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1、BRITISH STANDARD BS 490-11.2: 1991 Conveyor and elevator belting Part 11: Methods of test for safety Section 11.2 Low energy and high energy propane gallery tests Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 This British
2、Standard, having been prepared under the direction of the Plastics and Rubber Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 28 February 1991 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference
3、PRM/67 Draft for comment 89/46839 DC ISBN 0 580 19383 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical Committee PRM/67, upon which the following bodies were represente
4、d: British Coal Corporation British Rubber Manufacturers Association British Steel plc Chief and Assistant Chief Fire Officers Association Electricity Supply Industry in United Kingdom Engineering Equipment and Materials Users Association Health and Safety Executive Loughborough University of Techno
5、logy Malaysian Rubber Producers Research Association Man-made Fibres Producers Committee Mechanical Handling Engineers Association Plastics and Rubber Institute Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Un
6、controlled Copy, (c) BSI BS 490-11.2:1991 BSI 10-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Apparatus1 3Method A. Low energy test1 4Method B. High energy test2 5Termination of tests4 6Measurement of damage to test pieces5 7Calculation and expression of results7
7、8Test report7 Figure 1 Propane burner trestle showing positions of burner and test piece3 Figure 2 Burner4 Figure 3 Arrangement of 25 thermocouples in vertical plane5 Figure 4 Location of thermocouple for measuring the temperature of incoming air and indication of length of gallery6 Figure 5 Measure
8、ment of length of undamaged belting7 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 ii BSI 10-1999 Foreword This Section of BS 490 has been prepared under the direction of the Plast
9、ics and Rubber Standards Policy Committee. The methods are intended to provide a realistic indication of the reaction of a conveyor belt to a fire. However, in assessing the overall flammability characteristics of conveyor belting for specific installations, it is not sufficient to rely solely on th
10、is or any other single method of test. It is essential that consideration be given to the individual site location, and reference should be made to DD 180 “Guide to the assessment of toxic hazards in fire in buildings and transport” and to ISO/TR 3814 “The development of tests for measuring “reactio
11、n to fire” of building materials”. Attention is drawn to the Health and Safety at Work etc. Act 1974, and the need to ensure that the methods of test specified in this standard are carried out under suitable environmental conditions to provide adequate protection to personnel against the risk of fir
12、e and inhalation of smoke and/or toxic products of combustion. 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 fr
13、om legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendm
14、ent table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 BSI 10-19991 1 Scope This Section of BS 490 describes two methods, using different levels of heat energy, for measuring the effect on a con
15、veyor belt of being subjected to a simulated fire. Method A is a short duration, low energy test. Method B is a longer duration, high energy test. The damage suffered by the conveyor belt is measured as well as its tendency to support combustion. NOTEThe titles of the publications referred to in thi
16、s standard are listed on the inside back cover. 2 Apparatus 2.1 Gallery, of square section 2 m 2 m, through which air is drawn by a fan. The gallery shall have a concrete floor and shall be not less than 16.0 m long measured from the gallery entrance. 2.2 Trestles (see Figure 1), each consisting of
17、a framework 2.2 m long 1.25 m wide and constructed of steel tubing complying with BS 1387, having a bore designation of DN 15 heavy series. The upper sides of the trestle frame are fitted with rod retainers in order to position and retain 15 steel bars manufactured from an austenitic chrome/nickel s
18、teel of an appropriate quality, such as 302S31 complying with BS 970-1 and resistant to rust, acid and heat. The bars are 10 mm diameter 1.4 m long and form the frame on which the belting rests. The upper surface of the bars is 350 mm from the floor. NOTEOne trestle is required for method A and two
19、for method B. 2.3 Burner, constructed in accordance with Figure 2 and consisting of a 450 9 mm square having an overall height of 220 5 mm. The burner is made of welded steel tubing complying with BS 1387 having a bore designation DN 15 heavy series. The tubing shall have 52 holes, each 1.5 0.1 mm i
20、n diameter, at 50 mm intervals. 2.4 Bottled propane gas, complying with BS 4250-1, which is fed to the burner through a pressure reducing valve, a non-return valve and an orifice plate 1.7 mm thick and with a 2.5 mm diameter hole, using high pressure hose complying with type 2 of BS 3212 having a mi
21、nimum internal diameter of 6.3 mm. Before and during the test, the gas cylinder shall be immersed to approximately two-thirds of its height in a bath of water at a temperature of 25 3 C. Ensure that the gas cylinder is not emptied at the end of a test by more than 90 % of its gas weight capacity. NO
22、TEThe rate of gas consumption may be regulated by controlling the gas pressure at the high pressure side of the orifice plate to approximately 0.20 MPa for the high energy test and 0.16 MPa for the low energy test. The pressure reducing valve, the non-return valve and the orifice plate should be pos
23、itioned as close to each other as possible. A sensitive precision pressure gauge should be used to monitor the pressure at the high pressure side of the orifice plate. Alternatively the orifice plate and sensitive pressure gauge may be replaced by a flowmeter, calibrated to ensure that the correct w
24、eight of gas is consumed, inserted into the gas supply line after the non-return valve. 2.5 Flowmeter, or other means of measuring the air velocity in the gallery (see 2.1). 2.6 Nickel-chromium/nickel-aluminium thermocouples (required for method B only), mineral insulated, stainless steel sheathed,
25、having a nominal outside diameter of 2 mm, complying with BS 4937-41) (see clause 4.2). Thermocouples shall be located at the 25 points illustrated in Figure 3, in a vertical plane normal to the longitudinal axis of the gallery and 6 m behind the leading edge of the test piece. A further thermocoupl
26、e, shall be placed 300 mm from the entrance to the gallery in the position shown in Figure 4, to measure the temperature of the incoming air. It shall be shielded from any local heat sources. 2.7 Weighing instrument (required for method B only), of capacity not less than 120 kg, graduated in 0.5 kg
27、intervals, to weigh the belting samples. 3 Method A. Low energy test 3.1 Preparation of test pieces Cut two test pieces, if the conveyor belt covers are of equal thickness or three test pieces if the conveyor belt covers are of unequal thickness. Test pieces shall be 2 m long 900 mm wide or of full
28、width if the conveyor belt is less than 900 mm wide. Lay the test pieces out for 24 h in dry conditions at any ambient temperature above 0 C immediately prior to testing to remove residual curvature. 3.2 Temperature at commencement of test The ambient temperature at the commencement of the test shal
29、l be between 0 C and 30 C. 3.3 Number of tests For belting with top and bottom covers that are identical, test two test pieces with the top cover uppermost. For belting with top and bottom covers that are of unequal thickness, conduct three tests as follows: a) test one test piece with the top cover
30、 uppermost; b) test one test piece with the top cover face downwards; 1) BS 4937-4 implements CENELEC HD 446.1. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 2 BSI 10-1999 c) test the third test piece in accordance with it
31、em a) or with item b) depending on which test gave the worse results. NOTEThis procedure is necessary to ensure that the required minimum of two samples are tested in identical conditions. 3.4 Procedure WARNING. The tests described in this Section of BS 490 can generate large amounts of smoke and he
32、at. It is therefore essential to conduct the tests with caution, having due regard to health and safety considerations and to terminate any test immediately if at any time it is considered advisable to do so. In this regard it is recommended that no test should be supervised by only one person. Inst
33、all a trestle centrally on the longitudinal axis of the gallery with the burner end facing the direction of the ventilation flow. The burner end of the trestle shall be 8 m from the gallery entrance. Place each test piece in turn centrally on the trestle with its transverse edge flush with the burne
34、r end of the trestle. Adjust the air current in the gallery to give an average velocity of 1.5 0.1 m/s at a height of 350 mm. Take the measurement on the centreline of the trestle and at a distance of 750 mm from the end of the trestle nearest the gallery entrance (see Figure 1). Place the burner ce
35、ntrally with the four parallel burner tubes in line with the longitudinal axis of the test piece, and position it so that the distance from the top of the burner to the top of the bars on which the belt rests is 130 5 mm, with the transverse end row of burner holes 50 mm inside the vertically projec
36、ted transverse edge of the test piece. Light the burner and adjust the rate of gas consumption immediately to 1.30 0.05 kg per 10 min. After 10 min switch off the gas and withdraw the burner from under the trestle as this prevents molten and charred material from falling on to the burner and blockin
37、g the holes. Leave the test piece on the trestle until all flame and glow have disappeared. Measure the damage to the test piece in accordance with clause 6. 4 Method B. High energy test 4.1 Preparation of test pieces Cut two test pieces if the conveyor belt covers are of equal thickness or three te
38、st pieces if the conveyor belt covers are of unequal thickness. Test pieces shall be 4 m long 1 050 mm wide or of full width if the conveyor belt is less than 1 050 mm wide. Lay the test pieces out for 24 h in dry conditions at any ambient temperature above 0 C immediately prior to testing to remove
39、 residual curvature. 4.2 Temperature at commencement of test The average temperature of the 25 thermocouples (see 2.6) at the commencement of the test, shall be within the range 0 C to 30 C. 4.3 Number of tests For belting with top and bottom covers that are identical, test two test pieces with the
40、top cover uppermost. For belting with top and bottom covers that are of unequal thickness, conduct three tests as follows: a) test one test piece with the top cover uppermost; b) test one test piece with the top cover face downwards; c) test the third test piece in accordance with item a) or with it
41、em b) depending on which test gave the worse results. NOTEThis procedure is necessary to ensure that the required minimum of two samples are tested under identical conditions. 4.4 Procedure WARNING. See warning note in 3.4. 4.4.1 Determination of mass Weigh the test piece and record the mass as m1 (
42、see clause 6). 4.4.2 Installation and combustion Install two trestles (2.2), positioned end to end, so that the total trestle length is 4.4 m, centrally on the same longitudinal axis as the gallery, with the burner end facing the direction of the ventilation flow. The burner end of the trestle shall
43、 be 8 m from the entrance to the gallery. Place each test piece centrally on the trestles with its transverse edge flush with the burner end of the trestles. Adjust the air current in the gallery to give an average velocity of 1.5 0.1 m/s at a height of 350 mm. Measure the air current at a position
44、on the centreline of the trestles and at a distance of 750 mm from the end of the trestle nearest to the gallery entrance (see Figure 1). Place the burner centrally with the four parallel burner tubes in line with the longitudinal axis of the test piece, and positioned so that the distance from the
45、top of the burner to the top of the bars on which the belt rests is 130 5 mm, with the transverse end row of burner holes 50 mm inside the vertically projected transverse edge of the test piece. Light the burner and immediately adjust the rate of gas consumption to 7.5 0.25 kg per 50 min (1.25 0.05
46、kg per 10 min). Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 BSI 10-19993 Figure 1 Propane burner trestle showing positions of burner and test piece Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:0
47、0 2006, Uncontrolled Copy, (c) BSI BS 490-11.2:1991 4 BSI 10-1999 Record continuously throughout the test, or at intervals not exceeding 6 s, the average temperature of the 25 thermocouples (see 2.6) and also the temperature of the incoming air. After 50 min, switch off the gas. Measure the damage t
48、o the test piece, and calculate the maximum average temperature rise in accordance with clauses 6 and 7. 5 Termination of tests 5.1 Normal termination A test shall be terminated, and shall be deemed to be terminated normally, when both the following conditions are satisfied: a) a period of at least
49、70 min has elapsed after the beginning of the test; and b) a period of at least 10 min has elapsed after all flaming on the test piece and debris has ceased. 5.2 Premature termination Any test terminated for safety reasons (see foreword and warning note in 3.4) shall be deemed to be terminated prematurely and shall be recorded on the test report (see clause 8) as “test terminated prematurely”. Figure 2 Burner Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 07:48:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
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