Downloaded from https://www.everyspec.com MIL-STD-810D.; 19 July ‘1983 a. lvDe of exu~. In order to determine the test temperatures, the determined first. The way in which the test item is exposed to heat must be o exposure conditions that mu.Stbe considered include: (1) Ambient air conditions. Of interest are the most severe conditions that materiel, which could be deployed in any climatic area of the world, wculd experience when under cover in fully ventilated locations such as open cabins, sun-shaded areas, and underside regiona of aircraft where the test item is.shaded from direct solar heating.
Ambient air temperature and humidity conditions are those measured in standard meteorological shelters at a height cf 1.2 to 1.8 meters (4 to 6 feet) above the ground. If field data are not available, the conditions for this exposure may be approximated from’tables 501,.2-1and 501.2-II. Table 501.2-III gives a summary of high-temperature. diurnal cycle.ranges for different areas cf the world. (2) Induced conditions. These conditions are from the same regions as the ambient air conditions but with an allowance made for the effect of solar heating.
These are typical conditions to which materiel .is exposed while under cover where there is little or no ventilation and where the effects of solar heating on the cover causes a rise in the air temperature adjacent to the materiel. Examples of where these conditions cccur are: (a) Inside unventilated enclo?urea. (b) Within enclosed vehicle bodies. (c) Within heating. aircraft.sections having surfaces expcsed’to solar o (d)” Inside of tents. (e) Under olosed tarpaulins. These conditions are not the temperatures attained by equipment, but rather the air temperature observed irivarious locations.where materiel is operated or stored.
The cycling conditions for this exposure are given in tables 501.2-I and 501.2-II and are to be.used only if,appropriate field measured data do not exist. ,. (3) Extreme induced conditions. These conditions are induced but involve temperatures as high as 70° to 850c (1600 to 18s° F), making greater d10WSIICf2for the effects of solar radiation, Applicable conditions for such testing include equipment that is employed in the cpen (for which method 505.2 should be used) and in enclosed compartments having glazed or transparent panels (aircraft ccckpits, vehicle compartments, etc.).
Another consideration is the location of equipment near heat-producing devices which influence intensify the air temperature surrounding the test item. These extreme induced . conditions would be applied by.extending the levels of the temperatures given in tables 501.2-I and 501.2-11. b. Iest temDerature(s). Determine the test temperature(a). If field measurements of actual exposure and response are available, the chambar conditions shall be derived from t.besedata. Without availability of field measurements, the chamber conditions will be derived from the following o information and evaluations. 501.2-5 METHOD 501.2 19 July 1983