BS 8499:2017 pdf download

BS 8499:2017 pdf download.Specification for domestic gas meter boxes and meter bracket
1 Scope
This British Standard specifies requirements for gas meter boxes for use with single gas meter installations conforming to BS 6400, which: .
a) are supplied with gases of the 2nd and 3rd family, with a maximum capacity of 6 m3/h and a maximum operating pressure not exceeding 2 bar; and
b) incorporate any of the following meters: diaphragm, ultrasonic, credit or prepayment.
It does not apply to multiple meter installations which are installed in the same housing.
NOTE 1 The composition of fuel gases of the 2nd and 3rd family is specified in BS EN 437
NOTE 2 All pressures quoted in this standard are gauge pressures.
It covers the following designs of meter box, including any associated box extensions:
1) built-in;
2) surface mounted;
3) semi-concealed;
4) universal.
It does not cover security shrouds intended to provide additional protection to meter installations.
This British Standard also specifies requirements for the design of the standard meter bracket.
4.1 All box types
4.1.1 Gas integrity
COMMENTARY ON 4.1.1
It is essential that a meter box is impermeable to gas at atmospheric pressure such that any leaking gas is prevented from directly entering the wall, cavity or property. The gas integrity of a meter box is affected by:
a) the composite material from which the box is manufactured; and
b) the design and assembly of the box.
If a meter box conforms to Clause Z the finished material will provide adequate gas integrity.
Requirements for the design and assembly of the box are specified in 4.1.1
4.1.1.1 To ensure that the meter box is impermeable to gas at atmospheric pressure, the surface and structure of the finished box shall be complete and, when installed in accordance with the manufacturer’s instructions, there shall be no paths for leaking gas to directly enter any adjacent wall,cavity or property. This shall be verified by visual inspection.
4.1.1.2 For a built-in box, the manufacturer’s installation instructions shall provide information on the method of sealing the spigot to the box and the gas pipework within the spigot to ensure that leaking gas is prevented from entering the wall, cavity or property.
4.1.3 Ventilation
4.1.3.1 General
The meter box shall be ventilated by the inclusion of purpose-designed, non-closable ventilation,sized and located in accordance with 4.1.3.2 or 4.1.3.3, as appropriate.
NOTE For meters installed to BS 6400, a meter box conforming to 4.1.3.1 is deemed to be a Zone 2 hazardous area as defined by BS EN 60079-10 and is suitable for 2nd and 3rd family gas installations with a maximum operating pressure not exceeding 2 bar.