scope:

This Reference Standard addresses the issues arising from the proposal to distribute Hydrogen through existing NG steel and PE pipelines (mains and services) repurposed for Hydrogen service at pressures not exceeding 7 bar. Where the term pipeline is used it applies to both mains and services and specific requirements for mains and services will be specified as mains or services.

This Reference Standard aims to identify and discuss the principles required for the repurposing of existing NG PE, steel and iron mains and services for use with Hydrogen at pressures not exceeding 7 bar.

For the purposes of this Standard, the term "service" is used throughout for all requirements and is not limited to "service pipework".

Note: The European Standard BS EN 12007-5 describes the specific functional requirements for service lines in addition to the general functional requirements of EN 12007-1, which describes the general functional requirements for pipelines for operating pressure up to and including 16 bar.

This Reference Standard covers existing NG mains and services operating at MOP not exceeding 7 bar

• polyethylene (PE100) between 0ºC and 40ºC

• polyethylene (PE80) between -20ºC and 40ºC

• steel between -25ºC and 40ºC.

Note: This Standard does not specifically cover the construction of mains and services of other materials. Engineers may consider alternatives brought about by advances in technology and proven concepts (see clause 1.7).

Hydrogen as referred to in this document, is as per the specification set out in Appendix 3, and therefore does not cover blends of Hydrogen and NG.

This reference standard covers Hydrogen distribution for use in domestic and small commercial premises up to the supplier's emergency control valve (ECV).

This Reference Standard is developed in the first instance to consider repurposing of existing domestic and smaller commercial gas infrastructure. Additional safety measures and precautions determined by risk assessment may be required for gas supply to more complex users such as:

• educational establishments

• multi-occupancy buildings

• non-standard distribution networks (networks which supply gas to commercial and domestic premises where there are sections of above and below ground pipework in accessible areas such as shopping centres etc.)

• non-standards services to caravans, residential parks, and moored boats.

Pressures quoted 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".