2 - 9 . S u s p e n s i o n o f H o s e l i n e .
a. General. Aerial Suspensions are the most effective and readily installed means of crossing streams and
deep gorges or ravines. Suitably protected and secure suspension crossings must be used in these cases.
Adequate provision must be made to permit free passage of the displacement ball. For wide crossings a
suspension bridge should be built to provide a flat deck or floor, which will support entire length of hose and
eliminate bends which would occur if suspension cables were used. The practice of laying hose across decks of
actively used bridges, or suspending hose from bridge structures, should be avoided due to the danger of fire in
the event of hoseline failure. Under emergency usage conditions, hose maybe installed across an actively used
bridge if found to be necessary on a calculated-risk basis. If a hoseline is installed on an actively used bridge, it
must be secured outside bridge structure on downstream side if possible. Crossings must not interfere with
passage of ships, and must provide clearance from flood stages. The hoseline suspension kit provides adequate
material for one 200-foot-wide (60m) crossing or two 100-foot-wide (30m) crossings. Construction of several
shorter suspension spans, or additional large spans, would require additional stakes, tackle blocks, and
S u s p e n s i o n T o w e r s .
W A R N I NG
Aerial crossings over rivers and streams must provide adequate clearance for
flood stages. Crossings must not interfere with the passage of ships on
(1) Short spans. For spans up to 75 feet (22.5m), short towers constructed of 2 x 6 timber or similar material
can be utilized, as long as adequate clearance is ensured.
(2) Long spans. For spans over 75 feet (22.5m), towers must be constructed of 4 x 4 timer or similar
material to provide adequate clearance and strength.
(3) Use of natural materials. Existing trees may serve as towers if they provide adequate clearance. Trees
must be a minimum of 8 inches (203.2 mm) in diameter, sound, and well-routed to serve as towers.
c. Installing Hoseline On Towers.
(figure 2-8) After suspension towers have been erected, install cable and
hoseline as follows:
Drive a guy stake (1) into ground approximately 15 feet (4.5m) from each tower (2) in line with and
leaning away from both towers. Stake should protrude from ground approximately 6 inches (152.4mm).
Hang a tackle block (3) off of each tower (2) and thread wire rope (4) through sheave on near side stream
Pull wire rope (4) across stream or obstruction.
Thread wire rope (4) through tackle block (3) on far side or stream or obstruction.
Make a loop (5) of wire rope approximately 9 inches (228.6mm) from wire rope end and insert thimble (6)
Secure wire rope end with two clamps (7) and nuts (8).
Place a shackle (9) onto stake (1). This may require tapping on shackle in order for it to slip around stake
due to close fit of shackle to stake.
Install shackle bolt (10).
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