A fire engineer who has studied boarding house risks says the safety rules are too slack and need tightening.
Multiple people have been killed in a fire that swept the 92-room Loafers Lodge in Newtown, in Wellington early today.
Dr Geoff Thomas's research in 2014 found multi-unit buildings without sprinklers have the highest fire casualty rates.
"There's inconsistency in the treatment of fire safety," Thomas told Nine to Noon today.
For short-term accommodation "the risk is not dealt with very well".
"The rate of fire fatalities was about twice that for residential houses, but if it was unsprinklered it was four times that," he said.
Fire engineer: fire risks of short term housing
The old age of many short-term accommodation blocks or houses was another weak spot.
"If you look at any disaster, typically, a number of things have to go wrong.
"And quite often in older buildings or facilities, then you might have a fire safety feature that was already compromised. So rather than have say three or four things go wrong to create a tragedy, you may only have one or two."
He conducted the research when he was at Victoria University, when he realised the residential fire safety requirements were low.
Anywhere people slept raised the risk, as the sense of smell closed down when a person slept, he said.
If alarms did not work - as has been reported at Loafers Lodge by residents - a person might not wake up in time.
Ironically, shopping malls and office blocks, where no one sleeps, had a lot of protections, like mandatory sprinklers, as they were judged to be high hazard due to being crowded, he said.
The fire rules demanded sprinklers for anything over 25 metres tall, but not below that if a building had two stairwells, or one stairwell below 10m high.
What was needed in the first place was enforcement of the current rules around alarms and exits, Thomas said.
The research covered buildings all over the country and also drew on coronial data.