Q7

Question 1

What are the backdraught signs and symptoms?

Answer 1

1. Fires with limited ventilation
2. Hot doors and windows
3. Smoke pulsating around opening
4. Soot blackened windows
5. Smoke/air being drawn back into openings. (Possible whistling)
6. Lack of visible flames
7. Ghosting tongues of flames
8. Change in fire conditions with fast moving smoke seen from exterior to exit at high velocity, as if under pressure and a steady darkening in smoke colour.

Question 2

Why is it important to recognise backdraught symptoms?

Answer 2

This is where a limited ventilation fire can lead to a fire compartment producing fire gases containing significant proportions of a partial combustion products and unburnt purplish products. With the admission of air when an opening is made this can lead to a sudden deflagration. This moving through the compartment and out the opening is called a backdraught. It Is at a subsonic speed as an explosive driven by the transfer of heat. Causing a huge danger to anyone within the vicinity.