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Help. Hydraulic Calculation (water tank) 2

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AN1010

Mechanical
Mar 9, 2016
32
Hi, everyone. Please help me. My company will not have a hydraulic calculation for fire sprinkler system. because its part of the contractor . is there a way I can estimate or calculate or assume the capacity of the water tank we need to design given that i have the quantity of sprinkler, fire hose, and standpipe? please help me.
 
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Is this project in the US?
 
no sir. i'm from Philippines.
 
Can you help with my problem sir?
 
Not me someone else might post an answer
 
You can use your sprinkler demand + hose stream allowance, NFPA13/NFPA14

You can also check NFPA 1 or IFC per building construction type.

What about Fire Code of the Philippines?
 
You only need hose stream if there are hydrants downstream of the tank. But then, if there are hydrants downstream of the tank, you may have to account for site fire flow. If you are under the IFC, that could get real big, real quick.

Travis Mack
MFP Design, LLC
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Thank you ZDR1985 & TravisMack for the reply. Really appreciate it.
 
In your case, you are better off to hire an outside consultant as there are many variables involved in designing a sprinkler system , whether it is standard pipe system or a hydraulically calculated one. While figuring out the storage tank size is not a rigorous analysis, it lends me to believe that your water supply may be from underground which presents another problem that your outside consultant would need to evaluate.
 
@chicopee: Yes sir. The contractor will do the hydraulic calculation. I just want to ask if its possible to estimate the water storage without detailed calculation.
 
Yes, there is a way but you have to know something about the water supply to the tank; I personally would want to know, others may not.
 
Let me explain a little bit about the water tank supplying the sprinkler system. Once the sprinkler system is activated and draws off water from the tank, the fire department will then respond within a certain time element and hook up their pumper connections between fire hydrants supplied by the tank, fire engine and building. As the firemen enter the building, presumably not engulfed in fire, with their hoses flowing or not flowing, in all likely hood they'll turn off the sprinkler system and attack the fire. A lot more water may or may not be needed, therefore, your water tank may or may not have an insatiable desire for more water. An external dependable water source to the tank is crucial. All of these sequences along with sprinkler water demand and duration of that demand will dictate the size of the tank and then some for good measure.
 
To size the water tank you don't need to do have a exact hydraulic calculation which normally come from contractor side If you are working for consultancy.
Once you have pump size then you can size your tank based on the time duration required to supply the water.
For example
If you're pump size 1000 gpm and time duration 60 mim (Usually)
Tank size will be
1000x60
=60000Gal
=228m3
 
add the flows of the sprinklers that would be running if there is a fire and multiply by 3 or 4 hours. Check the standards you are using there for hours needed.
 
the fire department response time may be of interest...
 
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