Pumping through LDH

[Georgetown18]

This may seem like a dumb question to you city boys, but what is the best way to pump through storz LDH? We are a rural department that only drafts but come the first of the year there is a chance we could be using some hydrants that are very spread out so we would probably have to pump from the hydrant to the attack engine.

[Dickey]

This may seem like a dumb question to you city boys, but what is the best way to pump through storz LDH? We are a rural department that only drafts but come the first of the year there is a chance we could be using some hydrants that are very spread out so we would probably have to pump from the hydrant to the attack engine.

If you will be using hydrants, they are a positive pressure system meaning you don't have to suck it out of the hydrant, it comes to you under pressure.

You can lay your supply line of LDH from the hydrant to the attack engine without the need of an engine in the middle, that is if the water pressure is adequate.

You may pump through LDH just like any size hose, it's just a bigger hose.

Some departments always operate with an engine at the hydrant pumping to the attack engine to ensure water pressure is not an issue. Personally, in my department, I am not always guaranteed enough personnel to staff a second engine. We operate the first in engine drops a hydrant person and hose at the nearest hydrant, drive to the fire and commence fire attack. The hydrant person makes the connection, and the driver advises the hydrant person they have made the connection to the truck and they can turn on the hydrant. The hydrant person then comes back to the engine to be part of the back up team.

[Georgetown18]

I guess I misphrased my question... I completely understand the concept. Im just unsure of what hardware is best for the situation.

[tree68]

Check out the friction loss information for your chosen LDH. Up to a point the loss is negligible - laying in off the hydrant and working with hydrant pressure will work just fine for you.

Beyond a certain point you'll need to help it out a bit, usually with an engine at the hydrant. Consider your flows and the potential length of your lays.

We are also rural and generally end up drafting, at least from a drop tank. We are surrounded by villages with hydrant systems, however, as well as Lake Ontario and the St Lawrence River. Our LDH has been off the truck for a fair number of incidents both in hydranted area and where we've been drafting.

Another plus, LDH gives you the ability to move your tanker shuttle operation away from the fire scene, possibly even keeping it on a main road.

[DeputyChiefGonzo]

You'll want a hydrant assist valve on the hydrant. First pumper lays into the fire, a second pumper can then pump the hydrant through the HAV to maximize the water flow.

A "Z valve" can be used inline for long lays, a Z valave opeatresin a similat fashion, allowing an engine to boost the pressure tot he attack pump.

[nmfire]

You should have a gated Piston Relief Valve (PRV) on the engine's intake with a stortz fitting that matches your hose (4" or 5"). You should have a hydrant to stortz adapter for the hydrants. You may also want to get some gated wyes and a syamese. Maybe a manifold.

Other than that, its just a big hose.

[Dickey]

Oh yes, forgot that part.

make sure you have the proper adapters and train with them before you actually need to use them for real.

[nmfire]

Also, most LDH is limited to 200psi. This is what limits your length. With 5" LDH flowing 1000gpm on flat ground, you are limited to about 1,800ft because more than that will require more than 200PSI at the pump discharge. As you lower the GPM, you lower the pressure and subsequently can use more and more LDH.

By placing a relay pumper in the middle, you can double your distance.

[DeputyChiefGonzo]

You should have a gated Piston Relief Valve (PRV) on the engine's intake with a stortz fitting that matches your hose (4" or 5"). You should have a hydrant to stortz adapter for the hydrants. You may also want to get some gated wyes and a syamese. Maybe a manifold.

Other than that, its just a big hose.

I forgot that too... chalk it up to cranial flatulence.

[slackjawedyokel]

In case you have two ways(hydrants) - have several stortz X 2-1/2" hydrant adaptors in addition to the 4-1/2" X stortz. A 3 way manifold (stortz X three - 2-1/2"males "triplex") can come in handy , have dbl females attached so it can "swing both ways"

[tree68]

And, a little trivia I figured out some time ago:

Five inch LDH holds about a gallon per foot. That means it weighs something over 8 pounds per foot - once it's full, it pretty much stays put.

And, if you lay out 1000' (which is what we carry) you'll empty your booster tank charging the line (if you're drafting from a drop tank and waiting for water, and assuming you have a 1000 gallon booster tank).

Also, in 5" LDH flowing 1000 GPM the water is moving at about 11 MPH. Open and close valves s-l-o-w-l-y. That's a lot of momentum.

That all assumes I did the math right.

Back on topic - make sure you have adapters to fit your neighbors as well. We have a neighboring department with 4" LDH. We have 5" LDH. We carry 4"x5" Storz adapters for that reason.

If you use a manifold, it should also have a pressure relief valve.

[Jonnee]

Our procedure is to not lay over 800 feet on a relay. This allows you a section or two in case you have a bad coupling or burst section. Safety is always first.

Plus is necessary it also allows you to get the replay pumper out of the middle or edge of the road if the road is narrow.

[L-Webb]

I have a question too.

Is there a min flow the hydrant needs to have to use LDH. I have been told that if the flow is below 500 gpm, then it could cause problems and you would be better off laying dual 3 inch lines. Is this true?

Can you get 1000 GPM out of dual 3 inch lines @1000 feet?

[nameless]

I guess I misphrased my question... I completely understand the concept. Im just unsure of what hardware is best for the situation.

You'll want some 2 1/2 to however big your house inch Storz for hooking to hydrants and for working with other departments if they don't use storz LDH. You'll need adapters for the intakes and discharges for your own engines.

If surrounding departments use other sized LDH you might want some storz to storz adapters to compensate for the difference in size.

[MemphisE34a]

I have a question too.

Is there a min flow the hydrant needs to have to use LDH. I have been told that if the flow is below 500 gpm, then it could cause problems and you would be better off laying dual 3 inch lines. Is this true?

Can you get 1000 GPM out of dual 3 inch lines @1000 feet?

No and no.

[chiefengineer11]

I have a question too.

Is there a min flow the hydrant needs to have to use LDH. I have been told that if the flow is below 500 gpm, then it could cause problems and you would be better off laying dual 3 inch lines. Is this true?

Can you get 1000 GPM out of dual 3 inch lines @1000 feet?

The only problem would be the length of time it takes to get water from one end to the other. A good head math number is that 5" hose holds about one gallon per foot. So if you have 1000 feet out, once your hydrant is open and flowing, it will take about two minutes to get water flowing at the scene end. But your friction loss will be minimal.

On your 1000 gpm through dual 3" lines, do the math. All things being equal, each of the lines is flowing 500 gpm. A tolerably decent head math number there is 20 psi loss/100 ft. That would say 200 psi loss end to end. If you want 50 psi coming in to your relay engine, now you're at 250 psi. Not impossible, but not good practice either.

[MColley]

Also, most LDH is limited to 200psi. This is what limits your length. With 5" LDH flowing 1000gpm on flat ground, you are limited to about 1,800ft because more than that will require more than 200PSI at the pump discharge. As you lower the GPM, you lower the pressure and subsequently can use more and more LDH.

By placing a relay pumper in the middle, you can double your distance.

I have to disagree with that satement (a bit) it is not totally acurate. One of our negibouring departments has 5500 feet on one truck wich we use a supply truck. We have no hydrants other than dry hydrants so we do all of our pumping from draft. The truck has a 1750GPM pump on it and we can pump at around 150 to 175 and provide a fire flow of around 250 gpm (on a flat) of course if we drop trucks in every 1000 feet or so we can drive that up significantly. And it all depends on the terrain as well pumping downhill will take less pressure and provide more flow than up hill. I know for a fact I recently worked a large commercial fire and I was being fed through 3000' of 5" over ups and downs in the road with one truck. I was supplying off my truck 3 - 1¾", 1 - 2½" at about 150psi, and a deck gun at about 80psi. The truck feeding me was at 150psi and I was getting about 100psi and I was maintaining a residual pressure of about 30 to 40psi.

I guess the main point I'm getting at is we train with it and use it on a regular basis so we know what we can do with it. It's like anything in the service use it and know it. Just becuase the book say's something doesn't mean it's right.

As for gear and hydrants know the fittings you'll need get at least one gate two is better it would suck if you had to shut the hydrant down for some reason to hook another line on. And maybe do a hydrant bag up to carry everything you need

[neiowa]

For rural water supply, including LDH relay, best reference I know of is from isoslayer (Larry Stevens wrote).

Download "ASK ISO" from http://isoslayer.com/Links.html

[Catch22]

You'll want some 2 1/2 to however big your house inch Storz for hooking to hydrants and for working with other departments if they don't use storz LDH. You'll need adapters for the intakes and discharges for your own engines.

If surrounding departments use other sized LDH you might want some storz to storz adapters to compensate for the difference in size.

No matter what size of hose you're using, you're not going to get more than the hydrant or other supply restrictions will provide. If you're only getting 250 gpm out of a hydrant, you're only going to be able to push 250 gpm.

Where LDH comes in is that you can push that gpm further with less effort due to the decreased friction loss. Dual 3's is better than a single, a single 5" is better than dual 3's.

[nameless]

No matter what size of hose you're using, you're not going to get more than the hydrant or other supply restrictions will provide. If you're only getting 250 gpm out of a hydrant, you're only going to be able to push 250 gpm.

Where LDH comes in is that you can push that gpm further with less effort due to the decreased friction loss. Dual 3's is better than a single, a single 5" is better than dual 3's.

Thats great, but what does that have to do with my post?

The guy asked about hardware, and all of you guys are jabbering about hydraulics. Just answer the poor guys question.