# Motor Vehicles (Construction and Use) Regulations (Northern Ireland) 1999, Paragraph 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;
“double-check 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;
“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 a 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 gas-fired 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 a 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 that 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.

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Source: https://www.legislation.gov.uk/nisr/1999/454/schedule/5/paragraph/1 (the official version)
Page: https://openlegislation.uk/motor-vehicles-construction-and-use-regulations-northern-ireland-1999/schedule-5/paragraph-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.