1.1  This Specification is part of a series of Institution of Gas Engineers and Managers (IGEM) publications, providing a specification for gas meter and converter serial numbering and model identification formats. 
 
1.2  This Specification has been drafted by an IGEM Working Group, appointed and subsequently approved by IGEM’s Gas Measurement Committee, and has been approved by IGEM’s Technical Coordinating Committee on behalf of the Council of IGEM. 
 
1.3  This Specification 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 (ACoPs) or guidance, and reference needs to be made to such statutory Legislation or official guidance for information on legal obligations. 
 
1.4    New and improved products, materials or production methods may be adopted prior to this Specification being updated. Amendments to this Specification will be issued when necessary and their publication will be announced in the Journal of IGEM and elsewhere as appropriate. 
 
1.5    Requests for interpretation of this Specification in relation to matters within its scope, but not precisely covered by the current text, are to be addressed to Technical Services, IGEM, IGEM House, 26 & 28 High Street, Kegworth, Derbyshire, DE74 2DA or [email protected]. Such requests will be submitted to the relevant Committee. Any advice given by or on behalf of IGEM does not imply acceptance of any liability, and does not relieve any party of their obligations. 
 
1.6    This Specification was published in September 2019. 

2.1   This Specification defines the requirements for gas meter and converter serial numbering and model identification formats. 
 
2.2     This Specification covers meters with a capacity not exceeding 99,999 m3 h-1. 
 
2.3     All pressures quoted in this Specification are gauge pressure unless otherwise indicated. 
 
2.4     Italicised text is informative and does not represent formal requirements. 
 
2.5 Appendices are informative and do not represent formal requirements unless specifically referenced in the main sections via the prescriptive terms “must”, “shall” or “should”.