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!”

IMAG2617 IMAG2614

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.

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.

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.

IMAG2637

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.

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.

IMAG2636

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.

Summary

 

A quick special thanks to my guys that insisted I take a look at this. Fort Walton Beach Fire 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?

25 thoughts on “1 ¾ for Commercial Attack……Why Not?

  1. Interesting numbers, and yes with the new “1.75” combat type hose you can obtain a higher GPM with lower pdp’s. As a fast attack option, I don’t see a problem (200′ max distance). However, the benefit of the 2 1/2 in a larger fire is the ability to produce more gpm’s almost instantly. Thanks for the through information.

  2. Excellent work Shannon, great article. This is a message that is worth passing along, especially in todays fire service where we are expected to do more with less.

  3. The manufacturers of fire hose are doing a good job realizing that we need more water to put out this higher “modern day” BTU fires, as well as tdying to fatigue the firemen less. Most of the low pressure 1 3/4″ hose is actually 1.9″ for the interior diameter of the hose. Therefore allowing more water with less friction loss.

  4. Great Article. And thanks for going through the process of testing it and backing up the theory. I always knew that Big Fire needed big water but I learned that a Big Building doesn’t necessary mean Big Water. Your size- up, knowledge of the building and fire spread should contribute to the selection of what hose you use. Great job brothers.

  5. Good info, BC Stone. With the right hose, operator, and well-trained crew – your guys have provided an option. Without disregarding lessons learned, sometimes wheels need reinventing (pumpers aren’t on wooden wheels anymore). The key would be to get those flow meters out and do the stretches before changing how an FD operates. Hard charging firefighters (like yours) – that do the drilling – continue to improve our fire service. Thanks for the idea.

  6. Interesting concept to explore further! Since FWBFD is going to a 2 pressure set-up, green for standard attack, red for added punch, ponders the question of going to a third pressure to provide another tool in the tool box. Maybe useful when resources can be combined and deployment of a larger 2 1/2 hose would prove to be too time consuming when the 1 3/4 hose is already in position. Nice write up Chief Stone, good job B-Shift.

    • Should of stated in my other post that I was thinking in the residential setting, although pulling 2 1/2 hose is/or should be your first thought in the commercial setting. Proper size-up/conditions could warrant pulling an 1 3/4 hose as well. Gotta love the dynamics of the job.

  7. What is the actual internal diameter of your 2.5-inch is the question you should be asking and why are you deploying 1.9-inch hose on your bread and butter line for flow of 160 gpm. Is your department actual hamstring yourself for the room and content residential fire as we all now seconds count why have larger then needed line for those flows? 1.75-inch and 2.5-inch should be as marked on the jacket. This is for many reasons, by the way dual flows out of the same size line leads to many operational issues. Two friction loss and flows for one line lead to pump operator confusion, line selection confusion, inability to tell flow from size of line, two different achievable length stretches depending on flow, low envelope of function in the stretch based on the higher flow, poor rig placement do to the desire to get with in 200 feet, blocking of truck placement in proper aerial sweep. as lines fall short pump differential increases when both 2.5-inch and 1.75 at the higher flow are deployed off the same pump etc… Do not take your eyes off the ball a over kink-able 2.5-inch line the seem heavy is it actual 2.75-inch? If they have cheated up the size of the 1.75-inch hose do you really trust your 2.5-inch is what it says. By the way I know it is not…,..In the end the greatest factor other then reaction force is the actual charged weight of the line and that in mainly attributed to water weight the greater the diameter of the hose the harder it is to advance with equal reaction forces. Keep it simple you only have half the answer moving back to actual 1.75 and 2.5 inch hose should be the mind set.

  8. Edited …. What is the actual internal diameter of your 2.5-inch is the question you should be asking and why are you deploying 1.9-inch hose on your bread and butter line for flow of 160 gpm. Is your department and many others actually hamstring themselves for the room and content residential fire; as we all now seconds count why have larger then needed line for those lower flows? 1.75-inch and 2.5-inch hose should have a internal diameter as marked on the jacket. This is for many reasons, by the way dual flows out of the same size line leads to many operational issues. Two different friction loss and flows for one attack hose-line leads to pump operator confusion, officer line selection confusion, inability to tell flow from size of line, two different achievable length stretches depending on flow, low envelope of function in the stretch based on the higher flow, poor rig placement do to the desire to get with in 200 feet envelope of function, blocking of truck placement for proper aerial sweep, as lines fall short pump differential increases when both 2.5-inch and 1.75 at the higher flow are deployed off the same pump etc… Do not take your eyes off the ball a over kink-able 2.5-inch line the seems heavy; is it actual 2.75-inch? If they have cheated up the size of the 1.75-inch hose do you really trust your 2.5-inch hose is what it says it is internal diameter-wise. By the way I know it is not…,..In the end the greatest factor in deployment of attack hose other then reaction force is the actually charged weight of the line and that in mainly attributed to water weight the greater the diameter of the hose the harder it is to advance with equal reaction forces. Keep it simple you only have half the answer moving back to actual 1.75 and 2.5 inch hose should be the mind set. I call as I see it, you ran a actual “2-inch hose drill” we are all the worse for the wear until the jacket size can be trusted (again) the vast majority of the fire service is hauling around extra water weight in their attack lines collectively for the flows we wish to achieve, this always slows time to “seat”. This problem in all likelihood has cost lives and property. A huge disservice to the citizens we are sworn to protect, we should know what we are deploying. We must demand it as the end users of this product. A return to a “true diameter” 1.75 and 2.5-inch attack hose is critical.

    • Dennis-you make some good points. One of the biggest areas of concern is the possibility of officer and or pump operator error. I think we would be setting ourselves up for failure if used an 1 3/4 line for normal flow (primary residential 150 GPM) and large fire flow-commercial (260+GPM). My biggest concern is confusing the two flows since 1 3/4 is not typically used to flow that much GPM. An option would be to have a pre-desinated line (pre-connect possibly) that was only used to flow high GPM and set in policy. But, a better option may be 2 inch which has far less limitations.

      • Dennis-what is your experiences using 2 inch line in place of 2 1/2 for large fire interior attack? This seems to be a much more viable option that would eliminate many of the concerns with high flow 1 3/4. I get the inside diameter of hose concer….but really does it matter? As long as the line is managable and staffed correctly, its a win win right? That was a large part of the point you appreared to be making with your “Nozzle Dreams” article, which by the way was an awesome read which I shared with my guys.

  9. Shannon first a commend you for flowing, testing, checking and trying to come up with the best possible handline attack package systems that work for you district or area of service. This obviously must include your limitations with staffing and responses. I can get you in contact with Dave Fornell about 2-inch it is really his domain. I do think 2-inch may have a place in short stretch large flow handlines, but I like oversimplification and a set-up that ensures minimizing mistakes and the right strategic/tactical handline outcomes in combat situations. I am working on an article that address the internal diameter issue in the end I feel that current 2-inch hose is about 2.25-inch in internal diameter and 2.5-inch hose is 2.75 inch internal diameter. Both can actually be a bit larger in light weight construction where the liner is allowed to stretch when charged, this has caused much of the delamination issue with liners (stay away for light weight hose). Light weight hose has only a 5-year warranty and a higher chance of failure on the fire ground do to a less robust construction mainly attributable to less mass a good analogy is light weight vs legacy building construction simple laws of physics. That being said I am a numbers guy based in fact and I am a big believe in over simplification of system used under combat stresses. If you wish to move to a higher flow out of a smaller line I would recommend still sticking to a designated two flow system or residential vs commercial flow. Select true DJ rubber lined hose this minimizes the internal diameter issue find the smallest spec 1.75 (160gpm/actual FL38psi) and the smallest spec 2-inch (260gpm/actual FL50psi) deploy these off the rig ensure the 100 gpm differential between large and small attack line. The “actual friction loss” is for true internal diameter every 100 feet. Then have 2.5-inch DJ hose for standpipe packs and for filling out your 2-inch and 1.75 static beds. Your 2-inch static line should only have a working lead of 100 feet, the rest should be filled out with your departments 2.5-inch spec hose. This would create a 265 gpm flow 2-inch attack line with 50psi of FL in 100 feet of 2-inch plus 50 psi nozzle pressure or a starting pressure of 100 psi followed by 15 psi per 100 feet in your actual 2.5-inch hose at 265gpm. This would allow for lengthy stretches from a static bed while keeping the deployability on the working length you are looking for during 265 gpm large flow operations off your pumpers (you are coreect on this line should be staffed up as a large flow line). So your department would have three specs of hose 1.75 (normal amount), 2 (small amount), and 2.5-inch (normal amount used as static fill and SP ops) as close as actual internal diameter as you can get. Still I strongly recommend just two attack hose line sizes 1.75 and 2.5-inch and ideally pre-connects should be reserved for the low flow operations only, this ensures a static pull for the larger flow fires, where lengthy stretches are a routine possibility, especially when reserving space for truck placement, but the above may work for you. Please contact me via Linked In, I will then share my e-mail and phone number and we can talk directly. I believe Dave or myself would be more then happy to provide some consultation regarding hose bed design or working with what you currently have.

    Shannon I added to the below original comment:

    What is the actual internal diameter of your 2.5-inch is the question you should be asking and why are you deploying 1.9-inch hose on your bread and butter line for flow of 160 gpm. Is your department and many others actually hamstring themselves for the room and content residential fire; as we all know seconds count why have larger then needed diameter line for those lower flows? 1.75-inch and 2.5-inch hose should have a internal diameter as marked on the jacket. This is for many reasons, by the way dual flows out of the same size line leads to many operational issues. Two different friction loss and flows for one attack hose-line leads to pump operator and line member confusion (low flow when high is desired or vise versa), officer line selection confusion, inability to tell flow from size of line, two different achievable length stretches depending on flow, low envelope of function in the stretch based on the higher flow, poor rig placement do to the desire to get with in 200 feet envelope of function, blocking of truck placement for proper aerial sweep, as lines fall short pump pressure outlet differential increases when both 2.5-inch and 1.75 at the higher flow are deployed off the same pump etc… Do not take your eyes off the ball a over kink-able 2.5-inch line that seems heavy; is it actual 2.75-inch? If they have cheated up the size of the 1.75-inch hose do you really trust your 2.5-inch hose is what it says it is internal diameter-wise. By the way I know it is not…,..In the end the greatest factor in deployment of attack hose other then reaction force is the actually charged weight of the line and that is mainly attributed to water weight the greater the diameter of the hose the harder it is to advance with equal reaction forces, based on that fact. Strive to keep it simple you only have half the answer moving back to actual 1.75 and 2.5 inch hose should be the mind set and the goal of the fire service. I call as I see it, you ran a actual “2-inch hose drill” with “mystery hose” we are all the worse for the wear until the jacket size can be trusted (again) the vast majority of the fire service is hauling around extra water weight in their attack lines collectively for the flows we wish to achieve, this always slows time to “seat” and increases kinking issues. This problem in all likelihood has cost lives and property. A huge disservice to the citizens we are sworn to protect, we should know what we are deploying. We must demand correction of this issue as the end users of this product. A return to a “true diameter” 1.75 (160-185gpm) and 2.5-inch (250-300gpm) attack hose is critical, this would allow two simple choices for operational members, two FL consistent numbers for pump operator for each line / flow, realistic ability for lengthy stretches in both lines, and a large attack line that would operate on all standpipes effectively. It also simplifies training, muscle and mind set memory, helping ensure the right line is pulled for confronted fire conditions in a time compressed and task saturated environment.

  10. u increased the pressure of the inch and three quarter to the two and a half capability, not that hard to do, but hard to hold, but easy to move, give a large fire a couple of hours holding, and the fireman will be just as tired , maybe? on the other hand, holding a duece and a half has the capabity of pumping out some serios gpms, if in trouble, great read shannon, got me thinking

    • Frank, the nozzle reaction for the 1 3/4 high flow set up and the 2 1/2 set up is identical. In fact, when flowing each line you can’t tell a difference. Several firefighters said they thought the 1 3/4 was easier to work due to the the smaller diameter and the ability to hold it easier; however, it still has to be staffed just like a 2 1/2. Additionally, I did not mention this in the article but with the 2 1/2 you have more weight of the hose/water itself which helps absord some of the nozzle reaction in comparision to the 1 3/4. But honestly, my guys said they could not tell a difference.

      • Dennis-thanks for the feedback, alot of info! We are about to do the same testing with 2 inch hose and now after reading your post, I plan on doing additional testing with 2 1/2 with 2 inch lead outs. In talking with Ray Mcormack this past year he was telling me about some FDNY units using this with positive results. I do believe in the future we will see a tactical shift to smaller diamter hose with greater flows. Regardless, good stuff and thanks for your feedback!

  11. “…The diameter of the nozzles were the same”. Why use the same size nozzle diameter on both hose lines? Through the same-sized nozzle, even on 2 different sized lines, you can still only put so much water through that hole at the end of that nozzle at one time. The advantage of 2.5″ hose is the availability of more (gpm) water (the reason it weighs more) and therefore, if you maximized your nozzle sizes and pressures for each hose size, I think you will find you will get more gpm from the 2.5″ versus the 1.75″. …and that is the only advantage of 2.5″ hose. You are right in looking for changes … the 2.5″ line is difficult and labor intensive to deploy and just beats you up. I think the real issue will be examining the way we attack fires … smooth bore nozzles, hybrid sized hoses(2″), etc… In the end, on a large fire, gallons per minute is the answer and I believe you will find that you will get more gpm from a larger diameter hose when it is deployed with the maximum sized nozzle. Good luck and thank you for challenging the status quo …

    • Ed-thanks for great feedback. I agree, you will get more GPM out of 2.5; however, we were specifically lloking for the 265 GPM mark for interior advancment. Generally speaking a nozzle reaction greater than around 99 lbs is very difficult to manage even when properly staffed. Furthermore, if you exam what many urban departments use, one would find that 2.5 hose equiped with 1 1/8 SB nozzle/tip flowing 265 GPM is what is used. The primary reason for this is with a 1 1/4 tip you greatly exceed the recommended nozz

      • Cont. recommended nozzle reaction of 99 lbs (2 firefighters at 99lbs, 1 firefighter at about 69lbs-general rule). With the 1 1/4 tip its more like 120 lbs. I state this because this was a primary factor we are evaluating; an interior large flow line that in managable. We feel that anything greater than 265 GPM is not well managed. We learn this alot from our urban counterparts. Some may argue that they dont always do it right…..however, its hard to argue that they dont get more

  12. Cont. experience utlizing the 2.5. Without question, 1 3/4 has limited flow applications. I’m in agreement….2 inch hose is likely the next best option. We will be doing additional tests on 2 and 2.5 flows which hopefully we will follow up on CF Tactics with the results. Thanks for reading and providing feedback. Be Safe!

  13. Great stuff! I just would not want anyone to think they could replace their 2.5 for high rise attack with this 1.75 because it is flowing the same gpm. The discharge pressure of the 1.75 to reach the desired high flow is 140 which is easy when connected to an apparatus but may be hard to achieve this pressure on upper floors of a high rise standpipe where the 2.5 can easily flow that big water with a lower available pressure.

  14. We have had problems with the new hose that is advertised as low friction and greater volume. We had significant kinking issues which we know decreases the volume. We have only tried the “new” 1.75″ hose not 2.5″ hose. We use a clamp slide to advance hose and accordion forward or reverse to lay hose to the objective before charging the line. We also use 2.5″ hose with 1.125″ smooth bore pumping at 50 psi tip presure. It does not kink as easy but you have to be manage the kinks and re gate the line. We use the gate up technique to charge our lines before entry.

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