All firefighters need an adequate understanding of the development of fires in ventilation-controlled and under-ventilated states, so they can recognise potential backdraught conditions. Tactics such as venting and/or the indirect and direct application of water can then be used more effectively and safely.

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