Gas explosion fears raised at hearing
SHELL EP Ireland consultants have conceded that safe shelter in the event of a rupture and explosion has not yet been identified for residents living close to the proposed Corrib gas onshore pipeline.
The consultants also told the An Bord Pleanála oral hearing in north Mayo yesterday that houses within 230 metres of the pipeline could “burn spontaneously” from heat radiation if gas in the pipe was at full pressure.
The Shell team involving Shell, RPS, JP Kenny and Det Norske Veritas (DNV) was responding to a series of questions on safety scenarios put to its members by An Bord Pleanála’s pipeline expert, Nigel Wright.
Mr Wright, a consultant and former British Gas engineer, is one of two experts retained by An Bord Pleanála for the oral hearing into the modified onshore route for the pipeline.
Residents would have just 30 seconds to escape from thermal radiation if gas within the pipe was at full pressure, the team acknowledged in response to Mr Wright’s examination.
Houses within 171m would be at risk if the gas pressure was at 144 bar – the pressure level agreed by the developers after a State-commissioned safety review – the Shell team admitted when it was put to them in questions.
Both 171m and 230m are greater than the minimum separation distance of 140m from houses allowed for in the pipeline route, Mr Wright observed.
The “assumption is that there will be shelter”, Mr Wright was told by the Corrib project team.
Mr Wright confirmed with the Shell team yesterday that this pipeline was unique.
He asked why the onshore pipeline beyond the landfall had been designed for 345 bar when it had been agreed to limit pressure to 144 bar onshore.
Mr Wright was told by a team representative that this was “appropriate to prudent design”.
The integrity management system also allowed for small leaks past valves in the network, the Shell team said.
The Shell team also acknowledged that the controversial practice of gas flaring would be used if pressure crept up in the system, in response to a leakage scenario outlined by Mr Wright.
Mr Wright asked the developers why a recommendation in the Advantica safety report on use of an isolation joint at the landvalve installation at Glengad was not being applied
A Shell representative said that such joints created “inherent weaknesses”.
Mr Wright questioned the developers on the security of the beach valve, and why potential damage in a terrorist attack had been excluded from the quantified risk assessment (QRA) submitted.
Shell responded that including this information was “not part of a normal QRA”.
Mr Wright referred to evidence given last week by former Army bomb disposal expert Comdt Patrick Boyle, representing community group Pobal Chill Chomáin.
Comdt Boyle had outlined the impact of the July 2004 gas pipeline explosion in Ghislenghien, Belgium, in which 24 people died and more than 120 people were injured.
Mr Wright also questioned the team on frequency of accidents.
Last week Desmond Branigan, of DB Marine Research and Associates, told the hearing that Lloyd’s Marine Intelligence Unit had recorded 1,200 deaths in the past decade (to 2008) as a result of pipeline fractures in 58 countries.
Questioned on State responsibility for the safety of staff at the land valve installation, the team said a document would be sent to the Health and Safety Authority.
The hearing, chaired by Martin Nolan, continues today.
It is expected to run into next week.