Recognizing Probability of Building Collapse
—photo by Michael Kosinenko.
— FDNY photo, Biondi.
The possibility of structural collapse is of primary consideration in the development of strategy and tactics by the officer in command of a serious fire situation.
Were the factors leading to collapse simple, always evident and easily recognizable, the problems would be greatly minimized. We would then resort to an exterior attack and make our principal goals the protection of exposures and the maintenance of adequate distances between the building and the fire fighting forces.
Indications of collapse
The probability of collapse in commercial buildings is usually indicated when:
- Two or more floors are fully involved in heavy fire,
- Unprotected steel columns and beams are exposed to heavy fire, or
- Occupancies heavily involved in fire contain machinery or supplies with a heavy weight concentration, such as plumbing supply houses.
There are few instances where the probability of collapse is so clear-cut as the conditions just described. In other situations, the proper decisions that lead to success rather than tragedy depend on the training and experience of the operating personnel, the recognition and transmittal of information about conditions, and the collating and evaluation of this data by the officer in command.
We in New York City formerly directed most of our concern about collapse to commercial buildings. Collapse of residential buildings was rare and was usually the result of a longburning fire so that collapse could be anticipated and safety precautions could be established. However, in recent years vacant buildings, often residential, have become the most frequent scenes of collapse. The reasons for this may be summarized as follows:
Arson: While the vacant building fire problem has been with us for more than a decade, the extent and intensity of fire found by the New York City Fire Department upon arrival has been greatly magnified recently. Often three, four, and five floors of a 60 X 80-foot or larger building are involved. The use of accelerants such as gasoline is common, providing heat concentrations that seriously weaken structural members quickly. The weight of water from attacking streams is then often sufficient to induce collapse.
Looting: Recently vacated buildings are the targets of thieves who remove anything salvageable. Looters often cut floor beams, damage fire escapes, remove stairs and cut large holes in the floors and roof (for lowering salvageable material from upper floors). All of these detrimental “alterations” tend to affect the stability of a building.
Repeated fires: This is particularly perilous in partially tenanted buildings where vacant apartments are set afire accidentally by addicts and vagrants or by someone with a financial or political incentive.
Collapse traps fire fighters
The life hazard to occupants mandates an aggressive interior attack, search and rescue. This requires immediate feedback of information on stability conditions derived from the knowledge of previous fires and fire scene observations.
A recent fire in the Bronx in New York City led to the collapse of a portion of the fire building. Seven fire fighters plunged from an upper floor to the first floor and several were seriously injured. This situation produced a rescue operation amidst the possibility of an additional collapse. A study of this fire incident provides insight into several phases of the overall problem of collapse.
Description of building
The fire was in a five-story, brick, 75 X 100-foot tenement building, erected in 1908, at 862 Jennings Street in the Bronx. There were five apartments per floor.
The building was at Intervale Avenue and Jennings Street. Three stores in this building fronted on Intervale Avenue, but are carried in the plans as part of the basement. (Jennings Street is a hill.) The building was actually six stories above the ground on Intervale Avenue.
The building was vacant except for one store and a bar at Intervale Avenue and Jennings Street. The adjoining store had a rolling steel door that was closed, indicating a current occupancy. Although the building was later determined to be vacant, almost all the windows were still glazed.
There had never been a serious fire in this building. However, since March 12, 1971, there had been nine fires at 862 Jennings Street, five with light damage to the building and four with no damage. This year there were two fires, both in the vacant store at 1379 Intervale Avenue. These fires occurred on May 6 and 7, and only one engine and ladder was used at each. There was no reason to suspect a lack of stability from the building’s history or exterior observation.
Situation upon arrival
All three stores on Intervale Avenue were involved in fire this last time. Flames were showing at three windows on the second floor and one window on the third floor. A man was trapped at a top-floor window in line with the fire below. A woman, who probably had been patronizing the bar was screaming that her children were in the building. This was later proven to be false.
The rapidity of fire spread on the first floor was indicated by the fact that the owner of the bar fled the premises, leaving the cash register open and without removing the money. Burned paper money was found after operations were completed.
From the open lot at the rear of the building, flames could be seen on all floors in the outer court. The fire spread to the cockloft on the top left side of the building. Trenching prevented extension to the other side.
Due to the large amount of fire traffic at the time of this fire, response varied from the normal. Box 2739 was transmitted at 6:54 p.m., and a 10-75 was transmitted by Squad Engine 85 at 6:56 p.m. The deputy chief of Division 6 arrived at 7:00 p.m. and an all hands was transmitted at 7:03 p.m. The second alarm was transmitted at 7:04 p.m. (A dispatcher’s third alarm was transmitted.)
Lines stretched inside
Operations consisted of lines stretched to the interior, lines operating in the stores, and a deluge set providing a water curtain on the second and third floor windows to cover the aerial removal of trapped citizens.
After all the occupants were removed and the extent of fire was reported to Deputy Chief Byrne of the 6th Division, all members were withdrawn from the building and heavy outside streams were placed on three sides.
When these streams had darkened down the main body of fire, they were shut down. An appraisal of conditions was made and at least twice, selective outside streams were used intermittently to extinguish pockets of fire that could be reached from the exterior. When it appeared that conditions had fully stabilized, units were returned to the interior via the stairs and fire escapes. These advances were made with deliberate caution under the supervision of battalion chiefs. Speed was not a consideration.
Overhauling operations had proceeded for some time when suddenly an area above the center store, approximately 25 X 40 feet, running from Intervale Avenue to the interior public hall, collapsed. This occurred at 8:48 p.m. without any noise or warning, plunging seven members into a pile of rubble in the store below.
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Photo by Vincent Ferrullo
—photo by Michael Kosinenko.
Byrne immediately ordered two additional rescue companies, two additional ambulances with doctors—or the disaster unit—fire department ambulances, clergymen, and an additional battalion chief. A battalion chief was ordered to continue with the fire extinguishment where necessary while another battalion chief supervised the rescue operations.
Two of the seven members caught in the collapse were near the top of the pile of rubble and were removed immediately. The remaining five were buried in the rubble and had to be found, dug out, and removed. Despite the unknown condition of the remainder of the building, the very real possibility of additional collapse, or at least the falling of dislodged material, members on the scene never hesitated. Members worked without respite until the seventh victim was removed at 10:11 p.m.
While several members received serious injuries, at the time of this writing all are on the road to recovery. Some members have already returned to some form of duty.
Signs of collapse present
The general attitude of all present was that the collapse was sudden, unanticipated, and without noise or warning. However, investigation revealed that there were several things known to different members which, if collated into a single data package, would have alerted the commander to the impending danger. Several of these items became known only seconds before the collapse, so time was not available for communication. The factors involved were:
Water on floors: Several members stated that water was ankle deep on the floor, particularly in the area that collapsed. Units were ordered to, and did, cut holes in the flooring to relieve the water situation. Runoff water is not usually a problem in multiple dwellings. However, the depth and area of the water in this instance (concentrated in the center of the floor) indicated a possible bowing of floor beams.
Holes in floors: Several officers found holes in the floor at the fifth and sixth floors. A number of them were large enough to prevent advance. While the holes were recognized and cautious tactics were used, their presence was not reported to the officer in command. A possible explanation for this is the repetitive operations that our members respond to in vacant buildings. They are aware of the holes normally found, but associate them more with injury from falling, rather than with the stability of the structure.
Sagging floors: One officer nqted that the floors were sagging and had a wall opened at the beam ends to determine the amount of support. Finding only a half inch support, he continued examining beam ends prior to communicating this information to the chief. Moments later, the collapse occurred before the information could be relayed.
Sliding plaster and plaster dust: Another officer noticed large pieces of plaster “sliding” off the wall, and the presence of plaster dust clouds. He moved his unit to the safety of the interior stairway and was trying to contact the deputy chief by walkie-talkie when the collapse occurred.
Had most, or all, of these conditions been reported, they would have mandated a reassessment of conditions and might have led to the withdrawal of forces—at least to the interior public hall, which remained intact.
Victims must be identified
Concurrent with rescue operations, an immediate assessment of the number and identification, by name and unit, of all trapped members must be made. This is necessary to allow:
- A determination as to how extensive the operation is, and the amount of assistance needed,
- The pinpointing of an area where a victim might be located (using unit association), and
- The discontinuance of search operations as soon as all known victims have been removed. With the possibility of further collapse, the importance of this should be self-evident.
The above can be accomplished by a roll call conducted in each unit and a report submitted to the commander. The riding list provides the most expeditious means of accomplishing this. The accuracy and presence of these riding lists at this particular operation provided the information needed within a reasonable time, long before all the victims were removed.
Maintaining riding list
It is, therefore, imperative that the riding list be kept up to date. Remember:
- Only those men actually responding with the apparatus should be on the riding list. (This has no relation to roll call entries accounting for men scheduled to work that tour.)
- The riding list must be maintained in legible condition. Often poor handwriting, or perspiration, makes the list difficult to read (even by the writer).
- The riding list must be constantly revised, covering such situations as when a member goes to the store, is detailed, acts as messenger, or in any way changes his riding status.
FDNY photo, Tufte
- A copy of the riding list must be kept in the cab of the apparatus. This list must be available in the event the officer is one of the trapped victims.
Research is under way to develop a more practical method of maintaining an up-to-date, legible, easily available riding list.
Chance of second collapse
Perhaps the most pressing problem in an operation such as this is control. The chance of a second collapse is often very real and it could easily become a more tragic occurrence than the original collapse.
At this operation, the bravery, dedication, and skill of all members assisting in the rescue operation were beyond question. Observations on the scene, however, pointed to steps we could take to assure a safer and more coordinated operation.
The first few minutes after a collapse are minutes filled with trauma and confusion, even for the veteran fire fighter. Often those who have escaped injury in a collapse can’t remember anything of their experience. They sometimes find themselves several buildings or hundreds of feet from their original position without knowing how they got there.
Others who have witnessed the collapse, seeing brother fire fighters or civilian victims within the rubble, rush headlong into the midst of the danger area without a plan or tools. Of course, their immediate thought is to extricate these victims. While there are times when this is necessary and productive (the victim is on top of the rubble, can be easily removed, and there is danger of another immediate collapse), most often an organized operation will produce the fastest, safest, and most positive results.
Conducting rescue operations
The following procedures are offered:
- Company officers should form their members into a unit, and operate as a unit. Do not allow men to wander and free-lance it.
- Officers should supervise their unit, not engage in actual manual operations. Coordinating their men, observing the surrounding area for unsafe conditions, and rotating men to avoid fatigue will pay much greater dividends than adding one more “work unit” to the company.
- Only the number of men actually needed should be permitted in the danger area.
- If the particular assignment can be done by two or three men, the remaining members of the unit should be ordered outside the danger area and used for relief on a rotating basis.
- If the assignment requires the entire unit, a relief unit should be assigned by the chief. These two units should rotate as units to avoid fatigue.
- When the operations are lengthy (more than half an hour), rotation of personnel is mandatory. While perseverance and courage are noteworthy, this type of operation requires exceptional physical and mental input. Fatigue develops quickly, resulting in accidents, injuries and less productivity.
- One unit (or battalion chief with unit) should be given the responsibility of keeping track of all victims leaving the scene. Assure positive identification. Record ambulance attendant’s, or doctor’s name. Assure definite hospital destination. Record any diagnosis of injury. Turn over all this information to the officer in command.
A fire department exists because things happen that are not supposed to happen. The way we respond to the unexpected and unusual is the measure of our success. It is the ability to look at our operations in retrospect that produces the fund of knowledge that marks the fire service as a profession.
Adapted from WNYF, Issue No. 3, 1974, official publication of the New York Fire Department.