Downloaded from https://www.everyspec.com MIL-STD-81OD 19 July 1983 A-1.2.1.11 Ekctrical svs tern. All electrical component, of this facility shall be explosionproof and conform to the applicable portion of the National Fire Underwriters Code. The chamber shall be equipped with sealed male ‘plugs and female jack feedthroughs to transmit power as required through the chamber wall to the item under test. For example: 12 - 150 tip. jack and plug terminals 12 - 75 SMP. jack and plug terminals . . 12 - 40 amp. jack and plug terminals 12 - 10 amp. jack and plug termina~s (male jack and,female plug).
Studs may be used through the chamber wall provided they are wired to jacks located on a panel mounted on the facility. Jacks and plugs should be similar - to and interchangeable with existing laboratory equipment. A-1.2.1.12 Yacuum DU mQ. A vacuum pump capable of producing and maintaining within the test chamber any desired pressure altitude within the performance . limits specified in A-1.3.2 shall be provided. The pump shall be mounted on the same chassis as the chamber. Five minutes shall be the maximum allowable time to produce any pressure altitude desired. A-1.2.1.13 ~. A sampling chamber equipped with a blower and a spark plug shall be provided.
The blower shall be capable of mixture circula- tion at the velocity specified.in A-1.3.3 and shall be appropriately located. The volume oC.the sampling chamber shall be not less than 1 cubic foot and the configuration symmetrical, to prevent end effects resulting from ignition o! explosive mixtures. The sampling chamber shall be of a strength equal to that of the main test chamber. A maximum pressure indicator shall be furnished for the sampling chamber. The sampling chamber shall be external to the main cham- ber but in.as close proximity thereto ae possible.
The inlet side of the sampling chamber mixing blower shall be provided with a flexible probe which can be placed in the vicinity of any potential arcing sources on the test item. Provision should be made to insure that sampling chamber wall temPerattirewill be equal to main chamber wall temperature. A-1.2.l.14~. A thermostatically regulated heater system capable of controlling the air temperature in the chamber within performance limits SDeCified in A-1.3.4 shall be Drovided. The heater system shall be built into tie chamber walls-so that the &hamber air temperature-is controlled by heat from the walls. The time required to attain any desired temperature shall not exceed 1 hour”.
Temperature fluctuations due to the introduction into the test chamber of air-vapor mixtures shall not exceed 5.5° C (10.OoF) in magnitude,nor 2 minutes in duration. * The following instruments shall:be provided: A-1.2.1.15 ~. ,. a. Altimeter 0-25,000 meters (o-80 ,000 feet) b. Maximum pressure indicators (2) 0-2400 psscals (0-350 psi) . Chamber air temperature indiCat6r 0-260° C (0-500° F) ,, d. Chamber wall temperature indicator 0-2600C (0-500° F) MSTHOD 511.2 APPENDIX K 19 July 1983 511.2-14