9. August 2012 08:12
Hey FireIce Bloggers! Check out todays question and answer below:
Describe this operation. How must the blower be placed at the open entry point?
Positive Pressure Ventilation or PPV is defined as: “A method of ventilating a confined space by mechanically blowing fresh air into the space in sufficient volume to create a slight positive pressure within and thereby forcing the contaminated out the exit opening”.
The fan or blower is placed 4’ to 10’ from the entry point you must ensure the fan cone completely covers the entry point. An exit point MUST be created opposite the entry point to push the smoke out of the exit opening. This exit opening should be the same size or slightly smaller than the entry opening. The entire goal is to create postive pressure an it is important that no other exterior doors or windows are opened during this operation.
Once the structure is stabilized you can open and close interior doors and exterior windows to pressurize one area at a time. Opening and closing interior doors at the proper time can accelerate the removal from heat and smoke. Also removing cold smoke from a building after the fire is extinguished is achieved by placing a negative pressure fan at the exit opening. Source: Chapter 11 Ventilation, Essentials of Fire Fighting 5th Edition. (See Illustrations)
If deployed properly PPV can prove to be a useful tool on the fire ground Proper Training and Practice on this operation is essential to ensure “Everyone Goes Home”. Stay Safe!
By Rob Rosovich, Fire Protection Engineer