MIL-DTL-13623E
4.8.2 Sand and dust resistance. To determine conformance to 3.4.2, the switch shall be tested as
specified in MIL-STD-202, method 110 except that steps 1 through 4 shall be deleted from the procedure
and parts I and II below shall apply instead. No electrical load shall be connected to the terminals during
this test.
Part I. The specimen shall be placed on a test chamber which has been vented to the
atmosphere. The internal temperature of the chamber shall be maintained at 25C
(77ºF) with a relative humidity that shall not exceed 30 percent at any time during test.
The sand and dust density shall be raised and maintained at 0.1 to 0.5 gram per cubic
foot within the test space. The sand and dust velocity through the test chamber shall be
2500 ± 500 feet per minute. This portion of the test shall be continued for 6 hours.
Part II. At the completion of the 6-hour period stated in part I the temperature shall then be
raised to and maintained at 71ºC (160ºF) for an additional 6 hours with all other
conditions remaining the same as in part I.
4.8.3 Fungus resistance. To determine conformance to 3.4.3, the switch shall be subjected to the
fungus resistance test of ASTM-G21. Fungal incubation shall be for 90 days per method B for class 2
specimens.
4.8.4 Waterproofness. To determine conformance to 3.4.4, the switch shall be tested by submersion
as specified in 4.8.4.1. Subsequently, verify that the switch is operable.
4.8.4.1 Waterproofness test method
4.8.4.1.1 Step 1. Prior to submersion, the sample switch shall be installed in a test circuit equivalent
to the normal dry environment and operating both mechanically and electrically, as applicable, for a
period of 30 minutes at full rated current and voltage.
4.8.4.1.2 Step 2. The component with its electrical connections shall be submerged in a container
with the uppermost surface a minimum of one inch below the surface of the saline solution and installed
in the chamber. The component shall be carefully observed during its entire period of submersion and
shall be operated while submerged for 30 minutes at full rated current and voltage. The chamber shall be
evacuated to a pressure six pounds below atmospheric so as to apply a minimum of six pounds per
square inch (psi) in internal pressure to all voids within the component. During this period the component
shall be carefully observed for poor seals, as evidenced by bubbles escaping from the interior of the
component (see 4.8.4.1.5). Leakage thus indicated shall be considered as noncompliance with the
waterproofness requirement and the component shall be rejected. Bubbles that are the result of
entrapped air on the exterior surfaces of the component shall not be considered a leak.
4.8.4.1.3 Step 3. The chamber shall then be pressurized to six pounds above atmospheric and the
component again operated for 30 minutes. Test results obtained shall be compared with the data from the
test of 4.4.
4.8.4.1.4 Step 4. The switch shall evidence no leakage and shall be mechanically and electrically
operable during and subsequent to submersion, when subjected to the tests specified in 4.8.4.1.2 and
4.8.4.1.5 Step 5. The term "leakage", as used in this document, is intended to mean that there shall
be no bubbles escaping from the interior of the component when the test chamber is evacuated to a
pressure six pounds below atmospheric
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