# Motor Vehicles (Construction and Use) Regulations (Northern Ireland) 1999, Paragraph 2: Gas containers


(1) A 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 practicable, the 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 adverse effect from the heat of the exhaust system of an engine or other source of heat.
(2) A 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) A 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 a fixed gas container is required to be fitted in a particular attitude or location, then it shall be conspicuously and permanently marked to indicate that requirement.
(5) If the operation of a pressure relief valve referred to in sub-paragraph (3) may cause gas to be released from the gas container, an outlet shall be provided to lead the gas to the outside of the vehicle so that the outlet shall not suffer any adverse effect from the heat of the exhaust system of an engine or other source of heat, and that outlet from the pressure relief valve shall not be fitted with any other valve or cock.

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Source: https://www.legislation.gov.uk/nisr/1999/454/schedule/5/paragraph/2 (the official version)
Page: https://openlegislation.uk/motor-vehicles-construction-and-use-regulations-northern-ireland-1999/schedule-5/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.