Signs of backdraught include:
- Fires in tightly closed compartments, especially in energy efficient buildings
- Dark oily deposits and condensation running down the inside of windows
- Windows, doors and door handles that are hot to touch (back of the hand)
- Rattling sounds or smoke pulsating around openings
- Smoke being drawn back into openings and large air movements (draughts) seen heading into openings as the fire searches for more oxygen
- Ghosting tongues of flame seen in the compartment
- Turbulence in the smoke layer (previously referred to as the neutral plane), sometimes seen to ‘bounce’ up and down
- Whistling and roaring sounds, sometimes denoting high-velocity air flowing in or gases burning off in the compartment, preceding a backdraught event
- A change in fire conditions, with fast-moving smoke seen from the exterior to exit at high velocity, as if under pressure, and a steady darkening of smoke colour
This video demonstrates the phenomenon of backdraught