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April-May, 2001 |
Advancing the First Handline
Part 4
After a fire has been knocked down, the nozzle should be closed to allow the swirling steam and smoke to "lift." In order to improve visibility still further and to reduce the heat and humidity in the fire area, a window should be located and a fog stream or broken solid stream directed through the opening. If done correctly, the negative pressure created by the stream will produce a noticeable draft into and through the fire area, effectively clearing the atmosphere of lingering combustion products. Any remaining pockets of fire will be revealed and smoldering materials will "light up" for final extinguishment.
If a combination nozzle is used, simply change from a straight stream to a fog pattern. If a solid stream nozzle is used, simply close the shutoff part way to break up the stream and effect ventilation. Removing the nozzle tip will further increase efficiency. It is best to remain several feet back from the window and to stay low in order not to impede air movement. The pattern should be adjusted until the stream fills most of the window area.
At this point, truck company personnel should enter the fire area and begin "opening up" in order to expose any hidden fire extension and to ensure complete extinguishment. During overhaul, it is usually best to remove the handline from the fire area to prevent it from being buried by sheetrock or lathe and plaster. This will also allow the secondary search to be conducted with increased efficiency.
It is tempting to open the nozzle as soon as a hole is made in a wall or the ceiling and fire is seen, but all this will do is create unwanted steam and eliminate almost all visibility. Particularly in the case of ceilings, it is best to wait until the entire ceiling has been "pulled" before operating the nozzle. An important consideration during this phase of the firefighting operation is the need to replace the initial nozzle team with fresh troops. The physical effort exerted during firefighting activities coupled with the physiological performance limitations imposed by bunker gear will rapidly fatigue these firefighters. When personnel resources are less than what they should be (as is almost always the case), the onset of fatigue will be even more rapid and the need to relieve the first due engine company becomes critical in order to avoid injuries.
The so-called "one-cylinder rule" should apply whenever possible. During overhaul, the nozzle pressure can be reduced in order to avoid unnecessary injuries to personnel and damage to property. Water point should be directed into any area of the structure or contents where the potential for a rekindle is likely. If there is any doubt, have the truck company personnel open up further or turn the pile of debris one more time.
Foamed plastic seat cushions and mattresses must be thoroughly soaked (even submerging chair cushions in the bathtub is an option to be considered) or removed to the outside for further extinguishment. NEVER enter a stairway or elevator car with a partially extinguished foamed cushion or mattress. The draft created by moving the cushion or mattress may cause the foamed insulation to burst into flame, trapping you with no escape. It is best to thoroughly soak it first, or toss it out the window to a clear area on the ground below.
In order to efficiently overhaul the exposed studs and joists in the fire room, it is best to first overhaul the contents remaining on the floor before bringing the handline back inside the room. This reduces the chances of the line sitting in smoldering debris, which could unknowingly damage the hose. Utilizing only a single firefighter (remember, the nozzle pressure has been reduced and no one really wants to get wet, particularly in winter), position at a far corner of the room with the nozzle pointed back towards the entrance. While leaning against the wall and using your leg and foot to anchor the handline and resist the nozzle reaction, sweep the stream back and forth along each joist from sidewall to sidewall. Concentrate on the joists that are the most deeply charred and don't hesitate to agitate the stream by shaking the nozzle. Once the joist bays have been washed down, perform the same operation on any studs that look charred (pay close attention to the framing around window openings) and direct the stream from ceiling to floor and back again. Let the officer take a peek, and, if all looks good, reposition the line at the door opening and repeat the process. This will ensure that both sides of each charred joist have been washed down, as well as all affected wall studs and window framing materials.
Don't forget to drive the stream into any area where a pipe (steam, soil, or water), electrical wires, or ductwork pierces the floor above. At this point let the officer make another examination to ensure a satisfactory job has been done. This is actually a good time to bring a thermal imaging device into the room and scan the area for hot spots.
Consider, as well, the following additional points:
Unlike fire attack operations, water application during overhaul should be very specific. Use water judiciously to avoid unnecessary property damage. Move undamaged valuables if possible.
Reckless overhauling can destroy evidence of arson. Use care and limit water application to only what is absolutely necessary until the officer or fire investigator takes a look at the area.
It is easy to confuse steam and smoke. If it is smoke, additional water application is necessary.
Be cautious of holes in the floor, water accumulations, protruding nails and screws, untrimmed window glass, and other sharp objects.
Ensure the area is properly illuminated to help avoid injuries.
Until next time, stay low and stay safe!
CORRECTION: Last time, I mentioned a burn prevention poster available online from the New York Firefighters Burn Center Foundation. The correct title of the poster should have been “Sweep-Switch-Squat-Shift.” The poster is available for a small donation by contacting the New York Firefighters Burn Center Foundation at their website: www.NYFFBurnCenter.org.
Andrew Fredericks is the author of three "Bread and Butter" Operations videos titled Methods of Structure Fire Attack, Stretching the Initial Attack Handline and Advancing the Initial Attack Handline. To purchase, click here.
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