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 TB 740-97-4
sorbent type, 10,000 cubic foot capacity, 110-volt, alternating-current, will be installed, generally, as shown in figure 53. The
machines will be mounted on stands and protected with covers fabricated in accordance with figure 52. Each machine will
dehumidify one refrigerated compartment. The machines will be installed on the top of the refrigerated barge adjacent to the cargo
loading hatch. An extension, terminating in a 90elbow, will be fitted to the reactivation air inlet on each dehumidification machine in
order to extend the outlet beyond the exterior side of the sheet metal cover. The elbow will be turned away from the reactivation inlet
side and turned downward 450 to prevent direct entry of water.
1. Duct installation No. 2. The cargo loading hatches atop the reefer barges will be raised, as specified, and the four
sides blanked with galvanized sheet metal or -inch, exterior-type, grade A/C plywood. The blanks will be sealed with strippable
coating and bituminous coating. Suitable penetrations large enough to permit the introduction of air ducts, humidistat cable, and the
mounting of sensing elements will be provided. The air from the dehumidification machines will enter from the center cargo loading
hatch, and the moist air will be removed from the farthest-lowest point of the refrigerated compartment. A length of flexible 4-inch
hose, conforming to MIL-H-8796, will be connected to the moist-air return line to remove the moist air from the lower extremities of
the refrigerated compartments.
2.
Air duct installation and machine connections. Four-inch, No. 26 gage, galvanized tubing, with necessary ells, tees,
reducing fittings, supports, and connections, will be installed. Ducts will run with a minimum of bends, as shown in figure 53.
Connections of the duct to the dehumidification machine will be made with unions or slip joints connections, which permit easy
removal of the machine for servicing.
3. Humidistats. A hair-type humidistat with a control setting of 52 percent relative humidity, plus or minus 2 1/2
percent, will be installed in each refrigerated compartment of the barge from which the moist air return duct goes directly to the
dehumidification machine. The humidistats will be connected to the dehumidification machine with No. 18 two-conductor, rubber
covered cable with suitable terminal connectors. The humidistats will be installed at a height of approximately 3 feet above the deck
and at a distance of approximately 3 feet from the intake end of the moist air return ducts. Instruments will be mounted, so that they
are protected against movement or damage.
4. Sensing elements. Two sensing elements, with cable, will be installed, two to each refrigerated compartment: one
fore, one aft, as shown in figure 53.
c. Ventilation of spaces not under dehumidification. Provisions will be made for ventilation of the following spaces not under
dehumidification:
(1)
Anchor windlass cover. A ventilated, demountable cover will be installed over the windlass. The sides and ends
will be pained as specified and fabricated, generally, as shown in figure 50. To facilitate disassembly, the sides and ends will be
fastened to each other with galvanized hooks and eyes. A minimum of two fasteners will be used at each junction of a side and end.
A roof, fabricated from minimum No. 20 gage galvanized sheet metal, will be fitted over the sides and ends and will overlap
approximately 2 inches. Two lengths of minimum No. 12 gage, black, annealed wire, positioned approximately one-third the length of
the cover from each end, will be used to secure the roof in place. The wire will run across the roof and will be secured to screw eyes
located in the sides of the cover. The cover will be secured by wiring to convenient points.
(2)
Screening of ventilation openings. Louvered faces of covers, fabricated to provide ventilation, and openings on
gooseneck-and mushroom type vents, will be covered with standard aluminum insect screening.
(3) Forward and aft rake ends. The openings, resulting from removal of the access hatch covers to the rake ends will be
fitted with blanks fabricated from exterior grade plywood or minimum No. 20 gage galvanized sheet metal. The blanks will be
secured over the opening and will be provided with minimum, 6-inch, gooseneck-type, galvanized vents.
(4)
Storage Compartments. The access hatches to the four hold storage compartments shall be secured in partially
open position and a ventilated cover, painted as specified, and fabricated, generally, as shown in figure 50, will be fitted over the
hatches and secured by wiring to convenient fittings. The gooseneck vents will be secured in the open position. The manhole covers
and drain plugs on the tanks located in the storage compartments will be removed and secured adjacent to their places of use. The
tank vents will be secured in open position.
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