1、CEN PREN*K2825 95 3404589 0304957 705 H AECMA STANDARD NORME AECMA AECMA NORM prEN 2825 Edition P 1 January 1995 DITE PAR LASSOCIATION EUROPEENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1) 47.36.98.76 UDC : Descr
2、iptors : ENGLISH VERSION Aerospace series Burning behaviour of non metallic materials under the influence of radiating heat and flames Determination of smoke density Srie arospatiale Luft- und Raumfahrt Comportement au feu Brandverhalten des matriaux non mtalliques sous laction de chaleur rayonnante
3、 et de flammes Dtermination de la densit de fume nicht metallischer Werkstoffe unter Einwirkung von strahlender Wrme und Flammen Bestimmung der Rauchdichte This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Aros
4、patial). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an
5、extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft Europea
6、n Standard to CEN (European Committee for Standardization) for formal vote. Nota - Extra copies can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISSY-LES-MOULINEAUX CEDEX C7 Chairman I Comments should be sent within six months after the date of Dublication to I
7、Edition approved for publication 1 995-0 1 -3 1 AECMA Technopolis - 1 75, rue Jean-Jacques Rousseau 921 38 Issy-les-Moulineaux Cedex - FRANCE M. Bottrell I I - aecrna 199 CEN PREN*2825 95 m 3404589 0104958 641 m Page 3 prEN 2825 : 1995 1 Scope This standard defines a test method for determination of
8、 the smoke density due to pyrolitic decomposition of solid materials and composite materials of up to 25 mm in thickness under the influence of radiant heat only or with simultaneous flame application. The test results enable a comparison of the smoke production of different materials or material co
9、nfigurations under the conditions specified in this standard. NOTE : The smoke gas density is determined according to the specific environmental and test conditions defined in EN 2824 and this standard. No studies have been made up to now to determine whether the results can be transferred to differ
10、ing conditions, particularly to actual fire conditions. The burning behaviour - and consequently the smoke density - of aerospace materials are not only influenced by the type of material but also to a large extent by the configuration, the specific surface and mass, the combination with other mater
11、ials, the means of joining as well as the processing technique. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed here
12、after. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. IS0 3261 Fire tests - Vocabulary EN
13、 2824 Aerospace series - Burning behaviour of non metallic materials - Determination of smoke density and gas components in the smoke of materials under the influence of radiating heat and flames - Test equipment, apparatus and media 1) 3 Short description of the test method The specimens are vertic
14、ally arranged in a closed test chamber according to EN 2824 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 de
15、rived from a geometric factor and the measured light obscuration. 4 Definitions See IS0 3261 i 1) Published as AECMA Prestandard at the date of publication of this standard Previous page is blank - CEN PRENx2825 95 3404589 0304959 588 Page 4 prEN 2825 : 1995 5 Designation EXAMPLE : Identity block I
16、EN2825A Description block TEST I Number of this standard Code letter of test method (see below) I The letter code A indicates that the method is used to test a material in the Flaming mode only. The letter code B indicates that the method is used to test a material in both the Flaming mode and the N
17、orm-Flaming mode. 6 Test equipment Testing shall be carried out in a test chamber according to EN 2824. 7 Specimens 7.1 Number of specimens According to EN 2824. 7.2 Conditioning According to EN 2824. 7.3 According to EN 2824. Dimensions and shape of specimens 7.4 Specimen mounting According to EN 2
18、824. 8 Procedure 8.1 from the area of operation. When performing the test, precautions shall be taken to remove potentially hazardous gases 8.2 During the warm-up period, all electric systems (furnace, light source, photometer-readout) shall be switched on, the exhaust vent and chamber door shall be
19、 closed and the inlet vent be open. When the temperature on the centre surface of the back wall has reached a steady-state value of (35 f 2) OC, the chamber is ready for calibrating or testing. To increase the chamber wall surface temperature to the stated level, an auxiliary heater may be used, but
20、 shall be removed prior to performing tests. Conversely, to decrease this temperature, the exhaust blower may be used to introduce cooler air. The furnace shall be calibrated at periodic intervals. 8.3 A specimen holder with inserted calcium silicate sheet shall always be located directly in front o
21、f the furnace, except when it is replaced by the specimen holder during a test or the radiometer during calibration. It shall be returned immediately to this position when testing or calibration is completed to prevent excessive heating of the opposite wall surface. CEN PRENWZ825 95 3404589 0304960
22、2TT = Page 5 prEN 2825 : 1995 8.4 During the daily calibration, the radiometer shall be placed on the horizontal rods of the furnace support framework and accurately positioned in front of the furnace opening by displacing the “blank“ specimen holder against the prepositioned stop. With the chamber
23、door closed and the inlet vent opened, the compressed air supply to the radiometer cooler shall be adjusted to maintain the radiometer body temperature at (93 f 3) OC. After the system has reached steady-state the furnace transformer shall be adjusted to obtain - as per radiometer calibrating curve
24、- an output signal corresponding to an irradiance of (25,O f 0,5) kW/m2 averaged over the radiometer receiver area. After the prescribed irradiance level has reached steady- state, th,e radiometer shall be removed from the chamber and replaced by the “blank“ specimen holder. A suitable voltmeter or
25、recorder shall indicate the radiometer signal. The calibration of the radiometer has to be checked regulary because the characteristics may change by use. The whole system has to be verified finally by testing standardized samples or by comparative testing. 8.5 After the system has reached steady-st
26、ate (end of warm-up period), the amplifier sensitivity shall be adjusted to obtain a 100 % transmittance indication in the least sensitive measuring range with free light path. The “dark current“ reading shall be set to zero by compensating the dark current with the light beam blocked in the most se
27、nsitive measuring range of the photometer to O % transmittance. Prior to commencing the test the zero line of the recorder shall be adjusted accordingly. 8.6 For non-flaming exposures the burner shall be removed. For flaming exposures the burner shall be positioned in front of the lower edge of the
28、specimen, as described in clause 8.3 and figure 8 of EN 2824. The burner distances relative to the blank specimen holders shall be checked prior to testing. 8.7 Before accurately positioning the specimen in front of the furnace, the chamber shall be flushed for about 2 min with the door and exhaust
29、and inlet vents open. The wall temperature, measured with the back wall thermocouple according to EN 2824, shall be verified when starting the test (see 8.2). 8.8 The exhaust vent and blower shall be closed. The loaded specimen holder shall be placed on the bar support and pushed into position in fr
30、ont of the furnace by displacing the blank holder to the stop. The chamber door shall be closed quickly, starting simultaneously the recorder or plotter. The inlet vent shall only be completely closed when the photometer indicates the presence of smoke. 8.9 necessary full-scale range changes shall b
31、e made and noted in decade steps. The light transmittance and the corresponding time shall recorded as a continuous plot. The 8.9.1 The percentage error of a reading becomes progressively worse at the lower portion of the scale. Avoid light transmittance measurement on scale readings less than 10 by
32、 making the appropriate decade range change. 8.10 The increase in chamber pressure shall be observed using the manometer described in EN 2824. If negative pressure develops after very intense burning of specimen, the inlet vent shall be slightly opened for pressure equalization. During the test, the
33、 gas flow of the burner shall be kept constant. 8.1 1 Unless otherwise specified, the test duration shall be 6 min. 8.12 If transmittance falls below 0,Ol %, the chamber window shall be covered with an opaque screen to avoid possible light-scattering effects from room light. The ND-2 filter in the p
34、hotometric system according to EN 2824, figure 5, shall be removed from the light path to extend the measuring range. The filter shall be replaced before exhausting smoke from the chamber. , CEN PREN*ii2825 95 W 3404589 0304963 336 Page 6 prEN 2825 : 1995 8.13 Within 1 min after termination of the t
35、est, the specimen shall be displaced from the front of the furnace by pushing the blank specimen holder with the positioning rod and exhausting of the chamber be started. Continue to exhaust with the inlet vent open until maximum transmittance is reached. This transmittance value shall be recorded.
36、9 Calculation of test results The specific optical density Ds shall be calculated to the following formula : t where : D, Tt G is the specific optical density ; is the percent light transmission at the time, in minutes ; is a geometric factor (see below). 91,4 cm x 91,4 crn x 61 cm 6,5 cm x 6,5 cm x
37、 91,4 crn here : G = = 132 v A.L G=- where : V A L The arithmetic mean for the smoke density Ds shall be calculated in each case from the individual values measured. For very high D, values the ND-2 filter shall be removed and then a correction factor shall be added to the calculation. is the chambe
38、r volume in cubiccentimetres ; is the exposed specimen surface area, in squarecentimetres ; is the light path length, in centimetres. 10 Test report The test report ( see annex A) shall include the following : 1 O. 1 Complete description of the specimen material and the specimen construction (materi
39、al designation, manufacturers identification, manufacturer/supplier, manufacturing batch number, order number, construction, specimen thickness, density etc.). 10.2 Period and conditions of specimen conditioning. 10.3 Test conditions (with or without flame application). 10.4 Number of tests performe
40、d. 10.5 Tabulation of individual results after 1 min, 1,5 min and 2 min and in 1 min intervals (up to 6 min). 10.6 Observations concerning smoke generation, such as colour of the smoke, nature of soot deposits, etc. 10.7 Date of testing. 10.8 Signature. CEN PREN*i!25 75 3404587 OL09762 072 Page 7 pr
41、EN 2825 : 1995 Annex A (normative) Example for a test report on the determination of smoke density Material . Material standard Technical specification Semi-finished product standard . Trade-mark of the product . Name and address of manufacturer Name and address of supplier . Purchaser . Order no De
42、livery bill no . Date of manufacture . Manufacturing batch no . Test report n O . of test laboratory 1) . Specimen construction : Specimen conditioning : 1 ) Only to be filled in if the tests are carried out in the manufacturers laboratory. - - CEN PREN*Z825 95 3404589 0304963 TO9 = Page 8 prEN 2825
43、 : 1995 I Table A.l Testing without flame application Ds after t in min Specified value as per material standard Specimen NO Mean value Specified value as per material standard Observations during testing : Notes : (Place and date) Testing with flame application (Signature of the inspector) (Stamp of the company and division)
