BY FRANCIS L. BRANNIGAN, SFPE (FELLOW)
The National Institute of Occupational Safety and Health (NIOSH) has issued its report F-13 2000 on the McDonald’s Restaurant fire in Houston, Texas. Chief Vincent Dunn and I separately served as consultants on the report. I developed the following thoughts from reading the NIOSH report. Some of them were incorporated in the final report.
THE BUILDING
I first saw parallel chord wood trusses in 1953, in the construction of a supermarket. At the time, I did not know what they were called, but looking at them told me they were more likely to collapse than solid- sawn joists. I wrote to the then New York fire commissioner suggesting they be examined. There was no reaction. As an Atomic Energy Commission staff member, I turned my attention to being the expert on explaining the true hazards of radiation to firefighters.
In 1971, in the first edition of Building Construction for the Fire Service (BCFS), despite the fact that I had no fatal experience to cite, I ended my description of trusses with “BEWARE THE TRUSS,” because of its apparent inherent hazards.
 The webs of wooden I-beams in this structure were destroyed, leaving the top and bottom flanges in place. [Photo by Steve Corwin, Oregon (IL) Fire Protection District.] |
There are still fire departments that operate under trusses as if they present no hazard. It would appear from the text that there was no adequate recognition of the hazard despite the fact that three Texas firefighters had died in a truss collapse some months earlier.
Any one-story commercial building built in the past almost 50 years should be assumed to have a truss roof or its equally hazardous cousin, the wooden I-beam (see photo below) until it has been otherwise determined. The presence of long, clear spans is another clue that the roof is probably trussed. Trusses may also be found on recently constructed roofs of multistory commercial buildings not tall enough to require fire-resistive construction. Check with your local building department to see what is permitted in your locality. In Florida, wood trusses were permitted on the top floor of a high-rise concrete condominium.
The presence of heavy air-conditioning units and other heavy equipment on the roof should be assumed. These items are supported on closely spaced trusses (a grillage). The multiple trusses do not increase fire safety because all the trusses can be burning at the same time. Take the tower ladder out when traffic is quiet, get up, and look down at the roofs in your area.
Do not assume that there is no problem if the roof is sawn wood joists. Three Fire Department of New York (FDNY) firefighters died when overhauling a fast-food restaurant in an old one-story commercial building. There was no recognition of the hazard presented by air-conditioning equipment on the roof. They literally pulled the air-conditioning unit down on themselves.
I witnessed a fire in a supermarket with a steel-bar joist and gypsum plank roof. To support the sealed gypsum ceiling in the meat-cutting area, required by health rules, a wooden structure was hung from the bar joists. This structure, ignited by an electrical short, was the only fire. The refrigeration units were hung from the wooden structure. A truck company was pulling down the wooden structure. Sensing the hazard, I asked them to hold up and, from a distance, carefully pull away the gypsum board so I could get a picture of the connection. As the firefighter put his hook into the gypsum board, the refrigerating unit crashed down where they would have been standing.
Two Orange County firefighters died in a truss roof collapse somewhat similar to the Houston collapse. They thought they had a minor fire above their heads and sent for pike poles and a salvage cover to protect the stock below when they pulled the ceiling. As a result, I was asked to give a special training program for all officers and engineers (who serve as acting officers) in the hazards of roofs and trusses.
Not long afterward, Orange County units responded to a fire in a restaurant. The fire started from an exterior neon sign and entered the sawn joist roof at the rear of the restaurant through a vent. The engine officer went up a scuttle ladder and observed the wind pushing the fire into the truss area over the dining room. The building was cleared of firefighters; shortly thereafter, there was a total collapse. A fire officer of an automatic mutual-aid company criticized the pullout as “premature.” In fact, the units could not hit the fire because of a gypsum ceiling (to be described later). To squelch any rumors, the shift commander brought back all the same units to the scene. He and I discussed the situation for the benefit of all.
THERMAL IMAGING CAMERAS (THE FIREFIGHTER’S RADAR)
The flimsy nature of many of today’s buildings indicates the extreme hazard of the headlong rush into the burning building. The thermal imaging camera (TIC) should not be an afterthought. It should be thought of as an immediate tool that is as necessary as the nozzle. It should be used to determine on the first attack whether the hazard of burning trusses or I-beams or sawn beams is overhead or in the floor.
The Granbury (TX) Fire Department was one of the first to use the TIC before entering a one-story commercial building. The firefighters saw fire in the overhead and were outside when the collapse occurred. Boston firefighters discovered through use of the TIC holes in the floor that would have pitched firefighters into the fire.
Once trusses are involved in fire, it is unconscionable to permit firefighters to be on or under them because the time to collapse is absolutely unpredictable. “Get in and get out” can be a suicide mission. Incredibly, after an officer sent into a burning church in Memphis, Tennessee, to examine the (wood-truss) roof had reported it unsafe, units were still permitted to operate inside the building. Two fatalities occurred when the roof collapsed.
THE CEILING
Typically, but not universally, the ceiling on the truss-roof building will be a layer of gypsum board intended to delay a contents fire from entering the roof void. Its efficiency is dubious. Such a structure with a peaked roof or vents is not equivalent to test structures that have received a fire-resistance rating because of the unlimited amount of air in the void. So, despite what the building department might think, it is not the equivalent to an assembly that has been rated for fire resistance. When fire starts above or gets above the gypsum board, it is not an asset to the firefighter; it is a detriment. It hides the fire and prevents the hose stream from hitting the fire. If, as is often the case, thermal insulation has been placed on the top of the gypsum board, the ceiling will fall faster because the heat is retained, which causes the nails to heat up and fall out.
THE HAZARD OF SUSPENDED CEILINGS
One of the weapons of the Roman gladiator was a net and a trident (a three-pronged spear). The opponent was entangled in the net and stabbed to death. Many ceilings consist of tiles that meet the ASTME 84 flame spread standard, not fire resistance. Note that the undefined term “fire-rated” is used indiscriminately (see BCFS3, 294-296). These ceilings are supported by a lightweight steel grid that is suspended by wires. At the McDonald’s fire, one Houston firefighter, who escaped, and one victim were entangled in the wires. The breathing apparatus tank is particularly vulnerable to entanglement.
A Memphis, Tennessee, firefighter died in a high-rise fire when he became entangled in wires that were above the ceiling in the hallway. FDNY firefighters have reported becoming entangled in cable TV and other wiring that was just glued in place; the adhesive melted.
There is no ready solution for this problem. Some agencies with adequate resources should work on it. Where possible, avoid open areas, and stay as close as possible to walls or half-high partitions, which may keep the ceiling from coming all the way down. Surprise may cause panic-driven efforts that are ineffective and waste air. Firefighters should be trained about this hazard and call a “Mayday” as soon as they become entrapped. Wire cutters were found near one victim. These cutters could be used to cut wires but would be ineffective on the metal grid units. Rapid intervention teams should be aware of this hazard and be equipped with a tool that can cut the metal grid units rapidly.
Another Suspended Ceiling Danger
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It is appropriate to mention another hidden hazard-the suspended tile ceiling. This type of ceiling is often used to rehabilitate older buildings that have combustible acoustical tile installed, either glued up or on a wooden structure. The following is excerpted from the September 2000 Ol’ Professor column:
“A most serious related hazard is often created when a building is remodeled. The code requires that a new ceiling that meets flame-spread requirements be installed. No code of which I am aware requires that the old ceiling be removed.1 The new “fire-rated” ceiling is installed below the old ceiling, leaving the dangerous combustible ceiling above. Fire will burst down out of that void. Two firefighters died in Wyoming, Michigan, when fire burst out of the ceiling. Even then, the city did not amend the code. Sixteen persons died in the fire at the John Sevier Nursing Home in Johnson City, Tennessee. The fire involved combustible tile left in place when a new grid ceiling was suspended below.”2 [See Figure 1.]
“The National Institute of Standards and Technology estimated that the CO production in the void could be as much as 50 times greater than without the void.”
NIOSH Report #98F-06 describes a basement fire in which an inferno burst out of the ceiling when the new tile ceiling was opened. Two firefighters died. When inspecting a rehabilitated building that shows a new suspended ceiling, pop a tile and see if old combustible tile is above. In a fire, I would use a big line with an open bore tip to tear down the ceiling and eliminate the void.
If the department becomes aware of a rehabilitation project, let the owner know how hazardous it is to hide the old tile. Recommend that it be removed, to avoid the creation of a bomb. If the owner refuses to remove the tile because “the Building Department said it was OK,” describe how operating a big line that throws one ton of water a minute to blow down the ceiling will eliminate the bomb.
TACTICS
Force all building doors as soon as possible. At the Houston McDonald’s fire, note that one firefighter died near the rear door. Sometimes exit doors are chained or otherwise impossible to open, particularly in the rear. Firefighters’ presence in the building makes the building “occupied,” and all exits should be available, even if the doors must be torn down.
In the Orange County, Florida, fatal fire, a firefighter used his SCBA to break the glass in a locked exit door. I noted in the report that the first firefighters entered though the door’s lower panel. The entire doorway should be cleared out before a firefighter enters so that there will be a clear exit path.
BACK TO TRUSSES
All should be trained in the maxim “You can have raging fire over your head and not know it.” I brought this hazard to attention in 1971 in the first edition of BCFS (page 125). As described in the September 2000 Ol’ Professor column, firefighters narrowly escaped a collapse because the incident commander saw fire coming from the scissor truss roof and ordered an evacuation. The collapse occurred as they exited.
Maryland firefighters had a similar experience in a fire in a Jiffy Lube. In another reported fire, fire sparks fell from the ceiling, which was then prodded with a pike pole. Heavy fire was seen. An evacuation was ordered. The ceiling fell before all could get out.3
If a “firefighter’s radar” (TIC) had been in the hands of the first crew at these fires, the raging fire above the ceiling would have been detected.
TACTICAL SUGGESTION
For one-story, free-standing buildings like a McDonald’s Restaurant, I suggest that fire departments consider using a tower ladder to permit a crew to open a hole into the void on the windward side. In a typical McDonald’s, the first hole would only be into the mansard. Another hole would be needed to open the void. This should be a small inspection hole to admit limited oxygen and reduce the flame area if fire comes out. If fire is found, the building should be evacuated and a line should be directed into the void. Stay clear of the mansard. An interior truss collapse caused the collapse of the mansard and the death of a Los Angeles County firefighter.
For roof ventilation, it would appear that the only relatively safe method is to work from an aerial apparatus that has a third articulating boom that can put the crew in a horizontal position directly over the roof. Be aware that ventilation of the truss space intensifies the fire and can cause a burst of fire to come out the opening and precipitate an earlier collapse. If heavy smoke or solid fire exits the ventilation hole over a truss roof, evacuate the building. The structure is being destroyed. Conventional training pictures of ventilation show smoke from contents escaping, making it possible for firefighters to work in the interior. I have seen none that discuss the burning of the building. If you are on the roof and make a good cut in a truss roof and heavy smoke and fire come out, get off the roof. Notify the IC so the affected area, which may be the whole building, can be evacuated.
THE AUTOPSY
The autopsy report said both firefighters died of suffocation and smoke. This reportedly has led some proponents of trusses to take the position that “they were not killed by trusses; they died of suffocation.” This same problem occurred in National Fire Protection Association firefighter fatality reports some years ago. Several people complained about the false impression given, and the report procedure was modified.
TRAINING DEFICIENCY
Firefighters are given live training in structures that are built so they cannot collapse and that have no hidden spaces where fire can burn undetected. They are taught to take the punishment and “put the wet stuff on the red stuff.” All this is necessary, but it should be supplemented with a heavy dose of structure hazards presented by lectures, slides, movies, and reports such as this one-to teach the students the difference between the training fire and the real fire.
By nature and training, firefighters are aggressive and often resist orders to back out. The overall gravity of the situation may not be apparent, particularly on a dark night when the volume of smoke going upward may not be evident.
“We’ve got a good shot at the fire” is often the excuse for delay. Some aggressive fire departments resent any intimation of retreat. I know of no fire department that drills on immediate evacuation. The argument that it is not very macho doesn’t stand up. The U.S. Navy considers itself quite macho; however, when you join a ship, you learn three things immediately: where you sleep, where you eat, and how to get off the ship in a hurry. The signal “Abandon Ship” triggers an immediate response.
I continue to urge a specific change in dispatching language. Apparatus should be dispatched to a building fire. As soon as Command determines that the fire involves the structure-as distinguished from the contents (which may be the case on arrival), it is a radically different situation. The gravity resistance system is now under attack. All units should be sent-and acknowledge the receipt of-this emergency message: “This is now a structural fire.” The word structural should be reserved for just such a situation. This does not necessarily mean a defensive operation, but it is a “heads up” for all concerned. In the case of trusses or wooden I-beams, I believe that department SOPs should provide for evacuation of the affected area as soon as it is involved in fire.
MANTRAS
Some mantras that should be taught to all firefighters and officers include the following:
- The most important duty of an officer is to bring his or her firefighters home safely.
- The building is your enemy. Know your enemy.
- A nighttime fire in an unoccupied building has probably been burning for some time.
- You can have heavy fire overhead and not know it.
- No building is worth a firefighter’s life. (Vincent Dunn)
- Falling debris has the right of way. (John Mittendorf)
MANAGEMENT IMPERATIVE
I think every chief should take seriously the legal liability that might be incurred if a firefighter is killed under circumstances that indicate that using a thermal imaging camera would have shown that entry was too hazardous. Some day, somewhere, a chief will be personally sued for flagrant disregard of personnel safety by not providing available equipment that would have prevented the loss. Criminal prosecution for “flagrant disregard of safety” is not beyond the range of possibilities. I realize cameras are expensive, but a clever trial lawyer will find many expenses in your budget that could have been forgone to provide the necessary funds.
ANOTHER MCDONALD’S RESTAURANT FIRE
Pennsville, New Jersey, firefighters found smoke issuing from the eaves of a McDonald’s Restaurant on arrival. After 15 minutes, the interior attack was abandoned because of concern about the structure’s stability. Shortly thereafter, the roof collapsed.
Endnotes
1. I have been told that the Standard Building Code can be read to prohibit this practice. It should be forbidden in so many words.
2. Isner, M. and Cahanin, G., “Fire Investigation Report, Elderly House Fire,” Johnson City, Tenn., Dec. 24, 1999.
3. See “Five Companies Trapped: A Lesson in Accountability,” Charles J. Kortlang, Fire Engineering, March 2001, 69-76.
FRANCIS L. BRANNIGAN, SFPE (Fellow), recipient of Fire Engineering’s first Lifetime Achievement Award, has devoted more than half of his 59-year career to the safety of firefighters in building fires. He is well known as the author of Building Construction for the Fire Service, Third Edition (National Fire Protection Association, 1992), and for his lectures and videotapes. Brannigan is an editorial advisory board member of Fire Engineering.
