Hello everybody ,I m dealing with a challenge. I appreciate if you could help .here's my question: is it possible to use an underground tank as the source of water for pump station of sprinklers and fireboxes? The depth of the water tank is about 5 meters from the surface. Thanks in advance for your time.
Thanks a universe Alireza for your helpful answer
So dear Alireza,under this condition (suction lift more than 3 psi) using an UNDERGROUND tank is accepted?
So dear Alireza ,is using UNDERGROUND tank totally unacceptable? in what
case can we use underground tank of water instead of ground and elevated
tank. any reference to read about? THANKS
No, it's not acceptable. In this situation vertical inline pump should be used.
Underground tanks are acceptable when made of concrete and complies with chapter 10 of NFPA 22. Fiberglass reinforced tanks could be used, but I doubt they can be furnished in for large capacities.
If the pump is going to be higher than the tank/reservoir then the pump must be a vertical turbine type. It is the only type of pump permitted by NFPA 20 for suction lift applications. See section 7.1.1.
I work in fiber reinforced plastic (FRP) underground storage tanks for motor fuels.
Most USTs can be built with FRP or steel.
Mazimum size for motor fuels range 30,000 to 50,000 gallons.
You get USTs for fire water but the warranty is only one year.
Warranty is for corrosion.
The same UST made for motor fuels is warranted for 30 years
Under Ground Tanks are totally acceptable and allowed by code. I am from Bermuda and our main water supply for most buildings are underground tanks. The size of the tank has to be hydraulically calculated to ensure that it meets the system demands but other than that they meet the definition of a reliable water source. In some instances the water levels are electronically supervised to ensure that the levels do not go below the system requirements.
Thanks for your helpful answer
Hello
You should calculate suction lift for the pump, it shall not drop below the -3 psi, dou to 4.15.3 NFPA 20.