Criteria for Facility Selection.

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--

humidity levels.

(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

louvers.

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

monoxide gas.

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;

distribution stocks.

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

physical properties.

funds.

(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

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