With several devastating fires recently, the relationship between building materials and fire damage has been thrust into the spotlight, with opinions falling along fairly predictable lines.
For example, the Canadian Wood Council Supports has come out in support of a third-party independent study that claims there is little difference in fire spread, death and injury rates in residential fires across buildings constructed with wood, steel and concrete, provided the buildings are properly equipped with smoke alarms and automatic fire sprinkler systems.
The February 2014 report “Fire Outcomes in Residential Fires by General Construction Type,” released by the University of the Fraser Valley (UFV) in British Columbia, challenges the general belief that completed buildings built predominantly with steel or concrete are significantly safer in a fire than those built predominantly with wood.
“The report doesn’t favour one building type over another – if anything, it shows the value of sprinklers and smoke alarms in protecting lives and property in all types of buildings,” says Len Garis, City of Surrey, B.C. Fire Chief and UFV adjunct professor. “The report adds valuable science-based data into the public arena so that better informed decisions can be made in our efforts to improve our building practices.”
Changes to the British Columbia Building Code to permit taller wood-frame buildings, along with pending changes to the Model National Building Code of Canada, have sparked a debate in Canada’s construction sector, as well as the first responder community and different building material interests, about best practices for these buildings.
“With our findings in mind, and in parallel with other research findings from the authors, it should be considered that more emphasis is placed on ensuring all buildings have operating, current and optimal fire safety systems,” says Garis.
The report reviewed a set of 11,875 fires in residential buildings of five broad construction types that were reported to the B.C. Office of the Fire Commissioner between October 2008 and October 2013. The 11,875 fires were divided into five construction type categories for comparison purposes: uUnprotected wood construction – exposed wood joists and trusses; protected wood construction – wood joists and trusses protected by plaster or gyprock; heavy timber construction; unprotected steel construction – exposed steel joists and trusses; and protected steel or concrete construction.
Overall, the report shows that the fire safety of buildings has more to do with effective fire safety systems, such as working smoke alarms and complete automatic sprinkler protection, than with their construction materials. The report goes on to show that the presence of a working smoke alarm reduces the death rate for all construction types, while the presence of a sprinkler system brings the death rate to zero for all types. The data also shows a reduction in injuries across the board for all construction types with sprinkler systems, but an increase, except for heavy timber construction, when smoke alarms are the only fire protection system.
Yet how much of an impact building materials used to construct a building has an impact on the safety of its inhabitants, firefighters and property remains unknown, according to Marcus Poirier, president of MasonryWorx, the trade association of brick, block and stone masonry industry professionals. This is because, according to Carl Pearson, past president of the Fire Fighters’ Association of Ontario, “the Province of Ontario doesn’t gather any statistics on the impact of building materials on fire damage and fire spread.”
The Ontario Fire Marshall and Emergency Management’s Standard Incident Report (SIR), which must be filled out after every fire in the province, tracks the operation and type of smoke alarms, fire alarm systems and sprinkler systems, as well as, the cause of injury or death including from falling debris. The SIR even tracks where an injury takes place in relation to the fire – at the fire origin, in the same room, on the same floor, on the floors above or below the origin of the fire.
“What isn’t tracked are the building materials used in the building to determine over time if some building materials and practices have an impact on the spread of fire, any injuries or deaths resulting from the fire, or increased property loss,” says Poirier. “This is a gap in the fire incident data that needs to be filled.”
The National Research Council tests the fire resistance of building materials in the laboratory, but does not track those results in the field.
According to Pearson, the use of lightweight building practices such as engineered wood in floor joists and roof trusses is changing the way firefighters fight fires because of the unpredictability of these materials. This can have a dramatic impact on the property loss and insurance claims.
“The widespread use of lightweight construction and contents made from oil based/synthetic materials throughout buildings today means that when they catch fire, they burn with more intensity than ever before,” says Pearson.
The Ontario Ministry of Labour Fire Fighters Guidance Note #6-18, states that, “Buildings constructed using lightweight materials that are not sufficiently protected by sprinklers or effective non-combustible structural protection systems may collapse much sooner than expected and without the warning signs that are commonly present in fires that involve legacy construction.” The Guidance goes on to recommend that firefighters, “Consider employing defensive fire attack strategies where no threat to human life exists within buildings that contain unprotected lightweight construction.
“The comparison between combustible and non-combustible firewalls too should be tracked in the field to compare fire spread, injury, loss of life and property damage,” says Poirier. “The performance of exterior claddings in real-life situations should also be assessed.”
The association believes more complete fire statistics about the behavior of building materials and effectiveness of building practices in the field will assist the public and policy-makers at all levels of government – municipal, provincial and federal – in identifying safer building practices for the public and firefighters, and in understanding the true costs, both public and private, associated with building practices and materials.