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 Dr. Carlos Estuardo Ventura, professor of Civil Engineering at UBC, expressed doubt about Premier Gordon Campbell’s taller wood-framed buildings. (Carmine Marinelli, 24 hours) |
An investigation by 24 hours has uncovered serious concerns about the government's controversial decision to allow construction of five- and six-storey wood-frame buildings.
Premier Gordon Campbell first announced his intention to allow such buildings in May. This, after the ailing forest industry lobbied the government to promote provincial wood products by making the B.C. Building Code "wood-centric" and requiring all new private buildings to use such products in their construction.
At the time, 24 hours revealed senior engineers were worried about how such buildings would respond to earthquakes. And, in the United Kingdom, there have been calls to halt their construction because of fire safety issues.
Despite those worries, though, the government enacted an amendment to the code earlier this month that will allow for the construction of five- and six- storey wood-frame buildings effective April 1, 2009. But 24 hours has uncovered numerous concerns related to that amendment and the process by which it was introduced. Among them:
In an exclusive interview, B.C.'s fire services liaison group chair Stephen Gamble stated, "We have some real big concerns" about five- and six-storey wood-frame buildings.
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In a letter sent to the government last year, Gamble warned, "Many fire departments do not have the training or resources to respond" to fires in buildings of that height. Moreover, "the more floors a building has, the longer it takes to escape and with our aging population, more time will be needed ... for occupants to safely exit a structure during a fire."
The government is requiring five- and six-storey wood-frame buildings to have sprinklers and fire-resistant exterior cladding, which Gamble - the president of the Fire Chiefs' Association of B.C. - acknowledged will give firefighters "at least some chance to deal with the issue."
But the government hasn't acted on other recommendations made by the fire services liaison group, which has suggested those buildings have non-combustible exit stair shafts, smoke control measures and emergency generators - among other features.
In response to questions as to whether six-storey wood-frame construction is safe, the government has claimed "six-storey wood frame construction is already practiced in other places, such as Seattle, Washington and Portland, Oregon. Buildings recently constructed there have performed well."
But Seattle and Portland officials have confirmed their cities only allow for the construction of five-storey wood-frame buildings.
Asked about that conflicting information, a provincial housing and social development ministry spokesperson maintained such buildings do exist in Seattle and Portland - citing the example of a "six-storey all-wood condo development that is visible from Interstate 5."
But when contacted by 24 hours, American local government officials in cities that presently allow five-storey wood-frame buildings questioned B.C.'s decision to allow six-storey wood-frame buildings.
"Nobody even wants to talk about six wood" because of its "inherent dangers," said Des Moines, Washington plans examiner Greg Fox. "Wood burns, obviously. And I know that sounds like a ridiculous statement. But it's a very basic statement. And the premise is you're not going to have enough time to get people out of six on wood."
For his part, Portland chief engineer Jed Sampson told 24 hours, "At some point, it doesn't become economically reasonable to stack up that much wood. And it doesn't perform very well for you."
Even at five storeys, Portland plan review section manager Terry Whitehill said he's seen some buildings where "they end up putting so many nails in those wooden panels that the plywood and board behind it just splinter."
"Myself, I'd be a little nervous about it - probably more than a little," said Seattle principal engineer and building official Jon Siu. "I think we are getting toward the edges of what we can do [with wood.]"
In response, the provincial government has stated, "We are not aware of any instances where mid-rise wood-frame buildings in neighbouring jurisdictions have not performed well."
A government analysis of the issues surrounding multi-storey wood-frame construction relied heavily on the work of Kevin Cheung, who is described as "an expert in the field of multi-storey wood-framed construction and an advocate for increasing this type of construction."
But what the analysis doesn't mention is Cheung is the technical services director for the Western Wood Products Association, an industry association representing softwood lumber manufacturers in the United States. In response, the government has denied it relied "on any single opinion expressed in the scoping review" in making its decision to allow five- and six-storey wood-frame buildings. Instead, that decision relied "on the extensive advice of our B.C./Canadian experts to develop Code changes that meet B.C.'s needs."
The analysis, while discussing the vulnerability of multi-storey wood-frame buildings to earthquakes, paraphrased Cheung as stating "wood is timeless building material known for its structural capabilities ... During recent earthquakes, damage to most wood-frame structures occurred to homes built prior to modern seismic code requirements."
But the analysis provided just one example of such a building being subject to seismic testing.
That building, however, was built using special materials and techniques. So the results of the test aren't "directly transferable to the typical North American wood-framed building," according to the analysis.
The government won't allow five- and six storey-wood-frame structures constructed in the province's earthquake zones to have irregular shear walls. In other words, according to Structural Engineers Association of British Columbia interim president David Davey, those walls - which are meant to protect against seismic and wind forces - must "line up" and the building "must be of a regular shape."
The government has described this as a "conservative approach" to ensuring such buildings are earthquake resistant. But UBC earthquake engineer facility director Carlos Ventura told 24 hours, "I doubt it."
"We don't have evidence to state these are conservative provisions," continued Ventura. "Is that sufficient? Maybe it is. Maybe it is not. But we just don't have the hard data to show that works."
In the midst of this doubt, the Structural Engineers Association of B.C is developing guidelines for the construction of five- and six-storey wood-frame buildings.
But there is presently no requirement for builders to follow those guidelines when they are released.
And that was a disappointment for the association's interim president Davey, telling 24 hours "the time was not sufficient for that to be done. So they will come out more as recommendations and assistance to designers."