The province is again calling on municipalities to implement a new fire-safety standard, this time for new houses under construction.

The standard is supposed to ensure there is not another massive fire like the one that razed dozens of houses in Edmonton’s MacEwan neighbourhood in 2007.

Alberta Municipal Affairs has issued a notice to every safety-code officer in the province. The notice recommends municipalities implement a new fire-code standard for oriented strand board, or OSB, coated with a fire-resistant paint.

Those coated boards are now installed on the sidewalls of houses to stop fire from easily spreading from house to house.

If implemented, the standard would require coated OSB to be certified, through testing by an independent testing agency, that it meets a flame-spread rating of less than 25.

The flames-spread rating is a measure of how fast a flame spreads along the face of a board. Plain OSB has an average flame-spread rating of about 140.

The city of Calgary has already adopted this standard. Edmonton has announced it will follow suit May 1.

Questions about effectiveness of standard

But at least one fire-safety expert has some doubts about the effectiveness of the flame-spread standard.

"Those requirements are kind of an educated guess," says Igor Oleszkiewicz. "I don't think they are supported by thorough research. "

Oleszkiewicz is a former National Research Council scientist who helped create both federal and provincial fire codes, including the code for Alberta. He says there are tougher standards that could better test whether these products will adequately slow the spread of fire.

This is the second notice issued by the province in the last few weeks. The notices follow a CBC News investigation that highlighted confusion surrounding regulations for the fire-resistant coated OSB and raised questions about its effectiveness as an alternative to gypsum board.

The first notice recommended changes to the building code, but those changes also focused on coated OSB.

Province steps in

Municipal Affairs spokesman Parker Hogan previously told CBC the coated OSB must retard fire as effectively as gypsum board, which is the standard, or it should not be used as an alternative under either the building or fire codes.

"In some ways we are stepping in and saying, ‘We need to make sure that any alternative product (such as coated OSB) meets or exceeds that existing standard,’" he said.

Both notices also recommended that coated OSB must continue to meet fire-safety standards even after it has been exposed to the normal weathering – rain and sun – encountered in construction.

The fire-safety standards implemented after the 2007 MacEwan fire created a new industry in Alberta, with several manufacturers producing fire-resistant coated OSB.

Oleszkiewicz said he doubts the industry is mature enough to meet the standards the province expects the municipalities to enforce.

He said some coated boards taken from a manufacturer’s factory may meet fire-safety standards in a testing agency’s laboratory.

But he questions whether those mass-produced boards could meet the same fire-safety standards if chosen randomly from a distributor or from a construction site after exposure to the elements.

Consistency an issue

"I think the key question here is consistency and reliability of the product," he said.

"For example, if you use gypsum board, and you go to a store, you will get a product that the consistency and reliability of this product is supported by a third-party agency that does testing and then follows up during the manufacturing and distribution process. I don’t yet see the (coated OSB) industry at this stage."

Fire officials in Edmonton and Calgary have told CBC News they don’t know how they would ensure coated OSB products would meet fire-safety standards after being exposed to weathering.