Many elements contribute to the strategies and tactics used to fight structure fires. This month’s article focuses on how reading smoke and understanding fire behavior affect fire attack. Specifically, Report No. 07-805 thoroughly chronicles both the development of the fire and the actions of the first-arriving crews. Following is an excerpt. To view the full report, visit www.firefighternearmiss.com, and click on “Search Reports.” Then click on “Search by Report Number,” and enter 07-805 in the text box.
“At 0749 hrs, 911 received a report of ‘cabinets on fire’ in a house. Engine went en route with five firefighters, and Tanker with two firefighters. Engine arrived at 0755 hrs to find a ’24’ x 40′ stick-built house with heavy gray smoke showing.’ The captain assumed command, performed a 360 and completed ventilation. The lieutenant took two new firefighters and made an aggressive offensive attack. Two 1 ?” handlines were pulled: one handline was taken to the front door and the other to the rear. The handline at the front door was charged, and the line to the rear was left uncharged. The captain walked to the rear of the structure and noted that fire was venting from two windows. He noted that the fire was not ‘pushing’ from the windows but ‘just coming out.’
“The lieutenant and the two firefighters opened an unlocked front door and entered the structure. The lieutenant was in the lead. Firefighter No. 1 followed with the nozzle, and the other firefighter advanced the hoseline. The lieutenant noted that the smoke condition was worsening. He called for the nozzle and aimed it at the visible fire. The smoke color had now changed to black and had banked down to within 12-18 inches of the floor. The attack did not help and conditions worsened. The lieutenant instructed the firefighters to exit the building immediately. He followed the hoseline, but it became blocked by falling furniture. Firefighter No. 1 maintained contact with the lieutenant’s SCBA cylinder. Firefighter No. 2 had turned around toward the door. He was not aware that the door had closed. Handprints show that he found the door but did not realize what it was and proceeded in a right-hand search for the door. He ended up where he had started. Conditions continued to deteriorate and, without a way out, the lieutenant started yelling to get the attention of firefighters outside.
“The driver/operator heard the firefighters inside. He opened the front door and found the leg of Firefighter No. 2, grabbed it and pulled Firefighter No. 2 out. He then looked for and found the leg of Firefighter No. 1. He pulled on his leg and yelled. Firefighter No. 1 was holding onto the lieutenant. Both the firefighter and the lieutenant then made their way out.
“This incident was typical of the type of structure fire this department runs. The incident commander (captain) was confident that the fire would be quickly controlled and extinguished. The lieutenant also felt very confident that this fire would be a good educational event for the two new firefighters.”
The single-family dwelling is the No. 1 structure fire fought by fire departments across the country. Despite this everyday encounter, well-equipped and highly trained firefighters initiate attacks with precision and confidence, and then find themselves fighting for their lives.
A key contributor in this type of situation: the speed with which a fire develops. Fire is observed venting from the structure. A crew enters from an opposite side. Smoke is suspended on the heated, oxygen-diminishing currents. A fresh supply of oxygen is introduced, carried on air currents drawn into the structure when the door is opened to begin the attack. As the fire consumes the oxygen in the atmosphere, negative pressure develops. The air provides a fresh supply of nutrients to the fire at an ever-increasing rate when the positive-pressure currents of the outside atmosphere are entrained into the negative pressure. The reaction that ensues accelerates fire behavior exponentially.
All the while, the crew continues on its mission to find the fire. They lose track of time and don’t account for the fire doubling in size every 60 seconds. The smoke “curtain” turns black and drops to the floor, heating the entire atmosphere almost instantaneously. Within seconds, the heat penetrates the protective layers of today’s PPE, and the crew that was initially on the offensive now finds itself struggling to exit the structure. Clearly, even the “vented” fire can flash when fresh air is introduced. With all this in mind, let’s address some ways we can prepare for and prevent such a situation.
- Seek out training on reading smoke.
- Seek out training on fire behavior and fire chemistry.
- Attend flashover recognition/survival training and review information/case studies on flashover.
- Become familiar with the specifications of your PPE.
- Keep your PPE clean. Smoke-saturated PPE is impregnated with millions of highly flammable carbon particles.
- Take time to assess the heat, smoke and flow of the fire. Recognize the signs of a high-heat, oxygen-starved fire. A vented fire on one side of the structure should cue attack and vent teams alike that once the attack begins, entrained fresh air will cause the fire to double in size every minute.
- Check the atmosphere as you enter. Enter low and on your knees. Once you ensure the floor is sound, slowly raise your arm into the atmosphere above to check the heat level. Once you feel heat penetrating your PPE, note how quickly you feel the heat against your extended arm. This will tell you what’s happening in the atmosphere above.
- If you feel heat above or around you, direct the nozzle stream into the atmosphere. If you hear steam, the atmosphere is above 212 degrees F, and it must be cooled immediately.
- If you’re advancing a line, sweep the upper atmosphere as you advance to break up the thermal laminar flow of smoke passing overhead. As the column is cooled during the advance, the likelihood of flashover is reduced. Apply the stream at a rate that doesn’t invert the thermal layer. You want to cool the atmosphere enough to interrupt the carbon particle heating process, not invert the layer. This will allow the column to continue to pass overhead, supporting ventilation of the structure. In today’s solidified gasoline environment, water damage should be considered secondary to firefighter survival.
A Call for Reports
Submit near misses related to fire-prevention activities
Attention fire-prevention specialists and firefighters who conduct occupancy inspections, public education, fire investigations and any other element of fire prevention work! We have received a number of inquiries regarding near-miss reports related to fire inspectors, investigators and public educators. I’m calling on you to submit near misses that have occurred in the course of such activities. Here’s a short list of experiences relayed to us:
- While conducting a new construction inspection, a uniformed code enforcement team walked in on a drug deal, prompting both the dealer and buyer to brandish guns.
- An inspector nearly fell through a hole that had been cut in a floor for a stairwell; the hole had been covered by a piece of discarded drywall.
- An inspector came face to face with a venomous snake coiled on top of a hot water heater.
- While children walked through a heavy-rescue truck’s walk-through body during fire-prevention activities, the truck was alerted for an incident. The unit began responding while the children were still exiting.
File your account online at www.firefighternearmiss.com.