UFC 3-420-01
25 October 2004
are provided, the capacity of each pump is to be sufficient to meet the requirements of
the facility. For Army and Air Force projects, pumps with discharge capacities in
excess of 25 gallons per minute (1.6 L/s) and with a total head of at least 20 feet (6 m)
will be of the duplex type."
B.
SECTION 712.3.2 Sump pit. Add after the last sentence: "Sumps are to
contain, in gallons, between the high level and low level operating switch settings
approximately twice the capacity of the sump pump, in gallons per minute. The depth of
the pit, below the finished floor, will be in even feet to conform to standard lengths of
submerged pump shafts."
C.
SECTION 712.3.4 Maximum effluent level. Add after the last sentence: "A
high water alarm actuator is to be installed within sump and operate an audible or visual
alarm when the normal high-water level within sump has been exceeded."
D.
Add "SECTION 712.3.6 Controls. Automatic controls are to be provided for
each pump. Duplex pump units are to be equipped with controls to alternate the
operation of the pumps under normal conditions and to operate pumps simultaneously
when one pump cannot handle the flow."
E.
SECTION 712.4 Sewage pumps and sewage ejectors. Add after the last
sentence: "Detailed requirements for pumps and ejectors will be in accordance with the
standards of the Hydraulic Institute. Where sewers are not of sufficient depth to drain
the lower floor fixtures by gravity, the main toilet rooms should be located on higher
floors. Sewage ejectors will be of the duplex pneumatic type and will be located in a
concrete pit below the lowest floor. Ejectors will utilize a high-velocity steam, air, or
water jet for ejecting the sewage. When the sewage must be pumped, duplex units will
be provided below the lowest floor in a concrete sump protected by a safety railing.
Duplex sewage pumps will be installed in a separate pump house when the sewage
from a group of buildings must be pumped and where it is not possible to install sewage
pumps in the buildings. Pump motors will be located so as not to become submerged
by an electrical service interruption. Packaged pumping systems installed in vertical dry
or wet basins with non-clog centrifugal pumps are acceptable, if the influent line leads
directly to the discharge line of both pumps and all incoming sewage passes through
self-cleaning screens. Auxiliary screens will be installed in influent lines within wet
wells, since built-in, self-cleaning screens of the pump discharge lines may not be able
to handle extreme peak flow conditions. Combination "T" and check valve
arrangements will be provided in the influent line to each pump to prevent raw sewage
from backing into incoming sewer lines, when pumps are operating."
F.
SECTION 712.4.2 Capacity. Add after the last sentence: "The capacity will
be determined by the fixture unit method described in Section 710.
G.
SECTION 715.5 Location. Add after the last sentence: "A gate valve shall
be installed on the sewer side of each backwater valve, and both will be installed in a
manhole."
A-22
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