The province wants municipalities to immediately impose tougher standards for fire-resistant sheets that already have been installed on hundreds of new houses in Alberta.

CBC News has learned Alberta Municipal Affairs is issuing a notice today to every safety-code inspector in the province.

The notice recommends they increase regulation of oriented strand board, or OSB, coated with a fire-resistant paint, to ensure it meets fire-safety standards.

The province’s building code requires houses with flammable siding to be sheathed underneath with gypsum sheets, or, alternatively, with OSB coated with a fire-resistant paint that provides the same level of protection as gypsum.

"What we’re saying is, it appears right now from the information we have, that OSB sheathing with a fire-resistant coating on it, at this point, what is on the market, may not meet that standard," Alberta Municipal Affairs spokesman Parker Hogan told CBC News in an exclusive interview.

"In some ways we are stepping in and saying, ‘We need to make sure that any alternative product meets or exceeds the existing standard.’"

Notice recommends standards 

The notice follows a CBC News investigation last month that highlighted confusion surrounding regulations for the fire-resistant coated OSB and raised questions about its effectiveness after it is exposed to weathering.

The notice recommends coated OSB not be approved for use in new-house construction unless it meets a 15-minute standard for both fire resistance and flame spread.

Edmonton now has a standard that only requires fire resistance while Calgary has only a flame-spread standard.

The province says the coated OSB also must be capable of maintaining its 15-minute, fire-resistance and flame-spread standards after outside exposure to water and ultraviolet light.

Hogan said this is critical because the coated OSB may be exposed for days, or even weeks, before it is covered by siding.

"What it does is it allows the accredited safety code officers, throughout the province, when they’re reviewing this material, to make determinations based upon our new recommendations," Hogan said.

The notice also recommends manufacturers of the coated OSB must demonstrate the fire-resistant coating is manufactured and applied to the wood in a consistent and verifiable manner.

Edmonton's MacEwan fire sparked standards

Alberta introduced new fire-protection standards in 2009 following a massive fire in the MacEwan neighbourhood of south Edmonton in 2007.

It razed dozens of houses and caused millions of dollars in damages.

At the time, fire officials blamed the blaze on a combination of flammable siding and the close proximity of houses, which allowed flames to readily jump from house to house.

Hogan said Alberta was a leader in implementing new standards aimed at ensuring such massive blazes do not reoccur.

He said the province also assumed a leadership role in allowing coated OSB as an alternative to gypsum sheeting.

Edmonton and Calgary served as a test for the standards governing the use of these new products, and the cities were allowed to determine which standards they enforced.

How did the test fare?

"I think you can see from this notice we have said, ‘We need to make sure that if there is an alternate product, it has to be properly tested, properly documented and properly verified,’" Hogan said,

He added that officials from Municipal Affairs will be following up with safety-code inspectors around the province to ensure there is no more confusion.