TM 5-814-9
4-9. Protection against freezing
c. Water pressure and flow rates. The recommended de--
sign pressure is 75 pounds per square inch (psi) (5.2 atmo-
In regions where freezing conditions may occur, the water
spheres). The water pressure is measured at the nozzle. The
supply piping, valves and fittings at the wash stations must be
recommended design flow rate is 25 gallons per minute (95
self-draining and designed for protection from damage due to
liters per minute). Pressures and flow rates are given here to
freezing.
facilitate pump selection. Control should be provided to limit
maximum pressures at the nozzle to 90 psi. Valving must be
4-10. Water supply piping
installed to allow each island to be isolated from the water
Valves which will be frequently operated on the supply piping
supply. Manually operated valves are required to allow troops
to the wash stations must be accessible through valve pits, valve
to control flow from each hose on the island.
boxes, or manholes. Isolation valves within the system can be
directly buried.
d. Hoses. The hoses to be specified at the vehicle wash
stations are made of reinforced rubber. The reinforcement
4-11. Paved area drainage
should be an all-textile braid made of resilient synthetic yams;
this material is covered with thick rubber. The hoses must be
and cleaning the CVWF as well as all precipitation falling on or
flexible for ease of handling and rated for a minimum working
flowing through the paved area shall be collected through a
pressure of 300 psi (20.4 atmospheres). Hoses must be durable,
drainage system that flows to the primary treatment basin. This
suitable for use in water, and resistant to abrasion, oil, and
volume may be captured as makeup water if necessary. The
sunlight. Orifice diameter of the nozzle should be 5/16 inch in
assembly area located after the wash area and the preparation
order to provide chosen flow at 75 psi (5.2 atmospheres)
area shall be paved and sloped toward a grated trench drain.
pressure at the nozzle inlet. Each hose must be long enough at
Concrete curbing should be installed at all pavement/ soil
each location to reach the side, front, and back sections of the
interfaces when the designer deems necessary to contain and
vehicles being washed.
direct the runoff to the treatment system. In areas where water
is not expected to occur and vehicular control is not required,
e. Nozzles. The nozzles must be durable to withstand
such as the preparation area, the designer may choose to limit
frequent punishment and heavy use. The inner diameter of the
or not use curbing. Other surface water shall be drained away
hose connection at the tower will be determined by the required
from the facility unless it is to be captured for use as makeup water.
pressure and flow rate. The hoses should be designed with
rubber nozzles built in by the manufacturer.
4-5
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