f HyDeploy Report: Summary of Gas Appliance and Installation Testing

The HyDeploy project has undertaken a programme of work to assess the effect of hydrogen addition on the safety and performance of gas appliances and installations. A representative set of eight appliances have been assessed in laboratory experiments with a range of test gases that explored high and low Wobbe Index and hydrogen concentrations up to 28.4 % mol/mol. These tests have demonstrated that the addition of hydrogen does not affect the key hazard areas of CO production, light back, flame out or the operation of flame failure devices. It was identified that for some designs of gas fire appliances the operation of the oxygen depletion sensors may be affected by the addition of hydrogen. Testing of the gas fires that are present at Keele University that use oxygen depletion sensors have been shown to operate satisfactorily.
A comprehensive onsite survey programme at Keele University has assessed 95% of the installations (126 of 133) that will receive the hydrogen blended gas during the HyDeploy trial. Where access to properties was not possible then the information obtained revealed that the appliances were annually checked either through British Gas service contracts or as a result of being rental properties. The onsite testing programme assessed installations for gas tightness, and appliance combustion safety and operation with normal line gas, G20 reference gas and two hydrogen blended gases. The checks identified a small number instances were remedial work was required to correct poor condition or operation. Only one case was found to be immediately dangerous which was capped off until repair work was undertaken. CO and smoke alarms were fitted in approximately half of properties, and alarms were provided as required to the occupants. Gas tightness tests identified leaks in three installations. Where installations are gas tight then analysis has shown that no additional leaks would occur with hydrogen blended gas. There were no issues identified with the combustion performance of those appliances that were operating correctly and results were in line with those obtained in the laboratory testing programme.
The findings of the Appliance and Installation testing program have been used to define the input values into the HyDeploy quantified risk assessment (QRA) where Keele University specific operation is different to GB as a whole, or where the findings show the addition of hydrogen will change the risk profile.
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