Inquest hears fatal Slacks Creek fire has too many unknowns
A FIRE investigator who tried to re-create various scenarios to determine how a blaze that killed 11 people ignited has told a coronial inquest there were too many unknown variables to give a definitive answer to what started the inferno.
He said it was possible a lamp in the downstairs study which somehow came into contact with paper could be to blame.
A coronial inquest is investigating the deaths of three women, four teenagers and four children under the age of 10, from two families, who died in a house fire at Slacks Creek, south of Brisbane, on August, 24, 2011.
The blaze is believed to be Australia's worst house fire.
Inspector Gordon Hemphry of the Queensland Fire and Rescue Service Fire Investigation Unit told the inquest on Monday he set up series of tests in shipping containers to determine whether a lamp could have been the ignition source.
He said the containers were furnished with what investigators believed was in the study at the time of the blaze, but stressed it was only a replication as there was no definite proof as where objects were actually located or the levels and exact location of fuel sources.
"We carried out a series of tests using the same make and model of lamp from the house in conjunction with different sized light bulbs," he said.
"In tests one and two, using a 40 watt light bulb, we could not get ignition when the lamp was placed in contact with paper.
"In test three, using a 60 watt globe, the lamp was placed on its side and in contact with paper and we were able to get ignition."
Mr Hemphry said the 60 watt bulb took 12 minutes to ignite and one hour for flames to spread and fully engulf the room.
He said it became obvious throughout the testing a globe needed to have direct contact with paper otherwise ignition was not achieved.
"The slightest difference can make a big difference in these types of situations," he said.
"One centimetre either way could mean ignition or no ignition.
"There are too many variables and those unknown variables can make a huge difference."
Mr Hemphry told the inquest it was his view that the cause of the fire was still undetermined.