Downloaded from https://www.everyspec.com MIL-sTD-810D 19 July 1983 METHOD 506.2 RAIN SECTION II II-1 MEMAXQS 11-1.1 ,. a. For prooedure 1, the rain faoility shall have duoing falling rain accompanied by wind blowing at the The facility temperature shall be uncontrolled, except the capability of pro- rate specified herein. as regulated by water introduced as rain. The rain shall be produced by a water distribution device of such design that the water is emitted in the form of droplets having a dia- meter range predominantly between O,5 and 4.5 millimeter:.(see I-3.2c). The rain shall be dispersed completely over the test item when accompanied by the prescribed wind. b.
The wind source shall be positioned with respect to the test item so that it will cause the rain to beat directly, with variations up to 45° from the horizontal, and uniformly against one eide of the test item. The wind source shall be capable of producing horizontal wind velocities equal to and exceeding 18 mls (40 milh). The wind velocity shall be measured at the position of the test item before placement of the test item in the facility. No rust or corrosive contaminants shall be imposed on the test item by the test facility. a c. A water-soluble dye such as fluorescein may be.added to the rainwater to aid in locating and analyzing water leeks. d.
For procedure II, the test setup should.provide a vol~e of water greater than 280 (+30, -O) L/m2/h (7 gal/ft2/h) dripping from a dispenser with drip holes on a 25.4 mm,pattern, “asshown in figure 506.2-1. e. For procedure III, the.nozzlee used should produce a square spray pattern or other overlapping pattern (for maximum surface coverage) and droplet size predominantly in the 2 to 4.5 mm range at a proximately 3’75kFa (40 psig). ; At least one nozzle should be used for each 6 ft of surface area and should be positioned 19 ~ 1 in. from the test surface.~/ ,,. 11-1.2 ~ a. For procedures I and II, immediately before each test. the rainfall rate““shallbe verified . b.
For procedure 1, the air each test. velocity shall be verified immediately before c. For procedure III, the nozzle spray pattern and pressure shall be verified before each test. 3/ From MIL-S-55286 and MIL-S-55541. MSTHOD 506.2 19 July 1983 . 506.2-8 I