1 March 1997
b. Special considerations. The amount of storage required for plant and special projects will be based
on industrial, domestic, and fire-protection requirements. Each project will be considered on the basis of
specific need. Hospital storage facilities will be designed in accordance with the latest edition of the Joint
Commission Accreditation Manual for Hospitals, American Hospital Association.
c. Amount of water available under emergency conditions.
(1) The amount of water available under emergency conditions is considered to be that available
from auxiliary-powered pumps during electric-current outage, from electric-motor-driven pumps with the
largest pump out of service, from one or more supply mains with the main of greatest capacity out of
service, or from the water-treatment plant with one filter out of service. Normally the capacity of the
clearwell storage at the treatment plant will not be considered part of the required storage.
(2) Where the water supply is obtained from wells, all of which are equipped with standby power and
located within the distribution system, the emergency supply will be considered as the quantity available
from all but one of the wells. Where one well has a capacity greater than the others, that one will be
assumed out of service. Where only 50 percent of the wells have standby power, the emergency supply
will be considered as the quantity available from the wells having standby power.
(3) Where the project is supplied from a dependable existing source, such as a municipal system
with adequate storage and standby facilities, through supply lines not subject to damage by floods, high
pressure, or other unusual conditions, the amount of water available under emergency conditions is that
obtainable with the largest connection inoperative.
(4) Where the supply is delivered through a single supply main, the maximum amount of storage as
determined in paragraph 1a will be provided.
(5) Where the peak demand for water is available at adequate residual pressure through two or
more lines while the line having the greatest capacity is out of service, no storage will be required.
(6) Where the peak demand for water is available through two or more lines but is not available if the
line having the greatest capacity is out of service, storage will be required. The quantity of water available
under emergency conditions with the line of greatest capacity out of service will be considered
in calculating the amount of storage required.
d. Irrigation requirements. Where irrigation requirements, are justified in arid or semi-arid regions, such
irrigation quantities will be included as an industrial requirement of Items 1, 2, and 3 of subparagraph 1a
and not as a domestic requirement. Water requirements may be increased above those indicated in TM
5-630 for Army installations provided that the increased rates can be substantiated by a local or regional
Soil Conservation Service or recognized local authority as the minimum rate to sustain lawn-type turf.
Irrigation requirements for Air Force installations should be substantiated by a local or regional Soil
Conservation Service or recognized local authority as the minimum rate to sustain lawn-type turf.
2. ELEVATED STORAGE CAPACITY. The total elevated storage capacity at all military installations,
except plant and special projects, should not be less than the amount determined in paragraph 1a Item 2,
nor less than 50 percent of the total required storage, unless special conditions prevail which would negate
the need for such storage. For projects with design populations of 10,000 or less, consideration will be
given to providing all elevated storage where the storage will result in an economical and reliable system.
For projects such as storage depots or aircraft hangers with deluge sprinkler systems, ground storage
reservoirs with booster pumps will generally be the more economical method of supplying large volumes of
water for fire protection. Elevated tanks will normally be provided for initial sprinkler demand in storage
warehouses. Water storage can be most economically provided by constructing ground storage reservoirs
on high ground. However, in the absence of suitable terrain, elevated tanks will be required.