“Water on The Fire” with the mindset of “Gallons Per Second” is a tactic that creates and maintains survivable space for fire victims. Regardless of rank, we must evolve our fireground mindset from Gallons Per Minute, and Punch the Fire right in the Throat!
If you are FLOWING enough water to truly overwhelm the BTUs, then in only SECONDS you will see a RAPID change in conditions. Gallons Per Second will provide the best chance of survival for THEM. Utilizing a 2.50″ Smooth Bore Nozzle at the right pressure on advanced fire conditions makes a difference for the citizens in only seconds, lots of gallons per second.
The video below shows a mobile home well involved with fire and a back bedroom that had a fully survivable space for occupants. The 2.50″ hose and 1 1/8″ tip in the video punches this fire in the throat. Even though the fire rapidly self-vented from the front windows, the temperature in the rear bedroom never surpassed 100 degrees because the bedroom door was closed, and only had light smoke infiltration.
Tip Size and Water Delivery in Gallons Per Second on 2.50″ hose.
1 1/8 at 40psi = 3.95 GPS
1 1/8 at 50psi = 4.42 GPS
55 Gallons in 13 seconds
1 1/8 at 60psi = 4.85 GPS
1 3/16 at 40psi = 4.40 GPS
1 3/16 at 50psi = 4.93 GPS
55 Gallons in 11 seconds
1 3/16 at 60psi = 5.40 GPS
Modern fires must be “Hit Hard, Hit Fast, and Backed Up”. Not all citizens have the benefit of an Engine and Truck Company rolling out of the same station to their home when it is on fire. While a number of initial fire ground tactics are necessary, fire ground incident commanders and initial company officers must choose how to make the biggest impact in the shortest amount of time.
This can be seen as an example of “Time Delayed Tactics”. A number of tactics must be accomplished by the initial arriving companies at the scene of any incident. But implementing the ones that will make the biggest impact first is graduating beyond minimum standards and the “Check-In The Box” style of incident command.
By applying the right amount of water right away to offset the tremendous BTU’s makes a difference for the citizen. Gallons Per Second is like dropping a Five Gallon Bucket on a Cigarette. Damage to property occurs during a fire, however, “You Can Dry It Out, But You Can’t Unburn It, FLOW WATER”.
Water On The Fire makes everything better and on a 1.75″ hose the 7/8 tip is Chief Isakson’s personal choice. It’s is the original Select-O-Matic nozzle delivering solid water without fog.
Tip Size and Water Delivery in Gallons Per Second on 1.75″ hose.
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 useit 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!”
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.
Although hard to tell by looking at pictures but the kink factor was decreased significantly. Notice the nice stiff bends in the hose in comparison to the pictures of the 2 ½ hose.
Wrapping the wall, stairwell, and rooms are essential with minimal staffed fire departments. The 1 ¾ worked very well due to the high pump pressure. It never kinked when utilizing these advancement methods. However, 2 ½ would kink immediately rendering this technique less effective resulting in numerous kinks.
Here are additional facts:
Nozzle reaction for both the 1 ¾ and 2 ½ are virtually identical since the GPM and diameter of the nozzle are the same.
Kink flow testing revealed that on average a kink in the 2 ½ hose would result in the flow decreasing from 265 GPM to 240 GPM.
Kink flow testing revealed that on average a kink in the 1 ¾ hose would result in the flow decreasing from 260 GPM to 210 GPM. The significant decrease is obviously due to the amount of water flowing through a smaller diameter hose.
2 ½ hose was guaranteed to kink, 4 firefighters could not manage all the kinks resulting in a decrease average flow of GPM.
1 ¾ hose was extremely difficult to kink due to the high pump pressure. Only one kink that was corrected easily and quickly. The average GPM was around 250-260.
Low friction loss hose was used (Ponn Conquest). Anyone who is a student of the fire service understands the actual diameter of this hose is slightly larger that standard hose (or slightly larger than what the manufactures actually advertises it as); however, manageability of the low friction loss hose vs the standard hose is identical.
High pump pressure had no negative bearing on advancement or operation of hose
The nozzle man has the same range of motion with the 1 ¾ line as the 2 ½ line
Reach, penetration of the fire stream of each was identical
Advantages of the 1 ¾ option
Literally ½ weight in comparison to 2 ½
Nozzle controllability was the same if not better with the 1 ¾
Line advances easier, faster, and more efficient
Fatigue factor was much less that 2 ½
Average GPM was greater than the 2 ½ (kink factor)
Disadvantages and limitations to the 1 ¾ high flow set up
It is likely that anything over 200 ft of 1 ¾ set up will not work due to high friction loss factors.
This should not be considered in high rise fires due to high friction loss factors. This would include most if not all standpipe operations.
If the 1 ¾ nozzle is operated too far out in front of the nozzle man, a serious “whipping or snapping” action of nozzle can occur. This is easily controlled by proper nozzle control and operation.
A quick special thanks to my guys that insisted I take a look at this. Fort Walton BeachFire Department Engine Company 7– Acting Captain Justin Westmoreland, Engineer Mark Birchett, and Firefighter Brandon Waterhouse.
The testing we performed was much more comprehensive than what this article shows, but in an effort to make it brief and a quick read I stuck the meat and potatoes of the issue. In no way am I implying that we in the fire service move away from use of 2 ½ hose for large fire or commercial fire attack. However, the numbers and facts speak volumes that I believe are worthy of evaluating. If you think about it, this is no different from the evolution of 1 inch hose, to 1 ½ hose, to 1 ¾ hose, to low friction loss hose which now allows us to flow larger volumes of water under manageable conditions. I do buy into the concept of limiting your nozzle reaction and insuring you have a manageable line so the nozzle is ALWAYS operated properly during significant fire conditions-nozzle all the way open. This is why this 1 ¾ set up absolutely has to be operated as if it is a 2 ½ line insuring adequate staffing to insure correct deployment and operation.
So I beg the question….what are we missing here? What’s your thoughts and/or experiences with high flow, smaller diameter hose? Should this be a viable option for large fire attack?
What’s the difference between the two set-ups? Is your department open to stretching & Flowing the 2.5″ attack line first due, with only a three person crew? Will your FD allow stretching & Flowing a 2.5″ off tank water?
When do you stretch a 2.5″ over a 1.75″ attack line? Do you ever stretch a 2.5″ on a house? Do you ever take a 2.5″ in a house? Do you think two 1.75″ are better than one 2.5″? When do you think it’s a mistake to stretch a 2.5″? Are you one of those that’s worried about running out of water? How do you determine the 2.5″ over the 1.75″?
How many Firefighters required to flow a 2.5″ Attack Line? How much does a 50 section of 2.5″ weigh when charged? How much can you flow through your 2.5″? Do you leave the 1″ tip on? Does your FD deploy 2.5″ on commerical building fires? WHY NOT? Does your FD use 2.5″ on fully involved garage fires? Why is this method above more effective than the coil?