Hand line pressure: How to bleed the nozzle
Releasing air from the nozzle prior to entry ensures firefighter safety by providing adequate flow and pressure
During a live-fire training class I was recently conducting at an acquired structure, I noticed that many of the crews assigned to the attack function were bleeding off their hand lines or nozzles prior to making entry. As this is a basic skill taught in recruit training, there is a methodology to how we want to bleed off our hand line to avoiding any dominoes being lined up to create a bigger problem for us.
What I observed was a nozzle person grabbing the hand line, opening up the nozzle half-way or a quarter-of-the-way open so that only a small amount of water would come flowing out, then closing the nozzle. In that person’s mind, their hand line was ready to go, but, was it?
Bleeding the nozzle benefits
The nozzle is opened before the water is turned on to release all the air from the hose line before making entry into the structure. Releasing the air is important because we don’t want to have to wait when we are inside the structure, and it tests that we have adequate water flow and pressure.
A quick open and close of the nozzle is not enough time to accurately check if there is adequate flow and pressure. It’s important to open the nozzle fully so we can flow water for a short period of time – around 10 to 15 seconds. By doing this, we can determine if we have enough flow and pressure at the nozzle. It also allows for the pump operator to adjust the settings to ensure enough flow and pressure is being delivered.
If a team were to enter a structure fire with a hose line that does not have enough flow and water pressure at the nozzle, that team will not be properly armed to combat that fire. The results will be the fire gaining the upper hand on them, which will lead to other bad outcomes for the crews operating inside the structure.
Modern fires require adequate hand line pressure
The fire loads that we are facing today have higher heat release rates than in the past, and produce quicker and higher levels of energy, which are focused upon surrounding objects, including the firefighters, that are in the pathway.
Water is our best defense against the heat release rates and energy production that we face with fires, and having a hand line that is flowing the right amount of water and at the right pressure is paramount. So, the next time you are bleeding off the nozzle, make sure you open it all the way and flow it for about 10 to 15 seconds.