Thread: Dry Hydrants...annual upkeep???
04-05-2000, 05:08 PM #1Dalmatian90Firehouse.com Guest
Dry Hydrants...annual upkeep???
My department doesn't currently use dry hydrants (although I'm one of the few who know where a 1940s vintage 2.5" one is located in a mudhole near the town center!). We're very good in getting hard suction into action.
A main project this year is to review & rate our water holes, and work with private landowners, ourselves, and the Town Public Works to improve quality & access. A couple of these, the best all-season access might be dry hydrants.
What kind of annual maintenance needs to be done on the dry hydrants? It would seem to me the suction strainers on them would get grown in/silted in/etc regularly.
04-05-2000, 05:50 PM #2DDFirehouse.com Guest
Contact your local Soil & Water Conservation Service office. They should be able to provide you with information on the type of dry hydrant for drafting use.
[This message has been edited by DD (edited April 05, 2000).]
04-05-2000, 07:48 PM #3Sand Creek LynnFirehouse.com Guest
Ahhh what a timely question. We have 3 and are installing 2 more. 2 of our 3 are now out of service. 1 broken by ice, one plugged at the strainer. All are 6" pvc.
All are in moving water. We have found that what works best is to leave them up off the bottom and let tham "float" in the current. Staked a few to the bottom with steel fence posts but the post just collected debris, sand washed in around it and then the strainer plugged.
We are now going to try going with no strainer on the lower end and just have the screen in the hydrant head.
If you do have a strainer on the bottom end you can buy a strainer from an irrigation supply house for about 1/4 the price from a fire supply place. Will get you an 800# when I go to the station tonight.
Don't know about how much ice you have there but here in Wisconsin it is a major problem in a flowing stream. We try to put them low enough to avoid ice but when the ice goes out in spring and you get an ice jam the ice can get pretty deep. We are thinking of putting the next one inside a concrete dry well set in the river to protect it.
The time you take to design properly will be well spent. Broken ones are a pain to re dig and repair and here in the Northwoods it's hard to get a fireman in the water before June.
Need any thing more just ask.
And I'd appreciate any advice others have.
And... one we are putting in is near a large poultry complex. Poultry farmer is paying for the parts, our neighboring dept. is doing the digging free since they are right across the road. We provide some manual labor.
04-05-2000, 08:08 PM #4Dalmatian90Firehouse.com Guest
It's interesting you mention dry wells...we have one location were the brook has a terrific year round flow of 2000-3000gpm even in the summer, but it's about 6' wide and 2" deep -- not enough to draft a 1500gpm pump from!
I'm wondering how big of problem it would be to get Inland-Wetlands Commission approval to dig a hole in the middle of the stream and pop in a dry well. We'd still have to clean it out annually to maintain it...but at least we could draft at will.
04-05-2000, 09:41 PM #5Sand Creek LynnFirehouse.com Guest
I'm thinking it would fill in pretty darn fast. And cleaning it out would be pretty tough unless you could get the city to do it with a storm drain vacuum truck.
The place we would put it is deep enough so it would just sit on the river bottom and our hydrant pipe could go into it about halfway up.
I've heard some places they have pipes under the ground that connect to some sort of tower that is filled with water so they have what would be called a "wet hydrant".
Probably just a rumour though. I've never seen one around here.
04-06-2000, 08:46 AM #6Bob SnyderFirehouse.com Guest
We run lots of mutual aid in rural areas with dry hydrants and often get involved in water supply from them. Over the past four or five years since they've been widely installed, we've only had one failure, which was discovered during a drill and promptly fixed (we think someone walked out on the underwater part of the PVC pipe and broke it that way). All of ours are 6" PVC and all are suspended (floating) underwater, without supports at the end. They are made as long underwater as is practical, to keep the intake ends out of the vegitation. We have strainers at both intake and drafting ends. All but two are in standing water, and, wherever possible, are below the ice line in a normal winter.
We've never experienced the sort of chronic difficulties that Lynn talks about. A few times a year, a tanker-pumper is sent around to backflush the dry hydrants and pull a draft from them. On occasion, they need to be flushed on a call. For example, one is in a pond with a snail problem...in the summer, you need to dump tank water through to knock the snails off the strainer before you can draft...all the engineers and officers know it, so it's no problem.
All in all, I'll take dry hydrants over dropping a strainer in the pond any time. No matter how fast you are with that operation, you'll be even faster with dry hydrants.
04-06-2000, 12:06 PM #7Sand Creek LynnFirehouse.com Guest
I forgot to mention this. If you have a choice put them in standing water [pond] rather than moving water. I think that is why Bob has so few problems compared to us. Our best one is in a pool formed near a bridge in a little trout stream. The worst in a large river where a lot of debris comes through in the spring flood.
04-10-2000, 05:45 PM #8LHS'Firehouse.com Guest
ISO will expect you to draft test with a pumper and back flush all dry hydrants twice a year and keep records.
04-20-2000, 01:07 AM #9FireMedic38Firehouse.com Guest
We had all our dry hydrants installed by a local contractor. We back flush them with approx. 3/4 tank of water and then test them. Our procedure if we use one for a fire is to always back flush first to remove and silt or weeds that may have settled. We have 13 dry hydrants and all are currently rated at 1000gpm. Occasionally we do have one float or get a break in the PVC. We contact the same contractor and it's usually repaired in a week. The testing and flowing is divided up between the three shifts and is done as regular training in the spring and fall. Cost of installation is relatively inexpensive. There a lot of people out there who will do good work at a low cost when they get the recogintion and realize the benefits. Our installer has become quite busy installing for many neighboring comunitees. Obviously at a high cost than he charges us.
In Illinois there are grants available to cover the cost of dry hydrants. You may also be able to pass the cost off to a developer who will reep the benefits from his sales.
04-20-2000, 02:24 PM #10Jim M.Firehouse.com Guest
What works well for us is to install 8 inch PVC and run that right up to ground level. At ground level we transition to 6 inch and then glue on the head. We install in mostly standing water. The PVC pipe with drilled holes works well but it's expensive and a pain in the *** to make. Recently our local supplier came out with a strainer that fits on the end of the pipe, looks like the ace of spades in aluminaum about 18 inches high. No cleanout necessary. Supposed to last forever. We'll be trying one this year. I think its made by Kochek.
We have found that its a good idea to plant the pipe on top of a large granite block or cement pad to keep it from sinking into silt of its own weight.
Dalmation, unless you carry dynamite to get though the ice, you can definitely draft faster in winter from dry hydrant than from strainer. Then again, you're in the deep South of New England - does ice form there? (:')
04-20-2000, 11:39 PM #11Dalmatian90Firehouse.com Guest
We do get ice Jim! But nothing like Maine!
I can drop oak trees on my ponds during winter, but I'll be damn if I'll ever drive a tractor or pickup on them like y'all do! But with slick ice, I can fling cordwood across a 1 acre pond in two shots
I'd say we only get about 8-10" of ice during a typical year, many years less...we carry a 14" electric chainsaw on a cord reel...adds a minute or two to cut the hole, but it's a pretty rare event. (For those of you wondering, no it's not a shocking experience! Cutting ice isn't that wet of an activity, and the Honda generator always starts compared to a 2 cycle chainsaw!)
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