Description of BS 6400-2:2018 2018

This British Standard specifies requirements for the installation, exchange, relocation, maintenance and removal of credit or prepayment or smart meters of the following types: diaphragm, ultrasonic and thermal mass gas meters with a maximum capacity not exceeding 6 m³/h.

NOTE 1 For the purposes of this standard, installation includes design, inspection and commissioning. It is recognized that each of these tasks can be performed by the same person.

NOTE 2 For smart meters this standard only covers the associated gas work.

This part of BS 6400 is applicable to primary meter installations:

1. supplied with 2nd family gases from medium pressure gas distribution systems with a maximum operating pressure exceeding 75 mbar but not exceeding 2 bar and with a design maximum incidental pressure of 2.7 bar;

   NOTE 3 Some legacy MP networks can operate at a design minimum pressure (DMP) of 35 mbar, 65 mbar, 105 mbar, 180 mbar and 270 mbar.

2. only fitted downstream of the emergency control valve;

3. that utilize a pressure control and protection system contained within a regulator assembly that is downstream of the emergency control valve;

4. 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;

   NOTE 4 It is recognized that the final connection(s) to the gas service would not be subject to a strength test.

5. where the operating pressure at the outlet of the meter is nominally 21 mbar; and

6. installed external to the building.

NOTE 5 Installation, exchange, relocation, maintenance and removal of a secondary meter with a maximum capacity of 6 m³/h is specified in BS 6400‑1.

NOTE 6 Installation pipework is specified in BS 6891.

NOTE 7 Service pipes (including the emergency control valve) are specified in the Institution of Gas Engineers and Managers’ publication on gas services, IGE/TD/4 [18].

NOTE 8 All pressures quoted in this standard are gauge pressures and all pressure absorption values are for natural gas unless otherwise specified.

NOTE 9 Additional guidance on domestic gas systems can be found in the European functional standards BS EN 1775 and BS EN 12279.

NOTE 10  Additional guidance on measuring systems can be found in the European functional standard BS EN 1776.

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