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• an orange glow or a fi re which is not visible can indicate<br />
that the fi re has been burning a long time with a lack of<br />
oxygen.<br />
• smoke gases drawn back through the opening, indicating<br />
that an air current has entered the room. Hot smoke gases<br />
will leave the room, perhaps through another opening<br />
and replacement air will be drawn in through the<br />
opening. It may seem as if the smoke gases are being<br />
drawn towards the fi re.<br />
• The neutral plane is close to the fl oor.<br />
• A whistling sound may occur due to air being drawn in<br />
through small openings at high speed. Unfortunately, a<br />
backdraught may have already occurred and those people<br />
standing at the opening may be seriously injured, even<br />
fatally.<br />
6.6.2 Course of action<br />
It is very important for us to assess the risks thoroughly. Each<br />
person involved is responsible for their own safety and should<br />
think carefully about some of the following questions:<br />
Figure 106. The fi re<br />
offi cer in charge must<br />
assess the risks in<br />
relation to what can be<br />
achieved by the<br />
operation.<br />
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