of the rail bed (if possible). Do not lay the hose directly in the trench
or rail bed because the shifting gravel can gradually damage the hose.
c. Aerial suspensions are the most effective and readily installed
means of crossing streams and deep gaps.
Suitably protected and secure
suspension crossings must be used in these cases. Adequate provisions must
be made to permit free passage of the displacement ball.
For wide
crossings, a suspension bridge is built to provide a flat deck or floor to
support the entire length of the hose and eliminate bends which occur if
suspension cables were used. If available, the hose line may be installed
on an actively used bridge. If the hose line is installed on an actively
used bridge, it is secured outside the bridge structure. Crossings must not
interfere with the passage of ships and must provide clearance from flood
stages.
Each hose line suspension kit provides adequate material for one
300-foot wide crossing or two shorter crossings.
Materials for the
construction of suspension towers are not included in the kit and must be
obtained locally.
When constructing suspension towers for spans up to 75
feet, short towers constructed of 4 by 4-inch timber or similar material can
be used as long as adequate clearance is ensured. For spans over 75 feet,
towers must be constructed of 6 by 8-inch timber or similar material to
provide adequate clearance and strength.
All suspension towers must be
anchored by guy lines to pickets provided in the suspension kit.
d. If required, install the pressure-reducing valve at the location
determined by calculations.
To install the pressure-reducing valve,
disconnect hose line lengths at the site designated for installation of the
pressure-reducing valve by removing the victualic coupling.
Position the
pressure-reducing valve between the hose line lengths with the directional
arrow on the valve pointing in the direction of the water flow.
PART D - SUPERVISE TWDS DISASSEMBLY AND PACKING
1. Disassembling the 10-mile hose line segment requires the same tools,
equipment, and personnel needed to install the hose line. The displacement
and evacuation kit, and the packing kit will be required to pack the hose
line segments into their flaking boxes. If a forklift is not available, the
lifting sling will be required to load, unload, and stack the flaking boxes.
a. The hose line is evacuated by passing the displacement ball through
the hose by air pressure. The ball receiver is placed on one end of a 500-
foot segment, and the pneumatic
3-9
QM4912
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