By Mark van der Feyst
When an interior fire attack is warranted, having a proper water flow and nozzle pattern is the start of an operation that will go well. In basic training, new firefighters are instructed to bleed off the nozzle before entering the structure. This is to exhaust the air that is pushed in the hose line as water from the apparatus is discharged to the nozzle.
If the air was not bled off outside the structure before entry, then a blast of air will be administered to the fire when trying to suppress it. This only adds to the problem.
Another good reason to bleed the air from the nozzle prior to entry is to check the nozzle pattern and the flow rate of the line. Having the correct nozzle pattern will knockdown the fire as opposed to creating steam and upsetting the thermal balance.
Ensuring that you have the correct amount of water flowing at the proper pressure and volume will increase the knockdown capacity of the hose line and crew. If inadequate volume and pressure are discovered at the door prior to entry, this can be fixed quickly either by removing kinks or increasing the pump pressure.