The safety of the future hydrogen economy

Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of the required infrastructure. Significant international effort has been initiated to develop relevant codes and standards. To prevent emerging codes, standards and local regulations from being unnecessarily restrictive, real operating experience is needed using full-scale experimental trials. This paper begins with an overview of experimental work commissioned by both the regulator and industry to help quantify the hazards and risks. It then summarises work co-funded by the GB regulator and EU on: Jet releases, barriers to reduce safety distances and self ignition undertaken using high pressure hydrogen compression, storage and release equipment. Liquid hydrogen spills from a road tanker through a vacuum insulated transfer hose. Findings include: jets are predominantly momentum-driven; a 600 barrier reflects less heat back to the source than a 90 degrees barrier; the lowest burst pressure for self-ignition is 3.55 MPa; and initial findings suggest a pool can be formed if a liquid release is made onto the ground. The experimental data from this work has been used to establish safety distances, and define conditions under which self-ignition may occur. Crown Copyright (C) 2011 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.