MIL-HDBK-1032/2
Section 8: CONTROLLED HUMIDITY WAREHOUSING
Dehumidification. Warehouses designed for dehumidified storage
8.1
shall be vapor sealed against entrance of moisture from points of higher vapor
pressure. Refer to NAVFAC DM-3.03 for additional design criteria. A dry
desiccant-type dehumidifier shall be used. The preferred unit is a
steam-fired type with two stationary beds operating alternately on the drying
and regeneration cycles. Rotary-type units may also be used. If steam is
not available, electric or gas-fired units may be used. A study evaluating
the energy efficiency of the desiccant system compared to a refrigerated
dehumidification system shall be made. Section 8 provides additional specific
criteria applicable to controlled humidity storage.
Carbon Monoxide Control. Supply outside air ventilation if
8.2
gasoline-driven materials handling equipment is operated in a dehumidified
warehouse and the average concentration of carbon monoxide in the space will
exceed 50 parts per l,000,000 parts of air. Provide portable carbon monoxide
detection equipment to periodically check for carbon monoxide concentrations
in facilities with gasoline powered equipment. Ventilation may be obtained by
opening operable material transfer doors. Provide a 20-ampere electric power
outlet receptacle at t each operable transfer door to operate a portable
circulating fan when natural ventilation in inadequate. Use of battery
operated vehicles is recommended where practical.
New Construction. For new construction, the following sealing
8.3
methods and materials shall be used.:
Floors. Vapor barriers having a permeance characteristic of 1.0
8.3.1
perm or less, laid on a gravel capillary barrier and finished to a smooth
surface, shall be provided beneath concrete slabs laid on-grade.
Walls. Insulation shall not be provided for walls. Apply two coats
8.3.2
of cement water paint to exterior exposed surfaces of concrete masonry unit
walls. Sprayed-on cement mortar coating 1/8 inch (3mm) in total thickness may
be used as an alternative method.
Joints. All joints in precast concrete construction shall be
8.3.2.1
sealed, caulked, and made as airtight as possible.
Sides and End Laps. All sides and end laps of metal or similar type
8.3.2.2
walls shall be sealed with bituminous mastic as erected.
Fire Walls. If only certain areas are to be dehumidified, the fire
8.3.2.3
wall between the dehumidified and general storage areas shall be made airtight.
Junctions. Exterior junctions between walls and roofs shall be made
8.3.2.4
as airtight as possible.
Roof. Vapor barriers shall be provided. All sides and end laps in
8.3.3
steel or similar roof decking shall be coated with bituminous mastic as laid.
Scuttles shall be gasketed and fitted with inside and outside locks.
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