NFPA 13D Water Storage 1

[sia101]

Hello,

I have a question. There is a fire sprinkler project I having diffuculties for single family residence. This site already has a well pump and will have a cylinder tank that services domestic water system. My guess is the cylinder tank what looks like an LPG tank is a pressre tank.
I have no problem with sprinkler layout but this project will need a separate sprinkler pump & water storage need for 10 minute duration.
In my case this will come down to 320 gallons of reserved water from somewere. I haven't experenced sizing prssure tanks and 320 gallons for sprnkler use. Would it be possible to size the pessure tank for the sprinkler duration and domestic needs?

Thank you.

 

[cdafd]

Would it be possible to size the pessure tank for the sprinkler duration and domestic needs?


not a designer, and not sure of the question, but if one is can you use the same tank for domestic use and sprinkler use???

my question would be how do you know at any given point that there is enough water in the tank to meet the sprinkler requirement???





6.1.2 Where stored water is used as the sole source of supply, the minimum quantity shall equal the water demand rate times 10 minutes unless permitted otherwise by 6.1.3.
6.1.3 Where stored water is used as the sole source of supply, the minimum quantity shall be permitted to equal the two-sprinkler water demand rate times 7 minutes where dwelling units meet the following criteria:
(1) One story in height
(2) Less than 2000 ft2 (186 m2) in area


6.2* Water Supply Sources.
The following water supply sources shall be considered to be acceptable by this standard:
(1) A connection to a reliable waterworks system with or without an automatically operated pump
(2) An elevated tank
(3) A pressure tank designed to American Society of Mechanical Engineers (ASME) standards for a pressure vessel with a reliable pressure source
(4) A stored water source with an automatically operated pump
(5) A well with a pump of sufficient capacity and pressure to meet the sprinkler system demand. The stored water requirement of 6.1.2 or 6.1.3 shall be permitted to be a combination of the water in the well (including the refill rate) plus the water in the holding tank if such tank can supply the sprinkler system.
6.2.1* Prior to system acceptance, a system utilizing a pump shall be tested by opening the drain/test connection. The pump shall sense the flow, turn on, and flow water for the required duration of 6.1.2 or 6.1.3 (as appropriate) without interruption.

 

[chevy4x4trucks]

You can also see if they can increase the size of their well pump. We've been succesful having a variable speed well pump that can provide 40 gpm at 40 psi which is usually sufficient for most 13D designs. It's usually about 2k-3k more than your standard well, but still more cost effective than an additional pump and tank (not to mention the space savings).

Something to look into.

 

[stookeyfpe]

Be careful. The used propane tank needs a pressure relief device and propane is neither the same molecular weight or vapor pressure of water. Unless it is designed for underground service, you need to size the PRV for steam service because of the potential for overpressure from an external heat source, like sprinkler failure and pressure vessel being heated from a structure fire.

Sizing the pressure tank is not that hard. You need to consider the design pressure for your most 2 remote sprinklers based on pressure and the 10 minute demand and move forward.


Is this project in North America?

 

[MaInspector]

Question, Will the well pump that feed a 13D system require emergency backup power in the event of a power failure?