Fire engine pump pressure needs to match fire, nozzle
Like Goldilocks looking for just the right fit, it is critical for firefighter safety and effectiveness to have the right pump pressure at the hand line
One of the most common tools for the fireground is the hose line. Most front-line quints and fire apparatus will have a hose line on them with the exception of the dedicated truck company, rescue company and some water tenders. All in all, you will find a hose line on the fireground being used in some capacity.
One of our main handicaps on the fireground is the amount of pressure being pushed through the hose line to supply enough water pressure for nozzle and water applications. Sometimes there is not enough pressure being supplied and at other times there is way too much pressure being supplied.
Good pump operators will know exactly how much pressure to supply for the required hand line being used by knowing their equipment, knowing the situation and knowing simple hydraulics.
When there is not enough pressure being supplied, it hinders the ability to effectively knock down or extinguish a fire. At the same time, this exposes the crew to the intense heat or dangers that are present from the fire.
When there is way too much pressure being supplied, it will certainly provide for fire knockdown. But depending upon the type of nozzle being used, it may not be adequate based upon the amount of water being discharged.
Right Pressure for fireground situation
Whenever firefighters are using hand lines, they need to be familiar with the amount of pressure that is required to supply those lines and be capable of handling that amount of pressure.
Sometimes a firefighter may have to be alone when applying water without a back-up firefighter to help with the nozzle reaction. When this is the case, firefighters may find themselves becoming handicapped by being overrun by the pressure being supplied by the pump.
Changing a combination nozzle from straight stream to a fog pattern will relieve some of the nozzle reaction.
I have witnessed firefighters during pump practice holding a 100-foot 1¾-inch hand line with an automatic nozzle complain that there was too much pressure being supplied when actually it was the required pressure needed to make that nozzle work adequately and effectively. They were just not familiar with what that pressure felt like.
In the corresponding video, you will see how firefighters can be caught off guard when there is too much pressure being supplied to the hose line. As mentioned previously, a good pump operator will know just how much pressure to send for the needed application.
For a vehicle fire, the pressure needed may be less than that required for an interior attack — so why not dial down the pressure?
When getting the hand line charged and ready for defensive or offensive operations, do not send the water to the nozzle at full pressure — let the hose fill with water first, then gradually dial the pressure up. When this is not done correctly, you will see how it affects the firefighter holding or operating the hand line.
Become familiar with the pressures required for your particular hand lines and practice with that pressure. Get used to it so that you will not get caught off guard.