FOR GENERAL CIRCULATION
Date issued:1st November02 Approved: Tony Whelan Date 1st November 2002
Period between reviews: 12 Months
New British Standard
British Standard (BS 6400-1:2002) Specification for installation of domestic-size gas meters
maximum rated capacity not exceeding 6m 3 (2nd and 3rd family gases)-
Part 1: Low pressure (2nd family gases).
Note: Parts 2 and 3 are being developed and will not be published until 2003.
A Period of three months has been allowed for user’s of the old standard to convert to the new
Commencing from 20th September 2002.
The Above Standard partially supersedes BS 6400:1997 which will be withdrawn when
all three parts have been published.
Note: Some additions to (BS 6400-1:2002)
The items listed below high-light where significant changes have been made to the existing
3 Terms and Definitions
A number of new definitions are now included e.g. maximum incidental pressure (MIP),
maximum operating pressure (MOP) and medium pressure. These reflect the standard being
sectioned into parts, which will cover the differing pressures now occurring.
Requirements of the Gas Safety (Installation & Use) Regulations for CORGI registration and
Ofgem registration for OAMI are now reflected.
6.1 Design parameters for the meter installation
6.1.1 Gas Family
All gas fittings shall be a type appropriate for 2nd family gas as defined in BS EN 437.
6.1.2 Flow rate
The meter shall be rated for the maximum gas flow likely to be encountered (see 6.2.1). All
components of the installation shall be designed to pass gas at a flow rate not less than the
meter’s maximum flow rate.
6.1.3 Pressure absorption
The pressure absorption across the primary meter installation shall not exceed 4 mbar at a
flow rate equivalent to the maximum capacity of the meter with a pressure of 19 mbars at the
outlet of the emergency control valve. Secondary meter installations shall be designed to
ensure that any connected appliances are supplied with adequate pressure to ensure that they
operate safely.( This is further explained in the Gas Industry Bulletin Service (GIBS) October
Note It is assumed that the installation pipework (whether installed before ore after the meter installation) will have
a maximum pressure absorption of 1 mbar. The limit of 4 mbar is to ensure that the pressure absorption across
the meter installation and installation pipework (to any appliance) dose not exceed 5 mbar at a flow rate
equivalent to the maximum capacity of the meter, with a pressure of 19 mbar at the outlet of the emergency
control valve, so that the pressure at the inlet to any gas appliances is not less than 14 mbar.
C&R on 6.1.3
It is a requirement of BS 6891 that the maximum pressure absorption across the installation
pipework is 1 mbar.
7 Gas transporter appraisal of primary meter installations
This clause specifies requirements involving the Gas Transporter (GT), requiring their approval
for meter housing, location, pressure control and OAMI authorisation.
8.10 Gas tightness testing and purging
This now aligns with BS 6891 and requires tightness testing to be in accordance with Institution
of Gas Engineers & Managers (IGEM) document, IGE/UP/1B Tightness testing and purging of
domestic sized Natural Gas installation.
Please find a copy of the new Standard attached. This should be read to ensure that you are
fully conversant with its requirements.