1、BRITISH STANDARD AEROSPACE SERIES BS EN 3475-408:2005 Cables, electrical, aircraft use Test methods Part 408: Fire resistance The European Standard EN 3475-408:2005 has the status of a British Standard ICS 49.060 BS EN 3475-408:2005 This British Standard was published under the authority of the Stan
2、dards Policy and Strategy Committee on 13 February 2006 BSI 13 February 2006 ISBN 0 580 47790 8 National foreword This British Standard is the official English language version of EN 3475-408:2005. The UK participation in its preparation was entrusted by Technical Committee ACE/6, Aerospace avionic
3、electrical and fibre optic technology, to Subcommittee ACE/6/-/2, Aerospace Cables, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests i
4、nformed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred
5、 to in this document may be 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 provision
6、s of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 8, an inside back cover and a
7、 back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN3475408 November2005 ICS49.060 EnglishVersion AerospaceseriesCables,electrical,airc
8、raftuseTest methodsPart408:Fireresistance SriearospatialeCbleslectriquesusage aronautiqueMthodesdessaisPartie408:Rsistance aufeu LuftundRaumfahrtElektrischeLeitungenfr LuftfahrtverwendungPrfverfahrenTeil408: Feuerbestndigkeit ThisEuropeanStandardwasapprovedbyCENon12September2005. CENmembersareboundt
9、ocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuro
10、peanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus
11、,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKO
12、MITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2005CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN3475408:2005:EEN 3475-408:2005 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Preparation of specimens 4 4 Apparatus
13、 4 5 Method .5 6 Requirements 8 EN 3475-408:2005 3 Foreword This European Standard (EN 3475-408:2005) has been prepared by the European Association of Aerospace Manufacturers - Standardization (AECMA-STAN). After enquiries and votes carried out in accordance with the rules of this Association, this
14、Standard has received the approval of the National Associations and the Official Services of the member countries of AECMA, prior to its presentation to CEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the
15、latest by May 2006, and conflicting national standards shall be withdrawn at the latest by May 2006. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such
16、patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, It
17、aly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. 4 1 Scope This standard specifies a method of testing the fire resistance of “fire-proof“ electrical cables. 2 Normative references The following r
18、eferenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2685:1998, Aircraft Environmental test procedure for airborn
19、e equipment Resistance to fire in designated fire zones. EN 3909, Aerospace series Test fluids for electric components and sub-assemblies. 1)3 Preparation of specimens Six test specimens, 0,75 m minimum length, shall be selected at random from a quantity of cable. 4 Apparatus 4.1 List of apparatus T
20、he following shall be required for this test: a burner, a test fixture, and test fluids. 4.2 Burner The burner shall be as described in Annex A of ISO 2685 or any other burner or assembly of burners satisfying the following conditions: the minimum width of the burner shall be 50 mm; cable length exp
21、osed to the flame: 152 mm; diameter or width of the flame at the base of the burner(s) 2 D (D diameter of the cable under test); flame temperature: (1 100 80) C; heat flux density received by the calorimeter described in Annex B of ISO 2685: (116 10) kW/m 2 . 4.3 Test fixture Refer to Figures 1 and
22、2. The distance between the burner nose and the cable under test shall be as specified in ISO 2685 Annex A. The frame of the test fixture shall be vibrated with the following characteristics: direction perpendicular to the axis of the cable; frequency: (30 5) Hz; minimum acceleration: 4 g. 1) Publis
23、hed as AECMA Prestandard at the date of publication of this standard. EN 3475-408:20055 4.4 Fluids The test fluids listed below shall be in accordance with EN 3909. aircraft fuel (kerosene); hydraulic fluid (phosphate base); lubricant (synthetic oil); cleaning product (isopropylic alcohol); de-icing
24、 fluid (ethylene glycol). 5 Method 5.1 Preparation The test shall be conducted in still air. The centre section of each of the specimens shall be immersed over a length of 0,5 m for 24 h at ambient temperature, one sample in each of the test fluids. After removal from the test fluid any surplus flui
25、d shall be removed with a lint free cloth. The sample shall stand for 1 h. Each sample shall be mounted onto a frame as shown in Figure 1. Each sample shall be wrapped once around with two nickel-chrome ribbons with their inner edges spaced (25 5) mm apart. The sample and test ribbons shall be weigh
26、ted, as shown in Figure 1, and the test assembly adjusted so that the area wrapped by the ribbons is located at the appropriate distance above the burner where the temperature is 1 100 C. After tensioning with weights, the samples and test ribbons shall be locked at the pulley position to avoid the
27、weights giving high loading under vibration/resonant conditions. Single core samples shall be connected to a circuit as shown in Figure 2. Multi-core samples shall be connected to a circuit as shown in Figure 3. Screen cables (metal braid) shall be connected to a circuit as shown in Figure 4. 5.2 Pr
28、ocedure 5.2.1 Note the line current (approximately 2 A); 5.2.2 Operate the switch and observe a 25 mA reading; 5.2.3 Leakage current flow shall not exceed 12,5 mA during the test period. 5.2.4 Sample continuity is shown when a current flow of 2 A is registered with the electrical supply switched on.
29、 The insulation degradation detection circuit shall be checked by depressing the test switch; an indication of 25 mA flow should be registered. 5.2.5 Each sample shall be simultaneously subjected to the combined flame and vibration test. The test duration shall be: 5 minutes for fire resistant cable
30、s; 15 minutes for fire proof cables. EN 3475-408:20056 Key 1 Tensioning springs 2 Nickel-chrome ribbons 3 Cable test specimen 4 Test burner 5 Weights: cables 004 to 030: 170 g cables 050 to 220: 340 g Figure 1 Test fixture 5 1 2 4 3 1 (1,5 0,25) mm X 3 2 X EN 3475-408:20057 Key 1 Test switch 2 Nicke
31、l-chrome ribbons 3 Cable test specimen Figure 2 Circuit diagram for single core cables Test 1 Core-to-core integrity Key 1 Cable test specimen 2 Test switch Figure 3 Circuit diagram for multi-core cables 1 0 A 5 A 0 mA 100 mA (1,5 0,25) mm 2 3 0 A 5 A 0 mA 100 mA 1 2 EN 3475-408:20058 Test 2 Core-to
32、-screen integrity Key 1 Connect all cores together 2 Cable test specimen 3 Connection to metal screen 4 Test switch Figure 4 Circuit diagram for screened cables 6 Requirements Check electrical continuity and insulation resistance of the conductor before, continuously throughout and after the test. T
33、he maximum current value of 12,5 mA corresponding to an insulation resistance of 10 000 shall not be exceeded. 0 to 5 A 0 A 5 A 0 mA 100 mA 4 3 3 1 2 EN 3475-408:2005blankBS EN 3475-408:2005 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national bo
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