27. August 2012 09:23
Hey FireIce Bloggers!! FireIce Academy is back in session...Your engine company responds to a fire in a two story Victorian style single family residential structure. The house was built in the 1920s and has an open stairwell leading to the second floor. When you arrive you see fire coming from one of the front windows and from the open front door. You can hear sounds of glass breaking from that sam
e front room. The smoke is steady, not puffing. The back door is open but no smoke is coming from that door. There is a slight breeze blowing against the back of the structure.
What is the stage of fire at this time?
A1- The fire is in the growth stage. There is still fuel in the room of origin to be consumed and the fire is spreading in
to other areas of the structure.
Why is there no smoke coming from the open back door?
A2- There could be two reasons no smoke is visible from that door. First, there could be another interior door between the back door and the fire area that is closed. This would prevent any noticeable movement of smoke. The second reason is the slight breeze that is blowing. The air (wind) moving into the building will force the smoke out of the front door and any other openings in the front of the structure.
What is the primary means of heat transmission in this situation?
A3- The primary means of heat transmission in this structure is convection. The heated gases are rising and moving throughout the front of the structure. Even though it is not visible to someone outside, smoke and heated gases are moving into other rooms and up the stairwell and heat all the objects in those areas. In other areas this heat transmission will eventually result in ignition of the fuels. Remember, even though the front room is fully involved, other areas are not yet to that stage. Flashover is a potential in other rooms and areas as the fire spreads and increases in intensity. Don't disregard the risk of flashover in this type of structure simply because one room has been ventilated and is fully involved. Other rooms and areas may be nearing flashover and pose a deadly threat to any firefighters working in those areas.
Source: Essentials of Fire Fighting 5th Edition