Family lose everything after 'spontaneous combustion' sparks house fire
A fire that ravaged a Waitomo family's home leaving them with almost nothing was sparked by a phenomenon known as pyrophoric action.
And fire investigators say many Kiwis may be unaware of the risk.
In the last five years it has sparked 46 structure fires nationwide in the last five years.
About 9am on Monday a resident at the isolated rural hilltop home, about 20 kilometres from the Waitomo Caves, was in the kitchen when one of the overhead lights exploded.
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She was puzzled, and reached up to touch the ceiling. It was burning hot, specialist fire investigator Kevin Holmes said.
"There was a shower of sparks between the light fitting and the ceiling - and it wasn't from the bulb so she thought it might have been electrical," Holmes said.
"The fire was obviously well established in the ceiling of the house and it has blown the electricity."
Next minute, smoke was pouring from beneath the eaves of the 153sqm house.
Holmes said the woman grabbed her niece and fled the house.
With no cell phone reception, she drove two kilometres up the road to reach her husband who was working on a property nearby.
"Just after he arrived back the ceiling collapsed into the lounge and dining area, and the fire took hold.
"The fire had burned right across inside the ceiling space."
There was little the residents could do except smash a hole in the garage and drag a few items to safety.
Everything else went up in smoke.
"It's completely gutted - they've lost the lot."
Holmes said the fire ignited in the ceiling when the timber spontaneously ignited in a process called pyrophoric action.
"Over time the timber heating up and cooling down repeatedly around a fireplace can become brittle and can sometimes spontaneously combust.
"They've had their fire going most of the winter and at least all of last week due to the cold temperatures."
Repeated heating and cooling morphed the makeup of the timber.
"We have seen it before but it's not very common but people need to be aware of it."
People could lower the risk by ensuring chimneys and flues were regularly cleaned, and checking for discolouration.
"The metal and non-combustibles around the chimney itself still transfer heat."
The owners of the property said they were surprised to hear what had ignited the blaze.
A woman, speaking on behalf of the Osborne family, said the fireplace was cleaned regularly. The flue was last cleared five months ago.
The house was fitted with working smoke alarms and had two fire extinguishers, but it took about 30 minutes for the nearest firefighters to arrive.
They were covered by insurance, she said, but felt for the family with young children who were trying to deal with losing everything.
The woman, on behalf the Osborne family, wanted to thank the local Otorohanga and Te Kuiti fire brigades for their efforts.