BY HOWARD HILL
Firefighters operating in hallways of fire resistive multiple dwellings have reported an unusual event: When the door to the apartment is left open to allow the heat and hot gases to travel down the enclosed hallway, the movement of the hot gases toward the dead end of the hallway can result in the heat’s building up and radiating back down the hallway at an intensity higher than that of the area near the fire apartment door.
Ladder company members performing a search in heavy smoke with zero visibility are directed toward the fire by their sense of heat. They might be drawn toward the area away from the fire because there has been an increase in the heat flux from the ceiling layer in the dead-end area of the hallway. This condition has been reported to be particularly evident from the “T” configuration (see Figure 1). This condition can also occur when entering a straight hallway from an enclosed stairway (see Figure 2).
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This false sense of the fire’s location can delay attacking the fire. It creates dangerous conditions for ladder company members, who may move toward the dead end of the hallway without the protection of a handline and then become disoriented in the highly heated, enclosed area.
If an engine company should encounter this condition and direct a hoseline toward the dead-end area, the air movement from the hoseline can draw the fire from the open door of the fire apartment toward the backs of members operating the line.
Wearing bunker gear and mask limits the ability to detect increased levels of heat. When encapsulated in full protective gear, members might go the wrong way down a heated hallway. Also, the longer firefighters stay in a high-heat environment, the more difficult it is to distinguish the changes around them.
This does not mean that firefighters should alter their search practices. To locate the fire apartment in hallways with heavy smoke conditions, search toward the area that is hottest, BUT be aware that such a phenomenon could give a false impression of the fire’s location. Be prepared to alter tactics, if necessary.
LOCATE THE FIRE
Information gathered when responding to the fire may not be accurate with regard to the fire’s exact location. The caller might be from another area of the building and might be reporting conditions outside his doorway. It is imperative that you verify all information on arrival at the fire scene, especially at fire resistive buildings, where smoke can travel great distances inside buildings and fire conditions might not be evident on arrival.
Offices should attempt to gain access to an apartment window on the floor below the fire to look for the location of the fire. In fire resistive multiple dwellings, apartment layouts are generally the same in the vertical line of apartments above the first floor. “Take time to make time.”
Members performing an outside recon should use fire department terminology in defining the fire location, such as, “It is on the exposure two side.” Street locations can also be used: “It is on the Lincoln Avenue side of the building.” I would not recommend using compass points, such as “the north side of the building.” It becomes very difficult for members operating inside the building to retain their sense of direction after climbing stairs, entering twisting hallways, and exiting elevators. Of course, any familiarity gained during inspections or previous operations in the building will en-hance communicating its features.
The best terminology to use when trying to define the fire location would be the apartment line, such as the “B” apartment. Some building owners have been spray painting apartment designations such as “A” or “B” on the lower exterior walls, which enables members surveying the outside of the building to pinpoint the apartment line and give precise information. The combination of building-specific designations and fire department terminology, such as “Fire is coming out of two windows, exposure 4 side on the eighth floor in the ‘C’ line apartment” would get firefighting personnel on the same page and help them to understand operations on the fireground.
Once the fire apartment is known, the apartment designation should be repeatedly transmitted over the radio network to ensure that all members are aware of its exact location.
FIREFIGHTING OPERATIONS
If heavy heat and smoke are encountered in the hallway, this indicates that the door to the fire apartment is OPEN. Continue searching the hallway for the open apartment door that is allowing the heat and smoke to escape. Do not force open any doors until the officer is sure that all apartment doors have been checked. If high heat is present at the dead end of the corridor, this may not necessarily mean that the fire is in that area. Forcing the wrong door can create a sudden draft, pulling the fire toward that apartment and placing members and occupants in great danger.
Using a thermal imaging camera (TIC) on entering the hallway can assist in locating the fire. Normally the camera is aimed at the upper ceiling area to detect superheated gases. When the entire hallway area contains superheated gases at the ceiling level, you might be able to detect the source of the heat by aiming the camera at the lower floor area.
Engine companies entering hallways of fire resistive buildings should remain at the stairway entrance on the floor with a charged line until the location of the fire has been verified. It is difficult to turn around a charged hoseline in a highly heated narrow hallway and coordinate an aggressive attack on the fire. The old tried and true axiom of not stretching the line until the exact location of the fire is known should definitely be applied under heavy smoke conditions.
Considering all the factors that affect the air movement inside a fire resistive building, it is difficult to determine when this type of phenomenon might occur. Three factors must be present to create the conditions that might cause the buildup of heat in the dead-end area of a hallway or near hallway corridor doors:
- A fire must be large enough to create the movement of superheated gases,
- The door to the fire apartment must be opened or partially opened, and
- There must be a restricted amount of airflow into the hallway.
The use of fire resistive construction materials (masonry walls, concrete floors, and ceilings) creates tight spaces that increase the likelihood that high-heat conditions will develop. It should be noted, however, that this phenomenon has also been reported in nonfire resistive buildings where the hallways are very tightly sealed and the fire conditions create heavy smoke with high heat.
The natural movement of the heated, expanding gases leaving the fire apartment is to travel unimpededly down the hall until an obstruction or partition stops the flow. This will cause the heated gases to collect at the end of the hallway, radiating toward the floor below. This may cause the buildup of heat to increase at a rate faster than near the apartment door.
Elevator shafts do not appear to significantly draw the flowing heated gases. This might be because the wall area above the elevator doors is high enough to allow the gases to pass without being significantly drawn into the shaft.
The wall area above the stairway doors is similar in size to the area above the elevator doors; this also allows the superheated gases to flow past the hallway entrance door. However, if there is any type of draft at the stairway door, this will draw the fire and gases in the hallway toward the stairway door.
In windowless hallways, a fresh airshaft vent will be present, but it has a narrow amount of draft and does not appear to affect the flow of superheated gases toward the vent opening in the hallway.
Open hallway windows can produce various effects on the movement of superheated gases:
- When the windows in the hallway are open, the superheated gases are drawn toward the open window.
- High wind conditions blowing in from the exterior of the building can create a negative flow from the hallway window toward the interior of the building. Regardless of which conditions exist, once there is an airflow created by the open window, the stagnant heated gases in the hallway will be affected by it, resulting in limiting the buildup of superheated areas in the dead-end area of the hallway.
Likewise, any open apartment doors in addition to the open fire apartment door can pull the fire by creating draft effects similar to an open window in the hallway.
Officers encountering a hallway with high heat and heavy smoke conditions must take the appropriate time to size up the situation. All members entering this type of hallway environment must be closely supervised. Limit the number of personnel entering this “killing zone,” and maintain communications with the fireground supervisors.
HOWARD HILL is a deputy chief in the Fire Department of New York, where he has served for 29 years. He is an instructor and an author of the command course for the department’s chief officers. He has been published in various fire service periodicals.
