1、BRITISH STANDARD BS 4790:1987 Incorporating Amendment Nos. 1 and 2 Method for Determination of the effects of a small source of ignition on textile floor coverings (hotmetal nut method) UDC 645.13:536.468BS4790:1987 This British Standard, having been prepared under the directionof the Textile and Cl
2、othing Standards Committee,was published underthe authority of the BoardofBSI and comes intoeffecton 30 April 1987 BSI 04-1999 First published November 1972 First revision April 1987 The following BSI references relate to the work on this standard: Committee reference TCM/30 Draft for comment 85/361
3、87 DC ISBN 0 580 15720 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Textiles and Clothing Standards Committee (TCM/-) to Technical Committee TCM/30 upon which the following bodies were represented: The following bodies were also rep
4、resented in the drafting of the standard, through subcommittees and panels: Association of Consulting Scientists Department of Trade and Industry Association of Heavy Textile Proofers of (Consumer Safety Unit, CA Division) Great Britain Department of Trade the presence of this air will tend to assis
5、t combustion which can lead to the occurrence of a falsely high radius of char. 8.3 Method 2: fully-adhered Stick down the test specimen on the substrate using the type and quantity of adhesive recommended by the carpet manufacturer and applied in accordance with the instructions supplied with the a
6、dhesive. 8.4 Method 3: loose-laid with underlay Place the test specimen in the loose-laid condition with an appropriate underlay interposed between the specimen and the substrate, establishing that air is not present between the specimen and underlay and underlay and substrate, as described in 8.2.
7、NOTEIt is essential that the underlay specified in the contract is used in the test. 9 Test procedure 9.1 Testing atmosphere Conduct the test in the standard temperate atmosphere for testing textiles (see clause 5) or within 2 min of removal of the test specimen from the atmosphere. 9.2 Application
8、of nut Heat the nut (4.1) to a temperature of 900 20 C in the muffle furnace (4.4). NOTEIt is not always sufficient to assume the oven is at the indicated temperature and periodically a check of the temperature of the nut should be carried out. Mount the specimen, use-surface uppermost, on the floor
9、 of the test chamber as described in 8.2, 8.3 or 8.4 and lay the clamping ring horizontally on top so that it lies completely within the bounds of the specimen. Using the crucible tongs (4.7) place the heated nut onto the specimen within 3 s of its removal from the furnace. Ensure that the nut is pl
10、aced centrally within the clamping ring and immediately close the sliding panel. Open the sliding panel and remove the nut from the specimen after it has been in contact with the specimen for 30 2 s, and then immediately close the sliding panel once more. Keep it closed until all effects of ignition
11、 have ceased. After the measurements (see 9.3) on that specimen, repeat the test and measurements on the remaining specimens. 9.3 Measurements 9.3.1 If the specimen ignites and the effects of ignition do not reach the clamping ring, note the following by use of the stop-watch (4.6): a) the elapsed t
12、ime in seconds from the instant of application of the nut to the extinction of the flame; b) the time in seconds of any afterglow and/or smouldering subsequent to removal of the nut and to extinction of any flame. 9.3.2 Where the effects of ignition reach the clamping ring, note the time in seconds
13、to reach the ring from the instant of application of the nut. 9.3.3 Before removing the clamping ring, and by using the transparent grid (4.3), measure and record the radius of the circle that just contains the affected area on the use-surface. In making the measurement, ensure that the centre of th
14、e rings of the grid coincides with the central point of application of the nut. 9.3.4 Measure and record the radius of the effects of ignition on the under-surface of the floor covering if observable, using the procedure described in 9.3.3. 9.3.5 If the specimen does not ignite, this shall be noted.
15、 10 Calculation and expression of results For each of the three test specimens state the times to the nearest second for the items referred to in9.3.1 or 9.3.2, and the greatest radius to the nearest 5mm of the affected areas measured as described in 9.3.3 and 9.3.4.BS4790:1987 BSI 04-1999 3 11 Test
16、 report The test report shall include the following. a) The statement “The test results relate only to the behaviour of the test specimens after application of a small source of ignition; they shall not be used as a means of assessing how the product will contribute to an established fire”. b) A sta
17、tement that the test procedure was conducted in accordance with this British Standard, i.e. BS 4790:1987. c) Where appropriate, for each specimen the time in seconds for the extinction of the flame and of afterglow and/or smouldering, measured as described in 9.3.1. d) Where appropriate, for each sp
18、ecimen the time in seconds for the effects of ignition to reach the clamping ring, measured as described in 9.3.2. e) The greatest radius to the nearest 5mm of the affected area, measured as described in 9.3.3. NOTEThe radii of the other two tests may also be recorded. f) Where possible, the greates
19、t radius to the nearest 5mm of the affected area, measured as described in 9.3.4. If the under-surface is not observable the reason for this shall be stated. NOTEThe radii of the other two tests may also be recorded. g) The words “Did not ignite”, if the specimen did not ignite (see 9.3.5). h) If us
20、ed, the type and quantity of adhesive (8.3). i) If used, a full description of the underlay (8.4). j) The method of mounting test specimens, i.e.method 1, 2 or 3 (see clause 8). NOTEAny reference to the method of test described in this standard should include the appropriate method of mounting test
21、specimens as given in clause 8.BS4790:1987 4 BSI 04-1999 Appendix A Test chamber The test chamber is illustrated in Figure 1 and consists of an open-top box made of 6mm thick non-combustible heat resistant board to give inside dimensions of 380mm 380mm 380mm. The flat bottom of the box shall be made
22、 of the same type of material and shall be easily removable. The sides are fastened together with screws or brackets and a mirror is mounted at 45 above the box to permit observation of the test specimens. The front panel is divided, the lower panel being fixed, and the upper panel sliding and count
23、er-weighted for easy access and convenience. The box shall be situated in a draught-free room or fume cupboard when the tests are being conducted. Figure 1 Test chamberBS4790:1987 BSI 04-1999 Publications referred to BS 1051, Glossary of terms relating to the conditioning, testing and mass determina
24、tion of textiles. BS 3692, ISO metric precision hexagon bolts, screws and nuts. BS 4569, Method of test for ignitability (surface flash) of pile fabrics and assemblies having pile on the surface 1) . BS 4664, Methods of sampling and cutting specimens for physical tests on textile floor coverings. BS
25、 5287, Assessment and labelling of textile floor coverings tested to BS 4790 1) . BS 6105, Specification for corrosion-resistant stainless steel fasteners. BS 6307, Method for determination of the effects of a small source of ignition on textile floor coverings (methenamine tablet test) 1) . BS 6373, Glossary of terms relating to burning behaviour of textiles and textile products. 1) Referred to in the foreword only.
