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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 ian wilcox on
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we use 4 inch lines we carry 800ft on our engine,we have some old hydrants that only have 2 1/2 supply on them so we have a 2 1/2 to 4 adapters. we have a hydrant bag with every adapter neccessary to service our fire protection area in our engine and rescue truck i believe that all neighbouring departments also use 4 inch for their supply also so we would probably have all adapters neccessary to hook them up if we had to
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Permalink Reply by Eat The Roof on
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Don Catenacci-"The only reasons not to change to LDH are 1) This is how we have always done it. 2) Change is expensive in larger departments. It is cheaper to keep buying replacement hose of the same size than to try and replace it all with something different. Although it would be relatively fiscally responsible to change out a rig or 2 a year with LDH.
Everything that you do with single or multiple 2 1/2 or 3 inch lines can be done better with higher flows and efficiency with LDH, inclucing reverse lays."
You forgot reason 3) Because it is not as practical as using 2 x 3" lines or at least as it applies to larger older cities with narrow congested streets.
This is an example of - What makes sense for your FD may not be practical for my FD.
In the case of my FD(Old large City) 1st engine pulls past fire building(leaving room for 1st Truck) 2nd engine backs down and reverse lays supply to hydrant.
With LDH once it is dropped and charged this effectively blocks the street from any other arriving apparatus.No matter how carefully it is initially laid it will serpentine once charged and block the street.With 3" this may also be the case but it can be moved to the side with 1 or 2 guys quite easily to clear the way for other apparatus that needs to get down the street.
Believe it or not people do not always behave rationally or selflessly when confronted by supply lines laid on their street.In other words people will run over your supply lines no matter how much you are swearing at them not to.with a 3" line this is annoying but not usually catastrophic.5" lines offer a much larger chance that the car will snag on some part of the hose and puncture or damage it.This brings me to another advantage of "dropping 2 3's" -redundancy- I have two lines supplying instead of just one.If one line fails I still have a ~500-600 GPM supply until I can fix the problem.
Do I really need more than the ~1000GPM flow I get with 2X3 inch lines?
95% of the time the answer is NO
4% of the time the answer is maybe
and <1% the answer will be yes.
Most of our workload includes SFH and small apartment buildings which are easily contained using a couple of handlines.If more is needed we'll just grab another hydrant( usually within 200')and get another 1000GPM.Given a good hydrant we will almost always have excessive capacity GPM wise regardless.
Another question is when you are confronted by a body of fire requiring more than 1000GPM or 2000GPM How much are you actually saving be merely putting some more water on it? for instance -pulling up to a 100'X100' light industrial occupancy with a large volume of fire requiring a defensive operation.Whether I'm flowing 1000 or 10000GPM i'm going to most likely lose that building mostly because most of the water I'll be pouring on it will be wasted and not directly converting the seat of the fire.
Just my personal opinion, but I find the storch couplings finicky and a pain to break down or hook up compared to traditional 3" couplings especially in the winter months.For me I find 3" much easier to pick up and drain as compared to 5"-maybe that's just my comfort zone.
I'm not arguing against having 5"LDH altogether. I think it suits many rural and even some urban departments quite well.But I would argue against being dictated to and told we always have to use LDH no matter the situation.
Change for the sake of change is as stupid as ignoring emergent tactics just because they are something new and different.
Ben Waller-"If you have problems with the coupling locks, just get LDH spanner wrenches and use them."
At $30-$90 dollars a pop it won't be cheap to outfit an entire big city FD with a couple hundred.vs the ~$6-7 per it will cost for spanners for 3".
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Permalink Reply by Ben Waller on
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If your big city FD has the money to buy new engines or LDH, the $90 or so for a pair of LDH spanners per rigs is relatively peanuts.
Just spec the spanners - and a few spares - with the LDH or the rig.The ability to move the extra water makes it worth every penny, in my book.
As for big city LDH lays, there are some that use exclusively 5-inch LDH for water supply. Every issue you brought up can be addressed through training and careful hose lays, including a 2nd due "back down and reverse lay", if needed.
As for your percentages of what fire needs what water, there's a better way to look at it. A single LDH will supply all of the water you need, almost 100% of the time. It will supply more than two 2.5-inch or 3 inch lines.
Breaking it, draining it, and picking it up isn't a big deal once you get used to it and learn a few tricks. We routinely pick up LDH lays of up to 1,000 feet with three firefighters. We occasionally have a sticky Storz coupling, too, but since we're picking up the line, we're not generally in a big hurry. With a little troubleshooting, LDH spanners, and a little work, we manage to get the couplings broken down and the hose drained and repacked every time.
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Permalink Reply by Don Catenacci on
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Dude, if you like picking up 3 inch hose that you have to wash, dry, rack and get different hose off the rack to reload you engine with...More power to you.
If you lay hose properly whether it is 5 inch or 3 inch or 2 1/2 inch you shouldn't have to move it after it is charged. Please tell me you aren't saying that an engine equipped with LDH can't back down to the attack engine and reverse lay. I'm just amazed that my career FD can manage to fight fire using 5 inch with the doom and gloom picture you paint.
Hoselines do get run over on occasion, but I don't know it is something close to being a common problem. In the city I work in the cops close the street so nothing gets in other than fire apparatus. Seems like a simple solution.
I guess to me using 5 inch hose boils down to this: 1) All the water the hydrant can supply through one line over longer distances. 2) Laying one line meaqns picking up one line. 3) No playing catch up by having to add supply lines if the fire grows.
Like I said in the beginning, if you like your 3 inch lines, more power to you. We like the 5 inch and will continue to use it.
By the way, it is Storz couplings not storch.
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Permalink Reply by John Crabbe on
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Milwaukee and Tosa.......
I'm sitting back and tossing the popcorn on this one. Play on.
:-)
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No battle from me...Not with our new mutual aid partner!
They fight a lot of fire and seem to do just fine.
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Permalink Reply by Mark W on
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This is florida were talking guys, no big city and for the most part, the second or third unit arriving is laying in. Let's get back to the heart of the discussion, WHEN YOU NEED A WATER SUPPLY you need a good one. I would much rather have the 5' supply with less friction loss and be able to reach my capacity of my pump, without losing most to friction loss. Most of the homes in the area of protection are large custom homes, 2500-5000 sqft, along with alot of commercial store fronts and ect. When the fire goes beyond the room and content, or runs the attic, you start to push the gpm up needed for extinguishment or exposure protection. Not unsual for flows to get up into the 1500 to 2000 gpm depending on conditions, exposures and such. I know from close to 30 yrs of doing this, that personally I would rather have the bigger supply, but the point of the discussion was to see if anyone had come across this situation where a department was downsizing because of issues. I think it is a dumb move, but wanted to see before go off on the desk riding command on how stupid they are, if they had any valid come backs.
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Permalink Reply by 55 TRUCK on
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Don, we lay 3" on about 97% of our fires. We just rerack it, no washing or drying and putting on other rolls from a rack at station. Just rerack it and use it again. Another thing I'd like to point out is that in bigger cities like Indy,DC, Philly,Detroit etc. We have narrow streets that is why we use shoulder carries there are many times where I must step on the hood of a car to get down to the street. Another point is that there are alot of our inner city hydrants that only have dog ears no 5" connection.
Now myself and DC and the other guys on here who work in large cities, we arn't pulling the stuff out of our arses we are telling you how we do it and that it works.
Here is somthing else to ponder, I work in Indianapolis, I live in a suburb of Indy on the north side. The population of wich is 70,000. The fire department has 5 stations, there run load is about 5grand a yr give or take. Now the Indianapolis fire dept. does about 300 thousand runs per yr. of that 64 thousand are working fires. 2 companies not 2 stations just 2 companies in IFD will do the same amount of runs in a year as the entire department where I live does.
As I see it, most firefighters from smaller paid or vol. departments just can't comprehend what us city firemen are saying. We average about 2 to 3 working fires a shift in the inner city.
We have 5" on our engines, we mostly lay 3". A single 3" supply is called a residential lay. We will lay dual 3" on bigger fires. 5" can be laid that is up to the officer of the engine. SOP for us is that the second in engine co. must lay a supply line that is equal to or greater than the first in engine co.
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Permalink Reply by Tom Wallace on
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We carry 5" on our Engine and 4" on our Quint. I have to agree with John, friction lose not a big issue, mobility does suck if either are charged. But yes look at your MA. We have departments in our county most all are 5'. We also go MA to the neighboring county and they are 4" thats why we carry both.
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Dude, far be it from me to tell you that you are wrong.
Please explain to me the advantage of laying dual 3's over a single 5.
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We have departments that use 4 and 5, or 4 or 5, that we run mutual aid with. We use 5 inch but we cary adapters to go from 4 to 5, and 5 to 2 1/2.
It gets even more fun when we try to fill Tenders (tankers). Some have 5 inch Storz, some have 4 inch Storz, some have 2 1/2 inch NST, and some even have cam locks. Sooooo, we carry them all on our Tender so we can adapt to what ever FD is running the fill site.
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Don,I didn't paint a gloom and doom picture.I was just making a few points on why 5" is NOT an advantage in certain Urban settings. As I pointed out when the LDH is laid down a narrow street with cars parked on both sides(most of our fires) it blocks the street no matter how it is laid down. 2x3"s can be easily moved to the side to make room for the truck(s) who are usually arriving later.Getting cops on scene is usually well after the fact and that doesn't prevent cars from the middle of the block from trying to leave.Most of the 3" goes right back onto the rig after each use.If the fire grows that big your going to have to add supply lines in most cases anyway, even with 5".There is still a limit to what your 1st engine can pump regardless of how much it is being supplied.I never stated 5"LDH is not useful for other departments or even our own given certain circumstances ,just that in most cases 3" is preferable and sufficient in over 95% of our fires. "Storz" instead "Storch" got it.
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