Does NFPA permit Underground Conrete Fire Water tanks 2

[PrakMS]

Hi everyone,

I'm new to the filed of Fire fighting systems, because of which lot of people aer confusing me about the position of Concrete fire water tanks. My question is simple:

"Does NFPA allow industries to have a underground Fire water tank (concrete construction)? If yes can you pin point where it is stated in the standard"

I have gone through NFPA 22 and NFPA 24 briefly but it is not clear to me whether this is allowed.

Thanks..

 

[cdafd]

from 22

4.4 Tank Materials.

4.4.1 Materials shall be limited to steel, wood, concrete, coated fabrics, and fiberglass-reinforced plastic tanks.



Chapter 10 Concrete Gravity Tanks Suction Tanks


10.1 General.The design, materials, and construction of concrete tanks shall conform to ACI 318 and ACI 350R, with water considered as a live load.

10.2 Prestressed Tanks.Prestressed concrete water tanks shall conform to AWWA D110.

10.3 Standard Capacities.This chapter provides requirements for reinforced concrete tanks of 10,000 gal to 500,000 gal (37.85 m3 to 1892.50 m3) and prestressed concrete tanks of 10,000 gal to 1,000,000 gal (37.85 m3 to 3785.00 m3) net capacity.


10.3.1 Tanks of larger capacities shall be permitted.


10.4 Earthquake Load.Concrete tanks shall meet the requirements for resisting earthquake damage by complying with the earthquake provisions of ACI 350R.


10.4.1 Earthquake requirements for prestressed concrete tanks shall comply with the earthquake provisions of AWWA D110 or AWWA D115, as applicable.


10.5 Wall Treatments.Concrete tank walls shall be made impermeable by means of an impervious membrane or coating that is applied to the interior surface of the tank to prevent visible leakage or seepage through the tank wall.


10.5.1 Tank designs that are not subject to such leakage shall not be required to be made impermeable.




Chapter 17 Acceptance Test Requirements


17.7 Concrete Tanks.

17.7.1 Leakage Testing. On completion of the tank and prior to any specified backfill placement at the footing or wall, the test specified in 17.7.2 through 17.7.4 shall be applied to ensure watertightness.



17.7.2 Preparation. The tank shall be filled with water to the maximum level and left to stand for at least 24 hours.



17.7.3 Measurement. The drop in liquid level shall be measured over the next 72-hour period to determine the liquid volume loss. Evaporative losses shall be measured or calculated and shall be deducted from the measured loss to determine whether there is net leakage.



17.7.4 There shall be no measurable leakage after the tank is placed in service.

http://www.shawneesteps.com/Cisterns.htm

http://www.wedotanks.com/fire-protection-underground-tanks-water-supply-systems.html

 

[chicopee]

And don't forget to make the tank volume larger than the calculated value because overtime sludge will fill the bottom of the tank; overtime could mean decades.

 

[PrakMS]

Thanks guys.

From above text and the links i can interpret that NFPA allows you to have a underground tank made of concrete. Actually there is no explicit statement saying that you should have Underground / Aboveground tanks and its only a matter of interpretation (correct me if i'm wrong). Now assuming that my interpretation is right,it leads me to an another question.

"I heard that as per NFPA the pump room should not be flooded at any point in time, so that basically means the pump room has to be above ground only"

Thanks.

 

[sprinkler1000]

If the tank is underground, the fire pump room also must be at the same level, since you cannot have negative suction at the pump intake.

 

[LCREP]

Unless you use a vertical turbine fire pump to draw water from the tank.

 

[sprinkler1000]

Of course, I forgot that one, sorry.

 

[3cio]

Good discussion,

thnx guys,

 

[Davidson84]

According to my knowledge: maintenance cost and time of vertical turbine fire pump are significantly greater than using a centrifugal fire pump. so if money or terms is an important issue,the best choice is CP.

dont try, do it!

 

[DavidCR]

I have heard the same PrakMS:
"I heard that as per NFPA the pump room should not be flooded at any point in time, so that basically means the pump room has to be above ground only".

1.Does anybody know if this point is stated in some standard as obligatory?
2. Is it allowed to have a pit as pump room beside an anderground tank with anti-flooding pump system?.

Hi and thanks to everybody.