1、BRITISH STANDARD BS3900-A11: 1974 Combustibility Methods of test for paints Part A11: Small scale test for combustibility It is recommended that this Part be read in conjunction with the general information in the introduction to BS 3900 issued separately (revised edition published March 1969). UDC
2、667.61+667.612:536.468BS3900-A11:1974 BSI03-1999 ISBN 0 580 08057 9 Foreword This standard method was developed to meet a requirement to which special attention was drawn at the public enquiry prior to the issue of the Highly Flammable Liquids and Liquefied Petroleum Gases Regulations1972(SI917:1972
3、). The requirement is applicable to products which give a flashpoint within the terms of the regulations and differentiates between those which are combustible and those which are not. The method is technically identical with that in Schedule2of the above regulations, in which its application is not
4、 restricted to paint, varnish or to related products. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal
5、obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi and ii, pages1to3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover
6、. Amendments issued since publication Amd. No. Date CommentsBS3900-A11:1974 BSI 03-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Sampling 1 5 Procedure 1 6 Interpretation of observations 2 7 Test report 2 Figure 1 Combustibility tester 3 Table 1 Details of
7、combustibility tester 2 Table 2 Thermometer specification 2ii blankBS3900-A11:1974 BSI 03-1999 1 1 Scope This Part describes a go/no go procedure for use in the paint and allied industries to determine whether a product is combustible,i.e.has the ability to support combustion 1)within the meaning of
8、 the Highly Flammable Liquids and Liquefied Petroleum Gases Regulations. The method does not in any way apply to painted surfaces and their potential fire hazards. 2 Principle A block of aluminium alloy or a suitable corrosion-resisting metal block of high thermal conductivity with a concave depress
9、ion (called the well) is heated to the required temperature. A standard source of flame capable of being swivelled over the centre of the well and at a given distance from it is attached to the metal block.2ml of the product under test are transferred to the well and its ability to support combustio
10、n is noted after application of a flame under standard conditions. 3 Apparatus The following are required: 1) Combustibility tester, consisting of an aluminium alloy or a suitable corrosion-resisting metal block of high thermal conductivity, having a concave depression or well. The metal block has a
11、 thermometer embedded in it. A small gas jet on a swivel is attached to the metal block. The dimensions of the tester shall be as given inTable 1and shown in Figure 1. 2) Gauge for checking the height of the gas jet above the top of the well. 3) Thermometer conforming to the dimensions and tolerance
12、s given in Table 2. 4) Hotplate fitted with a temperature controlling device. Other controlled methods of heating the metal block may be employed. 5) Stop watch or other suitable timing device. 6) Hypodermic syringe, complying with the requirements of BS1619 2) , capable of delivering2ml to an accur
13、acy of 0.1ml. 7) Fuel source for the gas jet, normally butane fuel, but coal gas or natural gas are satisfactory alternatives. 4 Sampling 4.1 A representative sample of the product under test shall be obtained and prepared by the methods described in BS 3900-A1 3)and BS 3900-A2 4) . The sample shall
14、 be supplied and stored in an air-tight container. 4.2 Because of the possibility of loss of volatile constituents, the sample shall receive only the minimum of treatment to ensure homogeneity. After removing the test portion, the sample container shall be immediately closed tightly to ensure that n
15、o volatile flammable components escape from the container; in the event of this happening, an entirely new sample shall be taken. 5 Procedure 5.1 Set up the apparatus in a completely draught-free area (see precautionary note), and in the absence of a strong light (to facilitate observation of the fl
16、ash, flame,etc.). Precautionary note. The test should not be carried out in a small confined area,e.g.a glove box, because of the potential explosive hazard. 5.2 Place the metal block on the hotplate fitted with a temperature controlling device or heat the metal block by other suitable means, so tha
17、t its temperature as indicated by the thermometer embedded in the metal block is maintained at50(+0.5,0)C. Correct this temperature for the difference of barometric pressure from the standard atmospheric pressure101.3kPa 5)by raising the test temperature for a higher pressure or lowering the test te
18、mperature for a lower pressure at the rate of1C for each4kPa difference. Ensure that the top of the metal block is exactly level. Use the gauge to check that the jet is2.2mm above the top of the well when in the test position. 5.3 Light the test flame with the jet in the “off” position away from the
19、 well. Adjust the size of the flame so that it is spherical and3.5 0.5mm in diameter. NOTEThe size of the flame in plan view is conveniently matched to a4mm diameter circle engraved on the surface of the combustibility tester (indicated in Figure 1as “flame gauge ring”). 5.4 Using the hypodermic syr
20、inge, withdraw from the sample container at least2ml of the test material and transfer2 0.1ml of it to the well of the combustibility tester. 5.5 Immediately start the timing device. 1) BS 4422 “Glossary of terms associated with fire”, Part 1 “The phenomena of fire”. 2) BS 1619 “Hypodermic syringes
21、for insulin injection (Luer fitting)”. 3) BS 3900-A1 “Sampling”. 4) BS 3900-A2 “Examination and preparation of samples for testing”. 5) 1kPa=10mbar.BS3900-A11:1974 2 BSI 03-1999 5.6 After exactly1min, by which time the test portion is deemed to have reached the test temperature, swing the test flame
22、 into a position exactly central over the well. Hold it in this position for exactly15s and then return it to the “off” position while observing the behaviour of the sample under test. 6 Interpretation of observations 6.1 In carrying out the procedure one of the following phenomena may be observed:
23、1) a flash may be seen; 2) the product may ignite and burn vigorously or only weakly when the flame is over the combustibility tester and cease to burn when the flame is removed to the “off” position; 3) the product may not support combustion when the flame is positioned over it; 4) the vapour given
24、 off by the product may put out the test flame. 6.2 For the purposes of this method, the product is deemed to support combustion if, when tested in the manner described, in 5.1 to 5.6,one of the following occurs. 1) After the flame has been over the well, the product ignites and combustion is sustai
25、ned for more than15s when the flame is removed. 2) When the flame is in the “off” position, the product flashes and burns. NOTENormally, at the end of15s, the combustion has either clearly ceased or clearly continues; in cases of doubt, the product should be deemed to support combustion. 7 Test repo
26、rt The test report shall include the following information: 1) A reference to this British Standard. 2) Type and identification of the product under test. 3) Corrected test temperature in degrees Celsius and barometric pressure in kilopascals. 4) Statement that the product does or does not support c
27、ombustion according to the interpretation given in1) or2) of 6.2. 5) Date of test. Table 1 Details of combustibility tester Table 2 Thermometer specification NOTEWhen in position in the block, the thermometer bulb should be surrounded with thermal conducting thermoplastic compound. (Dow Corning340He
28、at Sink Compound supplied by Dow Chemical Co. has been found suitable.) Sample block details Dimensions in millimetres Diameter of block 61.5to62.5 Height of block 35.0to38.0 Diameter of flange 94.5to95.5 Flange thickness 3.0approx. Height of well “lip” above flange 0.6to1.0 Diameter of well “lip” 4
29、1.0approx. Spherical radius of well 33.0to33.5 Depth of Well 6.2to6.4 Distance from top of block to thermometer hole 16.0to17.0 Thermometer hole diameter 7.0approx. Test gas jet details Outside diameter of jet 3.0to4.0 Jet end tapered to 1.7to2.3 Bore of jet 0.6to0.8 Length of jet (from centre of ax
30、is to tip) 36.00to36.25 Distance of axis from centre of well 38.00to38.25 Flame gauge ring diameter 4.0 “Swing” of jet (from stop to stop) 90 1 Height of jet above top of well “lip” 2.2 Type: Mercury in glass, nitrogen filled for horizontal operation Range 0 C to110C Graduation small divisions at ea
31、ch 1 C long lines at each 10C numbered at each 10C Top finish Plain Scale error not to exceed 0.5C Total length 2005mm Stem diameter 6.5 0.5mm Bulb diameter 4.51mm Bulb length 122mm Length of graduated portion 125 10mm Distance, bottom of bulb to0C mark 502mm Bulb shape ElongatedBS3900-A11:1974 BSI
32、03-1999 3 Figure 1 Combustibility testerBSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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