DELAYED BACKDRAFT

BY THOMAS DUNNE

One of the most common commercial establishments in any city or suburb is the tire repair/ storage occupancy. It can range in size from the small storefront repair shop to the large sole-occupancy tire dealership. Under the best conditions, an advanced fire in one of these stores presents a difficult challenge to firefighters.

On May 6, 2002, the Fire Department of New York (FDNY) confronted a challenging scenario involving an inaccessible cellar fire and eventual backdraft in just such an occupancy that would ultimately require nearly 20 hours for complete extinguishment.

A phone alarm was transmitted to Bronx units at 0105 hours that morning for a fire in a tire store at the corner of Third and Tremont avenues. Units responding to the scene received building information through the Critical Information Dispatch System (CIDS), a computerized program that provides information on specific hazards at selected street addresses. Typically, CIDS provides units with information on the size of the building, type of construction, and presence of hazardous contents or structural conditions.

The CIDS informed the initial assignment of three engines, two ladders, a rescue, and a battalion chief that the tire shop shared a common cellar with another store in the building and that cellar access was through the tire store. In addition, the company officer who had originally recorded the CIDS information included a consideration of an outside attack for a cellar fire in the building. This information would prove to be vital in formulating the strategy for attacking the fire.

The first units to arrive observed smoke showing from a tire repair shop on the first floor of a two-story, 50- 2 100-foot commercial building of brick and wood-joist construction that contained, from left to right, the tire shop, a mattress store, and a storefront church. The entire second floor was an office occupancy.


Front view of the fire building soon after personnel were withdrawn. The visible fire was extinguished but continued to develop in the basement. (Photos by Steve Spak.)

Third Avenue (exposure 1) was in front of the building; exposure 2 was a similar attached commercial building; and a 10-foot-wide alley separated the fire building from exposure 3, a one-story taxpayer (strip mall). Exposure 4 was an open lot on the corner of Third and Tremont avenues (see diagram and photos).

With no visible fire showing, the first- arriving chief (Battalion 18) directed the units to stretch 21/2-inch handlines and to begin opening the rolldown gates of all the first-floor occupancies to determine the extent of the situation. Once accomplished, it was clear that the smoke was contained to the tire store alone, and Ladder 27 entered the store to search and locate the source of smoke.

Visible fire was spotted at the base of the cellar stairs in the tire store, and Engine 46 was able to extinguish it with a handline. At the same time, the adjoining stores were searched and monitored for smoke or heat extension, and they continued to show clear.

As the on-duty deputy chief, I arrived at the scene to assume command of the fire. Battalion 18 apprised me of the situation. I directed the second-arriving battalion chief (Battalion 19) to take a position at the rear of the fire building to supervise units attempting to locate a rear entrance to the cellar and position a handline to protect exposure 3.


The exterior attack continued in the front of the building after the backdraft occurred.

At this time, the black smoke originally coming from the tire shop started to turn white, indicating at least partial fire extinguishment. Efforts were continued to check the adjoining stores for extension and to locate other means of cellar access, since there were reports of floor-to-ceiling tire storage in the common cellar. The two-story attached commercial building (exposure 2) was checked and found to be protected by a substantial fire wall.

Approximately two minutes after the initial appearance of white smoke, the smoke color emitting from the tire store started to turn dark again. Smoke also started showing from the mattress store next to the tire shop.

Positioned in front of the building, I observed a situation in which smoke was growing rapidly, increasing in pressure, and remaining dark in color. Clearly, the quick initial attack performed by first-arriving units had not completely extinguished the fire in the cellar.

At this point, I ordered all members out of the fire building, transmitted a second alarm, and began to set up for an outside operation. The time of day, nature of storage, and rapidly expanding fire problem were all factors in this decision. The firefighters were the only life hazard. The possibility of this change in strategy had, of course, been considered even before the first units arrived, given the information and clear message CIDS provided.

A portable deck gun, a handline, and Tower Ladder 58 were all in position at the front of the fire building. Fire was still confined to the cellar, but the limited access and likelihood of tire storage throughout a common cellar presented the problem of applying water directly to the flames.

A high-expansion foam attack was considered to confine and suffocate the fire in the cellar. This tactic was not pursued because of the limited means available for applying foam: The stairs within the tire store were still the only means of access to the cellar. Equally important, there were very limited means of venting the cellar.

A roll call of all units at the scene was conducted to ensure that all members were accounted for. Battalion 18 was placed in charge of protecting the exposure 2 building, and Battalion 19 remained at the rear of the building to cover the alleyway that separated the fire building from the taxpayer on the exposure 3 side. The safety officer viewed the operation from all sides to ensure that the proper collapse zones had been set up and maintained.

Instructions were transmitted for Tower Ladder 33, responding on the second alarm, to set up on Tremont Avenue in the Battalion 19 sector. This provided another means of protecting the rear as well as a different angle of attack on the fire building. Similarly, an additional tower ladder (Ladder 51) was special-called to the scene with instructions to set up at the corner of Third and Tremont avenues.

With lack of a direct means of applying water to the burning tires in the basement, and with very limited ventilation, heavy smoke continued to generate. Smoke color varied, turning at times brown, green, and black. At ap-proximately 0200 hours there was a smoke explosion, or backdraft, which drove out heavy black smoke under strong pressure from the first floor in the front and rear of the building. It is worth noting that this occurred about 45 minutes after the arrival of the first units and initial application of water on the fire.

Immediately following the backdraft, more fire became visible on the first floor, extending from the now fully involved cellar. This was actually viewed as a positive development, since the cellar fire was now self-venting and there were finally a few direct means of applying the master streams on it.


The building’s structural integrity was evaluated, and although a few storefront signs had blown out onto Third Avenue, there were no indications of any cracks or other damage. Early in the operation, all of the first-floor occupancies were opened up to determine the extent of the fire. This probably helped minimize the damage incurred by allowing the force of the cellar-generated explosion a less restricted path through the first floor.

Despite continued master stream application, the volume of fire soon led to extension to the upper floor and cockloft by interior shafts and structural components that were not accessible to the streams.

Now facing what would obviously be a lengthy and large-scale operation, plans were established for continued monitoring of exposures and relief schedules for the units operating. As a precaution, surrounding areas were surveyed to determine if any combustible structures might be affected by flying brands from the cockloft/roof fire. This did not prove to be a problem, although units in a large area of the Bronx were dispatched throughout the night for reports of smoke caused by this fire.

The outside attack continued through the night; the fire was finally declared “under control” at 0641 hours. Two tower ladders were kept in operation for the duration of the following day tour, extinguishing hidden pockets of fire and preventing the possibility of a rekindle.

Most fire departments can expect to have similar occupancies in their communities. Proper inspection and awareness of the fire potential are the first steps in dealing with them.

Check for a certificate of occupancy for the premises and a permit for the air compressor, if one is required. This is also the ideal time to become familiar with the layout of the building and the amount and nature of storage. Note and record any condition that might create a problem in a fire.

Inspections will generally reveal the presence of large tire inventories. In New York City, for example, nonsprinklered tire shops are allowed a maximum of 1,000 square feet of tire storage. If sprinklered, up to 14,700 square feet are allowed in a nonfire-resistive building. A sprinklered, fire-resistive building has no limit on storage permitted.

The NFPA Handbook indicates that sprinklers on their own might control but not extinguish these fires. Each day many fire departments face huge product inventories that will inevitably require a taxing application of handlines or master streams for fire suppression.

LESSONS LEARNED

The problems encountered at this incident highlight some basic concepts applicable to many fire operations.

  • Critical response information. It is absolutely vital that fire units be provided with information on potential building dangers before they arrive at the fire scene. Ideally this would be in verbal and printed forms as they are responding. The CIDS information provided at this fire undoubtedly prevented serious injuries.
  • Backdrafts. Most firefighters are trained to recognize the signs of a possible backdraft when first arriving at the scene. A sealed-up taxpayer pushing and sucking smoke with high heat and no visible fire would be a typical scenario. Perhaps there is not enough emphasis on the possibility of a backdraft occurring after units have been operating for awhile.

In my assigned division alone, there have now been two instances of a backdraft occurring sometime after units began their initial firefighting operations.

Beware of any enclosed space that is issuing heavy smoke and is not properly vented. Explosive carbon monoxide and other gases may be building up in cellars, dropped ceilings, cocklofts, and so on. Proper ventilation is the key to prevention; if that is not possible, exercise extreme caution.

  • Exposure 3 awareness. At most fires we respond to, the rear of the fire building is not immediately visible. Often, as in this incident, this can be the most seriously threatened exposure. Any member in a position to do so should quickly inform the company officer of conditions in the rear. Urgent information should be relayed directly to the incident commander.
  • Flexible planning. A chief needs a basic plan of action when managing a fire or emergency. He must also allow for the possibility of changing plans. At this fire, an interior attack was initiated and subsequently changed to an exterior operation because of conditions encountered. Another tactic (high-expansion foam) was considered and rejected.

If things are not working, the incident commander must be receptive to alternate ideas and initiate change when the situation calls for it.

The finest strategy is absolutely useless without the personnel to perform the tactics required. Firefighters and company officers are assigned the difficult and dangerous tasks of operating hoselines, search, ventilation, and overhaul. Throughout this prolonged operation, they once again displayed that they are truly the “backbone” of the fire service.

THOMAS DUNNE is a deputy chief and 21-year veteran of the Fire Department of New York with experience in midtown Manhattan and the Bronx. He is a graduate of Fordham University and an instructor at the Westchester County (NY) Fire Academy.

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