1、ASD STANDARD NORME ASD ASD NORM prEN 3475-601 Edition P 2 September 2006 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATION Gulledelle 94 - B-1200 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 763 3565 - www.asd-stan.org ICS: 49.060 Supersedes edition P 1 of No
2、vember 2001 Descriptors: Aerospace industry, aircraft equipment, electrical cable test ENGLISH VERSION Aerospace series Cables, electrical, aircraft use Test methods Part 601: Smoke density Srie arospatiale Cbles lectriques usage aronautique Mthodes dessais Partie 601 : Densit de fume Luft- und Raum
3、fahrt Elektrische Leitungen fr Luftfahrtverwendung Prfverfahren Teil 601: Rauchdichte This “Aerospace Series“ Prestandard has been drawn up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the needs of the Europe
4、an Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, withou
5、t re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a draft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national me
6、mbers have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national standards conflicting with the EN. Edition approved for publication 30 September 2006 Comments should be sent within six months after the date of publication to AS
7、D-STAN Electrical Domain Copyright 2006 by ASD-STAN prEN 3475-601:20062 Contents Page Foreword .2 1 Scope3 2 Terms and definitions .3 3 Principle of method.4 4 Test apparatus.4 4.1 Test chamber .4 4.2 Manometer .4 4.3 Pressure regulator 4 4.4 Chamber wall thermocouple 4 4.5 Electric power supply .5
8、4.6 Radiant heat furnace.5 4.7 Pilot burner system.6 4.8 Specimen holder .6 4.9 Support for radiant heat furnace and specimen holder 7 4.10 Photometric system7 4.11 Exhaust hood.8 5 Test specimens .8 5.1 General .8 5.2 Number of specimens.9 5.3 Specimen length9 5.4 Specimen preparation.9 6 Condition
9、ing 9 7 Check and maintenance of the test apparatus.9 7.1 Furnace protection9 7.2 Periodic calibration procedure 9 7.3 Chamber cleaning .11 7.4 Adjustment of test chamber.12 8 Test performance 12 9 Calculation .13 10 Requirements 14 11 Report .14 Foreword This standard was reviewed by the Domain Tec
10、hnical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publication. prEN 3475-601:20063 1 Scope This test method is intended for determinati
11、on of the specific optical density of smoke generated by electrical wire/cable insulation materials due to pyrolitic decomposition under the influence of radiant heat only or with simultaneous flame application. It is used for evaluation of insulation materials of electrical wire/cable used in the i
12、nteriors of aerospace vehicles but may be utilized in other applications as specified in applicable procurement documents. This standard should be used to measure and describe the properties of products in response to heat and flame under controlled laboratory conditions and should not be used to de
13、scribe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a
14、particular end use. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 Ds Specific Optical Density, is a dimensionless measure of the amount of smoke produced per unit area by a material when it is burned 2.2 Dm maximum value of Ds, that occurs
15、during the specified time of a test 2.3 F-mode Flaming mode, the pyrolitic decomposition of the specimen under the influence of radiant heat and with simultaneous flame application 2.4 NF-mode Non Flaming mode, the pyrolitic decomposition of the specimen under the influence of radiant heat only 2.5
16、T percent light transmission 2.6 Tt percent light transmission at the time t 2.7 Tm minimum percent light transmission 2.8 tDm time of the test in seconds at which the maximum optical smoke density occurs prEN 3475-601:20064 3 Principle of method The specimens are vertically arranged in a closed tes
17、t chamber and subjected to decomposition by radiant heat only or with flame application. The smoke density is measured by means of the reduction of light transmission as smoke accumulates and expressed in terms of specific optical density which is derived from a geometric factor and the measured lig
18、ht obscuration. 4 Test apparatus 4.1 Test chamber The test chamber shall be a square-cornered box with inside dimensions of (914 3) mm width, (610 3) mm depth, and (914 3) mm height. A typical test chamber is shown in Figure 1. The locations of size of items such as the chamber door, chamber control
19、s, flowmeters, etc., is optional except as mandated in the following sections. The interior surfaces (except for the chamber door, vents, etc.) shall be porcelain-enameled metal, or equivalent coated metal that is resistant to chemical attack and corrosion, and suitable for periodic cleaning. Commer
20、cially available panels of porcelain-enameled steel (interior surface) permanently laminated to a magnesia-insulation core and backed with galvanized steel (exterior surface) have been found acceptable. The chamber shall be equipped with a door such as indicated in Figure 1 to provide convenient acc
21、ess for changing test specimens, and for cleaning the chamber walls as required. The door shall have a viewing window to observe the chamber interior during a test, especially when any of the flamelets extinguish. The door shall have a seal so that when it is closed during tests, there will be no le
22、akage of chamber contents. A small positive pressure can be developed and maintained inside the test chamber. An inlet-outlet vent for pressure equalization shall be provided. The vent shall have a seal so that when it is closed during tests, there will be no leakage of chamber contents and a small
23、positive pressure can be developed and maintained inside the test chamber. To avoid an excessive increase of pressure in the chamber during testing an airtight safety disc is required, e.g. a sheet of aluminium foil of thickness not greater then 0,04 mm and a minimum area of 800 cm2 shall be provide
24、d in an opening of the chamber floor. 4.2 Manometer A device such as a manometer or pressure transducer shall be provided to monitor chamber pressure and leakage. The device shall have a range up to 15 hPa, and be connected to a suitable port in the test chamber wall. 4.3 Pressure regulator A pressu
25、re regulator shall be provided that consists of an open water-filled bottle and a piece of tubing, not to exceed 3 050 mm in length, that has an inside diameter of at least 25 mm. One end of the tubing shall be connected to a port on the top or within 152 mm from the ceiling of the chamber; the othe
26、r end of the tubing shall be held in position 102 mm below the water surface. 4.4 Chamber wall thermocouple The temperature of the test chamber wall shall be monitored by a thermocouple suitable for measuring a temperature of 35 C. The thermocouple shall be mounted with its junction secured to the g
27、eometric centre of the inner rear wall panel of the chamber using an electrically insulating disk cover. prEN 3475-601:2006 5 4.5 Electric power supply At least 650 W, single phase electric power shall be provided for the radiant heat furnace and accessories. Where line voltage fluctuations exceed 2
28、,5 %, a constant voltage transformer shall be provided. 4.6 Radiant heat furnace 4.6.1 General An electric furnace and associated controlling devices shall be provided that is capable of providing a constant thermal flux density of (25 0,5) kW/m2 on the specimen surface. 4.6.2 Furnace construction T
29、he dimensions of the electric furnace are shown in Figure 2. The furnace shall be located centrally along the long axis of the chamber with the opening facing toward and approximately 305 mm form the right wall. The centerline of the furnace shall be approximately 197 mm above the chamber floor. 4.6
30、.3 Heating element The heating element shall consist of a coiled wire capable of dissipating about 525 W. With the furnace installed, the heating element shall be positioned as shown in Figure 3. 4.6.4 Furnace control system The furnace control system shall be capable to hold the settings of voltage
31、 and current which is measured by the radiant heat output at the required level of (25 0,5) kW/m2 under steadystate conditions with the chamber door closed for at least 20 min. The control system shall consist of an AC solid state voltage or power controller and a voltmeter or other means for monito
32、ring the electrical input. It is recommended to use a digital voltmeter to monitor the furnace voltage output and a digital ampere-meter to monitor the furnace current. 4.6.5 Heat flux density gauge An air-cooled heat flux density gauge shall be provided for calibrating the output of the radiant hea
33、t furnace. The heat flux density gauge shall be a circular foil type. Compressed air at a pressure of 0,10 MPa to 0,21 MPa shall be provided to cool the heat flux density gauge. The body temperature of the heat flux density gauge shall be monitored with a thermometer having an accuracy of 1 C at 93
34、C in a 12,5 mm by 12,5 mm by 38 mm long brass or copper well drilled to accept the thermometer with a close fit. Silicone grease shall be used to provide good thermal contact. The circular receiving surface of the heat flux density gauge shall be spray-coated with an infrared-absorbing black paint.
35、A voltmeter or other device which has a resolution of 0,01 mV and an accuracy of 0,3 % is required to monitor the heat flux density gauge output. prEN 3475-601:20066 4.7 Pilot burner system 4.7.1 Pilot burner The pilot burner shall be a straight tip burner with six tubes, as shown in Figure 4. The s
36、ix tubes shall be fabricated from stainless steel tubing having an outer diameter of 3,2 mm and a inner diameter of (1,4 0,025) mm. The six tubes shall be attached to a common manifold, as shown in Figure 4 fabricated from stainless steel tubing having an outer diameter of 6,4 mm and a wall thicknes
37、s of 0,9 mm. One end of the manifold shall be closed, and the other end of the manifold be attached to a gas supply fitting in the chamber floor. All tubes of the pilot burner shall be directed perpendicular to the exposed surface of the specimen. 4.7.2 Pilot burner position The pilot burner shall b
38、e centred in front of and parallel to the specimen holder. The tips of the tubes shall be placed (6,4 1) mm above the lower opening of the specimen holder and (6,4 0,5) mm away from the face of the specimen surface, see Figure 4. A fixture to accurately position the pilot burner is recommended to es
39、tablish a precise pilot burner position for testing, and to facilitate accurate repositioning of pilot burner after removal and replacement. 4.7.3 Burner fuel The gas fuel for the pilot burner shall be prepared by mixing filtered oil-free air with 95 % minimum purity propane, and feeding the mixture
40、 to the pilot burner. Each gas shall be metered through separate, calibrated flowmeters and needle valves. The air-propane mixture shall consist of an air flow rate equivalent to (500 20) cm3/min (referred to 23 C and 1 013 hPa), and a propane flow rate equivalent to (50 3) cm3/min (referred to 23 C
41、 and 1 013 hPa). The compressed air supply shall be fed to its flowmeter at (0,14 0,03) MPa, and the propane at (0,10 0,02) MPa. A backflow valve or a flame arrester should be provided in the lines where air and propane are mixed. 4.7.4 Igniter System An igniter system is recommended to relight the
42、pilot burner flamlets to ensure that none of them extinguishes for more than 3 s during the test. If an electric sparking device is used, an appropriate method of supression and an equipment shielding must be applied to have no interference with ability of data acquisition equipment to accurately re
43、cord data. 4.8 Specimen holder 4.8.1 General The specimen holder shall consist of a stainless steel frame, a wire holder frame, a backing made of insulation millboard and a spring and retaining rod to secure the specimen in place. 4.8.2 Specimen holder frame The specimen holder frame shall be fabric
44、ated of stainless steel sheet by bending and brazing (or spot welding) stainless steel sheet of (0,60 0,05) mm nominal thickness to conform in shape and dimension to Figure 6. The frame shall be at least 51 mm deep, and shall provide an exposed specimen surface that is nominally (65 1,5) mm by (65 1
45、,5) mm. A trough to catch and retain dripping material shall be attached to the bottom front of the holder Guides to permit accurate centering of the exposed specimen area in front of the furnace opening shall be attached to the top and bottom of the holder frame. prEN 3475-601:2006 7 4.8.3 Wire hol
46、der frame Holder frame is used to support the specimens. Construction details of the frame are shown in Figures 7A and 7B. The frame is applicable for wires with an outer diameter up to 3,3 mm. 4.8.4 Specimen backing A piece of insulation millboard shall be used as a backing for the specimen and as
47、a simulated blank specimen. The millboard shall be (13 1) mm thick with a density of (800 160) kg/m3, or equivalent. Pieces shall be cut (74 1) mm by (74 1) mm to fit inside the specimen holder. 4.8.5 Retaining spring A spring from 76 mm by 75 mm by 0,25 mm thick stainless steel sheet, shown in Figu
48、re 6, shall be used with a stainless steel retaining rod to securely hold the specimen and millboard backing in position during testing. 4.9 Support for radiant heat furnace and specimen holder A typical support frame to support the radiant heat furnace and specimen holder is shown in Figure 9. This
49、 support frame shall have provision to establish accurate alignment for the furnace opening so that it is (38 1) mm away from, parallel to, and centered with the exposed specimen surface. Adjustment screws shall be provided to align the furnace with reference to the specimen. The framework shall have two 10 mm diameter transverse rods of stainless steel to accept the guides of the specimen holder. The rods shall support the holder so that the exposed specimen surface is parallel to the furnace opening. Spacing stops shall be mounted
