Wow, It’s Hot in Here!

VENTILATION MAKES FIRE attack quick and painless if you use it properly. Improper ventilation, however, spreads the fire, hinders fire attack, and worsens heat conditions for the attack and search crews.

We perform ventilation for life or for fire attack. When a search crew conducts a primary search, members will take windows to relieve the heat and smoke conditions, thus allowing a fresh air blanket to drop to the floor and hopefully provide any victims with fresh air, improve visibility for the search crew, and expedite locating the seat of the fire. Caution: If performing a primary search above the fire, firefighters must always use caution when venting to prevent autoexposure.

(1) If the attic is involved or if the fire is on the top floor of a multistory building, you must perform vertical ventilation. (Photo by Jim Cannell.)

When venting for fire, make the openings to draw the fire to where you want it or to relieve the building of hot smoke and fire gases, thus allowing crews to quickly find and extinguish the fire. Vertical ventilation (cutting a hole in the roof and knocking down the ceiling, skylights, roof vents, and so forth) reduces the possibility of backdraft and is a must for top-floor fires or when fire extends to a cockloft or an attic. Horizontal ventilation (breaking or opening up windows), used at most room-and-contents fires, reduces the chance of flashover and speeds fire attack for the above reasons. Caution: When performing horizontal ventilation, communicate with the engine company on the initial hoseline to confirm that members are in position to start the fire attack. Premature horizontal ventilation can increase the fire’s size and intensity.

Ventilation can be supplemented by using positive-pressure ventilation (PPV), in which fans are placed at the front door to blow fresh air into the structure. However, this tactic will fail if applied improperly. If fire is still burning and you place a fan to supply fresh air, some bad things can happen: The fire will intensify, be pushed into void spaces and uninvolved areas of the structure, and punish the interior crews with intense heat.

(2) You can use openings like this scuttle to aid vertical ventilation. (Photo by author.)

For example, if you open up a wall containing a small smoldering fire, the fire will light up and intensify when given air. Keep a pressurized water can or hoseline nearby. In balloon-type construction, wall studs extend continuously between two or more floors with an open uninhibited void space between floors. If fire enters such void spaces, it can rapidly spread to uninvolved structure areas, especially if you use a fan inappropriately.

For some ladder companies, fan deployment is among their top priorities. This is fine if fan deployment is carefully thought out. However, ladder crews often just place the fan at the front door and blast the structure with thousands of cubic feet of air per minute without any regard to its effect on fire conditions. It’s good to have that fan at the door supplying fresh air, but only when the fire is out! Problems arise when the exterior fire crews don’t communicate with the interior fire crews.

(3) This fan is properly staged to the side of the doorway and not blocking access. The fan is idling and ready for the order to deploy from interior crews. (Photo by Jim Cannell.)

The exterior crews should wait until the interior crews call for the fan to be placed into position. At that point, the fan can be staged near the door and turned on but idling and turned to the side so the air is not directed into the structure. Thus, the fan is in the proper location and running but not supplying air to the interior yet. Only after the interior crews radio the exterior crews to deploy the fan should the exterior crews turn the fan toward the opening, throttle it up, and adjust the distance.

Exterior crews must realize that prematurely cranking up the fan and supplying air into the structure changes the dynamics of the fire attack. For the safety of the interior crews and victims, interior firefighting crews must determine whether the fan is operating prematurely. One sure interior indicator that the fan is operating too soon is that search and attack crews feel excessive heat coming from behind or below them (if they are advancing up the interior stairwell) as they advance on the fire’s known location. This is most evident on the interior stairs. If the search or attack crews feel “pinned down” on the stairs because of excessive heat coming from behind, it is probably because the fan is pushing heat toward their position. Although heat travels up stairwells, if it feels out of the ordinary, this is a good indicator that the fan has been started too early. Also, if fire starts blowing out of wall openings or if a ventilated fire starts to intensify, suspect the fan.

4) Only after horizontal ventilation and extinguishment are complete should you use the fan to supply fresh air, and only on the order of interior crews. (Photo by author.)

Be aware that a strong wind can mimic the effect of a fan; hopefully, the crews thought about that on arrival. Use smart ventilation tactics during a strong wind, and get backup lines in place quickly to protect and support the initial attack and search teams.

Aside from windy conditions, ventilation should be a pretty straightforward tactic you use on every fire. It is only when you use improper techniques and tactics that problems arise for interior crews. Make smoke reading, fire behavior, building construction, and proper ventilation techniques essential training topics, especially for firefighters who perform outside functions.

(5) Only use positive-pressure ventilation (PPV) after attack crews have extinguished the fire. This fan is properly placed and operating after extinguishment. (Photo by author.)

Training is the key to successful fireground operations; without it, you may be saying, “Wow, it’s hot in here!”

MITCH BROOKS is a lieutenant with the Columbus (OH) Division of Fire and a 15-year veteran of the fire service. He is a state certified fire instructor, a paramedic, and a rescue technician. Brooks has an associate’s degree in fire/EMS from the Columbus State Community College and attends the American Military University.

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