1、CEN PREN*K2824 95 340Y589 0304943i 348 Edition approved for publication Comments should be sent within six months after the date of publication to AECMA Technopolis - 175, rue Jean-Jacques Rousseau 921 38 Issy-les-Moulineaux Cedex - FRANCE 1 995-0 1 -3 1 AECMA STANDARD prEN 2824 NORME AECMA Edition
2、P 1 AECMA NORM January 1995 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1) 47.36.98.76 UDC : C7 Chairman M. Bottieli Descriptors : ENGLISH VERSION Aerospace series Burning behaviour of
3、non metallic materials under the influence of radiating heat and flames Determination of smoke density and gas components in the smoke of materials Test equipment, apparatus and media Srie arospatiale Luft- und Raumfahrt Comportement au feu Brandverhalten des matriaux non mtalliques sous laction de
4、chaleur rayonnante et de flammes Dtermination de la densit de fume et des composants des gaz de fume des matriaux quipement, appareils et moyens dessai nicht metallischer Werkstoffe unter Einwirkung von strahlender Wrme und Flammen Bestimmung der Rauchdichte und der Rauchgaskomponenten von Werkstoff
5、en Prfeinnchtung, Prfgerte und Prfmittel This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial). It is published on green paper for the needs of AECMA-Members. It has been technically approved by the exp
6、erts 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 extent that interchangeability is affected, physically or functionally, without re-identification of the standard.
7、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 European Standard to CEN (European Committee for Standardization) for formal vote. aecma 199 - Copyright Association Europ
8、eene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEN PREN*2824 95 3404589 0304942 284 Page 3 prEN 2824 : 1995 1 Scope This standard defines the test equipment, apparatus and media
9、 required for determination of the smoke density according to EN 2825 and the concentration of the gas components in the smoke according to EN 2826 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 s
10、imultaneous flame application. This test method applies exclusively to materials whose specific standard requires this type of test. It cannot be substituted for the statutory tests required for a final specific use of the material concerned. NOTE : The smoke gas density and the gas components in th
11、e smoke are determined according to the specific environmental and test conditions defined in this standard, in EN 2825 and EN 2826. No studies have been made up to now to determine whether the results can be transferred to differing conditions, particularly to actual fire conditions. The inhalatory
12、 toxical risk and irritancy affect cannot be assessed by merely measuring the concentration of individual gas components in the smoke. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at
13、the appropriate places in the text and the publications are listed hereafter. 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 t
14、he publication referred to applies. IS0 2768-1 General tolerances - Part 1 : Tolerances for linear and angular dimensions without individual tolerance indications IS0 2768-2 General tolerances - Part 2 : Geometrical tolerances for features without individual tolerance indications EN 2743 Aerospace s
15、eries - Reinforced plastics - Standard procedures for conditioning prior to testing 1) EN 2825 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 - Determination
16、 of smoke density 1) EN 2826 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 - Determination of gas components in the smoke 1) 3 Apparatus The test equipment
17、comprises the test chamber described in 3.1, incorporating the devices specified in 3.2 to 3.8, as well as the ancillary equipment as detailed in 3.9 to 3.16. 1) Published as AECMA Prestandard at the date of publication of this standard Previous page is blank Copyright Association Europeene des Cons
18、tructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEN PRENr2824 95 m 3404589 0304943 330 m Page 4 prEN 2824 : 1995 3.1 Test chamber See figure 1. The test chamber shall be designed to provide i
19、nside dimensions of (914 x 610 x 914) mm I3 mm for width, depth, and height respectively. The interior surfaces shall consist of porcelain-enamelled metal or equivalent coated metal resistant to chemical attack and corrosion, and suitable for cleaning. Panels of 1 O mm thickness of porcelain-enamell
20、ed steel (interior surface laminated to a heat-resistant core and backed with corrosion-resistant steel (exterior surface) have been found suitable. Sealed windows shall be provided to accomodate a vertical photometric system. All other chamber penetrations shall also be sealed. When all openings ar
21、e closed, the chamber shall be capable of developing and maintaining positive pressure during the test period. In order 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 than 0,04 mm
22、and a minimum area of 800 cm2 shall be provided in an opening of the chamber floor. 3.2 Radiant heat furnace See figure 2. The furnace shall be located according to figure 3 equidistant from the front and back of lhe test chamber. The furnace control system shall maintain the required irradiance lev
23、el of (25,O f 0,5) kW/m2 on the specimen surface for 20 min under steady-state conditions with the chamber door closed (to be demonstrated in calibration). The control system shall consist of a variable transformer or an equivalent control device, and a voltmeter or other means for monitoring the el
24、ectrical input. Where line voltage fluctuations exceed f 2,5 %, a constant-voltage transformer is required to maintain the prescribed irradiance level. 3.3 Specimen holder Stops have to be provided to center the specimen accurately in front of the furnace. Figure 4 shows the construction of the hold
25、er. Two wires have to be placed in front of the specimen. 3.4 Photometric system The photometric system shall conform to figure 5. The light path shall be oriented vertically to reduce influences resulting from stratification of the smoke generated by materials under test. The system shall conform t
26、o 3.4.1 to 3.4.3. 3.4.1 The light source shall be a 6 V incandescent lamp, operated at a fixed voltage to provide a brightness temperature of (2200 f 100) K. The light source shall be located in a sealed and light-tight box. This box shall contain the necessary optics to provide a collimated light b
27、eam of about 50 mm diameter passing vertically through the chamber. 3.4.2 A photomultiplier with a spectral sensitivity rating of S-4 and a dark current of less than A shall be used. For amplification, a multirange amplifier shall be used, suitable to measure continuously the relative light intensit
28、y in percentage transmission over at least five orders of magnitude. The system shall have a linear response with respect to transmittance and an accuracy of f 3 % of the maximum reading on any range. A set of nine gelatin compensating filters varying from 0,l to 0,9 neutral density is mounted in a
29、number of one or more as required in the optical measuring system to provide for correction of light source or photomultiplier aging and reduction in light transmission through discoloured or abraded optical windows. A light-tight box located directly opposite the light source shall be provided to m
30、ount the photodetector housing and the associated optics. A glass window shall be used to isolate the photodetector and its optics from the chamber atmosphere. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IHS under license with AECMANot for ResaleNo reproduct
31、ion or networking permitted without license from IHS-,-,-CEN PRENs2824 75 m 3404587 0304944 057 m Page 5 prEN 2824 : 1995 3.4.3 In addition to the compensating filter as per 3.4.2, a neutral density filter ND-2 (grey filter) for extending the measuring range up to the optical density 6 is incorporat
32、ed in the smoke density chamber. Where values of smoke density D, 500 are measured, it may be necessary to provide a chamber window cover to prevent room light from being scattered into the photomultiplier and thus an incorrect higher transmission value. 3.5 Radiometer The radiometer according to fi
33、gure 6 for standardizing the output of the radiant heat furnace shall be of the circular foil type 1). It shall have a stainless steel reflective heat shield with an aperture of about 38 mm on the front and a finned cooler mounted on the rear, to which compressed air is supplied in order to maintain
34、 a constant radiometer body temperature of (93 f 3) OC. The radiometer shall be connected directly to a recorder suitable for recording an irradiance signal of 25,O kW/m2 to an accuracy of 0.5 kW/m2. 3.6 Thermocouple A thermocouple shall be fixed to the centre of the inner surface of the chamber wal
35、l opposite the door. 3.7 A U-tube manometer with a range up to 1490 Pa water column shall be provided according to figure 7 in order to monitor chamber pressure and leakage. The pressure measurement point shall be mounted through a 25 mm diameter vent in the chamber. Manometer for chamber pressure m
36、easurements 3.8 Burner A six-tube burner as shown in figure 8 shall be used for the flaming exposure test. The burner shall be centered in front of and parallel to the specimen holder. The orifices of the two horizontal tubes shall be centered at (6,4 f 1,5) mm above the lower opening of the specime
37、n holder and at a distance of (6,4 I 1,5) mm from the face of the specimen surface. Provision shall be made to move the burner out of the above-described position during non-flaming exposures. The fuel used shall be propane with a purity of not less than 95 %. Filtered oil-free air and propane shall
38、 be fed through calibrated flowmeters and needle valves at (500 k 20) cm3/min for air and (50 f 3) cm3/min for propane and premixed prior to the entry into the burner (related to 23 OC and 0,l MPa). NOTE : The flowmeters shall be calibrated at regular frequency. The burner is properly adjusted if th
39、e blue flame cone of the horizontal flames is approx. 6 mm long. 3.9 Gas-sampling probes The gas sampling is carried out by means of three probes of about 5 mm inside diameter (see figure 9) reaching into the geometrical center of the chamber. The distance between the three probes shall not exceed 1
40、2 mm. These probes shall be connected to the gas-sampling supply lines by means of tube connectors provided at the top side of the test chamber. Lines not in use have to be shut. For direct measurement in the chamber, a rubber sleeve shall be provided to hold colorimetric test tubes on one of the po
41、lypropylene probes inside the chamber. 1) The operation is described by : Gardon R, “An instrument for the measurement of Intense Thermal Radiation“, Review of Scientific Instruments, Vol. 24, 1953, pp. 366-370. Copyright Association Europeene des Constructeurs de Materiel Aerospatial Provided by IH
42、S under license with AECMANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEN PREN82824 95 M 3404589 0304945 T93 M I Page 6 prEN 2824 : 1995 3.10 The sampling bags shall consist of a plastic film having a high chemical and mechanical resistance. The minimum volume
43、shall be 10 dm3. The gas-sampling bags have to be constructed for minimal gas diffusion and water vapour transmissibility so that the gas composition changes by diffusion are negligible. Plastic bags for gas sampling 3.1 1 Vacuum chamber Gas sampling shall be made in such a manner that the compositi
44、on of the combustion gases will not be changed. A change in the gas composition may occur for instance when using unsuitable installation causing a loss of gas due to leakages or a condensation of the gases. A vacuum chamber, for example, is suitable for sampling. The filling of the bag is effected
45、by the differential pressure between the vacuum chamber and the test chamber. After termination of the gas analysis, the bag is evacuated. A typical sampling arrangement is shown in figure 9. The vacuum chamber is provided with two shut-off valves and and a transparent acrylic cover. The chamber is
46、connected to the vacuum pump through a shut-off valve 0. The venting of the chamber is performed after filling of the sampling bags through a second shut-off valve 0. Evacuation pressure can be controlled by means of a vacuometer. The transparent cover is provided with a fixable coupling 6) for conn
47、ection of the sampling bag. This is connected to the test chamber by a polypropylene tube with shut-off valve 0. The venting of the tube prior to gas sampling is effected through a bypass provided on the tube close to the transparent cover, through a shut-off valve and a coupling . 3.12 Vacuum pump
48、A vacuum pump shall be used which permits evacuation of the vacuum chamber according to 3.1 1 to 100 kPa within 60 s. 3.13 Alternative gas-sampling methods Alternatively to the method of filling the gas-sampling bags described in 3.1 1, other methods, e. g. filling of gas-sampling bags by a suitable
49、 pump, might be appropriate. 3.14 Colorimetric tubes The concentration of individual gas components in the smoke is normally determined using colorimetric tubes. 3.1 5 Dosing pump Dosing pumps shall be used for measuring the gases with coiometric tubes with a feed rate of (100 f 3) cm3 of gas per stroke. 3.16 if gas components cannot be satisfactorily determined by means of colorimetric tubes, a wet analysis shall be performed. The following ancillary equipment is requi
