Edmonton fire chief Ken Block is worried about changes to the national building code allowing the construction of six-storey wood-frame apartments and condominiums. 

The old rules limited the height of the highly flammable buildings to four storeys. 

Although the new six-storey structures will have to have sprinklers in attics and balconies and non-combustible siding, Block isn't sure those protections are enough.

He worries the structures haven't been safety tested enough for safety. 

If such a structure catches fire while still under construction, Block said it would present  a high risk to surrounding buildings.

"The amount of heat that will be displaced by a fire of a six-storey, wood-frame construction building is immense," he said. " It's like 40 per cent more than a four-storey."

The provincial fire commissioner's office thinks the new structures will be safe.

Acting Deputy Fire Commissioner Jeremy Wagner said he would feel comfortable living  in a six-storey wood-frame building.

"I do trust in the codes," he said. "They're taking my safety in mind."

But Block and his colleagues aren't so sure. They plan to lobby the province for revisions to the code.

Edmonton has had at least two massive fires in four-storey condos under construction in the past two years which caused millions of dollars in damages.