Expert?s fireball demo shown at LNG hearing
A professor in chemical engineering at the University of Arkansas, Dr Havens was present at Wednesday?s health and safety module at the expense of the Kilcolgan Residents? Association ? who are objecting to the proposed plant on safety grounds.
With decades of experience in investigating accidents caused by the accidental release of hazardous materials, Dr Havens presented a balanced and largely objective overview of the risks associated with the transportation and storage of LNG ? as proposed for the landbank.
He also told the hearing that he was instrumental in the preparation of a computer programme which ?models? projected LNG spills and is now the recommended programme in the States for companies applying to construct gas terminals.
Giving detailed information on the nature of LNG and the potential dangers associated with it, Dr Havens, however, commended the gas industry for what he called their ?enviable? safety record, saying they should justifiably be proud of it. He was simply present, he said, to point out what can happen in the result of an accidental gas leak; how it can happen and the potential devastation it could wreak.
Most notably, it was his presentation of the previously-unreleased footage of a test accident carried out by him and colleagues in the States some years ago that made, perhaps, the biggest impact.
Interested only in chronicling the movements of the gas, the testers did everything they could to reduce the risk of ignition as they unleashed a gas spill from a storage tank.
Watching as the gas ?vapour cloud? spread laterally out on all sides, the assembly was dramatically taken aback when it suddenly caught fire and exploded several times over a large area ? culminating in a fireball sent straight up into the sky. Despite having tried everything to reduce the risk of ignition, it is thought the vapour cloud ignited when it fired a concrete block at a fence which created a spark.
In the vapour cloud?s lateral expansion, viewers also saw inarguable evidence that LNG is not lighter than air ? the notion that it is lighter than air had been promoted around the landbank, Dr Havens said. While true at ?ambient? temperatures (the methane simply rises and disperses), it is far from the case with LNG transportation.
To reduce the gas for transportation and storage, the LNG is cooled to -165 celsius until it becomes liquid. If it escapes accidentally, it escapes at very cool temperatures, regasifying too slowly to rise and, hence, spreading out laterally ? over the ground.
Its chances of meeting an ignition source while escaping on the ground are obviously much greater than if it were to rise vertically.