Commentary by Glenn Corbett and Dr. Vyto Babrauskas
High-rise buildings are not simply bigger, ordinary buildings. They pose some unique challenges, both to their occupants and to the fire service. The biggest concern is that fire department ladders do not reach above about 75 feet. In a shorter building, the fire department can use ladders against the façade for rescue and also for suppression. But above that height, such operations are no longer possible. Thus, it should be obvious that additional fire safety measures are needed to ensure the safety of occupants in such buildings. These issues were generally ignored all over the world until 1973. But a little earlier, two fires in high-rise buildings in New York City led to adoption of Local Law No. 5 in 1973. Only five lives were lost altogether in these two fires (One New York Plaza and 919 Third Avenue), yet fire safety specialists in the United States realized that the time had come to control the safety of high-rise buildings from the specific perspective that they are high-rise buildings.
Local Law No. 5 did not mandate sprinklers, but rather listed them as one of the acceptable fire protection options. In subsequent decades, however, it became clear that sprinklers are an essential safety feature for all high-rise buildings. Today, in the U.S., essentially all new high-rise buildings are built fully-sprinklered, and sprinkler protection has been extended to countless vintage structures. And today in the U.S., fire safety professionals are unanimous in considering that fire sprinklers are, by far the single most important safety feature for high-rise buildings. Thus, from our perspective, we find it curious that in the United Kingdom and in many other European countries, fire professionals are significantly less enthused over sprinklers.
- The Grenfell Tower Fire and Fire Safety Materials Testing
- What Firefighters Need to Know About High-Rise Building Systems
- Lessons Learned from the Grenfell Tower Fire
While most of us have gotten to expect disastrous high-rise fires in third-world countries, I believe most of us were shocked when Grenfell Tower in London burned on June 14, 2017, killing 72 persons. London is quite at the other end of the scale compared to third-world countries. Ironically, it was the Great Fire of London in 1666 that led to the first fire safety regulations in modern world history. The focus both of the news and the British government investigation was on the combustible façade with which it had been retrofitted two years earlier, using a façade system containing polyethylene-core panels. Even worse, due to the “rainscreen” design, the façade featured a two-inch gap, creating a Schlyter effect (chimney effect), enhancing fire spread upwards on the façade. In our view, no high-rise building should be fitted with a combustible façade, even though such atrocities are not unknown in the U.S., either. Thus, we would like to focus on some other issues which we feel represented disastrous fire safety management and led to the demise of so many occupants.
As U.S. fire safety specialists, we find it beyond belief that the British government would allow high-rise buildings to be constructed with only a single staircase. Even in the early 1970s when Grenfell Tower was built, any U.S. professional would be astounded that such extreme endangerment to life would be countenanced. In the U.S., the notion that any sizable building—much less high-rise buildings—demands at least two means of escape was already known and practiced in the 19th century. Also going way back to the 19th century was the knowledge that smoke can readily make a staircase unviable. One common 19th century solution was the smokeproof tower. This is an escape stair which is accessed via open-air vestibules, a feature which allows the stairs to remain free of smoke. The Grenfell building did not have a smokeproof tower; in fact, it did not have any means whatsoever to keep smoke out of the staircase, which was the one-and-only means of escape for the occupants.
The Ups and Downs of Understanding High-Rise Stairwells
Even the British press noted that one reason for the Grenfell disaster was that although the building’s smoke alarm system detected fire conditions, it gave no warning to occupants of their impending doom. What is truly baffling is that, in the view of the London Fire Brigade, this was not a bug, but a feature! Evidently, the fire officials deemed that the proper way to configure a high-rise alarm system is that it only transmits an alarm signal to a central station, but not to sound an alarm within the building, even within the floor from which the alarm was initiated. It was stated that the reason for this, was to be consistent with the British ‘stay put’ policy. We address this next, but first we should consider the implications here, again from an American perspective. American designers consider it perfectly acceptable that fires in high-rise buildings should be handled so that only localized, limited evacuation would be done. But for this to be sensible, the context must be that the building design is such that the remaining occupants are in fact safe. This requires three things: (1) that uncontrolled fire spread be precluded; (2) that other floors or zones in the building be kept smoke-free; and (3) a zoned alarm/communication system which does allow occupants from the danger zone to be evacuated. None of these features were apparently present at Grenfell.
Another significant issue is that of communications between building occupants and firefighters. The Grenfell building offered no means of providing instructions to building occupants, no ability for firefighters to have directed occupants to evacuate. This unfortunately is also true of many existing high-rises in the U.S., despite the relatively cheap cost of retrofitting a basic public address system.
From the U.S. perspective, one of the most perplexing policies of British officialdom must be their rigid “stay put” policy, despite what happened at Grenfell, where a rapidly spreading exterior fire entered numerous apartments on multiple floors. The basic concept is that fire-resistive compartmentation will serve to keep fire confined locally, and occupants somewhat remote from the fire will be safer inside their units instead of attempting to flee. This is a policy followed by many U.S. fire departments in cases where the fire is indeed localized and not spreading. However, not every fire is always contained to a modest area, and partial or full evacuation should always be available to fire commanders. To assume that any and every fire will be small and localized and that remote areas will remain smoke-free is folly.
In any country, the reality of fire is that people are much more likely to die from smoke inhalation than from burns. From a design standpoint for large or tall buildings, U.S. designers have long had an option of “shelter in place.” If this is to be a design feature and part of the standard operating procedure for a building, however, it requires a refuge area that will be clear of fire and smoke. In other words, it must be a shelter area so designed that smoke will not enter and overcome the occupants. It makes no sense to “shelter” occupants in a location where they may be overcome with smoke and perish.
Glenn Corbett, P.E., is a former assistant chief of the Waldwick (NJ) Fire Department, an associate professor of fire science at John Jay College of Criminal Justice in New York City, and a technical editor for Fire Engineering. He served on the Federal Advisory Committee of the National Construction Safety Team and is a member of the Fire Code Advisory Council for New Jersey. He is the coauthor of the late Francis L. Brannigan’s Building Construction for the Fire Service, 6th Edition, editor of Fire Engineering’s Handbook for Firefighter I and II, and an FDIC International advisory board member.
VYTO BABRAUSKAS, Ph.D., earned degrees in physics and structural engineering and a Ph.D. in fire safety. As a researcher at the National Institute of Standards and Technology, he developed devices to measure the heat release rate of products and developed a computer program for modeling the development of room fires. He founded a consulting firm in 1993 and provides fire safety science expertise to fire investigation and litigation. His Ignition Handbook is widely used in the fire services, and he has two books forthcoming: Electrical Fires and Explosions and Smoldering Fires. He is currently based in New York City, where he is affiliated with the John Jay College of Criminal Justice.
This commentary reflects the views of the authors and not necessarily the views of Fire Engineering.
