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1、BRITISH STANDARD BS 7525:1992 Specification for Flammability of air cleaner elements for internal combustion engines Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 This British Standard, having be
2、en prepared under the direction of the General Mechanical Engineering Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 31 January 1992 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference GME/14
3、 Draft for comment 91/72925 DC ISBN 0 580 20129 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the General Mechanical Engineering Standard Policy Committee (GME/-) to Technical Committee GME/14, upon which the following bodies were repres
4、ented: British Compressed Air Society Engineering Equipment and Material Users Association Motor Industry Research Association Society of Environmental Engineers Society of Motor Manufacturers and Traders Ltd. Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank
5、University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 BSI 10-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Flammability requirements1 Appendix A Determination of flaming time, afterglow a
6、nd percentage of charring2 Figure 1 Test rig assembly4 Figure 2 Base plate assembly5 Figure 3 Top plate6 Figure 4 Typical needle7 Figure 5 Dimensions of test element8 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c)
7、 BSI BS 7525:1992 ii BSI 10-1999 Foreword This British Standard has been prepared under the direction of the General Mechanical Engineering Standards Policy Committee. It specifies the requirements for flammability of flame proofed filter media and other materials used in the manufacture of air filt
8、er elements, when ignited under the severest operational conditions which could be expected in service. WARNING. Appendix A specifies a method for the determination of filter element flammability involving fire tests and the use of a hazardous substance. Such tests should be conducted only by traine
9、d staff and adequate supervision should be provided. Precautions should be taken to safeguard the health of personnel conducting the tests against the risk of fire and the inhalation of smoke and toxic products of combustion. A British Standard does not purport to include all the necessary provision
10、s 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 obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8 and a b
11、ack 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. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolle
12、d Copy, (c) BSI BS 7525:1992 BSI 10-19991 1 Scope This British Standard specifies requirements for the flammability of materials used in the production of air filter elements for internal combustion engines. A method of determination of flaming time, afterglow and percentage of charring is given in
13、Appendix A. 2 Definitions For the purposes of this British Standard, the following definitions apply. 2.1 flaming time the time during which burning occurs with a visible flame from ignition to extinction, expressed in seconds 2.2 afterglow the time during which glowing is visible following self-ext
14、inction of the flame, expressed in seconds 2.3 charred area the surface area enclosed by the extremity of flaming or glowing, following light brushing 3 Flammability requirements 3.1 General When tested in accordance with Appendix A the material shall comply with 3.2, 3.3 and 3.4. 3.2 Flaming time T
15、he flaming time shall be no greater than 200 s. 3.3 Afterglow The afterglow shall be no greater than 230 s. 3.4 Charred area The charred area shall be less than 1 % of the total area of the media. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:0
16、0 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 2 BSI 10-1999 Appendix A Determination of flaming time, afterglow and percentage of charring A.1 Principle A sample of unused filter media is made into a filter element that fits into the test rig. Petrol is sprayed onto the element and the fumes are i
17、gnited under controlled conditions. The flaming time, afterglow and percentage of charring are noted. A.2 Apparatus NOTEThe test rig assembly is shown in Figure 1. A.2.1 Base plate, of diameter 250 mm, fitted with a bridge, an inside diameter (i.d.) 6 mm pressure tapping, and a rectangular, sharp-ed
18、ged orifice plate. The base plate shall be permanently fixed to a smooth bore tube i.d. 63.5 mm 300 mm long, provided with a means of generating a steady air flow of approximately 0.5 m3/min and an i.d. 6 mm downstream tapping 127 mm from the base plate (see Figure 2). The rectangular sharp-edged or
19、ifice plate shall be 1.0 + 0.5, 0.0 mm thick, with a hole diameter of 20 0.05 mm. A.2.2 Top plate, of diameter 250 mm, provided with an access tube to inject the petrol and a flash hole to ignite the fumes (see Figure 3). A.2.3 Hypodermic syringe with a needle.1) The capacity of the syringe shall be
20、 5 mL and the needle shall be 75 mm long 1.4 mm outside diameter (o.d.) 1 mm i.d. (see Figure 4). A.2.4 Manometer, reading up to 120 mm H2O (12 mbar). A.2.5 Gas ignitor, with flame. A.2.6 Camel hair paint brush A.2.6 Two stop watches A.3 Preparation of test element A.3.1 Paper media Leave a sample o
21、f the media to stabilize for 24 h at a relative humidity of 55 15 % r.h. and a temperature of 20 2 C before the preparation of the test element. Cut a strip from the material, 87 mm wide and of sufficient length to provide, when pleated and formed into a circular test element, an internal pleat gap
22、in the range 1 mm to 3 mm (see Figure 5). Measure the area of the strip, before pleating to form into the test element. A.3.2 Other media Form a sample of the media into a circular test element. Measure the area of the test element. A.3.3 End seals Fix end seals to the test element to ensure sealing
23、 between the element and the top and base plates (see Figure 1). A.4 Procedure A.4.1 Ensure that the edges of the orifice plate are sharp and cleaned of soot and other deposits before each test. A.4.2 Place the element in the test rig with the media joint at 180 to the point of injection. A.4.3 Inse
24、rt the needle through the access tube until the syringe rests on the tube, and spray 5 mL of unleaded petrol with an octane rating of 95 onto the paper in 2 s. A.4.4 Apply the ignitor to the flash hole and start the stop watches. Ensure that ignition of the petrol vapour takes place within 5 s, and
25、then remove the ignitor and close the hole. A.4.5 Start the air flow immediately after ignition, and adjust to give a reading of 100 2 mmH2O (10 mbar) within 5 s of ignition. A.4.6 Measure the flaming time and afterglow (in s). A.4.7 Stop the air flow and remove the element from the rig. A.4.8 Remov
26、e the charred filter media by light brushing. A.4.9 Cut the element at the joint, and pin it onto a piece of flat wood. A.4.10 Measure the charred area and express it as a percentage of the total area. A.4.11 Measure and note the relative humidity and ambient temperature. NOTE 1If the element is sti
27、ll glowing brightly after 4 min, the test should be aborted and the flame extinguished, e.g. with a CO2 extinguisher. NOTE 2The test should be performed at a relative humidity of 55 15 % r.h. and a temperature of 20 2 C. NOTE 3It is recommended that the test should be performed in a fume cupboard or
28、 in an area with suitable fume extraction and with subdued lighting to ensure the visibility of the flame through the filter media. A.4.12 Repeat the test at least a further two times. 1) For information on the availability of suitable hypodermic syringes and needles, apply to Enquiry Section, BSI,
29、Linford Wood, Milton Keynes, ME14 6LE. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 BSI 10-19993 A.5 Expression of results A.5.1 Express, as the average of at least three tests, the flaming time
30、 in seconds. A.5.2 Express, as the average of at least three tests, the afterglow in seconds. A.5.3 Express, as the average of at least three tests, the charred area as a percentage of the total media area. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:5
31、5 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 4 BSI 10-1999 Figure 1 Test rig assembly Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 BSI 10-19995 Figure 2 Base plate assembly Licensed
32、 Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 6 BSI 10-1999 NOTEA plug or blank has to be provided to close the ignition orifice during the burn period. Figure 3 Top plate Licensed Copy: London South Ban
33、k University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 BSI 10-19997 Figure 4 Typical needle Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 75
34、25:1992 8 BSI 10-1999 Figure 5 Dimensions of test element Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:48:55 GMT
35、+00:00 2006, Uncontrolled Copy, (c) BSI BS 7525:1992 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incor
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