Releasing air from the nozzle prior to entry ensures firefighter safety by providing adequate flow and pressure
It has become a standard operating procedure for fire instructors to have fire recruits bleed off their hand lines or nozzles before performing forcible entry in the basic firefighting course. By that I mean a process conducted by relieving pressure from the hand line safely to enable subsequent phases of the operation to go smoothly and avoid the effect of sudden depressurization, creating bigger problems such as shock forces or fluid-disposal hazards.
In almost all the recruit training courses, you can always see a nozzle operator, holding the hand line, turn the nozzle half-way or a quarter-of-the-way open to allow a small amount of water to flow out, and then turn it back off again. By so doing, the nozzle operator believed that his hand line is ready, and he was good to go. Is that true?
The nozzle man opened the nozzle before the water flow began so as to force all the air out of hose line prior to making entry into the building. Expelling the air out of the hose line is important because you don’t want to waste any more time waiting for the water to come out when you are already inside a structure and ready to fight a fire in that structure. The action of expelling air ensure that the nozzle man have immediate, adequate water flow at desired pressure.
Nonetheless, turning the nozzle on and back off quick might not guarantee that you can have adequate flow and pressure. You have to make sure that the nozzle is opened completely, allowing water to flow for a certain period of time (10-15 seconds or so) and see if we have desired flow and pressure. This will contribute greatly to the pump operator’s setting adjustment as well.
You don’t want a team, while fighting a structure fire, to enter the building holding a hose line without adequate water flow and desired pressure at the nozzle. A team armed with the poorly operable hose line can’t combat the fire. Not only that, but the fire will eventually gain the upper hand, leading to potential fire hazards that are highly likely to harm fellow crew members inside the structure.
The fire loads that need to be dealt with today have much higher heat release rates than those in the last few decades. That means quicker and higher levels of energy will be produced, putting surrounding objects as well as firefighters in harm’s way.
Only adequate, powerful water flow from the hand line can help the firefighters protect themselves and then fight against such high heat and quick energy. So please bear in mind that whenever you bleed off the nozzle, open it completely and let the water flow for at least 10 to 15 seconds.