TM 38-400/NAVSUP PUB 572/AFMAN 23-210 MCO 4450.14/DLAM 4145.12
economically in permanent and standard portable frame
efficient operation of equipment and maintenance of
warehouses such as--
(3) Correct, or bring to the attention of the
(1) Permanent-type warehouses constructed
proper persons, any conditions exposed which indicate
with a build-up roof, concrete roof decking with steel
undesirable trends in inside moisture levels,
framing or laminated wood roof framing, block or brick
unreasonable continuous operation of dehumidifying
sidewalls, and dock level floors.
equipment, excessive "open door time," or any other
(2) Permanent-type warehouses, gabled roof
factor which suggests excessive moisture ingress.
with steel framing, block or tile walls, windows, and
(4) Assure that the full objectives of the CH
storage program are realized (i.e., maximum practical
(3) Permanent-type warehouses constructed
utilization of this asset by reduction and retention of
with a monitor in center third of roof, block or brick
inside RH at prescribed level through prudent control of
sidewalls, and dock level floor.
"open door" time as well as other applicable moisture-
(4) Standard portable frame warehouses of a
influencing considerations set forth herein). Ensure the
type properly constructed for CH installation.
existence and maintain surveillance over safe operating
g. The mobilization-type warehouses (e.g., built-up
conditions with regard to the potentiality of carbon
roof with timber framing, monitor on roof with continuous
window openings, wood or asbestos siding, etc.) should
b. A centrally located exterior RH recording
not be considered for conversion to CH space, except
instrument will be used as a means to advise CH space
as a low priority, due to the expense of such conversion.
users when outside relative conditions are at such level
as to allow access doors to remain open if desirable,
3-51. Selection of Supplies.
and also to close doors when outside conditions rise
a. Supplies to be stored in CH areas will be
above 50 percent RH.
selected in accordance with the criteria and provisions
c. Conditions in CH buildings which require repair
prescribed by the military service or agency.
will be reported as soon as detected.
b. In the storage of ammunition, safety factors
inherent to this commodity will be followed.
3-50. Criteria for Facility Selection.
c. Humidity affects materials as follows:
a. CH storage space should be provided for areas
(1) Ferrous metals corrode in varying
where the outdoor RH is above 50 percent for more than
degrees above 50 percent RH.
50 percent of the total time.
(2) Aluminum alloy and nonferrous metals
b. Equipment for the control of humidity in storage
deteriorate to a limited extent at 90 percent RH.
space will be operated to provide an environment not to
(3) Minerals such as mica, asbestos, and
exceed 50 percent RH.
fibrous glass show no deterioration by moisture.
c. The modern, permanent warehouses (WW II
(4) Fibers of manila and sisal rope may
and later) are preferred for the storage of current
become very brittle at humidities under 30 percent RH;
These warehouses should be
however, upon exposure to normal humidities, they
converted to CH space (by section or complete
absorb normal water content and resume normal
warehouse), as required and permitted by available
(5) items such as voltmeters, resistors,
d. The older type permanent warehouses with
telescopes, pressure gauges, and items comprised of
inconvenient loading docks or ramps, or other features
both electrical parts and ferrous metals such as electric
which prevent maximum efficiency in storage operations
motors, controllers, telephone handsets, amplifiers,
will, when economically practicable, be converted to CH
circuit breakers, and mechanical fire control computers
space for the long-term storage of selected items,
show deterioration by moisture on various components
including mobilization reserve stocks and industrial
and in various degrees above 50 percent RH.
equipment reserves, which normally are not stored with
regular distribution stocks for rotation.
(6) If the RH falls below 30 percent, there is a
tendency for rubber cable coverings and other insulating
e. Sections of warehouses used exclusively for
materials or electronic equipment to dry out and crack.
shipping receiving, and box shop operations normally
will not be converted to CH space.
d. Equipment items, mobile and immobile which,
because of their physical characteristics, are not
f. Considering cost of installation and continuing
adaptable to stacking, should, when committed to CH
cost of operation, CH space can be installed most