scope:

This Reference Standard addresses the issues arising from the proposal to distribute Hydrogen through steel and polyethylene (PE) pipelines (mains and services) at pressures below 7 bar. Where the term pipeline is used, it applies to both mains and services; specific requirements for mains and services will be specified as mains or services.

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

This Reference Standard covers new Hydrogen mains and services operating at MOP not exceeding 7 bar for:

• polyethylene (PE100) between 0ºC and 40ºC

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

• steel between -25ºC and 40ºC

Note 1: 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 1.6).

Note 2: Steel pipelines for Hydrogen transmission at MOP of > 7 bar are covered in Hydrogen Supplement to IGEM/TD/1.

Note 3: For the repurposing of existing natural gas distribution network refer to IGEM/TD/22 Reference Standard for Repurposing Natural Gas Distribution Mains and Services for Hydrogen.

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 domestic and smaller commercial gas infrastructure. Additional safety measures and precautions which will need to be 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 "shall" or "should".