1、. .- Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, SEA 03442, Naval Sea Systems Command, 2531 Jefferson Davis Hwy, Arlington, VA 22242-5160 by using the Standardization Document Imp
2、rovement Proposal (DD Form 1426) appearing at the end of this document or by letter. MIL-B-24692A 6 August 1993 SUPERSEDING MIL-B-24692 26 October 1987 (See 6.7) MILITARY SPECIFICATION BREATHING APPARATUS, OXYGEN GENERATING, TYPE A-4 (METRIC) This specification is approved for use by all Departments
3、 and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers one classification of a self- generating, type A-4 oxygen breathing apparatus for use by firefighting, damage control, and other personnel. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications
4、. standards. and handbooks. The following specifi- cations, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards
5、 (DODISS) and supplement thereto, cited in the solicitation (see 6.2). SPECIFICATIONS FEDERAL PPP-B-636 - MILITARY MIL-P-116 - MIL-S-901 - MIL-C-17671 MIL-L- 19140 STANDARDS FEDERAL FED-STD-H28 FED-STD-151 FED-STD-191 FED-STD-595 FED-STD-601 Boxes, Shipping, Fiberboard Preservation, Methods of. Shoc
6、k Tests, H.I. (High Impact); Shipboard Machinery, - Canister, Oxygen Breathing Apparatus, for Type A-4. - Lumber and Plywood, Fire-Retardant Treated. Equipment and Systems, Requirements for. - Screw-Thread Standards for Federal Services. - Metals: Test Methods. - Textile Test Methods. - Colors Used
7、In Government Procurement. - Rubber: Sampling and Testing. MILITARY MIL-STD-2073-1 - DOD Material Procedures for Developing and Application of Packaging Requirements. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. MIL-B-24692A (Unless otherwise in
8、dicated, copies of federal and military specifications, O standards, and handbooks are available from the Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.1.2 Other Government documents. drawings and Dublications. The following other Government docu
9、ments, drawings and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. DRAWINGS NAVAL SEA SYSTEMS COMMAND (NAVSEA) 803-5184270 - Oxygen Breathing Apparatus Navy Type A-4, Assemblies 803-5184258 - Oxyge
10、n Breathing Apparatus, Canister. 804-5773272 - Lockers, Oxygen Apparatus Shelf Unit. And Details. (Application for copies should be addressed to: Commander, Portsmouth Naval Shipyard, Code 202.2, Portsmouth, NH 03801.) PUBLICATION NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NIST) NBS Circular Sp
11、ecial 374 - Methods of Determining the Resolving Power of Photographic Lenses. (Application for copies should be addressed to the Superintendent of Documents, 2.2 NonGovernment publications. The following documents form a part of this U.S. Government Printing Office, Washington, DC 20402.) document
12、to the extent specified herein. Unless otherwise specified, the issues of the documents which are DOD adopted are those listed in the issue of the DODISS cited in the solicitation. Unless otherwise specified, the issues of documents not listed in the DODISS are the issues of the documents cited in t
13、he solicitation (see 6.2). O AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) (DOD adopted) Flexible Substrate. (DOD adopted) of Transparent Plastics. (DOD adopted) Cracking in an Ozone Chamber. and Reinforced Material. D 412 - Standard Test Methods for Rubber Properties in Tension. D 413 - Standar
14、d Test Methods for Rubber Property - Adhesion to D 1003 - Standard Test Method for Haze and Luminous Transmittance D 1149 - Standard Test Method for Rubber Deterioration - Surface D 3935 - Standard Specification for Polycarbonate (PC) Unfilled D 3951 - Standard Practice for Commercial Packaging. (DO
15、D adopted) D 4727 - Standard Specifications for Corrugated and Solid Fiberboard Sheet Stock (Container Grade) and Cut Shapes. (DOD adopted) and Materials, 1916 Race Street, Philadelphia, PA 19103.) organizations that prepare or distribute the documents. available in or through libraries or other inf
16、ormational services.) (Application for copies should be addressed to the American Society for Testing (NonGovernment standards and other publications are normally available from the These documents also may be 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license fro
17、m IHS-,-,-MIL- B - 24692A Character ist ic Tensile strength (minimum) 1 Before aging After aging (percent change) 1.684 x lo6 Kg/m2 2/ +20 - 25 2395 psi Ultimate elongation (percent, min) Permanent set i./ (percent, maximum) 550 20 +20 - +20 - 15 Characteristic Before aging Minimum tensile strength
18、Ultimate elongation 1.14 X lo6 kg/mz 1621.5 psi (minimum) (percent) 750 After aging 8.437 X lo5 kg/m2 1200 psi 635 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-B-24692A 9999906 L8b11629 178 H MIL-B-24692A 3.2.4 Self-extinguishing material. T
19、he coated fiberglass cloth in accordanc The expose with Drawing 803-5184270 shall flame out within 2 seconds (see 4.6.8). side of the cloth shall be black in color in accordance with FED-STD-595. 3.2.5 Threads. Threads shall be in accordance with FED-STD-H28 and Drawing 803-5184270. 3.2.6 Recovered
20、materials. Unless otherwise specified herein, all equipment, material, and articles incorporated in the products covered by this specification shall. be new and may be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing the intended use
21、. The term “recovered materials“ means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials. None of the above shall be interpreted to mean that the use of used or rebuilt products is allowed under t
22、his specification unless otherwise specifically specified. 3.3 Assemblv. The breathing apparatus shall be a closed circuit and self- contained in accordance with Drawing 803-5184270. maximum safety and comfort of the wearer. The apparatus shall ensure the 3.4 Construction and maintenance. Any part o
23、f the apparatus that is in direct The apparatus contact with the wearers body shall be of nonirritating composition. shall contain the following principal parts: (a) Mask assembly (1) facepiece (2) facepiece form (3) lens (4) lens cover/protectorl (5) lens retaining ring (6) nosecup assembly (7) spe
24、aking diaphragm assembly (8) speaking diaphragm wrench (9) combination valve (10) head harness (11) buckles (12) breathing tubes (b) Body assembly (1) plunger assembly (2) canister guard and breastplate (3) retaining assembly (4) breathing bags (5) relief valve assembly (6) timer assembly (1) waist
25、belt (2) harness assembly (c) Harnesses For clarification, the lens protector is an adhesive backed paper to protect lens during shipping. Standard commercial protector is acceptable. The protector must be easily removed. 3.5 Performance characteristics. Performance characteristics shall be as speci
26、fied in 3.5.1 through 3.5.7. 3.5.1 Breathinp resistance. with a dummy canister shall not exceed 75 millimeters (mm) (2.95 inches) of water column height (see 4.6.3). Resistance to gas flow of an apparatus complete 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license
27、 from IHS-,-,-MIL-B-24b92A W 999990b LBb4b30 99T W MIL-B-24692A NOTE: The term tdummy canister“ in this specification refers to a canister of This maybe a spent canister the same weight and dimensions as a canister made in accordance with MIL-C-17671, but which is not operational. or a canister whic
28、h is specially constructed for testing purposes. in 3.6.1 for the facepiece assembl , 3.6.2 for the body, and 3.6.2.2.1 for the O 3.5.2 Leakage. There shall be no leakage in excess of the amounts specified relief valve assembly (see 4.6.9 t E rough 4.6.9.3). 3.5.3 Corrosion resistance. Immediately a
29、fter exposure to the salt spray atmosphere specified in 4.6.4, the apparatus shall have no visible sign of corrosion on the operating mechanism, canister guide, or facepiece. The apparatus shall exhibit no changes which could prevent the equipment from meeting the performance requirements of this sp
30、ecification. 3.5.4 High impact shock. 3.6.1 and 3.6.2 (see 4.6.5). 3.5.5 Impact. The apparatus body shall be dropped as specified in 4.6.6 and shall be fully operable without a facepiece attached. 3.5.6 Wear. Repeated operation of the bail as specified in 4.6.7 shall not degrade the operation of the
31、 apparatus. 3.5.7 ApDaratUS output. The apparatus, when used in conjunction with a canister which is in accordance with MIL-C-17671, shall supply breathable gas, as defined in MIL-C-17671, for a 50-minute minimum. The temperature of the breathable gas shall not exceed 46 degrees Celsius (OC) (115 de
32、grees Fahrenheit (OF) (see 4.6.10). apparatus shall not exceed 1.5 percent nor shall the carbon dioxide volumetric content of the gas exceed 5.0 percent at any time (see 4.6.10). The apparatus shall meet the leakage requirements of The average carbon dioxide volumetric content of the gas received fr
33、om the - 3.6 Components. Leakage requirements shall be as specified in 3.5.2 (see 4.6.9 through 4.6.9.4). 3.6.1 Facepiece assembly. The facepiece assembly shall be in accordance with Drawing 803-5184270. It shall include the facepiece, hoses, and valves necessary to bring breathable gas from the bod
34、y of the apparatus to the respiratory passages of the wearer and to conduct exhaust gas back to the body of the apparatus. allowable leakage shall be 0.02 percent by volume, during the 15 seconds after the test has started (see 4.6.9). The components of the facepiece assembly shall be in accordance
35、with Drawing 803-5184270 and the following as specified (see 4.6.9.2). 3.6.1.1 Facepiece. The facepiece shall be made of molded rubber as specified in 3.2.2. The facepiece shall have one lens. 3.6.1.1.1 Facepiece form. A plastic facepiece form in accordance with Drawing 803-5184270 shall be installe
36、d in each facepiece to ensure protection of the facial seal during storage. with Drawing 803-5184270 from a colorless polycarbonate resin in accordance with ASTM D 3935. The lens shall not crack, fracture, chip, or dislodge from the retaining rings (see 4.6.2.3). 3.6.1.2.1 Optical properties. The fi
37、nished lens shall be free of striae scratches, discoloration, or other defects interfering with clearness of vision or causing eyestrain under prolonged use. ophthalmic lenses and not those used for high precision optical devices. The lens shall transmit not less than 85 percent of light incident on
38、 the surface. The lens shall not be Dositive in refractive Dower and shall not have a negative refractive The 3.6.1.2 Lens. Each facepiece shall be fitted with a lens molded in accordance Standards in this respect are those used for power greater than 1/4 diopter (see 4.6.2.4) . a 5 Provided by IHSN
39、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-B-ZLlb92A W 9999906 Lb4b31 826 W Cylindrical powersl/ Prism power, vertical Prism power, horizontal diopters I/ These limits are applica3le MIL-B-24692A Convexity zero Concavity 1/4 diopter (Max) Superconducting 1/
40、7 Subducting 1/8 diopter Abducting zero diop ter to all points on the lens inside a line parallel e 3.6.1.2.2 Lens construction. The outer cylindrical surface of the lens shal be molded to the radii in accordance with Drawing 803-5184270. The inner surface shall be molded to a cylindrical form calcu
41、lated to accomplish an error refraction within the limits stated in table III. These limits shall apply to all points on the lenses inside a line, parallel to the axis of curvature, and subtending at an angle of 37 degrees with the optical axis (see 4.6.2.2). TABLE III. Lens construction details. I
42、I 11 3.6.1.6.1 Diaphragm wrench. A wrench for removing the cover over the speaking diaphragm shall be provided in the shipping container. 3.6.1.7 Combination valve. The facepiece shall be equipped with a combination valve body that directs the flow of exhalation and inhalation gas. The valve shall b
43、e of a sturdy leakproof construction, and shall direct breathable gas from the body of the apparatus toward the wearer, and exhaust gas to the body of the apparatus. 3.6.1.8 Head harness. The finished head harness shall be made of molded rubber as specified in 3.2.2 and shall be molded not greater t
44、han 12 months before delivery. The head harness shall be adjustable and shall maintain tension for 1 hour. The rubber of the head harness shall be black in color in accordance with FED-STD-595 and shall have physical characteristics as specified (see 3.8 and 4.6.1.1). with Drawing 803-5184270. strap
45、s, shall be constructed of stainless steel, and shall be the quick-adjustable, roller type. The facepiece shall be equipped with two breathing tubes, one for inhalation and one for exhalation. constructed from rubber as specified in 3.2.2 and shall be gas-tight (see 4.6.11). 3.6.1.8.1 Buckles. The f
46、acepiece shall be equipped with buckles in accordance The buckles shall be compatible with the head harness 3.6.1.9 Breathing tubes. O The breathing tubes shall be 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-B-2LIb92A m 999990b Lb4b32 762 m
47、 MIL-B- 24692A 3.6.1.9.1 Breathinv tube fittings. The ends of the breathin tubes shall terminate in quick-connect fittings that match those on the body o fi the device. The inhalation and exhalation hoses shall have different size fittings to prevent the wearer from attaching the hoses to the wrong
48、ports during operation of the device. The body of the apparatus shall be in accordance with Drawing 803-5184270. The allowable leaka e of the body (see 4.6.9) shall be 3.05 centimeters (cm) (1.2 setting of relief valve (see 4.6.9.1) shall be 1.90 cm (0.75 inches) of water column. The canister holder
49、 shall consist of the plunger assembly, canister guard, breastplate, and retaining system. In accordance with Drawing 803-5184258, these parts shall be assembled to permit the canister to be inserted and held in a standby position without puncturing the canister seal. Operation of the retaining assembly shall ram the canister home on the plunger assembly, piercing the canister seal and shall gas-tight seal the canister to the apparatus at the plunger assembly.
