scope:

This Standard applies to all new, onshore, Natural Gas (NG) supply meter installations (hereafter referred to as "installations") (and defined in IGEM/G/1) of flow rate (capacity) exceeding 6 m³ h^-1 and MOP upstream (MOPu) not exceeding 38 bar.

Installations with the following types of meter are covered:

• diaphragm

• rotary displacement (RD)

• turbine

• ultrasonic (USM).

Note 1: For installations of capacity not exceeding 6 m³ h^-1, intended to carry NG, BS 6400-1 or BS 6400-2 apply, as appropriate for MOP_u. For non-domestic premises, there are additional legal requirements that may have to be met, e.g. DSEAR.

The requirements of this document may be applied to installations of capacity not exceeding 6 m³ h^-1 and MOP_u exceeding 2 bar.

Note 2: For installations of MOP_u exceeding 38 bar, IGE/GM/4 applies and IGEM/TD/13 may be used for the regulation of pressure, however, where the metering pressure is not exceeding 38 bar, this Standard applies. Where IGEM/TD/13 is used, the control and fault pressure ranges have to be acceptable to the consumer; it may be necessary to apply tolerances required by IGEM/GM/8 to IGEM/TD/13 control philosophy.

Note 3: Primarily, IGEM/GM/8 has been produced for primary meters and other meters used for billing purposes. However, its principles may be applied for other meters, for example appliance check meters or departmental charging meters, when certain procedures may not apply.

Note 4: IGEM/GM/6 provides requirements for "standard" installations of MOP_u not exceeding 100 mbar. For other, "non-standard", installations of MOP_u not exceeding 100 mbar, IGEM/GM/8 applies. See also the note within Sub-Section 1.4.

Note 5: For turbine meters and USMs, in addition to IGEM/GM/8, some of the principles of IGE/GM/4 may apply and further useful information is also included.

Note 6: IGEM/GM/8 does not address the Network pipeline (see IGEM/TD/1, IGEM/TD/3, IGE/TD/4 and IGEM/G/5, as appropriate). IGEM/GM/8 does not address requirements for a pressure regulating installation (PRI) installed in a Network pipeline that is not part of the meter installation, when IGEM/TD/13 applies.

This Standard covers installations that are wholly downstream of the outlet of the ECV as recommended in IGEM/G/1, in which case the installation is not part of the Network. The owner or user of the installation would not, therefore, be a conveyor of gas on the Network and would not be subject to the general duties of the Gas Safety (Management) Regulations (GS(M)R). Similarly, the owner or user of the installation would not be an operator of a pipeline and, therefore, would not be subject to the requirements of the Pipelines Safety Regulations (PSR). However, the installation may be subject to the requirements of PSSR.

Notwithstanding the above paragraph, IGEM/GM/8 may be applied when undertaking work on legacy meter installations that do not have an ECV located on their inlet, but have a valve within the meter installation nominated as the ECV. In such installations the section of the installation upstream of the ECV will be subject to the requirements of GS(M)R which will have to be complied with in addition to IGEM/GM/8.

This Standard applies to installations intended to carry NG (a 2nd family gas as defined by BS EN 437).

Note: The Gas Safety (Installation and Use) Regulations (GS(I&U)R) define "gas" to include 1st, 2nd and 3rd family gases as well as other gases. The principles of IGEM/GM/8 may be used for gases other than NG but suitable adjustments to parameters and procedures will need to be considered by a competent person.

This Part 1 of IGEM/GM/8 deals with the design of relevant installations.

All pressures are gauge pressures unless otherwise stated.

Italicised text is informative and does not represent formal requirements.

Appendices are informative and do not represent formal requirements unless specifically referenced in the main sections via the prescriptive terms "must", "shall" or "should".