1 ¾ for Commercial Attack……Why Not?

By: Battalion Chief Shannon Stone

City of Fort Walton Beach Fire Dept. Fla.

Now that I have your attention, take a moment to read this and provide feedback.

Couple of disclaimers; I’m not a writer so please be kind and I’m not advocating the use of 1 ¾ for commercial fires, but rather reaching out to those who are knowledgeable in this area and asking for feedback.

Recently during flow testing apparatus in my department, an engine company approached me and asked me a question. “What do you think about flowing and operating a 1 ¾ line flowing 260 GPM in place of  2 ½ line flowing 260 GPM?” You can imagine my response….”No way, we don’t use 1 ¾ for high flow GPM and we certainly wouldn’t use it to replace a 2 ½ line on a commercial job.” As you can imagine this started a debate which led to much testing and this article for County Fire Tactics. I will make this as brief as possible.

 

All flows were flow tested with a flow meter at the intake, nozzle reactions calculated multiple times, and tested advancing lines in full PPE simulating fatigue factors (not live fire). An “apples for apples” comparison was done with two identical tests. Both evolutions were performed with a four man company, the same firefighters in the same positions every evolution. They advanced the hose lines into a drill tower room 1, flowing to the left, shut down moved to the right and flowed, advance to the next room and flowed, advanced to the 2nd floor and flowed, advanced to the 3rd floor and flowed. Each time the nozzle was opened it was operated at full capacity for 30-60 seconds. Here are the details:

 

Evolution #1 – 2 ½ inch Ponn Conquest hose, 200 ft, solid bore nozzle with 1 1/8 tip

  • Engine pressure of 80 PSI equaling 265 GPM
  • As everyone knows, 2 ½ hose advancement is labor intensive and even with four well trained firefighters, the fatigue factor was still a concern
  • Firefighters had to work extra hard to manage the kinks in the line. They were never successful in removing all the kinks and this was performed in a drill tower where the obstacles are far less than an actual building.
  • Proper techniques were used by all especially by the nozzle man and back up firefighter
  • General assessment of the evolution is that it was very tiring and all firefighters were winded, but of course they said what all firefighters say “But we got it!”

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Kink management was difficult at best with the 2 ½ advancement. The hose team was never successful in managing all the kinks in the line. Keep in mind there were numerous pivot points for this advancement.

Evolutions #2 – 1 ¾ inch Ponn Conquest hose, 200 ft, solid bore nozzle with 1 1/8 tip

 

  • Engine pressure of 140 PSI equaling 260 GPM
  • Half the weight allowed the firefighters to move the line very easily, much quicker, and more efficient than the 2 ½.
  • There was only 1 kink during the entire evolution which was easily corrected by a firefighter.
  • Proper techniques were used by all especially the nozzle man and back up firefighter. This is a 1 ¾ line but absolutely has to be operated and staffed like a 2 ½ line when flowing 260 GPM.
  • General assessment of the evolution is it was much easier to advance and the firefighters said they felt way less fatigued. They described it as no different than advancing any other 1 ¾ attack line. The nozzle man also stated that due to the smaller diameter of the 1 ¾ hose, he felt it was easier to hold and control the nozzle position.
Bleeding the line checking the stream preparing to advance the 1 ¾.

Bleeding the line checking the stream preparing to advance the 1 ¾.