HSE works with international partners to provide evidence for risk assessment of new technologies, keeping the UK at the forefront of scientific and engineering advances, while ensuring worker safety.
Liquid hydrogen is of interest in transport applications such as aeroplanes. ELVHYS is an EU project designed to enhance the safety and efficiency of liquid hydrogen transfer technologies during refuelling. HSE was involved in two experimental programmes.
Firstly, HSE investigated oxygen enrichment of liquid hydrogen spills. Liquid hydrogen is so cold that it solidifies nitrogen and oxygen in the air around it to form a solid/liquid slushy- like mixture. HSE engineers and scientists studied thermodynamic mechanisms during condensation and evaporation of air that could lead to oxygen enrichment.
Secondly, HSE studied the hazards of hydrogen liquid and vapour build-up in a tank connection space (TCS). Different ventilation rates and designs were generated to identify worst-case scenarios for the build- up of flammable concentrations. In these worst-case tests, the vapour was ignited to determine explosion hazards and overpressures.
HSE fluid dynamics modellers used this data to create a validated computational model of flammable vapour build-up in the TCS.
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