The use of positive pressure ventilation (PPV) has developed quickly in a relatively short period to the extent that even basic firefighring tactics have been influenced by developments in associated hardware. Many Fire and Rescue Services no longer refer to PPV but use the more correct term of tactical ventilation. Why is this case? In a nutshell, responders now no longer rely upon just positive pressure and prefer to use fans that can provide both positive and negative pressure ventilation. I no longer believe that positive pressure alone is always the most effective tactic in dealing with a compartment fire or ultimately in improving firefighter safety and providing potential victims with a greater chance of survival. Historically ventilation units have mainly been used to create positive pressure within a compartment or in multi-compartments. But the current way of thinking is to use ventilation fans in a more sophisticated manner. All of the basic questions must still be answered: 1. Is a suitable exhaust available? 2. Is there a route to the exhaust (ie doors wedged open etc)? 3. Have all other potential routes for the pressure to follow throughout the building been isolated? 4. Is the location of the fire known? 5. Are there signs and indicators of a backdraught occurring? 6. Has the fire reached flashover point yet? 7. Do we have a covering jet at the exhaust? 8. Do we know the location of the casualties? 9. Will defensive or offensive ventilation mode be adopted?
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