Downloaded from https://www.everyspec.com MIL-STD-1311D ENVELOPE STRAIN 1. Envelope strain (miniature and subminiature receiving tubes). All tubes subjected to this test shall have been sealed a minimum of 48 hours prior to conducting this test. All tubes shall be at room temperature. The tube holder shall be in accordance with Drawing 245-JAN. The entire tube shall be immersed in water at not less than 97 ° C for 15 seconds, and immediately thereafter immersed in water at not more than 5 ° C for 5 seconds. The volume of water shall be large enough so that the water temperature will not be appreciably affected by the test.
The tubes shall be placed in the water so that no contact is made with the containing vessel, nor shall the tubes contact each other. After the 5-second submersion period, the tubes shall be removed and allowed to return to room temperature on a wooden surface. After drying at room temperature for a period of 48 hours, the tubes shall be inspected for evidence of air leaks (see method 1267). 2. Use of rejects. Electrical rejects may be used for this test. METHOD 2126A METHOD 2126A 2126-1 28 March 1975