1、BRITISH STANDARD AEROSPACE SERIES BS ISO 14624-2:2003 Space systems Safety and compatibility of materials Part 2: Determination of flammability of electrical-wire insulation and accessory materials ICS 13.220.40; 49.025.01; 49.140 BS ISO 14624-2:2003 This British Standard was published under the aut
2、hority of the Standards Policy and Strategy Committee on 15 January 2004 BSI 15 January 2004 ISBN 0 580 43257 2 National foreword This British Standard reproduces verbatim ISO 14624-2:2003 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technic
3、al Committee ACE/68, Space systems and operations, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be
4、 found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are
5、responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and k
6、eep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 19 and a back cover. The BSI copyright noti
7、ce displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 14624-2:2003(E) OSI 3002INTERNATIONAL STANDARD ISO 14624-2 First edition 2003-06-01 Space systems Safety and compatibility of materials Part 2: D
8、etermination of flammability of electrical-wire insulation and accessory materials Systmes spatiaux Scurit et compatibilit des matriaux Partie 2: Dtermination de linflammabilit des systmes disolation des fils lectriques, et des matriaux accessoires BSISO146242:2003ISO 14624-2:2003(E) DPlcsid Fremia
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13、r ehe.r ISO cirypothg fofice saCe tsopale 65 eneG 1121-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mial coirypthgis.o gro We bwww.is.o groii ISO 2003 Allr ihgtsr eservedBSISO146242:2003ISO 14624-2:2003(E) I SO 3002 All irhgts seredevr iiiContents Page Foreword iv Introduction v 1 Scope
14、1 2 Conformance . 1 3 Normative references . 1 4 Terms and definitions. 1 5 Test materials 2 6 Electrical-wire insulation flammability test in a static environment (Test A) . 2 7 Alternative wire-insulation flammability test in a gas-flow environment (Test B) . 7 Annex A (informative) Competency and
15、 accreditation of test facilities . 13 Annex B (informative) Preparation and qualification of chemical ignitors 14 Bibliography . 19 BSISO146242:2003ISO 14624-2:2003(E) iv I SO 3002 All irhgts seredevrForeword ISO (the International Organization for Standardization) is a worldwide federation of nati
16、onal standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Internat
17、ional organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the ru
18、les given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at
19、 least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14624-2 was prepared by Technical Committee ISO/
20、TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations. ISO 14624 consists of the following parts, under the general title Space systems Safety and compatibility of materials: Part 1: Determination of upward flammability of materials Part 2: Determination of flammabilit
21、y of electrical-wire insulation and accessory materials Part 3: Determination of offgassed products from materials and assembled articles Part 4: Determination of upward flammability of materials in pressurized gaseous oxygen or oxygen- enriched environments Part 5: Determination of reactivity of ma
22、terials with aerospace propellants Part 6: Determination of reactivity of processing materials with aerospace fluids Part 7: Determination of permeability of materials to aerospace fluids BSISO146242:2003ISO 14624-2:2003(E) I SO 3002 All irhgts seredevr vIntroduction Throughout this part of ISO 1462
23、4, the minimum essential criteria are identified by the use of the imperative or the key word “shall”. Recommended criteria are identified by the use of the key word “should” and, while not mandatory, are considered to be of primary importance in providing serviceable, economical and practical desig
24、ns. Deviations from the recommended criteria may be made only after careful consideration, extensive testing and thorough service evaluation have shown an alternative method to be satisfactory. BSISO146242:2003BSISO146242:2003INTENRATIONAL TSANDADR IS-42641 O2:(3002E)I SO 3002 All irhgts seredevr 1S
25、pace systems Safety and compatibility of materials Part 2: Determination of flammability of electrical-wire insulation and accessory materials 1 Scope This part of ISO 14624 specifies two test methods for determining the flammability of electrical-wire insulation and accessory materials by exposure
26、to an external ignition source in a static environment (Test A) and in a gas-flow environment (Test B). 2 Conformance The tests shall be performed in an accredited test facility (see Annex A for guidelines). The authority having jurisdiction, or the test requester, shall provide properly identified
27、material(s) for testing. Alternatively, accredited test facilities may be authorized by the test requester to procure the appropriate material(s). 3 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition
28、cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 14624-1, Space systems Safety and compatibility of materials Part 1: Determination of upward flammability of materials 4 Terms and definitions For the purposes of this documen
29、t, the following terms and definitions apply. 4.1 burn length maximum distance over which the insulation has been damaged due to flame impingement NOTE This distance includes areas of partial or complete combustion, charring or embrittlement, but does not include areas which are sooted, stained, war
30、ped or discoloured, or areas where the insulation has shrunk or melted away from the heat. 4.2 self-extinguishing phenomenon wherein the burn length of a wire insulation system is less than 150 mm when exposed to an external ignition source 4.3 transfer of burning debris movement of burning particle
31、s from a burning specimen to adjacent materials BSISO146242:20031ISO 14624-2:2003(E) 2 I SO 3002 All irhgts seredevr4.4 good laboratory practice GLP practice which involves the testing of standard reference materials to verify data accuracy and repeatability 4.5 worst-case environment combination of
32、 test pressure, oxygen concentration and temperature that make the material most flammable 5 Test materials The minimum quantities of materials required to perform each test properly are summarized in Table 1. Actual test configurations and material quantities for material forms other than those lis
33、ted (e.g. sleeving, cable clamps, etc.) shall be established and approved by the responsible procuring activity/user materials organization. Table 1 Minimum quantities of materials required for testing for each atmosphere Form of material Test Minimum quantity A 10 m in length Insulated wire B 7 m i
34、n length As a minimum, all materials used in testing shall meet or exceed user specifications. Material and configured-system characteristics can be significantly compromised by sources of contamination, such as exposure to solvents, cleaning agents, abnormal temperatures, variations in humidity, en
35、vironmental pollutants, particulates and handling. It is important that exposure of test material(s) to these and other contamination sources be sufficiently controlled to minimize variation in test results. 6 Electrical-wire insulation flammability test in a static environment (Test A) 6.1 Principl
36、e The purpose of this test (Test A) is to determine if wire insulation and accessory materials, when exposed to an external ignition source, will self-extinguish and will not ignite adjacent materials by the transfer of burning debris. Electrical-insulation accessories include electrical wire, sleev
37、ing, heat-shrinkable tubing, solder sleeves, bundle ties, cable clamps, identification tape, etc. For a wire insulation system to be considered self- extinguishing, the burn lengths of at least three standard-sized replicate specimens (diameter 0,90 mm) shall be less than 150 mm at an internal wire
38、temperature of 125 C or at the maximum operating temperature of the wire. In addition, the ignited specimens shall not propagate a flame by the transfer of burning debris. Failure of any one specimen constitutes failure of the material. These tests shall be conducted on specimens of insulation use t
39、hickness. The test conditions (total pressure, wire temperature and oxygen concentration) shall simulate the worst-case environment in which the insulation material is to be used. The configuration (for example, wire bundles) or the use of another wire gauge can cause a variation in the test results
40、. 6.2 Reagents 6.2.1 Test gases, premixed before exposing the specimen to them and verified for conformity with the specification (including accuracy) for oxygen concentration to within 1 0 % + . 6.3 Test system 6.3.1 Test chamber, large enough so that complete combustion of the specimen can occur w
41、ith no more than a 5 % relative depletion of oxygen concentration. In addition, the test chamber shall not interfere chemically or physically with the test. The free space above and below the test fixture shall be at least 200 mm. BSISO146242:20032ISO 14624-2:2003(E) I SO 3002 All irhgts seredevr 36
42、.3.2 Measuring devices, properly calibrated. 6.3.3 Chemical ignition source, meeting the following specifications under ambient conditions: a) energy: 3 000 J; b) temperature: 1 100 C 90 C; c) burning duration: 25 s 5 s; d) maximum visible flame height: 65 mm 6,5 mm. Annex B provides a procedure for
43、 preparing, certifying and storing chemical ignitors. Alternative ignition mechanisms may be utilized if they meet the requirements outlined in a) to d) above. 6.3.4 AC power supply, capable of providing 15 A (RMS), connected to a bare 20 AWG nickel-chromium wire (6.3.5) to initiate the igniter. 6.3
44、.5 Bare nickel-chromium wire 0,90 mm in diameter, with a nominal resistivity of 2,3 m and of sufficient length to wrap three equally spaced turns around the chemical igniter. 6.3.6 Suitable specimen holder, capable of supporting the centre third of the wire or wire bundle from one top corner of the
45、fixture to the opposite bottom corner of the fixture at an angle of 15 2 to the vertical (see Figure 1). 6.3.7 Scale, attached to one side of the specimen holder, for measurement of the burn length. 6.3.8 Sheet of paper, mounted horizontally approximately 200 mm below the specimen holder, having the
46、 following characteristics: a) dimensions: 216 mm 280 mm; b) mass of 1 000 sheets (size 650 mm 770 mm): between 100 kg and 150 kg; c) type: chemical wood index; d) colour: uniformly white; e) condition: clean, free from dirt spots, oil spots and foreign matter (lint, fuzz, etc.), free from holes, te
47、ars, cuts, folds and scuff marks, and containing no splices. The sheet of paper is used to assess if burning debris from the specimen would cause ignition of adjacent materials. 6.3.9 DC power supply, capable of providing a regulated DC current (150 A maximum) to the conductor of the test specimen a
48、t the level required to reach the specified internal wire temperature. BSISO146242:20033ISO 14624-2:2003(E) 4 I SO 3002 All irhgts seredevrDimensions in millimetres Key 1 specimen 2 scale 3 insulating ceramic-fibre thread 4 ceramic insulator 5 ignitor Figure 1 Standard specimen holder and specimen c
49、onfiguration 6.4 Test specimens 6.4.1 Reception and inspection of material 6.4.1.1 Receive and visually inspect the test material: when received, it shall be accompanied by proper identification. Any flaws shall be noted. Specimens should have been cleaned and dried to the end-use specifications prior to receipt at the test facility. 6.4.1.2 If required, prepare specimens to the proper d
