Thread: YARD HYDRANTS
09-10-2001, 07:59 PM #1
RECENTLY THERE HAS BEEN A WAL-MART DISTRIBUTION CENTER BUILT IN OUR FIRE DISTRICT. IT WAS BUILT JUST OUTSIDE THE CITY LIMITS THEREFORE OUR LOCAL FIRE CODES DID NOT AFFECT THEM WHEN IT WAS BUILT. THEY PUT IN AN ADEQUATE NUMBER OF HYDRANTS AROUND THE BUILDING, BUT NONE OF THEM HAVE A 5" STEAMER. THEY ARE ALL 2X2.5" OUTLETS. MY QUESTION IS WILL WE BE ABLE TO GET ADEQUATE FLOWS FROM THESE HYDRANTS? ALSO WHAT WOULD BE THE DESIRED METHOD OF CONNECTING TO THESE HYDRANTS?Jeff Canada
Engine Co. 671
09-10-2001, 10:31 PM #2
- Join Date
- Apr 1999
- Nova Scotia
From my experiences with a "private" hydrant, you never can be sure what you get. If the water is also supplied to the warehouse for its sprinkler system, there should be enough water at the hydrant. I've hooked private hydrants in the past with little or no water. Note... if they are connected, you would hate to rob from the sprinklers to supply a pumper...
Looks like you are reverting back to the days of 21/2" supply line. An idea which unfortunately ties up a pumper, is to set out 2 2 1/2" for supply to the pumper and feed into the fire with 5" supply to another pumper. (anyone please comment on this idea)
Your volume or pressure shouldn't be affected too much by using 2 1/2" hose.
I would get a flow test done and have a pre-plan for the site... you can always practice methods and try them out... I am sure Walmart would be cooperative. If not, shop at KMart.
Regards from Nova Scotia Canada
09-11-2001, 01:36 AM #3
- Join Date
- Dec 2000
- F.L. CO,USA
I would get right out there and flow test those hydrants. Also ask for the plumbing blue prints for the lines. In respect to hookups, to get the most out of those hydrants you either need to hard suction to them or use both outlets with short feed lines to the intake on the pump.
09-11-2001, 02:07 AM #4
- Join Date
- Aug 2001
- Houston, Texas(or College Station)
My department is in a very small town so when we got a new pumper this year our city would not also allow us to outfit it with 5" hose like our existing pumper in the same fiscal year. Instead of stealing the 5" off the older truck we took two lays of 3" off the replaced pumper so when we get the new hose it can go directly on the new truck and we don't have to switch things around. So when we catch a hydrant with our first in pumper(never yet) we would use two 3" lines into a double intake on the new pumper. Of course you still have to worry about what the hydrants have available as far as water.
Hope this makes some sense,
P.S.- eyecue is right, flow test those hydrants as pre-planning, knowing whether or not those hydrants have enough water will be nice to know ahead of time.
09-11-2001, 07:59 AM #5
- Join Date
- Dec 1999
- Desoto County, MS
Since you are addressing this problem I will assume you are already using LDH. If so, do you have an adaptor for discharging a 2 1/2" into this LDH for relay purposes? If so you may want to CONSIDER using this at the hydrant to hook up your LDH to reduce friciton loss between the hydrant and the truck. This won't do anything to change the water available at the hydrant itself but should let you get most of that water to your truck instead of losing it friction loss.
[ 09-11-2001: Message edited by: Daron ]Daron
10-01-2001, 10:40 PM #6
- Join Date
- Aug 2001
I would suggest that you gain a much more detailed understanding of the fire protection systems that were installed. You need to get with the fire protection system designer and/or contractor and obtain the design details on the systems. I wouldn't test anything until you know the system.
I assume this facility is sprinklered. If it is, then the water supply will typically be for the sprinklers and a hose stream demand, probably 250 or 500 gpm. If you pump more than the hose stream demand, you will likely be robbing the sprinklers and potentially render then ineffective. Flow testing the hydrant without understanding the systems is very misleading. You cannot pump the entire flow from those hydrants, the sprinkler demand is included. So, testing the hydrants without knowing the sprinkler demand tells you very, very little.
Hydrants that are installed on private systems with only 2 -2 1/2" outlets WERE NOT intended to supply anything beyond the 250-500 gpm hose stream demand. There is absolutely no design intent when you see such a hydrant on a private main that the hydrant is intended to supply a pumper. In fact, the actual historical intent of such hydrants is to directly supply outside hose streams for exterior protection. If the designer wants to specify hydrants with larger outlets than 2 1/2", then he must include the actual intended demand (such as to a pumper).
You really need to understand the design and hydraulics of the systems at the site and also the hydraulics of your supply/attack lines and pumpers so that you only supply through the pumper the demand that was calculated for hose streams.
The experience of sprinklers is very good and the NFPA standards for sprinklers has plenty of safety factors built in. If the systems are designed, installed and maintained correctly and the FD support them properly and uses hose streams within the hose stream demand, the outcome will almost always be positive. Go outside of this and the building will likely burn down and will have put firefighters at risk in a large commercial building with a likely collapse potential.
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