Fire Behavior and Suppression
The use and set up of the drywall is very important in regards to its placement. The drywall provides several purposes. First it covers surfaces. It also can contain heat and it can direct heat and flame within the structure away from the structural members of the building itself. This is possible only for a certain amount of time before inevitably the structural components and void spaces of the structure would become affected. Remember we are only allowing the fire to grow and burn to a certain extent and only for a certain amount of time. In other words, we are not allowing the fire to rip through the house but to control it just enough to allow it to leave the upper doorway or entrance to a room. We judge this by flame fingering that is going across a ceiling within the fire gases along with the smoke velocity approaching and arriving at the entryway to the room as well as filling the rest of the house. When the flame fingers are just emanating out of the upper portions of the doorway to the room, extinguishment must take place immediately. In order for multiple burns to take place within the same room the training instructors should monitor the use of the application of water as well as nozzle operations. The suppression company and the nozzleman should direct short bursts of water to the flame fingering and gases at the ceiling level, then sweep the floor into the room and then aim for the origin of the fire. At this point the instructors will allow the room to lift insuring that the main body of fire is out. The instructors will then indicate to the nozzleman if continued extinguishment is required in short burst. The instructor will then direct the suppression company to exit the structure with the hose line while he remains inside ventilating and checking for extension. If fire is found into the structure it will be contained and controlled by any necessary overhaul utilizing the secondary line already placed in the structure near the fire area before the exercise began. At this time any areas that need recovering can be addressed by those assisting with the live burn. After each evolution training companies should be allowed back into the structure after its ventilation to critique the training experience.
It is at this point that the same type of exercise will be conducted on the secondary room that has already been previously prepared. By alternating rooms and their burns we allow for the burning of one room to help dry out the previous burn conducted to the other room. This along with the proper control by instructors in allowing specific water applications by the training companies will maximize the ability to acquire repeated burns of the rooms in the structure. By providing proper preparation of the rooms we will ensure not loosing them to full involvement causing severe fire damage to the structure limiting the amount of burns it can provide.
Let's go back to the materials list and how we incorporate it in preparing a room for a live burn. First we will not discuss the gathering and placement of furnishings other than you can be as creative as you want when setting up a furnished room. What is important is that you follow the same guidelines as required in the information provided earlier for burn buildings or fire training towers in order to adhere to NFPA1403.
The drywall as we stated earlier has its purposes in controlling, protecting and directing flame and heat. There is a specific layout of the drywall that should be applied similarly to every room we choose to burn in.
The pallets and hay used for acquired structures should be used to initiate the fires growth. Unlike burn buildings we cannot simply pile several pallets miles high and stuff it with bails of hay. If we did the structure and its infrastructure would be affected and we could loose the building to fire as well as jeopardizing the safety of those involved. We should also never attach pallets and hay to walls or ceilings in an acquired structure for live burns. In spreading these kinds of fuel loads along combustible walls and ceilings we are creating increased surface areas which can cause rate of rise temperatures to create premature flashover conditions.