Today, most fire trucks are equipped with a positive-pressure ventilation fan. This tool has been in the fire service for quite some time and is used for ventilation tactics at structure fires.
We see this fan being used at many fires and with some of them adding fuel to the fire.
The PPV fan was developed as a post-fire ventilation tool – meaning that the fire must be completely out before using the fan to ventilate the structure. For it to work, there must be an opening and an exhaust point within the structure. Only two openings can exist at one time for the PPV fan to be effective.
The fan works best at removing smoke from a structure one room at a time. By opening a window or a door one at a time, the house can be systematically cleared of smoke.
When fire is still burning in voids or in other areas of the structure, and a PPV fan is introduced at the front door or at any other opening, the results are going to be quite noticeable.
In the attached video, we see one example of such an incident where hidden fire was still present and the PPV fan made it worse.
There are tactics such as positive-pressure attack that can be useful for certain fire conditions within a residential structure fire. But this tactic is not suited for every fire.
Rapidly changing conditions
When a PPV fan is being used in the wrong fashion, it will change the conditions inside very quickly. What conditions will be experienced?
As you will hear from the testimony from the three firefighters who survived this ordeal in the video, you will experience extreme heat conditions. This is prime for flashover conditions to occur.
Being trapped by ensuing fire is also a possibility. In the attached video, the front door was relatively free from fire and smoke.
But when the fan was introduced, the front door became a ball of flame. Now we have trapped firefighters looking for another way out.
Fortunately, the three firefighters who went through this ordeal survived by bailing out the kitchen window. But we have seen fires where firefighters have not been so fortunate and have perished from being trapped by fire worsened by the PPV fan.
Before using the PPV fan at the next structure fire, be sure that all fire is completely out. Use the fan for post-fire ventilation – not before or during the fire ventilation.
These little dominos, such as hidden fire and a PPV fan being rolled in and started, will cause the fireground to change suddenly for the worse.
