You are assigned to an engine company in a mid to low income area of your city. Your engine is staffed with four personnel, a dedicated driver, an officer, and another firefighter in addition to yourself. Around midnight, you are dispatched to a house on fire. The address isn't specific. Typically, nonspecific address calls mean either the caller was passing by wasn't sure what they saw or are false calls (calls that originate but the occupants or neighbors didn't call). However, the CAD printer rolls a 2nd time dispatching your station's ambulance to the call (when this happens before the first engine arrives it means that multiple calls have been received. Multiple calls lend more legitimacy).
You don't notice a smoke plume, but it is dark outside and the passing street lights don't offer much illumination. As you come down the street, the ambulance (which was out of the house) arrives first and informs your officer that there is fire showing in the rear of the farthest window from the street they are positioned on. As you arrive a few seconds later the fire is visible, shooting from the window. The structure is a single story apartment building with four separate units, wood framed with brick veneer. From the exterior it is estimated that the structure is 10% involved
You pull a 150' 1-3/4" attack line from the bed and advance the line to the door closest the street. A member of another company forces the door while you put on your SCBA facepiece. They inform you and your officer that the door is blocked and go around the other side of the structure. You see the smoke coming out of the door and push the door in, then shove a table from behind the door out of the way. As you look in, you are informed that another entrance on the side is open and clear (the arrow in the exterior diagram). You reposition and wait for your line to charge before advancing. Another firefighter is ahead of you searching as he advances.
You locate the fire in the the rear of the structure in the bedroom, the approximate location of the window you observed when you turned on to the street. A window A/C unit is involved in fire and the flames have worked up over the room into the attic space. You extinguish this fire and the fire extending to the eves over the bedroom. The truck company on the exterior has placed a PPV fan at the first entrance and powers the smoke and heat out of the room. You can see that the bed has been burned up and a power cable to the A/C unit is partially burned. The truck company pulls ceiling around the point of origin and locates additional fire burning up the roof joists. This is extinguished and the fire is placed under control.
This is a classic example of common household fires. They do not usually get big enough to destroy a house when they are detected quickly but between ignition and suppression they generate a lot of smoke and heat. The initial report from the ambulance crew gave us a quick summary of what we would be facing, and from the exterior it appeared that there would be a lot of fire to deal with. The decision was made to attack with a 200 gpm nozzle due to the potential for structural involvement, and during overhaul it was discovered that the structure was minimally involved. This is a textbook operation as well as the standard procedure when the structure is involved. It is procedure to under pressurize the attack line at 90 psi until a water source can be established. Due to the proximity of a water source to the attack engine the line was brought to the full pressure of 100 psi while a connection using soft sleeve 5" hose was made.
Forcible entry was required due the security doors and bars on access points. This area is considered a high crime area, so it is not uncommon for additional hard security features to be installed. This can delay access to both the fire and trapped occupants, and as the fire grows the environment becomes more and more untenable for occupants who may be trapped inside. Visual examination of the wood around the point of ignition and other contents in the room suggest that the fire was never able to reach flashover (approx 1000 degrees F) but was hot enough to ignite the window frame, the eves of the roof directly over the window, and burn the roof rafters and roof sheeting. No insulation was present in the roof structure.
Lessons Learned and Conclusion
Be wary of exterior doors, especially when there are multiple entrance points. Occupants will block them to use the space (in this case, a kitchen table. The fire may appear larger on the exterior than the interior, but it is always a good idea to use a larger handline if it is believed that the structural components are involved. In this case, no rescue was necessary as the occupants were not at home, but it would have been difficult to access them if there were due to the security doors and bars. PPV proceeded quickly due to the point of origin being a window itself, no hole was cut in the roof as the fire was controlled rapidly.
\The point of origin was determined to be the window A/C unit. No investigator was needed and the fire was ruled accidental.