BS 6400 is a series of three standards consisting of the following parts:
- Part 1: Low pressure (2nd family gases)
- Part 2: Medium pressure (2nd family gases)
- Part 3: Low and medium pressure (3rd family gases)
BS 6400-2:2006 specifies the requirements for the installation, exchange, relocation and removal of primary meters with a maximum capacity of 6 m³/h. It is applicable to installations that incorporate credit or prepayment diaphragm and ultrasonic gas meters with a capacity of 6 m³/h.
For the purposes of this standard, installation includes design, inspection and commissioning. It is recognised that each of these tasks can be performed by the same person. This standard applies to primary meter installations:
- Supplied with 2nd family gases from medium pressure gas distribution systems operating with a maximum operating pressure exceeding 75 mbar but not exceeding 2 bar and with a design maximum incidental pressure of 2.7 bar
- Only fitted downstream of the emergency control valve
- That utilize a pressure control and protection system contained within a regulator assembly that is downstream of the emergency control valve
- Where all gas fittings subjected to medium pressure have been pre-assembled and where strength and gas tightness testing has been undertaken on the regulator assembly at the factory
- Where the operating pressure at the outlet of the meter is nominally 21 mbar.
- Medium pressure gas networks in Great Britain operate with maximum operating pressure in the range of 75 mbar or greater but not exceeding 2 bar with a design maximum incidental pressure of 2.7 bar.
Installation, exchange, relocation and removal of a secondary meter with a maximum capacity of 6 m³/h is specified in BS 6400-1.
For installation pipework is please refer to BS 6891.
Service pipes (including the emergency control valve) are specified in the Institution of Gas Engineers and Managers’ publication on gas services, IGE/TD/4.
All pressures quoted in this standard are gauge pressures and all pressure absorption values are for natural gas unless otherwise specified.
Additional guidance on domestic gas systems can be found in the European functional standards BS EN 1775 and BS EN 12279.
BS 6400-2:2006 supersedes BS 6400:1997 which is now withdrawn.
