1 March 1997
Fire demand =
(23,000 X 150 X 4)
(2,800 X 60 X 3) +
24 X 2
The irrigation requirement can be eliminated during the fire period, so it is not included in this computation.
This item will be reduced by the amount of water available during the period of the fire demand under
emergency conditions. TM 5-813-1/AFM 88-10, Vol. 1 recommends that a sufficient number of both raw
and finished water pumps be equipped with dual power sources (electric motor-internal combustion engine)
or standby internal combustion engines to be capable of supplying at least 50 percent of the required daily
demand under emergency conditions. In this case both raw and finished water both the raw water and
filtered water pumping equipment. The storage requirement for fire demands becomes 719,630 - (1,350 X
60 X 3) = 476,630 gallons.
50 percent of required daily demand plus fire demand minus the amount
of water available in 24 hours under emergency conditions =
1,925,000 + 719,630 - (1,350 X 60 X 24) = 700,630 gallons
The first item governs; storage of about 2,000,000 gallons should be provided. At least 50 percent of the
storage should be elevated since the population exceeds 10,000. Two 500,000-gallon elevated tanks
would be satisfactory, with the remainder of the required storage provided in a ground storage reservoir.
f. Raw-water pumping station. Two 2,700 gal/min electric motor driven pumps and a 1,350 gal/min dual
drive (electric motor with standby internal combustion engine) pump will be provided.
g. High-lift pumping station. Pumping facilities, similar to those for raw water pumping station, will be
h. Water main sizes. Water mains will be in accordance with the criteria of TM 5-813-5/AFM 88-10,
B-4. EXAMPLE NO. 3: A barracks, Type 1, Fire resistive construction unsprinkled facilities, floor area
125,000 sq. ft.
a. Effective population. 3,000.
b. Water source. Municipal system; 750 gal/min supplied at adequate pressure through three separate
pipelines having capacities of 350, 250, and 150 gal/min.
c. Required daily demand and fire flow.
3,000 X 1.5 = 4,500
Per capita allowance:
Required daily demand:
4,500 X 150= 675,000 gal/day, equivalent to a rate of 469 gal/min
1,500 gal/min for a duration of 2 hours=
1,500 X 60 X 2 = 180,000 gallons
(Exact value of fire flow should be in accordance with TM
5-813-6/AFM 88-10, Vol. 6.
d. Storage requirements.