Downloaded from https://www.everyspec.com MIL-STD-81OD”“ 19 July 1983 (2) Sealed with protective covers, caps, plugs, etc. (“3) Modified with kits for special applications. ,.. . ~.(4) Normal ‘operatingconfiguration. . ,, b.~. : This teat usually includes heating of the test item to induce expansion of materials and, after cooling, to establish a pressure differential to determine whether the seals or gaskets leak under relatively low Dressure. . (1) The test item temperature of 27° C (49° F) above (At) the water temperature is used to produce a pressure differential inside the test item following immersion. (2) The temperature of the water shall be 18° t 10° C (64° k 18° F). (3) Duration.
The test item shall be heated untii temperature stabi- lization of the test item has occurred or for 2 hours, whichever occurs first (a sufficient time to raiae the internal air temperature.to a value approach- ing 45° C (113° F)). .C. - of immersi~. The depth of immersion affects the pressure differential that develops on the test item. Since this method is designed to test the effectiveness of seals or gaskets, a l-meter test depth is suggeeted. This, combined with the initial teat item temperature, should result in twice the pressure differential of iuunersionto Im without heating. Other values such as those shown in table 512.2-I may be used if appropriate.. TABLE 512.2-I.
.Yater D~ures at various ~. Head of Water Pressure Difference (meters) (kPa) (1“psi = 6.895 Ma) 0.15 ... . 14.7 0.91 , ~ 90 1.0 ~~ 98 1.5 , 147 4.0. 392 6.o . - 588 . 10.0 980 . NOTE: The equivalent head of sea water is 0.975 times the head of fresh water for the same pressure difference. d. ~. Just as the test item is heated for at least ; 2 hours before immersion to.insure thorough heating, the immersion period of 2 hours is considered adequate.to develop leakage if it is to occur. NSTHOD 512.2 512.2-3 19 July 1983