Multifamily fire risk factors evolve over time

Multifamily fire risk factors evolve over time

21st century sees improved suppression and ignition source depletion
Wednesday, October 27, 2021

The advent of sprinklers and drop-off in smokers are two of the most influential fire risk factors in multifamily buildings over the past 40 years. A recently released study of U.S. statistics and trends from the National Fire Protection Association (NFPA) concludes that the combination of improved suppression and ignition source depletion has reduced the likelihood of fire-related fatalities within residential high-rises, and all dwellings in general, since 1980. However, analysts highlight other emerging concerns over the same period, tied to an aging population and new types of household furnishings.

“The NFPA Fire & Life Safety analysis shows that the most successful recipe for fire safety in the built environment is the implementation of fire safety technologies through mandated codes and standards,” assert the study’s authors, Marty Ahrens and Birgitte Messerschmidt. “Most of the common causes of fire are related to human actions or lack thereof. One of the ways to tackle this issue is with continued public education alerting people to the potential dangers of fire and how to prevent them. Another method is reducing the ignition risk by utilizing fire safety standards specific to the products involved.”

The latter tact includes product standards related to cigarette ignition, the ease of operability of disposable lighters, and the ignition point, flame height and uprightness of candles. Notably, annual deaths in the U.S. attributable to playing with fire dropped from 410 in 1994, at the time consumer protection standards for disposable lighters were introduced, to 50 in 2018.

In addition, new technologies, energy efficiency directives and evolving consumer preferences have brought LED lighting to replace the incandescent and halogen bulbs that can become hazardously hot, and to carve out a growing market share for artificial candles. Although not applicable to multifamily buildings, the study’s authors also credit the surging popularity of gas fireplaces for fewer fires due to castoff burning embers or creosote buildup in chimneys of wood-burning fireplaces.

Sprinklers bolster survival rates, gap widens with single-family homes

The data shows impressive life safety performance for sprinklers. Overall, Ahrens and Messerschmidt calculate fire-related death rates in the 2014-2018 period were 86 per cent lower in homes with sprinklers, and high-rise dwellers were particular beneficiaries of that trend. While just 7 per cent of all U.S. homes reporting fires had sprinklers or some other form of automated extinguishing system (AES), they were present in 48 per cent of the reported fires in multifamily buildings, seven storeys or higher.

The report compares four-year periods in three decades — the 1980s, 1990s and 2010s — and finds a relatively steep drop in the number of high-rise fires between the ‘80s and ‘90s, falling from roughly 10,400 per year to 8,700 per year. The number of fires dipped more moderately over the next 20 years, easing down to an annual average of 8,600 by the 2010s. However, there was a more marked difference in the average death rate during the three periods, from a high of 6 fatalities per 1,000 fires in an average year in the ‘80s, to an average of 5.1 annually in the ‘90s and to 3.4 per annually in the 2010s.

In multifamily buildings with sprinklers or AES, 89 per cent of deaths during 2014-2018 occurred in the room where the fire originated. Looking across the entire universe of multifamily buildings, deaths outside the room of origin accounted for 30 per cent of all fire-related fatalities in 2014-2018 compared to 49 per cent in 1994-1998.

“The decrease in fire deaths in high-rise buildings follows the increase in the use of sprinklers in these buildings,” Ahrens and Messerschmidt state. “While compartmentation is clearly successful in limiting the spread of fire outside the room of origin, adding the additional safety layer of sprinklers can confine even more fires to the object or room of origin.”

Multi-family buildings are also less likely to lack fire safety basics. Ahrens and Messerschmidt cite findings of the American Healthy Home Survey conducted in 2018-2019, which revealed that, among respondents, 8.2 per cent of single-family homes and 2 per cent of multifamily dwellings had no smoke alarms present.

More disconcerting, 20.5 per cent of single-family homes and 9.4 of multifamily homes did not have working devices. Looking at reported home fires in 2018, roughly 57 per cent of single-family homes and 28 per cent of multi-family buildings relied on battery-operated smoke alarms, which operated as intended 82 per cent of the time.

“These differences mean that roughly two of every five reported one- or two-family home fires had no operating smoke alarms compared to less than one-quarter of the reported apartment fires,” Ahrens and Messerschmidt observe. “In 1980, working smoke alarms were only four percentage points more likely to have been present in reported apartment fires than in fires in one- or two-family homes. The difference has grown wider over time. This is one of the main factors contributing to the sharper decline in apartment fire deaths than deaths in one- or two-family homes.”

Fewer smoking-related fires with deadlier consequences

Demographic shifts could be bringing new fire safety vulnerabilities to multifamily buildings. Ahrens and Messerschmidt foresee potential heightened risk in the increasing numbers of people living alone, particularly if they are seniors and/or have disabilities. Typically, people have a higher survival rate in fire situations if someone else is also on the scene to alert them to danger, help them evacuate or control the fire.

Death rates due to home fires, measured as the number of fatalities per 1 million people, declined significantly across all age groups between 1980 and 2018. The most improved results were recorded for children under the age of 10, while the lowest overall rate, at just two per million, was registered for youths aged 10 to 19.

At the other end of the scale, the death rate surpassed 10 per million in age cohorts above 50 — at 16 per million for people aged 65 to 74, and topping out at 25 per million in for the 75+ bracket. At the same time, stats from the American Housing Survey show that increasing numbers of people 89+ are living alone, often because a spouse has died or moved to a long-term care home.

“In 2014-2018, 17 percent of fatal fire victims who were 80 or older were unable to act at the time of the fire. Nearly one-third (31 percent) had some type of disability,” Ahrens and Messerschmidt report.

The flammability of home furnishings is another major cause of concern. Statistics show that kitchens were less risky places to be during a fire in the 2010s than in the 1980s, while bedrooms and living rooms were much more dangerous. Synthetic fabrics and polyurethane foam padding burn more quickly than the natural materials, such as cotton and wool, that predominated in the 20th century. Research indicates that flashovers can occur in as little as five minutes when some more recently manufactured furnishings ignite.

“Upholstered furniture and mattresses or bedding accounted for 1 and 2 per cent of the reported fires in 2014-2018, but 17 per cent and 12 per cent of the home fire deaths, respectively,” Ahrens and Messerschmidt note. “These are relatively low-frequency, high-consequence fires. On average, one of every 12 upholstered furniture fires and one of every 26 mattress or bedding fires in 2014-2018 resulted in death.”

The prospect of ignition due to smoking is considerably lower now than it was in the 1980s, although smoking remains a major cause of home fires and fire-related fatalities. Ahrens and Messerschmidt chart a 77 per cent decline in fires attributed to smoking in the years from 1980 to 2018 and a 62 per cent decrease in fatalities. In 1980, smoking caused approximately 70,800 fires in U.S. homes versus an estimated 16,100 in 2018.

Total fatalities fell from 1,820 in 1980 to 680 in 2018. However, that translates into a significantly higher death rate in 2018, at 42 per 1,000 fires, compared to 26 per 1,000 fires in 1980. “Although these fires have become less common, when such a fire has been reported in recent years, it was more likely to be deadly,” Ahrens and Messerschmidt affirm.

In the good news department, it’s estimated that just 17 per cent of the U.S. adult population smokes, compared to 33 per cent in 1980. Today’s smokers also typically smoke fewer cigarettes than smokers of earlier generations, while more smokers habitually step outside their homes before they light up.

Leave a Reply

Your email address will not be published. Required fields are marked *