Advantages/Disadvantages of LDH

[redtrucks]

What are the benefits of using LDH on a first in pumper? Our currenty 3 pumpers are set up with reverse lays with 2.5" hose which can put our pumper a distance from the scene. We are a all volunteer department with 5 or 6 stucture fires per year. Our trucks currently carry 1200' of 2.5" with 300' of 1.5 attached by a gated wye. Very seldom do we every have to dump all of the hose.

[npfd801]

What are the benefits of using LDH on a first in pumper? Our currenty 3 pumpers are set up with reverse lays with 2.5" hose which can put our pumper a distance from the scene. We are a all volunteer department with 5 or 6 stucture fires per year. Our trucks currently carry 1200' of 2.5" with 300' of 1.5 attached by a gated wye. Very seldom do we every have to dump all of the hose.

Namely the biggest advantage is very little friction loss. For us, we have a great public water system, so 99% of any fire we deal with we can forward lay from the hydrant with out pumping into the supply line. The 5 inch straight off the hydrant is giving us at least 60 psi or so at the intake. With our hydrant spacing, it puts the apparatus at the scene, shortening the length of our attack lines, etc.

Obviously, without a pump on the plug, if our attack engine goes down, we can't pump through it like you could if the attack engine goes down, so that's a drawback.

[chiefengineer11]

What are the benefits of using LDH on a first in pumper? Our currenty 3 pumpers are set up with reverse lays with 2.5" hose which can put our pumper a distance from the scene. We are a all volunteer department with 5 or 6 stucture fires per year. Our trucks currently carry 1200' of 2.5" with 300' of 1.5 attached by a gated wye. Very seldom do we every have to dump all of the hose.
How well I remember the days when we used to blame "Low water pressure" for all of the buildings that we burned down. And that, with our 150+ psi hydrants with large mains. The real culprit was the single line 2-1/2 supply line mentality. Then in the late '60s we modernized with 3" and only burned down the really big ones.

When we went to 5" in 1990, I came to realize one principle that really can be said for any major advance.
Having 5" hose allows us to think differently.
Having 5" hose requires us to think differently.

We're now allowed to think in terms of dropping a single supply line and having adequate water for many if not most jobs. Dropping the second line is never a bad idea, if you have somewhere to drop it from.

We're required to think differently because once we drop and charge that 5" line, if it's snaking across the road, you've effectively closed the road. You aren't going to move it to allow other apparatus to get in. At approximately 1 gallon/foot of hose, that just isn't happening.

But now go back to "allowed" to think differently. No longer are we necessarily married to the nearest hydrant (or other water source, for that matter). Is there another one within range that is stronger or that will allow us to bring the supply line in from a different direction, keeping the main access open? Is there better or more suitable draft source a little farther out? Can we use LDH to put a tanker drop site at a distance from the fire scene and allow the tankers to operate in a one-way continuous loop? Ditto, the fill site from the water source. I have seen all of these done very effectively. Without LDH they would not have been practical.

Yeah, 5" is a pain to pack. But usually you only have to pack one line instead of two or more.

Stay safe out there, everyone goes home!

[Fire304]

Advantages:

Low friction loss
High flow
Can be laid in both directions (fwd and rev) no special load needed
Universal couplings (no dbl male or female needed)
Quick lock Stortz couplings
Does not rot if loaded wet (though it may stick together)
Can carry more "flow per foot" of hose in same size hose bed
Only requires one line for monitors and FDC's


Disadvanaged:

Heavier to pick up, sucks when turnouts are soaked and you just want to go home (though I think it may be quicker)
Cannot be used as attack line in a pinch
If your FDC's are clappered siamese, requires you keep some 3" or make a short LDH to 3" pony rig
Engineers get fat from not having to run around like a mad man to hook up 4 supply lines ;)

[clifton36]

We have been using 5" LDH since the early 1990's, but it's taken us several years to realize there are LDH limitations too.

Our engines carry 1000-1200' of hose. If an engine lays the entitre bed from a hydrant, we require and engine at the hydrant relay pumping. For years we assumed 5" hose would pump as much as you want for any distance. Not quite

5" hose is good for a max 1600 GPM, maybe 2000 with a very short lay. However, this is a dramatic improvement from 2.5" hose at 400-500 GPM.

From a strong hydrant being relay pumped, we can lay a pair of 5" lines to the fire. One engine can easily supply 2500 GPM from a high-flow hydrant (1500 GPM pump) with a full hydrant connection (hard suction 6" or a pair of 5" hoses).

[Fire304]

5" hose is good for a max 1600 GPM, maybe 2000 with a very short lay.

5" has a friction loss of 24.4lbs/100feet at 2000gpm, this would allow you an un boosted lay of 600feet assuming 180psi working pressure and 20 psi residual at the end of the hose. At 1800gpm you have the same losses (20 per hundred) as 4" running 1000gpm

[mcaldwell]

Advantages:

Low friction loss
High flow
Can be laid in both directions (fwd and rev) no special load needed
Universal couplings (no dbl male or female needed)
Quick lock Stortz couplings
Does not rot if loaded wet (though it may stick together)
Can carry more "flow per foot" of hose in same size hose bed
Only requires one line for monitors and FDC's


Disadvanaged:

Heavier to pick up, sucks when turnouts are soaked and you just want to go home (though I think it may be quicker)
Cannot be used as attack line in a pinch
If your FDC's are clappered siamese, requires you keep some 3" or make a short LDH to 3" pony rig
Engineers get fat from not having to run around like a mad man to hook up 4 supply lines ;)


Pretty similar experience here with our 4", but we have also found that for long lays the forward rolling take-up (drive forward slowly straddling the hose) eliminates most of the bitching about it's size and weight on clean up.

We have 1500' of 4" on our main engine, and 500' on the telesqurt. We also keep 1000' (+200 rolled), and 500' of 2 1/2 on each truck respectively. I cannot think of the last time we pulled any 2 1/2. The guys are sold on the 4".

[HuskerMedic]

The first vollie department I was on used a 2 1/2" double reverse lay setup. We had two 2 1/2" lines, one set up as a 2 1/2" attack line with nozzle, the other gated down to 2-1 1/2" attack lines. On a house fire, we would just pull the gated side. With a large structure, we would pull both. It wasn't an impossible system to make work, but having used this system makes me appreciate the forward lay my current department uses.

Aside from the friction loss issues, the main disadvantage was that the truck, with all the equipment, spare SCBA bottles, ladders, etc. usually ended up a block away at the hydrant. Unless, that is, someone had the foresight to pull all of that stuff off while someone else was dropping the skid loads (happened rarely). Yeah, I know a block isn't that far, but if we had limited manpower, especially during the day, it usually took one person just to constantly run back and forth to and from the truck. It also placed the pump operator quite a distance from the scene, making effective radio communication a must.

[neiowa]

Namely the biggest advantage is very little friction loss. For us, we have a great public water system, so 99% of any fire we deal with we can forward lay from the hydrant with out pumping into the supply line. The 5 inch straight off the hydrant is giving us at least 60 psi or so at the intake. With our hydrant spacing, it puts the apparatus at the scene, shortening the length of our attack lines, etc.

Obviously, without a pump on the plug, if our attack engine goes down, we can't pump through it like you could if the attack engine goes down, so that's a drawback.

Joel I know a guy that will make you a good deal on a hydrant assist valve.

[LFDLT10]

We've used 5" LDH since the early 90's and I hope I never have to go back to using a dual 2 1/2" set-up.

Heavier to pick up, sucks when turnouts are soaked and you just want to go home (though I think it may be quicker)
I know it's quicker for us. While it's heavier you are only picking it up once...compared to rolling twice as much (or more) 2 1/2", then rolling it all back out to wash, rolling out and loading the same amount of replacement hose, and hanging or putting the wet hose in the dyer. I can recall early on our engine being OOS for up to two hours after a major call where we dumped the entire bed. Go back to that? No thanks.

[Eno821302]

Bring me LDH or bring me death. We used twin 3" and 2.5" on our trucks for the longest time and while it never did us wrong, it was really nice to get the LDH on our front line trucks. One potential disadvantage of the LDH is that you can't cut in on the line to boost it without shutting off your water supply. For the 1% of times you might actually have to do this and not have enough water in your workhorse pump to carry the balance until the transfer is complete... I think it's worth the risk.

The guy that mentioned all the extra work involved in taking up and putting trucks back in service... you get a platinum star! I totally agree with that and I'm just glad someone else typed it all out.

Another potential disadvantage involves another debatable subject and that's whether or not you can clamp LDH (5"). I've heard arguments on both sides- never really been sold on why you can't clamp it but depending on what your department SOPs become- not being able to clamp it might be a bit of a problem short handed. That hydrant guy may be your second man on your first team... Solutions to this include hooking deadman hydrants (for the next rig to connect- assuming it's even coming)... We took a about 500lbs off our truck when we upgraded as well.

Just a few thoughts- most of which had been mentioned already.

[taskforce16]

My department uses 5.0" LDH and with two new pumpers deliver last year, now all of our engines now carry 5.0". It works great. Would never go back to 2-1/2" or even using 4.0" LDH unless you have a real strong water supply system.

The one question I have does anyone have any pictures or power point presentations that show the proper way to repack 5.0". Or does your department have any tips or tricks for repacking LDH?

I've heard one where you cap the high end of your 5.0" hose lay and let the water drain out. By placing the cap on the one end, as the water drains it creates a vacuum and sucks the hose flat. Has anyone used this or tried this?

[Eng34FF]

I've heard one where you cap the high end of your 5.0" hose lay and let the water drain out. By placing the cap on the one end, as the water drains it creates a vacuum and sucks the hose flat. Has anyone used this or tried this?

That's how we always drained the 4" at my last department. Instead of capping, we usually folded the end over and let it drain or walked it out. We found that if you broke the line you tended to get a lot of air in the hose. Once the air was in the hose, it was almost easier to re-charge the line and drain it again than to get it out with a hose roller.

[chiefengineer11]

The one question I have does anyone have any pictures or power point presentations that show the proper way to repack 5.0". Or does your department have any tips or tricks for repacking LDH?

I've heard one where you cap the high end of your 5.0" hose lay and let the water drain out. By placing the cap on the one end, as the water drains it creates a vacuum and sucks the hose flat. Has anyone used this or tried this?

We pack our LDH "coupling forward" (learned from either Elkton or Havre de Grace, at MFRI, by the way). That is, all of the couplings, except the end one, go to the front of the hose bed, and are positioned so that they do not have to flip over when they are coming off. What's most important when doing this is to NOT pile the other folds of hose onto the couplings. The coupling goes against the front bulkhead and the folds of the hose are position a foot or so back. That includes the folds of the hose as you come across the bed. The next coupling goes into the space against the bulkhead. When all of that space is used, the next couplings go on top of the couplings below. I'll take some pictures, then get FWDbuff to show me how to post them here.

As far as draining the hose, we'[ve tried everything including capping and/or folding the high end. It works reasonably well, but if you need to expel all of the air so that you can get the most hose into your hose bed, the only thing that really works is rolling the hose. I had told the person who makes and markets the "Roll-N-Rack" system that until came out with some kind of a powered roller, we weren't interested. He has now done so, so we're going to take a look at it. I got a DVD from him and it looks pretty neat, but it's pricey.

Someone else mentioned straddling hose with the engine and moving as they repack it. We sometimes do that if we laid it but didn't charge it. Other times it's just as convenient to back up as you repack. Having a back up camera with audio on our newest engine make that much safer than the spotter using a buzzer along with waving at the driver.

Stay safe out there, everyone goes home!

[FWDbuff]

Now what I have been trying to tell Chiefengineer11 for years, is that there IS another method that works extremely well, which we used at my former career department. He doesnt want to believe that it works, but I happen to KNOW it works, as we laid our 5" line once a week, he's lucky if he lays his once a year.

Cap off the high end. You HAVE to use an extra cap, or some sort of device that will positively seal the end. Simply folding over the end alone will not work. Once it is capped off, the downhill end will drain out. When that is complete, get two guys, one on either side of the line, with a halligan tool (or something equal...) Each guy takes one side of the tool, and walks it under the line, from the capped end to the open end.

This, in conjunction with the capping/vacuum, does an incredible job and gets the line very flat.

[npfd801]

Joel I know a guy that will make you a good deal on a hydrant assist valve.

I need to get our second in engine to hit the hydrant like they're supposed to before we buy hydrant assist valves.

You have one used or something? :)

[Fire304]

The guy that mentioned all the extra work involved in taking up and putting trucks back in service... you get a platinum star!
Why thank you, I often get in trouble for daring to utter the truth ;)

Another potential disadvantage involves another debatable subject and that's whether or not you can clamp LDH
Done it, do it, will do it again. As long as you have the proper sized clamp for your hose. My last department we ran 2 man engines and our SOP was to wrap the hydrant, leave it, and lay into the scene. We'd clamp the LDH 20 feet back from the truck then hook to the pump, the 2nd due (full time staff so they were right behind) would dress the hydrant and charge it then drive to the scene. The clamp allowed us to not have to wait to charge the hyrdant, getting the manpower to the scene that much faster and avoiding related radio traffic.
http://www.nafeco.com/ProductImages/HC6.jpg
This is the clamp we used, it was set up so all you had to do was drop the hose into it and shut the bail (clip on left side allows it to hinge open). When you wanted water you'd unscrew the clamp if the hose was already charged, just kick the bail if not (and leave it right there).

[FyredUp]

Now what I have been trying to tell Chiefengineer11 for years, is that there IS another method that works extremely well, which we used at my former career department. He doesnt want to believe that it works, but I happen to KNOW it works, as we laid our 5" line once a week, he's lucky if he lays his once a year.

Cap off the high end. You HAVE to use an extra cap, or some sort of device that will positively seal the end. Simply folding over the end alone will not work. Once it is capped off, the downhill end will drain out. When that is complete, get two guys, one on either side of the line, with a halligan tool (or something equal...) Each guy takes one side of the tool, and walks it under the line, from the capped end to the open end.

This, in conjunction with the capping/vacuum, does an incredible job and gets the line very flat.

Hmmmm, I guess I better go back and tell the guys on 4 different departments I have been on that folding the end of the hose to do what is called the "vacuum drain" around here doesn't work. A couple of the departments drained this way and used a hand held hose roller to finish the drain off, the other 2 just used the motion of loading the hose into the hose bed finish the drain.

It might be more appropriate to say that a cap makes it impossible to screw up and open the end of the hose and allow air in. But to say folding the hose over doesn't work is a little extreme in my book.

[FWDbuff]

It might be more appropriate to say that a cap makes it impossible to screw up and open the end of the hose and allow air in. But to say folding the hose over doesn't work is a little extreme in my book.

When the two guys have to walk the line with a tool, it's kinda impossible for the fold not to flop around and come undone. If all you want to do is fold the line over and let it drain naturally, the fold will suffice.

[Doubleh49]

Here is a link to pictures showing "the Firetown Fold" a process that the Wellsboro PA department might have created?:
http://soddydaisy.org/library/August07Newsletter.pdf
it has worked well for our department too.There is currently an article in another fire magazine about the Wellsboro department (google Firetown fold)We also use the "vacuum drain " technique whenever the ground layout allows it.

[FyredUp]

When the two guys have to walk the line with a tool, it's kinda impossible for the fold not to flop around and come undone. If all you want to do is fold the line over and let it drain naturally, the fold will suffice.

Ummm, when the 2 guys with the roller start walking the hose we have a third guy pick up the hose at the fold and hold the fold untill they get far enough away that he can lay the hose back on the ground.

[GFD940]

One advantage that I was surprised wasn't mentioned yet was the ability to forward or reverse lay without the need of adaptors. Also, I second the RollNRack for draining hose. I was skeptical at first but used it and like it.

I have debated with numerous chiefs the merits of LDH and here in the Rust Belt I hear a lot of "Our water lines are old and don't have enough pressure." They can't seem to understand the difference between pressure and volume. My theory is if I have low pressure I don't want much friction loss from my hose. It doesn't matter if you can fill a 2.5" or 3" hose if the water doesn't make it to the pump.

Our SOPs at my career department are flexible as far as placing a pump at the hydrant or laying in with the first engine. It is left up to the OIC since no SOP can dictate for all fire situations.

[chiefengineer11]

One advantage that I was surprised wasn't mentioned yet was the ability to forward or reverse lay without the need of adaptors. Also, I second the RollNRack for draining hose. I was skeptical at first but used it and like it.

I have debated with numerous chiefs the merits of LDH and here in the Rust Belt I hear a lot of "Our water lines are old and don't have enough pressure." They can't seem to understand the difference between pressure and volume. My theory is if I have low pressure I don't want much friction loss from my hose. It doesn't matter if you can fill a 2.5" or 3" hose if the water doesn't make it to the pump.

Our SOPs at my career department are flexible as far as placing a pump at the hydrant or laying in with the first engine. It is left up to the OIC since no SOP can dictate for all fire situations.
Probably a reason no one mentioned the ability to lay out without adapters is that there are (or were), on the left coast, departments that were using it with NST couplings. I remember hearing of a ranking officer in a department out there who demanded that any couplings other than NST be outlawed.

Old water mains and low pressure are great justifications for using LDH. As you say, there's a huge difference between pressure and volume. Pressure doesn't put fires out, gallons of water doesn't either, GPM does. If you have the volume and can move it, you can make your own pressure. That's what engines do so well.

Another advantage is that you have the ability to go to a better source (if you have one) that's maybe a little farther away and still move the needed water. LDH allows us to think differently, LDH requires us to think differently.

Stay safe out there, everyone goes home!

[Eno821302]

If we want to reverse lay with high vol- assuming you're not doing it right from a truck- you still need a manifold to convert from 5" down to smaller attack lines.

But yes, I suppose the sexless couplings do make some of those different lays easier.

I know one other advantage we have is that when used with our floating pumps (currently volume based pumps), having that minute friction loss is helpful for moving the volume of water they're capable of. With any significant lays of 65-77 we lose a lot of our capabilities.

[GFD940]

We always have one engine at the scene so it is essentially our manifold. We have several older allotments without hydrants and lots of cul de sacs. First in goes to the scene possibly laying from the corner of the dead-end street. Second engine can reverse lay from the first or their line and head to the nearest hydrant.

[rotorsport]

We are looking at going from 4 inch to 5 inch and the debate is, do we use 4 inch coupling so the switch over is less costly? But we are unable to find info on the amount of reduced flow because of the smaller couplings. Does any one have any experience or knowledge to share.

Charles

[neiowa]

We are looking at going from 4 inch to 5 inch and the debate is, do we use 4 inch coupling so the switch over is less costly? But we are unable to find info on the amount of reduced flow because of the smaller couplings. Does any one have any experience or knowledge to share.

Charles

Better to buy a couple of 5"S x4"S reducers and buy the 5" LDH with 5"S. Otherwise in 10yr your FD be stuck with the 4"S couplings (and the FF of 2018 be taking your name in vain).

[Fokker416]

Agreed. We changed to 5" from 4" a few years back. All of our new apparatus were equipped with it when they were bought and we phased it in for the rest of the rigs over a couple budget years. An adapter or two on each truck worked out fine. It turned out good for us, the next Dept over uses 4" still so we're set up for mutual aid. Also, it turned out that 5" was too big to feed out of our Tower's supply hose chute (thanks engineers!) so we ended up with one apparatus that still carries 4". If you are going to go to 5" you may as well go all the way, otherwise you're creating choke points that work against the very reason you wrote the check for new hose in the first place.

[rotorsport]

Thank you for the input I'll forward it to up the food chain and hope for the best.

Charles

[Fire304]

Rotor, a quick search and I found 4 X 5 storz for about $180 each, 5 inch Kochek hose runs about $675 per 100', so for about half the cost of a roll of hose you can equip a truck with a pair of 4 by 5's and use them like a dbl male dbl female set. You'll be able to couple into just about any possible combination of hose that way.