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Is taller safer?

The presence of sprinklers and working smoke alarms play a larger role in building fire safety than height, suggests a study of 13 years of fire data in British Columbia.

A 2019 report from the University of the Fraser Valley in British Columbia (UFV) – Structure Fires in British Columbia: Exploring Variations in Outcomes as a Function of Building Height and Life Safety Systems – examined 31,582 structure fires in B.C. between January 2006 and August 2018 to explore the effects of building height and life safety systems.

The results may surprise those who equate taller buildings with increased fire safety risk. Not only did buildings with one to four storeys experience more and deadlier fires than taller buildings over the 13-year study period, but the damage and need for fire department intervention tended to decline the higher up in a building the fires started.

Similarly, fires in buildings of any height with working smoke alarms and complete sprinkler protection tended to have relatively low rates of casualties, required less fire department intervention and were largely contained to the room of origin than fires in buildings without those systems.

“When we first looked at the data, the annual rate of fires per building initially seemed to be higher for taller buildings,” noted Chris Biantoro, one of the report’s authors and the strategic planning analyst for the City of Surrey Fire Service in British Columbia.

“We realized we were considering all buildings – from single-family homes to high-rise condo buildings – as a single street address rather than considering the number of residential units inside. When you more accurately count each unit as a home, the relative risk in taller buildings is actually much less because they have better fire protection systems.”

The report was written by Len Garis, an adjunct professor at UFV, associate scientist emeritus for the BC Injury Research and Prevention Unit and retired Surrey Fire Chief; Dr. Joseph Clare, a senior lecturer with the University of Western Australia and former Surrey Fire Service strategic planning analyst; and Biantoro, who has a doctorate degree in operations engineering.

Data for the analysis came from the British Columbia Office of the Fire Commissioner (BCOFC) and BC Assessment (BCA). The number of structure fires (from the BCOFC) was cross-referenced with the number of buildings of a certain height across the province (from the BCA).

To determine the impact of building height, the researchers examined the frequency of fires grouped by the number of storeys – one to four, five to six, seven to 12, and 13 and up – compared with the relative frequency of fire-related casualties.

The data revealed that 92.5 per cent of fires occur in buildings no taller than four storeys in height, and that those fires also resulted in 94 per cent of injuries and 97 per cent of deaths. This is concerning when considering that, according to BCA data, almost all of B.C.’s building stock (99.8 per cent) is one to four storeys in height. Of note:

• Units in two-storey buildings have the greatest frequency of fire (0.33 per cent per year), followed by units in three-storey and four-storey buildings (both 0.16 per cent), and in five-to-six or seven-to-12 storey buildings (both 0.11 per cent).
• Units in buildings 13 storeys or highest had the lowest frequency of fires (0.04 per cent) – even less than those in one-storey buildings (0.09 per cent).

While the figures are estimates, they demonstrate the importance of considering both height and number of units when considering the relative risk of a building, as opposed to simply equating risk to the frequency of fire calls to a single street address. (For the purposes of the analysis, it was assumed that buildings of two storeys or less contained a single residential unit, and that taller residential buildings had eight units per storey.)

The authors also delved into the data to seek patterns in the heights that fires were more likely to occur in a building. Among the 31,582 fires analyzed:

• In buildings with up to four storeys, 94 per cent of fires started on the second storey or below.
• In buildings with five to six storeys and with seven to 12 storeys, 53 per cent of fires started on the third storey or higher.
• In the tallest buildings, 35 per cent of fires started in the first three storeys, 35 per cent of fires started at four to 12 storeys, and 30 per cent started at 13 storeys or higher.

To bring additional clarity and context, the authors also considered the relative rates of fire protection, extent of fire spread, fire department involvement in controlling fires, and fire-related casualties as a function of building height and level of fire origin. This analysis more clearly showed the trends related to the effects of building height and fire safety protections. Highlights included:

• As the level of fire origin increases, the percentage of fires that occurred in the presence of working smoke alarms and complete sprinkler protection also increases. Fires that occurred on the ground floor had working smoke alarms 27 per cent of the time and sprinkler protection 11 per cent of the time. By comparison, fires that started on the 13th floor or higher had working smoke alarms 71 per cent of the time and sprinkler protection 67 per cent of the time.
• Related to the increased presence of life safety systems at higher levels, the extent of fire spread also reduces as fires originate higher in buildings. Two-thirds of fires starting on the first floor are contained to the room of origin, compared to 96 per cent of fires that start on the 13th floor or higher.
• The likelihood of the fire department being required to control the fire also declined with building height. For fires starting on the first floor, 48 per cent were controlled by fire department intervention, compared to 16 per cent on fires starting on the 13th storey or higher.

There was also no indication in the data that fire-related casualties increase with building height.

When the researchers turned their attention to the type of fire protection provided in a building, they found the following trends in buildings of all heights:

• Injury rates are significantly higher in buildings with working smoke alarms but no sprinkler protection – likely because residents attempted to control the fire themselves when the alarms activated.
• The presence of working smoke alarms and/or sprinklers significantly reduced both the fire spread and the dependence on the fire department to control fires.

In addition, death rates in buildings with up to four storeys were significantly lower in buildings with working smoke alarms. Death rates were not considered for taller buildings because of the limited sample size.

The researchers also wanted to determine how fire departments across British Columbia responded to fires based on their height and sprinkler status. Surrey Fire Service initiated a self-report survey that received responses from 25 departments of varying size.

For the larger departments, the first-in response typically included an average of 15 firefighters, three engines, one ladder and one rescue. By and large, the departments reported that the presence of sprinkler protection at a building did not change their policy for first-in response to first alarms. Most also indicated that building height did not change their policy for first-in response to first alarms, with the exception of some departments that sent in larger first-in teams for very tall buildings.

In general, the patterns identified in the study were consistent with previous research the authors had conducted – although may not be widely known across the fire service.

“The results underscore the importance of life safety systems in all buildings, regardless of height,” Biantoro said. “We hope this will encourage the fire service to continue to push for complete coverage of life safety systems – ideally both alarms and sprinkler systems – in buildings of all heights, and also to consider historical fire outcomes as they shape their response policies, to make the best use of their resources.”

The study can be viewed at cjr.ufv.ca.

Len Garis: Fire Chief (ret) for the City of Surrey, British Columbia, Associate Scientist Emeritus for the BC Injury Research and Prevention Unit , an Adjunct Professor in the School of Criminology and Criminal Justice & Associate to the Centre for Social Research at the University of the Fraser Valley (UFV), a member of the Affiliated Research Faculty at John Jay College of Criminal Justice in New York, and a faculty member of the Institute of Canadian Urban Research Studies at Simon Fraser University. Contact him at len.garis@ufv.ca.
Dr Joseph Clare, Ph.D., formerly of the Surrey Fire Service, is a Senior Lecturer in Criminology at The University of Western Australia University, and an international member of the Institute of Canadian Urban Research Studies, Simon Fraser University. Contact him at joe.clare@uwa.edu.au.