MOBs Phase 3: Task 7 - Combined Effect of Hydrogen and Thermal Loading on Material Integrity

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). SGN is leading a feasibility project with some applied testing to understand the steps needed to convert to Hydrogen. This report is part of Work Pack 3 and summarises Task 7: combined effect of hydrogen and thermal loading on material integrity.
The aim of this task is to fill the following evidence gaps identified in ROSEN report entitled ‘16357-1 Document Landscape Review Report Issue 1-0’:
♦ Validity of current diameter, height, lateral length and material limitations and permitted jointing methods.
♦ Susceptibility of low strength steel to hydrogen cracking when subjected to stresses resulting from expansion and contraction and effect of hydrogen on likelihood of failure of risers which do not have the required allowance for expansion and contraction.
♦ Applicability of existing thresholds including minimum permitted wall thickness before isolation and corrosion damage categories for pipe designed to operate at stress levels not greater than 40% SMYS with hydrogen.
Finite Element Analysis (FEA) has been performed to assess the performance of existing carbon steel gas riser configurations when subjected to thermal loading to understand the suitability of converting the existing pipework to hydrogen.
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.