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4" vs 5" supply hose, which would you put on your truck?
I recently came in contact with a department that was looking to change from 5" LDH to 4" LDH, I Know that I work for a department that made the change in the opposite direction, saying that the one inch differece, was big to the extent of close to double the friction loss when moving big water. I would like to hear any other feed back from you all, so that when I debate with this desk commander, I can present a good case. I think they main objective is the weight and size of the hose when it is charged, which is in my opinion, most of the time when your needing a supply line its because you have a big enough fire that you need water, why not have alot of water.
Replies to This Discussion
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Permalink Reply by capcityff on
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I agree. This has been one of the better discussions lately. There were a solid 6-8 people make valid points but no one saying that the other departments are wrong. Many times on here people don't realize that every department is different. DC and Milwaukee will not operate like a suburb who will not operate like a rural department.
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Permalink Reply by Eat The Roof on
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Ben,
To your first point-when 2nd due is backing down and then laying to the hydrant this is true ,but once it takes the hydrant cars will be able to drive down the street.
Your second point here has already been thoroughly addressed in one of my previous posts.
http://www.fireengineering.com/articles/print/volume-153/issue-1/fe...
Seriously-Read The Article it's well written and offers some common sense, real world reasons why LDH is NOT always the best solution for establishing a supply.
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Permalink Reply by Ben Waller on
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I've read the article.
As for cars running over the hose, we carry traffic cones and use them as an additional barrier to traffic, which helps.
You can also park the relay rig (2nd due) to block both lanes and use either 25-foot or 50-foot sections of LDH to connect to the hydrant.
You can also use traditional hydrant positioning and use another rig to block the street.
Or - you can have the cops take care of traffic control.
I've also seen cars damage 2.5 or 3-inch hose by running over it - much more than cars even attempting to run over 5-inch.
The rest of Capt. Gustin's article focuses on hand-jacking LDH. That is something that is rarely necessary, and in the way Capt. Gustin describes it, it is an attack line issue, not a supply line issue.
It is also possible to change tactics for getting two supply lines with LDH. If you have short lays, just have two engines forward lay from opposite directions. If your area is well hydranted and you have typical big-city square street grids, this will work most of the time. That takes care of any issue if there's a problem with a single line.
I also strongly disagree with Capt. Gustin on one point. We never allow a firefighter to "heel" LDH for a hydrant lay - too much change of the firefighter being dragged if a coupling hangs up. We use flat lays with dutchmen to ensure that no coupling flips over, have high hosebed rear rails to ensure plenty of space for the coupling to clear the hose bed, and invented a hose finish that eliminates both hydrant wrapping and hydrantman heeling.
We put the hydrant tools and adapters in a hydant bag then roll the end of the LDH around it a couple of times. The first hose fold has a webbing loop laid into it, then the hose finish is secured with a Milwaukee strap. When catching the hydrant, we just drop the webbing loop over the hydrant and have the engine start the lay. When there is enough hose on the ground to keep the hose from dragging, the hydrantman simple releases the Milwaukee strap, removes the hydrant bag and webbing, and makes the connection.
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Ben,
I don't doubt that you have a very good system in place to deploy and utilize LDH,but it is really not pertinent to the point I was initially trying to make.Which is-
***LDH is not always the best solution for water supply, especially as it relates to large cities and tight quarters***
Now if you agree with that statement we have nothing else to discuss, but, if you still maintain that LDH is the best solution to EVERY water supply problem, under all circumstances vs. 3", than I would just say that I feel I have offered a compelling argument citing both personal experience and evidence from others that you are indeed,wrong.I think other FF's on this thread(most from big cities) have echoed my sentiments and would say you are mistaken as well.
I pointed out Captain Gustin's article specifically, because it directly addresses the issue at hand.
*A large metro department is using 3" hose for supplying it's engines.
*The department begins using LDH, likes it and equips all engines exclusively with LDH.
*Under many varied and real world situations Crews out in the field start to become aware that there are limitations associated with LDH and that it is not always ideal solution.
*The department realizes that LDH is not the panacea they thought it was, brings back it's 3" hose and switches to a mixed (3"/LDH) box.
When Supplying Engines in large cities- limiting your choices limits your effectiveness.
I'm not sure what part of that you don't get.
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Permalink Reply by Don Catenacci on
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Ben,
If you seriously believe that cones will stop a drunk, or a moron for that matter, I hate to say this but you are delusional. I was stopping traffic from driving through a flooded area and had a very irate lady almost run me over. The only thing that stopped her was me profanely telling her to stop or I was going to throw my litebox flashlight through her windshield. So cones are a nice touch for rational, sane, sober, drivers. But they are not an impenetrable force field that cars can't get past.
The point that Capcity and Eat the Roof are making is they don't want to block the road. That is why they believe that 5 inch isn't the best choice form their departments. They need to leave room for the truck and other engines.
The only hoseline I have ever seen damaged by a car driving over it was a charged 4 inch. The line was laid for a downtown fire and a drunk driver ran over it, tore a heck of a hole in it and dragged it for about half a block before he stopped. I think the truth is any hoseline that gets run over can be damaged.
My career department SOG for handjacking is the MPO can handjack a 5 inch line up to 200 feet. Generally it is less than 100 feet, but I have done 200 feet at a fire and while it is not a whole lot of fun, it is entirely possible.
I agree with the strap over the hydrant and my career FD uses that also. I disagree with wrapping the hydrant bag and that additional weight into the end of the hose. If the webbing lets loose you now have a weighted tail of the hose whipping around as it gets dragged down the street. The hydrant bag on all my FDs is either on the rear step or in the rear compartment. The hose is pulled from the rig, the hydrant bag is pulled off the rig and dropped by the hydrant. Once the hose has laid enough that it isn't tight anymore the strap is released and the connection is made.
I guess in my perspective the only right way to lay supply hose is the one that works for your department and allows you to get the job done. There are many different tools and many different techniques throughout the fire service and as long as you get the job done, and done safely, it doesn't really matter how it gets done.
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I think you're assuming something that I did not say. My point is that LDH can be very effective for big-city departments, IF that department is willing to invest the time and effort in the research and the re-training that it takes.
As for Capt. Gustin's article, once again most of what it discusses is not SUPPLY line problems, it's ATTACK line problems. LDH isn't a great choice for attack lines if you have to hand-jack very much of it, obviously.
If hand-jacking long distances for attack line is required, I prefer 2.5 inch to 3 inch. We never gave up that option when we switched to LDH supply lines.
I believe that you have been reading more into my comments than what I actually said.
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Don, respectfully, have you ever heard of a straw man argument? Your first paragraph is one of those. You are responding to something that I did not say.
Please re-read what I actually said, which is that traffic cones "help". Cops help even more.
Regarding your hydrant bag comment, we wrap the hose twice around the hydrant bag. We also use the hydrant bag style with the straps that double back through a buckle system. We have tested this extensively, train with it frequently, and use it on 100% of our forward lays (and on 100% of the forward half of split lays) and have had the webbing "come loose" zero times. I realize that there is always a chance that something can go wrong...but...
We also issue radios to every riding position, so in the unlikely event that either the webbing or the Milwaukee strap fails, the rig can be stopped very quickly to prevent the "whipping" problem. We so a lot of three-firefighter engine work, so reducing the time that it takes to make the lay even by a few seconds and by a few saved steps increases our per-company efficiency, especially for the first due.
On the other hand, we have experienced several problems with LDH hydrant wraps being dragged and unfortunately several injuries, one serious. That's why we prefer the hydrant bag/webbing option.
I understand what ETR and capcity are saying. We have streets just as narrow - or narrower - as those in DC, and our road network is much more limited than theirs, so blocking roads is a big deal here, too. We spend a lot of time training our operators to lay the line in ways that minimize the chances of blocking the street or having to move the line - no matter what size line is laid. We also have a couple of quints that minimize our issues with truck-vs-engine positioning, so that helps some of the time.
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I commented on what you said, nothing more.
We use the strap over the hydrant method also. the major difference is we do NOT include the hydrant bag in that. I would wager that the time difference between grabbing the hydrant bag seperately from the rig and unwrapping the hydrant bag from the hose is negligible. I am not telling you to change a thing.
We are going around in circles on this topic now. There is no dispute that 5 inch will move more water than one, or even two, 3 inch lines. That has never been denied. The point is quite clearly that if what they do works for them, that is a good enough reason to keep doing it. Once again both of those FDs can overwhelm most fires with staffing and aparatus. Most smaller FDs, whether urban, suburban, or rural, don't have that option so we set up for maximum flow with one LDH supply line. Which is right? BOTH.
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Actually Don, you didn't. You said that if I seriously believe that cones will stop a drunk or a moron that I'm delusional. You also stated that cones are not "an impenetrable force field".
Since I did not mention drunks or morons, nor did I claim that cones are impenetrable.
In other words, you are responding to more than one thing that I did not say. That equals "straw man".
In case you are not familiar with the term, a straw man is a reply that sounds like something that was said, but that is more extreme and easier to rebut.
In other words, you did not limit your reply to responding to something that I actually said.
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