TM-5-855-4
2-5. Temperature and humidity.
a. Temperature and humidity of an occupied space have a direct effect on the occupants. A
comfortable environment is essential for personnel who perform duties which demand reliable
judgement and mental or physical stamina. Psychological stresses are likely to be present in
individuals stationed in an underground structure under attack or alert. Where personnel efficiency is
bulb air temperature, and 50 percent RH (optimum for control of air-borne bacteria). For additional
guidelines refer to TM 5-810-1, and ASHRAE Handbooks.
b. Where operating equipment is the important consideration (electric racks, gyroscopic and
celestial navigation equipment, laser missile tracking devices, and other similar equipment)
temperature, humidity, flow, pressure, cleanliness, and other cooling air requirements will be designed
in accordance with the equipment manufacturer's recommendations.
table 2-3. The data indicated the necessity for a low humidity for the preservation of unprotected carbon
steel. As a result of these tests and other consideration, a RH of 35 percent was chosen for the interior of
many ships place in storage. The 35 percent figure is considerably below the demonstrated tolerance of
many materials, but it affords a factor of safety against equipment failure and against sharp temperature
changes that might cause condensation on some objects when the temperature is uncontrolled.
d. Excessive dryness is harmful to certain materials, such as commutator brushes in electric motors,
paper, excelsior, straw, leather, hemp rope, wood furniture, and dry-cell batteries. Recommended air
conditions for storage of propellants will not exceed 60 percent RH with dry bulb temperature kept between
50 "F and 600 F. The AC equipment for explosive storage chambers will be selected with reference to
minimizing pipe and duct runs. Where human occupancy is infrequent, little or no ventilation will be
required. Equipment capable only of dehumidifying and moderately heating such chambers may be
adequate in such situations.
2-6
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