This Standard sets out requirements for over-pressure and under-pressure shut-off devices up to 150 mm nominal bore (DN 150) for use on natural gas (NG), simulated natural gas (SNG), town gas (TG), tempered liquefied petroleum gas (TLP) and liquefied petroleum gas (LPG), intended to be fitted in the gas supply downstream of the consumer billing meter or an LPG first stage pressure regulator.
The requirements apply to over-pressure and under-pressure shut-off devices intended for installation into consumer piping either directly or as part of a gas pressure regulator.
NOTE 1 Over-pressure shut-off devices generally serve to protect equipment downstream of regulators from being pressurized beyond its rated working pressure if the regulator fails.
This Standard does not cover devices incorporating automatic safety shut-off valves actuated by electrical pressure-sensing devices.
NOTE 2 The requirements for pressure-sensing devices are covered in AS 4628 and the requirements for automatic shut-off valves are covered in AS 4629.
Conformance to the requirements of this Standard does not imply acceptability for use without supplemental tests in an intended application.
NOTE 3 For over-pressure and under-pressure shut-off devices with flows greater than 200 m3/h for natural gas and town gas refer to EN 14382.