Technical Bulletin 159
Developed by BSI, IGEM, HHIC and Progressive Energy
Natural gas standards when working on domestic installations being supplied with natural gas containing up to 20 vol% hydrogen Date issued: 23 March 2021
This Technical Bulletin provides guidance to Gas Safe registered businesses and engineers related to the impact on working practices when undertaking activities on domestic natural gas installations being supplied with natural gas containing up to 20 vol% hydrogen. Background Following research undertaken by the HyDeploy project(1), all IGEM and BSI standards that underpin ACS natural gas domestic and commercial competencies were reviewed; this review related to the potential impacts of a 20 vol% hydrogen blend on public safety and the function of appliances and domestic gas installations. The review process was carried out by Blue Flame Associates working in collaboration with the HyDeploy Consortium (Note 1). The review(2) of standards was further peer reviewed by the Institution of Gas Engineers and Managers (IGEM), the British Standards Institution (BSI), the Heating and Hot Water Industry Council (HHIC) and the gas industry Standards Consultation Forum (SCF). The conclusions of the review as it relates to domestic installations and appliances form the basis of this Technical Bulletin. Review process As part of the HyDeploy project, an expert group of technical and procedural specialists collated and reviewed all BSI and IGEM procedures that underpin natural gas competencies for domestic and commercial working practices. The purpose of this Technical Bulletin is to detail the output of the review as it relates to domestic working practices. Technical areas assessed included: 1. Chimney/flue design 2. Ventilation design 3. Seals and gaskets 4. Combustion analysis* 5. CO detection 6. Leak detection fluids 7. Proving devices 8. Pipework installation
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9. T ightness testing & purging 10. G as meters, including heat input calculations 11. Excess flow valves 12. Flame arrestors 13. Temperature exposure 14. A ppliance installation and maintenance 15. Commissioning * Technical detail on the applicability of combustion analysers and their associated performance criteria can be found in Technical Bulletin 157(3).
In total, 57 standards were reviewed and a total of 83 technical questions were generated; these questions related to the potential impact of a 20 vol% hydrogen blend on the routine application of the standard by a Gas Safe registered engineer. All questions were issued to an expert technical group of the HyDeploy Consortium to provide supporting evidence of any implications. An iterative process of review and discussion was undertaken to agree the impact that a 20 vol% hydrogen blend would have on all aspects of the standards reviewed. Following the preliminary review, a second peer review was undertaken by a mixture of industry experts, including both standard setting bodies, BSI and IGEM: 1. I GEM Gas Utilisation Committee 2. I GEM Hydrogen Committee 3. B SI GSE/30 – Gas Installations (1st, 2nd and 3rd family gases) Committee 4. A select group of manufacturers and installers (HHIC), and 5. M embers of the Standards Consultation Forum (SCF). The peer review process generated an additional 69
comments/questions, which were further addressed and the final conclusions issued to IGEM and BSI. Conclusion The review demonstrated that no change to domestic natural gas standards is required to account for the impacts associated with the introduction of a 20 vol% hydrogen blend within natural gas supplies. No additional measures, guidance or actions are necessary to account for the potential presence of a blend of hydrogen up to 20 vol% within natural gas supplies for domestic installations and appliances. A minority of technologyspecific commercial areas remain for possible future study (eg, internal combustion gas engines, CNG filing stations) and these will be addressed during future investigations. BSI Standards reviewed BS 715: 2005 Specification for metal flue boxes for gas-fired appliances not exceeding 20kW BS 5440: Flueing and ventilation for gas appliances of rated input not exceeding 70kW net Part 1: 2008 Specification for installation of gas appliances to chimneys and for maintenance of chimneys Part 2: 2009 Specification for the installation and maintenance of ventilation provision for gas appliances BS 5546: 2010 Specification for installation and maintenance of gas fired water heating appliances of rated input not exceeding 70kW net. BS 5864: 2019 Installation and maintenance of gas fired ducted air heaters of rated input not
exceeding 70kW net – Specification BS 5871: Specification for installation of gas fires, convector heaters, fire/back boilers and decorative fuel-effect gas appliances Part 1: 2005 Gas fires, convector heaters, fire/back boilers and heating stoves Part 2: 2005 Inset live fuel effect gas fires of heat input not exceeding 15kW, and back boilers Part 3: 2005 Decorative fuel effect gas appliances of heat input not exceeding 20kW Part 4: 2007 Independent gas-fired flueless fires, convector heaters and heating stoves of nominal heat input not exceeding 6kW BS 6172: 2019 Specification for installation, servicing and maintenance of domestic gas cooking appliances BS 6173: 2009 Specification for installation and maintenance of gas fired catering appliances for use in all types of catering establishments BS 6230: 2011 Specification for installation and maintenance of gas fired forced convection air heaters for commercial and industrial space heating BS 6400: Specification for installation, exchange, relocation, maintenance and removal of gas meters with a maximum rated capacity not exceeding 6m3/h. Part 1: 2016 Low pressure (2nd family gases) Part 2: 2018 Medium pressure BS 6644: 2011 Specification for the installation and maintenance of gas-fired hot water boilers of rated inputs between 70kW (net) and 1.8MW (net) (Incorporating Corrigendum No. 1)
