Well Supply for wet pipe system

[MountainRooster]

I am working on the design of a small scale experimental water treatment plant in a semi-remote area in California. No city water available. I believe a 100,000 gallon tank is needed, but a coworker wants to pursue using a 2000 gpm well to directly supply a wet pipe system. NFPA 13 (2010) Ch. 23 Water Supplies doesn't mention wells. I haven't had a chance to look into NFPA 20 or any others yet. I can’t envision it would be okay because you can’t predict future ground water levels.

Anyone ever heard of using well water or have a reference about it?

Assuming we did use a tank, is anyone familiar with AHJ waivers regarding the refill time for a tank?

 

[pipesnpumps]

This may be outside of NFPA. Water supplies are generally covered by AWBA (consider it as a public water supply). But I'll tell you just one reason why this isnt the best idea.. Unless there is a constant water demand greater than the minimum flow of the vertical well pump, the pump will have to shut off. If it shuts off the system loses pressure. If the system loses pressure it could conceivably not even properly eject the cap of the sprinkler head, which requires a min of 7 psi... I'd put in a tank. It doesn't have to meet NFPA 20 unless it is dedicated to fire protection. It could be treated just like any other municipal well pump and tank, in which case you need to consult civil engineers, not the fire protection engineers in this forum.

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[TravisMack]

We did a job several years ago along the Mississippi River. It was an existing warehouse and a change in storage required the addition of in-rack sprinklers. The municipal supply / fire pump could not handle the addition of the in-rack sprinklers. Instead of running about 2 miles to bring in a new fire line, we installed a vertical turbine pump in a well.

The system does not lose pressure as there is a check valve, so there is plenty of pressure on the system side of the check valve. The well was about 25% of the cost of a site water tank. It worked "well" (no pun intended) for the project at the time. Being near the Big Miss, there really weren't any issues of decreased ground water supplies. If I recall correctly, you have to test the well for an 8 hr period. It was able to flow the req'd amount of water without any issue.

Again, I don't know if it is the best solution for every project, but it worked well for this particular project.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com