1、- A-A-59110 9999974 0175117 TO5 A-A-591 10 02 July 1997 SUPERSEDING MIL-L-83 774A(USAF) 05 April 1989 COMMERCIAL ITEM DESCRIPTION LEAK DETECTOR, FUEL SYSTEM The General Services Administration has authorized the use of this commercial item description as a replacement for MIL -L- 83774 for all feder
2、al agencies. 1. SCOPE. 1.1 General. This Commercial Item Description (CID) describes an explosion-proof leak detector for locating fuel leaks in aircraft fuel cells and tanks using helium, argon, or nitrous oxide as a tracer media. Beneficial comments (recommendations, additions, deletions) and any
3、pertinent data which may be of use in improving this document should be addressed to: (SA-ALC/TILDD, 485 Quentin Roosevelt Rd, Kelly AFB TX 78241) by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FSC 4940 D TA E A.
4、 Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-59 1 1 O 2. SALIENT CHARACTERISTICS. 2.1 Design. The leak detector shall weigh no more than 25 pounds and shall be operable by one man. The p
5、ower supply shall be capable of operating the sensing unit a minimum of 4 hours without recharging. The leak detector will be explosion proof for operation in an invironment defined by the National Electrical Code, NFPA 70, as class I, division I, group D. The leak detector will be safe for use in a
6、n explosive atmosphere at 8000 feet altitude and 125 degrees Fahrenheit. The leak detector may be enclosed in one or two housings. The weight of the hand held unit for leak searching shall not exceed 8 pounds. The dimensions of the housing shall not exceed 6 inches wide by 12 inches long by 10 inche
7、s deep. If two seperate housings are utilized, the connecting cord shall be 8 feet in length with provisions for extending the working distance an additional 8 feet. The housings shall incorporate one common static electricity grounding point. A retractable (coiled) cable and spring clip shall be at
8、tached to that ground point for grounding to the aircraft. The cable retracted length shall be 12 inches. The extended length shall be 6 feet. The leak detector shall be funiished complete with all items and accessories required for proper operation. A meter as well as audio and light indicators sha
9、ll be the means by which leaks are indicated. The sampling probe shall be flexible, semi-rigid, non-kinking, with a minimum length of 12 inches. A Carrying Case shall be supplied with the leak detector to provide for storage and ease of transportation. 2.2 Compa Char acteristicq. 2.2.1 Sensing ufll
10、t. The sensing unit shall be capable of detecting the following gasses at the specified leak rate when tested in accordance with paragraph 4.4.2: Helium 1 X 10” cubic centimeter per second Argon 4 X cubic centimeter per second Nitrous Oxide 4 X 10” cubic centimeter per second 2.2.2 Respons e time. W
11、hen utilizing the sampling probe, the sensing unit full scale deflection response time to a 1 X 10” cubic centimeter per second helium leak shall not exceed one second. 2.2.3 Recovery h. When removed fiom a leak source, the sensing unit recovery time (meter return to 10 percent of fll scale) shall n
12、ot exceed 3 seconds. 2.2.4 11s . The sensing unit shall be capable of detecting a 5 percent by volume concentration of any of the tracer gases when operating in an atmosphere containing a minimum of 0.4 percent by volume concentration of JP-8 fuel vapor. 2 Provided by IHSNot for ResaleNo reproductio
13、n or networking permitted without license from IHS-,-,-A-A-59 1 1 O 2.2.5 R anne canability . The sensing unit shall be capable of locating a leak of 1 cubic centimeter per second helium and a leak of 1 X cubic centimeters per second helium when the leaks are 4 inches apart horizontally. There shall
14、 be evidence that two seperate leaks have been located. This shall be accomplished in still air without utilizing range swiches, zero adjustment, or other controls. 2.2.6 Power suply. The power supply shall be an internal power source capable of operating the leak detector for periods of 4 hours con
15、tinuously and shall be rechargeable. Batteries shall be capable of a minimum of 500 recharging cycles om the voltage cut-off depth of discharge to a fully charged condition. The power supply shall be capable of preventing erroneous readings or indications due to low voltage. The power supply shall i
16、nclude an internal recharger capable of recharging the batteries fiom a 110-120 volt AC, 50-60 cycle outlet. A detachable 3-wire charging cord (minimum length of 6 feet) shall be included. These requirements shall be obtained when the power supply is tested in accrdance with paragraph 4.4.7. 3. pEGU
17、L ATORY REOUREh$ENTS. 3.1 The offeror/contractor is encouraged to use recovered materials to the maximum extent practicable, in accordance with paragraph 23.403 of the Federal Acquisition Regulation (FAR). 4. QUAL ITk ASSURANC E PROVISIONS. 4.1 Product conformance. The products provided shall meet t
18、he salient characteristics of this commercial item description, conform to the producers own drawings, specifications, standards, and quality assurance practices, and be the same product (explosion proof) offered for sale in the commercial market. The government reserves the right to require proof o
19、f such conformance. 4.2 Jnspect ion and testing;. The inspection and testiing of the leak detector shall be performed as indicated in this section. 4.3 Test conditions. Unless otherwise specified, all tests required by this Commercial Item Description (0) shall be made at an atmosphereic pressure of
20、 28 to 32 inches of mercury, a temperature of 25h5 centigrade (C), and a relative humidity of 80 percent or less. 4.4 Test methods . All tests involving any aspect of leak detection shall be performed with the probe tip no closer than 3/8 inch to the leak. 3 Provided by IHSNot for ResaleNo reproduct
21、ion or networking permitted without license from IHS-,-,-A-A-5911110 9999974 011751120 5TT W A-A-59 1 O0 4.4.1 Noise level and zero drift test. The leak detector shall be checked to determine that the inherent electrical noise causes no more than 5 percent meter displacement. During the tests refere
22、nced in paragraphs 4.4.2, 4.4.3, and 4.4.4, the leak detector shall be checked to determine that the zero drift is not more than 5 percent meter displacement. This check shall be for a minimum of 30 minutes. 4.4.2 Sensit iwtv - test . The leak detector shall be exposed to a 1 X 10” cubic centimeters
23、 per second helium leak. A full scale deflection on the meter shall be recorded. This test shall be repeated two times. Any reading less than full scale either time shall be cause for rejection. The light and audio indicator shall be checked for visibility, audibility, and initiation at 30 percent *
24、5 percent full scale meter deflection. This same procedure shall be repeated for argon and nitrous oxide leaks of 4 X 10”cubic centimeters per second. 4.4.3 Respons e time test. The leak detector shall be tested for compliance with paragraph 2.2.2. 4.4.4 Recovery time tesi . The leak detector shall
25、be tested for compliance with paragraph 2.2.3. 4.4.5 J&rf erence test . The leak detector shall be tested for compliance with paragraph 2.2.4. 4.4.6 Ranee test . The leak detector shall be tested for compliance with paragraph 2.2.5. 4.4.7 Power supply t est. The leak detector shall be operated for 4
26、 hours. During this 4 hour period the power supply shall be positioned 1 hour on each side and 1 hour on each end. The leak detector shall be exposed to a 1 X cubic centimeters per second helium leak every 10 minutes. Sensitivity, response time, light, and audio indication shall be tested for compli
27、ance with paragraphs 4.4.2, 4.4.3, and 4.4.4. Any evidence of malfunctioning shall be cause for rejection. The leak detector shall then be operated until the voltage cutoff or other automatic device is actuated. The recharger shall be activated in acordance with manufacturers instructions allowing t
28、he batteries to be fully recharged in no more than 14 hours. 4.4.8 Fxplosion-proof test. Either Underwriters Laboratories, Inc certification as explosion- proof or factory mutual research approval as intrinsically safe for operation in a class I, division 1 , group D environment is acceptable for me
29、eting the explosion-proof testing requirement. . 5. PACKAGING. 5.1 Preservation, packing, and marking shall be as specified in the contract or order. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- A-A-59110 W 9993974 O175121 436 A-A-591 10 6. NOT
30、ES. 6.1 Source of Document. 6.1.1 Copies of the National Electrical Code may be obtained -om the National Fire Protection Association, Batterymarch Park, Quincy MA 02269. 6.2 National Stock Numbers (NSNs). The following is a list of NSNs assigne which correspond to this CID. This list may not be ind
31、icative of all posible NSNs associated with the CID. MILITARY INTERESTS: custodians: Air Force - 99 CIVIL AGENCY COORDINATING ACTIVITTES: Reviewing Activity: GSA-FSS NSN 4940-0 1-232-0694 Preparing Activity: Air Force - 82 Agent: Air Force - 99 Project Number 4940-0678 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
