1.1    This Reference Standard has been agreed between the IGEM Technical Coordinating, Gas Transmission and Distribution, Gas Utilisation, Gas Measurement and Hydrogen Committees, who are responsible for the publication of IGEM Standards and has been approved by IGEM’s Technical Co-ordinating Committee on behalf of the Council of IGEM.

1.2    This Reference Standard is aligned to IGEM/TD/13 Edition 3 and aims to identify and discuss the principles required for the safety and integrity of Hydrogen pressure regulating. 

This Reference Standard intends to provide a point of reference for those requiring an understanding of the implications of Hydrogen pressure regulating, detailing the characteristics of Hydrogen and detailing the comparisons between Hydrogen and Natural Gas (NG). It identifies the measures which need to be considered when designing, operating and maintaining pressure regulating installations not exceeding 7 bar.

This Reference Standard is intended to be a source of reference for any subsequent Hydrogen trials and any related IGEM documents.

1.3    This Reference Standard applies to the safe design, construction of new Hydrogen pressure regulating installations (PRIs) and the repurposing NG PRIs, as well as the inspection, testing, operation, maintenance, decommissioning and disposal of Hydrogen (PRIs) not exceeding 7 bar, in accordance with current knowledge and operational experience.

Note:    Reference is to be made to Appendix 1, which contains a glossary of terms, acronyms, abbreviations, subscripts, units and symbols used in this Reference Standard.

This Reference Standard reflects the need to ensure adequate reliability and continuity of supply at pressures that are safe for the downstream system and equipment.

1.4    This Reference Standard makes use of the term “must”, “shall” and “should” when prescribing particular requirements:

• the term “must” identifies a requirement by law in Great Britain (GB) at the time of publication
• the term “shall” prescribes a requirement which, it is intended, will be complied with in full and without deviation
• the term “should” prescribes a requirement which, it is intended, will be complied with unless, after prior consideration, deviation is considered to be acceptable.

Such a term may have different meanings when used in Legislation, or Health and Safety Executive (HSE) Approved Codes of Practice (ACoP) or guidance, and reference needs to be made to such statutory Legislation or official guidance for information on legal obligations.

1.5    It is now widely accepted that the majority of accidents in industry generally are in some measure attributable to human as well as technical factors. People who initiated actions that caused or contributed to accidents might have acted in a more appropriate manner to prevent them.

To assist in the control of risk and proper management of these human factors, due regard is to be taken of HSG48 and HSG65.

1.6     The primary responsibility for compliance with legal duties rests with the employer. The fact that certain employees, for example “responsible engineers”, are allowed to exercise their professional judgement does not allow employers to abrogate their primary responsibilities. Employers are required to:

(a)    have done everything to ensure, so far as is reasonably practicable, that there are no better protective measures that can be taken other than relying on the exercise of professional judgement by “responsible engineers”.

(b)    have done everything to ensure, so far as is reasonably practicable, that “responsible engineers” have the skills, training, experience and personal qualities necessary for the proper exercise of professional judgement.

(c)    have systems and procedures in place to ensure that the exercise of professional judgement by “responsible engineers” is subject to appropriate monitoring and review.

(d)    not require “responsible engineers” to undertake tasks which would necessitate the exercise of professional judgement that is not within their competence. There needs to be written procedures defining the extent to which “responsible engineers” can exercise their professional judgement. When “responsible engineers” are asked to undertake tasks which deviate from this they are to refer the matter for higher review.

1.7    This Reference Standard also considers specific requirements for “small PRI’s” with maximum operating pressure (MOP) of 7 bar and maximum capacity of 200 m3 h-1.

1.8    This Reference Standard does not attempt to make the use of any method or specification obligatory against the judgement of the responsible engineer. Where new and better techniques are developed and proved, they are to be adopted without waiting for modification of this Standard. Amendments to this Standard will be issued when necessary and their publication will be announced in the Journal of IGEM and other publications as appropriate.

1.9    Requests for interpretation of this Reference Standard in relation to matters within its scope, but not precisely covered by the current text, may be addressed to:

• Technical Services, IGEM, IGEM House, 26 & 28 High Street, Kegworth, Derbyshire, DE74 2DA or 
• emailed to [email protected].

These will be submitted to the relevant Committee for consideration and advice, but in the context that the final responsibility is that of the engineer concerned. If any advice is given by or on behalf of IGEM, this does not imply acceptance of any liability for the consequences and does not relieve the responsible engineer of any of their obligations.

1.10    This Reference Standard was published in January 2024.
 

2.1    This Reference Standard covers the design, construction, inspection, testing, operation and maintenance, decommissioning and disposal of any new installation within scope and the repurposing of existing PRIs for use with Hydrogen.

For the above phases in the lifecycle of an installation, a quality management system is to be applied in accordance with BS EN ISO 9001.

2.2    This Reference Standard covers pipeline PRIs containing Hydrogen with:

a)    MOP not exceeding 7 bar

b)    operating temperature:

• for Hydrogen , between -20°C and 120°C.

2.3    This Reference Standard gives recommendations relating to the repurposing of NG PRIs to Hydrogen service. 

These recommendations are only be considered for PRIs and installations which have been operated in accordance with an edition of IGEM/TD/13 (and its predecessors TD/9 and TD/10) and a full maintenance history is available. 

Note: The material performance factors defined in ASME B31.12 are based on limiting the hoop stress, not derating the tensile properties. 

2.4    This Reference Standard covers installations for Hydrogen in the vapour phase. This Standard does not address gases in the liquid phase and covers installations handling odorised or unodorised Hydrogen. 

2.5    All pressures quoted are gauge pressures unless otherwise stated.

2.6    Italicised text is informative and does not represent formal requirements.

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