Bad Fire Doors Can Cause Deaths

The taller the building, the more likely poor maintenance of fire doors can turn the entire structure into a massive chimney, funneling dangerous smoke and fumes far beyond the source of the fire. When fire doors intended to seal off circulation between floors are bad, they create the hazard rather than protecting against it.

By Rebecca Martin

The Bronx fire this week that took the lives of 17 people highlights the continuing concerns over the airflow dynamics of multi-story residential buildings. The fire began when a space heater burst into flames in one of the apartments. However, while the fire itself did not spread rapidly, two broken doors floors apart drew the resulting smoke in and upward much like a chimney flue. The resulting rapid distribution of smoke led to the resulting deaths. This kind of deaths from substandard housing is not an isolated issue in the New York Metropolitan area. 

Bad fire doors

Bad fire doors change the circulation patterns of smoke, changing a building’s air pressurization in ways that can turn an entire building into a chimney, funneling smoke far from the source of the fire.

Fire Door Malfunction

Residents had fled through a third floor door into the stairwell. The door featured a self-closing mechanism which malfunctioned. Another open door on the fifteenth floor drew the fire upward. Contributing to the situation was a resident population used to false alarms and other malfunctions in the building where alternative and dangerous solutions to heating problems were common. Space heaters and improper use of stoves were not uncommon during colder weather. The building was also unequipped with a sprinkler system which was not required.

Visibility was also an issue for those attempting to flee the building via the stairwell. Tragically, bodies in the stairwell also contributed to the difficulty in fleeing the smoke.

Several complaints had previously been filed about lack of adequate heating in the building and several citations over the failure of self-closing fire doors had previously been issued. Judith Goldiner, attorney in charge of the civil law reform unit oat the Legal Aid Society, involved in helping tenants find new homes, maintains this is usually a problem with older buildings yet that this particular building was in comparatively good repair.

“That’s why it’s so surprising that this happened,” https://www.nytimes.com/2022/01/10/nyregion/bronx-apartment-fire-smoke.html

Yet there should be nothing surprising about this event. The particular problems associated with multi-story buildings are well known. Most of the deaths associated with fires in multi-story residential buildings are caused by smoke rising in just such a way as to create a flue effect.  A published study from Warsaw, Poland last year found several problems intrinsic to multi-story structures. https://www.mdpi.com/2073-4433/12/6/705/htm

Fire Doors are Meant to Seal Smoke and Flames

Not only was smoke determined to be the leading cause of fatalities, this risk increased with the height of the building. They also determined that smoke could rise through stairways and elevator shafts. Bad fire doors are often a big contributing factor. 40% of fatalities in such cases were due to the toxic gases that accompany a fire, such as carbon monoxide or hydrogen cyanide. This increased the risk to firefighters responding to the scene of a high rise fire.

Upon examination of the airflow in medium-rise buildings there are other factors at work. The integrity of the stairwell itself, as well as a lack of other air sources can contribute to the flue-like function such as occurred in the Bronx fire. Simulations in this study showed stairwells could fill with smoke within 60 seconds, obviously impacting the amount of time that one could evacuate safely. As a result, evacuation plans need to be based on the actual conditions present at the scene.

This particular study concluded:

“(1) when the building is completely closed, smoke accumulates in the staircase, increasing the temperature and concentration of harmful fire gases, and making it difficult to carry out rescue operations and evacuation of residents; (2) the existence of a window leading to the roof is too small to effectively remove smoke from the entire building volume; (3) the use of mechanical ventilation significantly improves conditions in the staircase; (4) the provision of vents in the upper parts of the building is necessary for the extraction of smoke from the building—even the use of an axial fan with the window closed will not improve the conditions in the staircase; (5) the overpressure in the staircase caused by rising smoke will cause harmful gases to enter the apartments through all possible leaks in a door; (6) the use of an axial fan should be considered by the person in charge of the rescue operation each time during fires occurring in buildings higher than 12 m with large internal spaces—the rapid use of mechanical ventilation can shorten the time of operations and improve their safety.” https://www.mdpi.com/2073-4433/12/6/705/htm

Pressurization Problems Can Cause Safety Issues

According to sciencedirect.com: “A pressurization system is intended to prevent smoke leaking passed closed doors into stairs by injecting clean air into the stair enclosure such that the pressure in the stair is greater than the adjacent fire compartment.”

Traditionally evacuations of multi-story buildings during a fire are done in phases to maintain the correct pressurization needed to prevent smoke from flowing into the stairwell. Those on the floor containing the fire are evacuated first and then other floors, phase by phase. This allows for the maximum time for pressurization to keep the escape route clear.

The problems associated with pressurization are the result of the many variables which can exist in construction and design, as well as variables such as non-functioning self-closing doors. Older buildings which may have complied to an engineering standard when first constructed may not be in compliance due to structural leaks, added ventilation or addition of structural changes.

Atmospheric conditions such as wind and temperatures may also contribute to the efficiency of pressurization systems.

“The number of doors open at any one time is critical to determining the peak flow rate of the fans serving the pressurization system. Normally in the design process, a door at the foot of the stair is assumed to be open during fire fighting (for fire fighters entering the building) and also a single door on the fire floor. However, this may not represent the practicalities of evacuation or fire fighting in a tall building. Any doors being opened beyond the small number assumed in the design case will cause a loss of air, preventing the pressurization system from performing as intended, potentially allowing smoke into the core.” https://www.sciencedirect.com/science/article/pii/S2214398X13000046?via%3Dihub

Know Your Evacuation Plan

Clearly lack of a proper evacuation plan can contribute to the failure of effective stairwell pressurization in addition to mechanical failure.

In the case of the Bronx fire, most of the residents were immigrants from Gambia and many of the victims were children, including one two-year-old. 35 people were still hospitalized with life-threatening injuries while 37 were receiving treatment and expected to recover. 17 lost their lives.

While New York Attorney General Letitia James assured vigil attendees that the cause of the fire would be uncovered https://www.nbcnews.com/news/us-news/17-bronx-fire-victims-identified-youngest-was-2-years-old-rcna11883, most of the conditions which led to this tragedy are well-known and well-documented. Buildings with insufficient heat are nothing new to those in financially vulnerable populations. What we do have to address is that the potential for failure exists in multi-story buildings and just because we can build them and we need to build them doesn’t mean that we have addressed all of the problems associated with the basic physics of the structures satisfactorily.

 

 

 

 

 

 

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