requirements. It must also comply with applicable construction regulations. Primarily these are the Road Vehicles (Construction and Use) Regulations 1986 (C&U), as amended, and the Road Vehicles Lighting Regulations 1989, as amended.

New vehicles

The fuel systems of all new passenger cars using LPG for their propulsion must comply with internationally agreed safety standards (UNECE Regulation 67.01). This regulation includes specific provisions to ensure the safety of LPG fuel systems and requirements for the approval of the fuel tank.

Vehicles already in use

LPG systems fitted by a third party vehicle converter in the aftermarket must meet the legislative requirements set out in the Road Vehicle (Construction and Use) Regulations 1986 (as amended). Regulations 40 & 94 and schedules 4 & 5 lay down safety requirements for the LPG system. For information only, please refer to section 4 of this information sheet for the most relevant extracts from the Construction and Use Regulations.

In the UK, there is no statutory regime for inspecting the safety of aftermarket LPG installations before use on the road or at the annual roadworthiness (MOT) test. However, vehicles must meet the requirements set out in the C&U regulations at all times that they are used on public roads. Whilst there is no statutory regime for inspecting the safety of aftermarket LPG installations, there is a voluntary code of practice published by UKLPG and some insurance companies may ask for some form of certification before granting cover.

The Road Vehicle (Construction & Use) Regulations 1986

These regulations are not available on the internet and have been amended many times which makes it difficult to piece together the latest form of the regulations. However these regulations are available in a consolidated format in most city reference libraries, from companies who publish law. One example is Sweet and Maxwell who publish the ‘The encyclopaedia of road traffic law and practice’. This publication is continually updated and volume 4 contains a full version of the abovementioned regulations in consolidated format. Other possible suppliers include InterRegs.

Alternatively, it is possible to purchase printed copies of the Statutory Instruments that comprise the Regulations from the TSO at the following address:

$ The Stationery Office TSO Orders/Post Cash Dept PO Box 29 Norwich NR3 1GN $

Tel: 0870 600 5522
Fax: 0870 600 5533
e-mail: customer.services@tso.co.uk
Online ordering: http://www.tsoshop.co.uk/bookstore.asp
Customer service: http://www.tso.co.uk/contact/customerservices/

Extracts from C&U relating to vehicles using LPG for their propulsion

Regulation 40 – gas propulsion systems and gas fired appliances

(1) A vehicle which is -

(a) a motor vehicle which first used gas as a fuel for its propulsion before 19th November 1982; or

(b) a trailer manufactured before 19 November 1982 to which there is fitted agas container, shall be so constructed that it complies either with the provisions of Schedule 4 or with the provisions of schedule 5 or with ECE Regulation 67 or 67.01.

(2) Subject to paragraph (2A), a vehicle which is -

(a) a motor vehicle which firstused gas as a fuel for its propulsion on or after 19 November 1982;

or

(b) a motor vehicle first used on or after 1 May 1984 or a trailer manufactured on or after 19 November 1982 which is in either case equipped with a gas container or a gas fired appliance, shall comply with the provisions of schedule 5.

(2A) A vehicle which first used gas as a fuel for its propulsion on or after 13 November 1999 shall comply with the provisions of Schedule 5 or ECE Regulation 67.01.

(3) The requirements of this regulation are in addition to, and not in derogation from, the requirements of any regulations made under powers conferred by the Petroleum (Consolidation) Act 1928, the Health and Safety at Work etc. Act 1974, the Control of Pollution Act 1974 or any other Act or of any codes of practice issued under the Health and Safety at Work etc. Act 1974.

(4) In this regulation “gas container” has the meaning given in Schedule 4 where compliance with the provisions of that Schedule is concerned and otherwise has the meaning given in Schedule 5.

Regulation 94 - Use of gas propulsion systems

(1) No person shall use, or cause or permit to be used, on a road a vehicle with a gas propulsion system unless the whole of such system is in a safe condition.

(2) No person shall use, or cause or permit to be used, in any gas supply system for the propulsion of a vehicle when the vehicle is on a road any fuel except liquefied petroleum gas.

(3) No person shall use, or cause or permit to be used, on a road a vehicle which is propelled by gas unless the gas container in which such fuel is stored is on the motor vehicle, and not on any trailer, and in the case of an articulated vehicle on the portion of the vehicle to which the engine is fitted.

(4) In this regulation and in regulation 96 ‘liquefied petroleum gas’ means —

(a) butane gas in any phase which meet the requirements contained in the specification of commercial butane and propane issued by the British Standards Institution under the number BS4250: 1975 and published on 29th August 1975; or

(b) propane gas in any phase which meets the requirements contained in the said specification; or

(c) any mixture of such butane gas and such propane gas.

Schedule 4 (see regulation 40) gas containers: part I

1. Definitions relating to gas containers

In this schedule, unless the context otherwise requires, the following expressions have the meanings hereby assigned to them respectively, that is to say —

“gas container” means a container fitted to a motor vehicle or a trailer and intended for the storage of gaseous fuel for the purpose of the propulsion of the vehicle or the drawing vehicle as the case may be;

“gas cylinder” means a container fitted to a motor vehicle or a trailer and intended for the storage of compressed gas for the purpose of the propulsion of the vehicle or the drawing vehicle as the case may be;

“compressed gas” means gaseous fuel under a pressure exceeding 1.0325 bar above atmospheric pressure;

“pipe line” means all pipes connecting a gas container or containers —

(a) to the engine or the mixing device for the supply of a mixture of gas and air to the engine; and

(b) to the filling point on the vehicle;

“pressure pipe line” means any part of a pipe line intended for the conveyance of compressed gas; and

“reducing valve” means an apparatus which automatically reduces the pressure of the gas passing through it.

2. Gas containers

Every gas container shall—

(a) be securely attached to the vehicle in such manner as not to be liable to displacement or damage due tovibration or other cause; and

(b) be so placed or insulated as not to be adversely affected by the heat from the exhaust system.

3. Pipe lines

(1) Every pipe line shall be supported in such manner as to be protected from excessive vibration and strain.

(2) No part of a pipe line shall be in such a position that it may be subjected to undue heat from the exhaust system.

(3) Every pressure pipe line shall be made of steel solid drawn.

(4) The maximum unsupported length of a pressure pipe line shall not exceed 920 mm.

4. Unions

(1) Every union shall be so constructed and fitted that it will—

(a) not be liable to work loose or develop leakage when in use; and

(b) be readily accessible for inspection and adjustment.

(2) No union on a pressure pipe line or on a gas cylinder shall contain a joint other than a metal to metal joint.

5. Reducing valves

Every reducing valve shall be—

(a) so fitted as to be readily accessible; and

(b) so constructed that there can be no escape of gas when the engine is not running.

6. Valves and cocks

(1) Every valve or cock intended to be subjected to a pressure exceeding 6.8948 bar shall be of forged steel or of brass or bronze complying with the specification contained in Part II of this schedule.

(2) A valve or cock shall be fitted to the pipe line to enable the supply of gas from the container or containers to the mixing device to be shut off.

(a) In the case of a pressure pipe line the valve or cock shall be placed between the reducing valve and the container or containers and shall be readily visible and accessible from the outside of the vehicle and a notice indicating its position and method of operation shall be affixed in a conspicuous position on the outside of the vehicle carrying the gas container or containers.

(b) In other cases, if the valve or cock is not so visible and accessible as aforesaid, a notice indicating its position shall be affixed in a conspicuous position on the outside of the vehicle carrying the container or containers.

7. Pressure gauges

Every pressure gauge connected to a pressure pipe line shall be so constructed as not to be liable to deterioration under the action of the particular gases employed and shall be so constructed and fitted that—

(a) in the event of failure of such pressure gauge no gas can escape into any part of the vehicle;

(b) it is not possible owing to leakage of gas into the casing of the pressure gauge for pressure to increase therein to such extent as to be liable to cause a breakage of the glass thereof; and

(c) in the event of failure of such pressure gauge the supply of gas thereto may be readily cut off.

8. Charging connections

(1) Every connection for charging a gas container shall be outside the vehicle and in the case of a public service vehicle no such connection shall be within 610 mm of any entrance or exit.

(2) An efficient shutoff valve shall be fitted as near as practicable to the filling point. Provided that in cases where compressed gas is not used a cock or an efficient nonreturn valve may be fitted in lieu thereof.

(3) Where compressed gas is used an additional emergency shut off valve shall be fitted adjacent to the valve referred to in subparagratph (2) of this paragraph.

(4) A cap shall be fitted to the gas filling point on the vehicle and where compressed gas is used this cap shall be made of steel with a metal to metal joint.

9. Trailers

(1) Where a trailer is used for the carriage of a gas cylinder, a reducing valve shall be fitted on the trailer.

(2) No pipe used for conveying gas from a trailer to the engine of a vehicle shall contain compressed gas.

10. Construction, etc., of system

Every part of a gas container propulsion system shall be—

(a) so placed or protected as not to be exposed to accidental damage and shall be soundly and properly constructed of suitable and wellfinished materials capable of withstanding the loads and stresses likely to be met with in operation and shall be maintained in an efficient, safe and clean condition; and

(b) so designed and constructed that leakage of gas is not likely to occur under normal working conditions, whether or not the engine is running.

Schedule 4 (see regulation 40) gas containers: part II,

Specification for brass or bronze valves

1. Manufacture of valves

The stamping or pressing from which each valve is manufactured shall be made from bars produced by (a) extrusion, (b) rolling, (c) forging, (d) extrusion and drawing, or (e) rolling and drawing.

2. Heat treatment

Each stamping or pressing shall be heat treated so as to produce an equiaxed microstructure in the material.

3. Freedom from defects

All stampings or pressings and the bars from which they are made shall be free from cracks, laminations, hard spots, segregated materials and variations in composition.

4. Tensile test

Tensile tests shall be made on samples of stampings or pressings taken at random from any consignment. The result of the tensile test shall conform to the following conditions—

Yield Stress. Not less than 231.6 N/mm.
Ultimate Tensile Stress. Not less than 463.3 N/mm.
Elongation on 50 mm gauge length. Not less than 25%.

Note. When the gauge length is less than 50 mm the required elongation shall be proportionately reduced.

The fractured test piece shall be free from piping and other defects (see paragraph 3 of this part of this schedule).

Schedule 5 (see regulations 40 and 96)

Gas systems.

1. Definitions

In this Schedule—

“check valve” means a device which permits the flow of gas in one direction and prevents the flow of gas in the opposite direction;

“design pressure” means the pressure which a part of a gas system has been designed and constructed safely to withstand;

“doublecheck valve” means a device which consists of two check valves in series and which permits the flow of gas in one direction and prevents the flow of gas in the opposite direction;

“electrically operated valve” means a device which is electrically operated and opens when the ignition is switched on and closes when the ignition is switched off or the power is otherwise cut off;

“excess flow valve” means a device which automatically and instantaneously reduces to a minimum the flow of gas through the valve when the flow rate exceeds a set value;

“fixed gas container” means a gas container which is attached to a vehicle permanently and in such a manner that the container can be filled without being moved;

“gas container” means any container, not being a container for the carriage of gas as goods, which is fitted to or carried on a motor vehicle or trailer and is intended for the storage of gas for either—

(a) the propulsion of the motor vehicle, or

(b) the operation of a gasfired appliance;

“high pressure” means a pressure exceeding 1.0325 bar absolute;

“high pressure pipeline” means a pipeline intended to contain gas at high pressure;

“pipeline” means any pipe or passage connecting any two parts of a gas propulsion system of a vehicle or of a gas fired appliance supply system on a vehicle or any two points on the same part of any such system;

“portable gas container” means a gas container which may be attached to a vehicle but which can readily be removed;

“pressure relief valve” means a device which opens automatically when the pressure in the part of the gas system to which it is fitted exceeds a set value, reaches its maximum flow capacity when the set value is exceeded by 10% and closes automatically when the pressure falls below a set value; and

“reducing valve” means a device which automatically reduces the pressure of the gas passing through it, and includes regulator devices.

2. Gas containers

(1) Every gas container shall—

(a) be capable of withstanding the pressure of the gas which may be stored in the container at the highest temperature which the gas is likely to reach,

(b) if fitted inside the vehicle be so arranged as to prevent so far as is practicablethe possibility of gas entering the engine, passenger or living compartments due to leaks or venting from the container or valves, connections and gauges immediately adjacent to it, and the space containing these components shall be so ventilated and drained as to prevent the accumulation of gas,

(c) be securely attached to the vehicle in such a manner as not to be liable to displacement or damage due to vibration or other cause, and

(d) be so placed and so insulated or shielded as not to suffer any adverse effect from the heat of the exhaust system of any engine or any other source of heat.

(2) Every portable gas container shall be either—

(a) hermetically sealed, or

(b) fitted with a valve or cock to enable the flow of gas from the container to be stopped.

(3) Every fixed gas container shall—

(a) be fitted with—

(i) at least one pressure relief valve, and

(ii) at least one manually operated valve which may be extended by an internal dip tube inside the gas container so as to indicate when the container has been filled to the level corresponding to the filling ratio specified in the British Standards Institution Specification for Filling Ratios and Developed Pressure for Liquefiable and Permanent Gases (as defined, respectively, in paragraphs 3.2 and 3.5 of the said Specification) published in May 1976 under the number BS 5355, and

(b) be conspicuously and permanently marked with its design pressure.

(4) If any fixed gas container is required to be fitted in a particular attitude or location, or if any device referred to in subparagraph (3) above requires the container to be fitted in such a manner, then it shall be conspicuously and permanently marked to indicate that requirement.

(5) If the operation of any pressure relief valve or other device referred to in subparagraph (3) above may cause gas to be released from the gas container, an outlet shall be provided to lead such gas to the outside of the vehicle so as not to suffer any adverse effect from the heat of the exhaust system of any engine or any other source of heat, and that outlet from the pressure relief valve shall not be fitted with an other valve or cock.

3. Filling systems for fixed gas containers

(1) Every connection for filling a fixed gas container shall be on the outside of the vehicle.

(2) There shall be fitted to every fixed gas container either—

(a) a manually operated shutoff valve and an excess flow valve, or

(b) a manually operated shutoff valve and a single check valve, or

(c) a doublecheck valve, and all parts of these valves in contact with gas shall be made entirely of suitable metal except that they may contain nonmetal washers and seals provided that such washers and seals are supported and constrained by metal components.

(3) In every case where a pipe is attached to a gas container for the purpose of filling the gas container there shall be fitted to the end of the pipe furthest from the gas container a check valve or a double check valve.

(4) There shall be fitted over every gas filling point on a vehicle a cap which shall—

(a) prevent any leakage of gas from the gas filling point,

(b) be secured to the vehicle by a chain or some other suitable means,

(c) be made of suitable material, and

(d) be fastened to the gas filling point by either a screw thread or other suitable means.

4. Pipelines

(1) Every pipeline shall be fixed in such a manner and position that -

(a) it will not be adversely affected by the heat of the exhaust system of any engine or any other source of heat;

(b) it is protected from vibration and strain in excess of that which it can reasonably be expected to withstand, and

(c) in the case of a high pressure pipeline it is so far as is practicable accessible for inspection.

(2) Save as provided in subparagraph (4) below, every high pressure pipeline shall be -

(a) a rigid line of steel, copper or copper alloy of high pressure hydraulic grade, suitable for service on road vehicles and designed for a minimum service pressure rating of not less than 75 bar absolute, and

(b) effectively protected against, or shielded from, or treated so as to be resistant to, external corrosion throughout its length unless it is made from material which is corrosion resistant under the conditions which it is likely to encounter in service.

(3) No unsupported length of any high pressure pipeline shall exceed 600 mm.

(4) Flexible hose may be used in a high pressure pipeline either if -

(a) (i) it is reinforced either by stainless steel wire braid or by textile braid,

(ii) its length does not exceed 500 mm, and

(iii) save in the case of a pipeline attached to a gas container for the purpose of filling that container the flexibility which it provides is necessary for the construction or operation of the gas system of which it forms a part, or

(b) its length exceeds 500mm and it complies with Annex 8 of ECE Regulation 67.01 and is approved and marked in accordance with that regulation.

(4A) In the case of a motor vehicle which first used gas as a fuel for its propulsion on or after 1 January 2004 a flexible hoseof any length used in a high pressure pipe line shall comply with the requirements of Annex 8 of ECE Regulation 67.01 shall be approved and marked in accordance with that Regulation and shall be no longer than is reasonably necessary.

(5) If a high pressure pipeline or part of such a pipeline is so constructed or located that it may, in the course of its normal use (excluding the supply of fuel from a gas container), contain liquid which is prevented from flowing, a relief valve shall be incorporated in that pipeline.

5. Unions and joints

(1) Every union and joint on a pipeline or gas container shall be so constructed and fitted that it will—

(a) not be liable to work loose or leak when in use, and

(b) be readily accessible for inspection and maintenance.

(2) Every union on a high pressure pipeline or on a gas container shall be made of suitable metal but such a union may contain nonmetal washers and seals provided that such washers and seals are supported and constrained by metal components.

6. Reducing valves

Every reducing valve shall be made of suitable materials and be so fitted as to be readily accessible for inspection and maintenance.

7. Pressure relief valves

(1) Every pressure relief valve which is fitted to any part of a gas system (including a gas container) shall—

(a) be made entirely of suitable metal and so constructed and fitted as to ensure that the cooling effect of the gas during discharge shall not prevent its effective operation,

(b) be capable, under the most extreme temperatures likely to be met (including exposure to fire), of a discharge rate which prevents the pressure of the contents of the gas system from exceeding its design pressure,

(c) have a maximum discharge pressure not greater than the design pressure of the gas container,

(d) be so designed and constructed as to prevent unauthorised interference with the relief pressure setting during service, and

(e) have outlets which are—

(i) so sited that so far as is reasonably practicable in the event of an accident the valve and its outlets are protected from damage and the free discharge from such outlets is not impaired, and

(ii) so designed and constructed as to prevent the collection of moisture and other foreign matter which could adversely affect their performance.

(2) The pressure at which a pressure relief valve is designed to start lifting shall be clearly and permanently marked on every such valve.

(3) Every pressure relief valve which is fitted to a gas container shall communicate with the vapour space in the gas container and not with any liquefied gas.

8. Valves and cocks

(1) A valve or cock shall be fitted to every supply pipeline as near as practicable to every fixed gas container and such valve or cock shall by manual operation enable the supply of gas from the gas container to the gas system to be stopped, and save as provided in subparagraph (2) below, shall—

(a) if fitted on the outside of the vehicle, be readily visible and accessible from the outside of the vehicle, or

(b) if fitted inside the vehicle be readily accessible for operation and be so arranged as to prevent so far as is practicable the possibility of gas entering the engine, passenger or living compartments due to leaks, and the space containing the valve or cock shall be so ventilated and drained as to prevent the accumulation of gas in that space.

(2) Where a fixed gas container supplies no gas system other than a gas propulsion system -

(a) an electrically operated valve may be fitted in place of the valve or cock referred to in sub paragraph (1) above; and

(b) either -

(i) it shall be fitted as near as practicable to the gas container; or

(ii) if fitted in addition to the valve or cock referred to in subparagraph (1) above it shall either be incorporated into that valve or cock or be fitted immediately downstream from it; and

(c) it shall if fitted inside the vehicle be so arranged as to prevent as far as is practicable the possibility of gas entering the engine, passenger or living compartments due to leaks, and the space containing the valve shall be so ventilated and drained as to prevent the accumulation of gas in that space.

(3) A notice clearly indicating the position, purpose and method of operating every valve or cock referred to in subparagraphs (1) and (2) above shall be fixed—

(a) in all cases, in a conspicuous position on the outside of the vehicle, and

(b) in every case where the valve or cock is located inside the vehicle in a conspicuous position adjacent to the gas container.

(4) In the case of a high pressure pipeline for the conveyance of gas from the gas container an excess flow valve shall be fitted as near as practicable to the gas container and such valve shall operate in the event of a fracture of the pipeline or other similar failure.

(5) All parts of every valve or cock referred to in this paragraph which are in contact with gas shall be made of suitable metal, save that they may contain nonmetal washers and seals provided that such washers and seals are supported and constrained by metal components.

9. Gauges

Every gauge connected to a gas container or to a pipeline shall be so constructed as to be unlikely to deteriorate under the action of the gas used or to be used and shall be so constructed and fitted that -

(a) no gas can escape into any part of the vehicle as a result of any failure of the gauge, and

(b) in the event of any failure of the gauge the supply of gas to the gauge can be readily stopped. Provided that the requirement specified in subparagraph (b) above shall not apply in respect of a gauge fitted as an integral part of a gas container.

10. Propulsion systems

(1) Every gas propulsion system shall be so designed and constructed that—

(a )the supply of gas to the engine is automatically stopped by the operation of a valve when the engine is not running at all or is not running on the supply of gas, and

(b)where a reducing valve is relied on to comply with subparagraph (a) above, the supply of gas to the engine is automatically stopped by the operation of an additional valve where the engine is switched off.

(2) Where the engine of a vehicle is constructed or adapted to run on one or more fuels as alternatives to gas, the safety and efficiency of the engine and any fuel system shall not be impaired by the presence of any other fuel system.

11. Special requirements for buses

In the case of a bus there shall be fitted as near as practicable to the gas container a valve which shall stop the flow of gas into the gas supply pipeline in the event of—

(a) the angle of tilt of the vehicle exceeding that referred to in regulation 6 of the Public Service Vehicles (Conditions of Fitness, Equipment, Use and Certification) Regulations 1981, and

(b) the deceleration of the vehicle exceeding 5g.

12. Gasfired appliances

Every part of a gasfired appliance shall be -

(a) so designed and constructed that leakage of gas is unlikely to occur, and

(b) constructed of materials which are compatible both with each other and with the gas used.

13

Every gasfired appliance shall be -

(a) solocated as to be easily inspected and maintained,

(b) so located and either insulated or shielded that its use shall not cause or be likely to cause danger due to the presence of any flammable material,

(c) so constructed and located as not to impose undue stress on any pipe or fitting, and

(d) so fastened or located as not to work loose or move in relation to the vehicle.

14

With the exception of catalytic heating appliances, every appliance of the kind described in regulation 96(3)(b) or (c) which is fitted to a motor vehicle shall be fitted with a flue which shall be -

(a) connected to an outlet which is on the outside of the vehicle,

(b) constructed and located so as to prevent any expelled matter from entering the vehicle, and

(c) located so that itwill not cause any adverse effect to, or suffer any adverse effect from, the exhaust outlet of any engine or any other source of heat.

15. General requirements

Every part of a gas propulsion system or a gasfired appliance system, excluding the appliance itself, shall be -

(a) so far as is practicable so located or protected as not to be exposed to accidental damage,

(b) soundly and properly constructed of materials which are compatible with one another and with the gas used or to be used and which are capable of withstanding the loads and stresses likely to be met in operation, and (c) so designed and constructed that leakage of gas is unlikely to occur.

Legal information

This guidance is covered by the terms and conditions that apply to all GOV.UK content.