f MOBs Phase 3: Task 10 - Pressure Testing

There is a requirement for gas distribution network (GDN) operators to understand the cost, safety, and practicality of converting network pipelines from Natural Gas to Hydrogen in multi-occupancy buildings (MOBs). Previous work undertaken during project ‘MOBs Work Pack 2 Asset Information Review’ considered the requirements for pressure testing, commissioning and decommissioning of MOBs following a conversion to Hydrogen and identified the following gap in technical evidence.
A desktop study and testing are required to confirm the applicability of test pressures, test criteria and purge velocity with hydrogen to MOBs and the suitability of existing equipment for purging operation in MOBs. SGN is leading a feasibility project with some applied testing to understand the steps needed to convert MOBS to Hydrogen, including any testing required to address any evidence gaps.
This report focuses on the pressure testing requirements associated with the conversion of MOBs from Natural Gas to Hydrogen. The purging aspects of evidence gap are being addressed by Steer Energy as part of a separate task. It was proposed that ROSEN review the gas leakage and dispersion modelling of pure Hydrogen undertaken as part of the H21, H100, HyDeploy, and Hy4Heat projects, to determine the maximum permitted leak rate / pass criterion for pressure testing of network pipelines intended for Hydrogen operation.
This report was submitted to HSE for their assessment of the safety evidence for 100% hydrogen heating, which can be found at Hydrogen heating: HSE assessment of the safety evidence - GOV.UK.
Queries should be directed to DESNZ: https://www.gov.uk/guidance/contact-desnz.