In a revelation that has sent shockwaves through the hydrogen industry, gas distributor SGN has finally released an explosion risk report from 2018. The disclosure comes after an order from the UK’s information commissioner following a freedom of information request.
The report, accompanied by a revealing video, has raised serious safety concerns related to hydrogen usage, especially in residential settings.
SGN, set to conduct a hydrogen heating trial in 300 homes in Fife, Scotland, next year, initially refused to publish the full report due to fears of misinterpretation. The report’s key findings had been made public in 2021 as part of the Hy4Heat program, commissioned by the government to assess hydrogen’s feasibility in homes. The report underscores the potential risks associated with hydrogen leaks, especially in simulated domestic settings.
Conducted by consultant Kiwa, the tests aimed to simulate hydrogen gas escapes in a domestic kitchen using fire investigation boxes. These containers, equipped with windows and a door, were filled with kitchen contents, dummies representing people, and, notably, pig carcasses. The study discovered that at both low and high gas injection rates, methane and hydrogen caused similar levels of damage. However, at higher injection rates and specific concentrations, hydrogen transitioned from deflagration to detonation-type explosions, resulting in severe damage.
The report highlights a critical incident labeled “Ignition 4,” where a 20% hydrogen concentration caused significant damage. Debris was thrown up to 40 meters, and the explosive sound was audible 1 kilometer away. At concentrations of 20% hydrogen and 80% air, the potential for severe damage to brickwork and occupants was noted. Recommendations include developing techniques to minimize the risk of high hydrogen concentrations and exploring the feasibility of installing automatic shut-off valves and hydrogen detectors.
While the UK government recommends always-open air vents above hydrogen appliances to prevent hydrogen accumulation, SGN’s report suggests further investigation into automatic shut-off valves and hydrogen detectors. The industry now faces scrutiny, with safety concerns potentially impacting the widespread adoption of hydrogen for domestic use.
