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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7955:1999 ICS 13.340.2
2、0 91.220 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Containment nets and sheets on construction works Specification for performance and test methods Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled
3、 Copy, (c) BSI This British Standard, having been prepared under the direction of the Building and Civil Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 December 1999 BSI 12-1999 The following BSI references relate to the work on
4、 this standard: Committee reference B/514/27 Draft for comment 96/107981 DC ISBN 0 580 33087 7 BS 7955:1999 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee B/514/27
5、, Nets and sheets, upon which the following bodies were represented: Construction Confederation Construction Health and Safety Group Construction Industry Training Board Cordage Manufacturers Institute English Net Manufacturers Association Health and Safety Executive Institution of Structural Engine
6、ers Made-Up Textiles Association National Association of Scaffolding Contractors National Federation of Roofing Contractors Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7955:1999 BSI 12-1999i Contents Pag
7、e Committees responsibleInside front cover Forewordii 1Scope1 2Normative references1 3Definitions1 4Tests1 5Performance requirements1 6Flammability4 7Permeability4 8Light transmission4 9Marking4 Annex A (normative) Impact test5 Annex B (normative) Puncture test8 Annex C (normative) Flammability9 Ann
8、ex D (normative) Wind tunnel test to establish the permeability of nets used for cladding11 Bibliography13 Figure 1 Attachment point strength test2 Figure 2 Tie strength test3 Figure A.1 Preparation of sample sheet or net for impact test5 Figure A.2 Impact test Test rig6 Figure A.3 Impact test Test
9、apparatus7 Figure B.1 Preparation of sample sheet or net for puncture test8 Figure B.2 Puncture test Test apparatus9 Figure C.1 Arrangement for flammable liquid test11 Figure D.1 Log10permeability v log10form factor12 Licensed Copy: London South Bank University, London South Bank University, Fri Dec
10、 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 12-1999 BS 7955:1999 Foreword This British Standard has been prepared by Technical Committee B/514, Nets and sheets, and supersedes performance specifications contained within BS 8093:1991 annexes D and E. It supersedes the recommended p
11、erfomance specification for containment nets and sheeting contained in BS 8093. The flammability tests given in annex C are reproduced verbatim from the Loss Prevention Council Standard (LPS) LPS 1215. A British Standard does not purport to include all the necessary provisions of a contract. Users o
12、f 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 13 and a back cover. The BSI copy
13、right notice displayed in this document indicates when the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 12-19991 BS 7955:1999 1 Scope This British Standard specifies requirement
14、s and test methods for containment nets and sheets intended for use on construction works. It covers flame retardant and non-flame retardant containment nets and sheets. It also specifies test methods and performance specifications for ties used in conjunction with nets and sheets. It does not cover
15、 safety nets, barrier nets or temporary roofs. It does not cover installation and use. This British Standard does not specify ageing requirements. 2 Normative references This British Standard incorporates, by dated or undated reference, provisions from other publications. These normative references
16、are cited at the appropriate place in the text and the publications are listed hereafter. For dated references, only the edition cited applies; any subsequent amendments to or revisions of any of these publications apply to this British Standard only when incorporated in it by amendments or revision
17、. For undated references the latest edition of the publication referred to apply. BS 476-12:1991, Method of test for ignitability of products by direct flame impingement. BS 2576:1986, Method for determination of breaking strength and elongation (strip method) of woven fabrics. BS EN ISO 13468-1:199
18、7, Single-beam instrument. 3 Definitions For the purpose of this British Standard, the following definitions apply. 3.1 containment net net intended to restrain small objects, or tools and debris, to restrict dust, to reduce the effects of weather, to provide protection for persons from falling obje
19、cts and to reduce the risk of persons falling from scaffold platforms 3.2 containment sheet impervious sheet intended to protect a structure from inclement weather, to contain dust and other pollution, to prevent small objects, tools and debris from falling, and to reduce the risk of persons falling
20、 from scaffold platforms 3.3 ties means used to join nets or sheets into larger configurations and to secure them in position 3.4 attachment points designated points within nets and sheets through which ties can be threaded 3.5 form factor constant factor, characteristic of each different containmen
21、t material, relating the wind speed to the wind pressure that would be exerted on the material 4 Tests 4.1 Impact test The net or sheet and tie shall be tested in accordance with annex A. 4.2 Puncture test The net or sheet and tie shall be tested in accordance with annex B. 4.3 Tensile strength The
22、tensile strength of the net or sheet shall be determined in both directions by testing in accordance with BS 2576. Samples for testing shall be cut from the same roll as used for samples tested in annexes A and B. 4.4 Attachment point strength The tensile strength of the attachment points shall be d
23、etermined in accordance with BS 2576:1986. Samples for testing shall be cut from the same roll as used for samples tested in annexes A and B. The net or sheet shall be attached to the test apparatus as shown in Figure 1. 4.5 Tie strength The tensile strength of the ties shall be determined in accord
24、ance with BS 2576:1986. Samples for testing shall be of the same type and specification as those used for tests given in annexes A and B. The tie shall be attached to the test apparatus as shown in Figure 2. 5 Performance requirements 5.1 General The nets or sheets shall meet the following requireme
25、nts. a) When tested in accordance with annex A, the length of either 50 mm conditioning cut shall not increase in length to more than 100 mm. b) When tested in accordance with annex A and annex B, here shall be no failure, except that described in a). Licensed Copy: London South Bank University, Lon
26、don South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 12-1999 BS 7955:1999 Figure 1 Attachment point strength test Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 1
27、2-19993 BS 7955:1999 Figure 2 Tie strength test Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 BSI 12-1999 BS 7955:1999 1) If the net is of a blue colour, then the band should be in red. 5.2 Tensile strength
28、 When tested in accordance with 4.3, nets or sheets shall have a minimum tensile strength of 630 N. The actual performance shall be stated. 5.3 Attachment point strength When tested in accordance with annex A and annex B, the attachment point shall maintain the connection between tie and net/sheet.
29、When tested in accordance with 4.4, the minimum tensile strength shall be 500 N. The actual performance shall be stated. 5.4 Tie strength When tested in accordance with annex A and annex B, the tie shall not fail. When tested in accordance with 4.5, the minimum tensile strength shall be 500 N. The a
30、ctual performance shall be stated. 6 Flammability When tested in accordance with annex C, the nets and sheets shall be resistant to fire at a rate set by the appropriate flame tests. Nets and sheets conforming to annex C shall be regarded as flame retardant. 7 Permeability When tested in accordance
31、with annex D, the nets shall have a form factor of not less than 0.4. 8 Light transmission When tested in accordance with BSENISO13468-1:1997, light transmission properties shall conform to the requirements in that standard and shall be designated in accordance with Table 1 of that standard. 9 Marki
32、ng 9.1 Nets and sheets 9.1.1 Nets and sheets Nets and sheets shall be either marked directly or manufactured with the relevant identification strand or tape as stated in a) and b) as follows. a) If marked directly, this shall be with letters not less than 25 mm high. The information shall be repeate
33、d at regular intervals along the entire length of the roll. The marking shall not be obscured by any overlapping sections, when fixed according to the manufacturers recommendations. The following information shall be stated: 1) the manufacturers or suppliers name, trade mark or identification mark;
34、2) the number and year of this British Standard, BS 7955:1999. b) If manufactured with a strand or tape, this shall be a Royal blue1)identification strand or tape supported by an attached label. The strand and tape shall be continuous along the entire length of the roll and shall not be obscured by
35、overlapping sections when fixed according to the manufacturers recommendations. Fire resistance nets shall have two tapes. The minimum width of the tapes shall be 25 mm. The distance between the two tapes shall be 25 mm. The following information shall be stated: 1) the manufacturers or suppliers na
36、me, trade mark or identification mark; 2) the number and year of this British Standard, BS 7955:1999. 9.1.2 The following information shall be stated on the packaging: a) the manufacturers or suppliers name, trade mark or identification mark; b) the number and year of this British Standard, BS 7955:
37、1999; c) the dimensions of the net or sheet; d) the weight of the net or sheet; e) the manufacturers or suppliers recommended type of tie; f) designated attachment points. 9.2 Ties The following information shall be stated on a label attached to the product or its packaging: a) the manufacturers or
38、suppliers name, trade mark or identification mark; b) the number and year of this British Standard, BS 7955:1999; c) the net or sheet with which the tie has been tested in clauses 4 and 5 of this British Standard. 9.3 Additional information The following additional information shall be supplied on t
39、he packaging or separately on an information sheet: a) tensile strength of net or sheet, determined by the test in 4.3; b) tensile strength of the attachment point, determined by the test in 4.4; c) tensile strength of the tie, determined by the test in 4.5; d) flame retardancy, determined by the te
40、sts in annex C; e) light transmission, determined by testing, as described in clause 8; f) for nets, the wind coefficient, determined by the test in clause 7. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS
41、7955:1999 BSI 12-19995 Figure A.1 Preparation of sample sheet or net for impact test Annex A (normative) Impact test A.1 Principle The net or sheet is subjected to impact from a soft body impactor, capable of being swung at the sample to determine the resistance to impact. A.2 Sampling Test specimen
42、s for any given material shall be identical in type, construction, composition, nominal thickness and manufacture to the material to be assessed. A test sample shall contain 5 net or sheet test specimens and sufficient ties as described in A.5 for each test. A.3 Preparation of test specimens Prior t
43、o the test the net or sheet and ties shall have been stored at a relative humidity of (505) % and an air temperature of (232) 8C for 24 h. Each net or sheet test specimen shall be rectangular, with nominal dimensions of 1 000 mm wide 3 2 000 mm high, as shown in Figure A.1. The actual size shall be
44、calculated from the eyelet positions nearest to the nominal size. The actual dimensions of the test specimen shall be a minimum of 150 mm beyond the eyelet, or the edge of the net or sheet, if this dimension is less than 150 mm at the time of manufacture. One long side of the test specimen shall be
45、the manufactured edge of the net or sheet (see Figure A.1). Each net or sheet test specimen shall be prepared by cutting two 50 mm long cuts in the material at the point of impact as described in A.4 and as shown in Figure A.1. One cut shall be made in the machine direction of the material, the othe
46、r in the transverse direction. The two cuts shall intersect at their central point. Where nets or sheets are manufactured by welding or otherwise joining together, the test specimen shall be prepared from a section containing a joint where each piece either side of the joint is of approximate equal
47、dimensions. The sample shall be installed on the test frame hand tight without any slack. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 10:43:54 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 BSI 12-1999 BS 7955:1999 Figure A.2 Impact test Test rig A.4 Test appa
48、ratus The test apparatus shall consist of the following. A.4.1 A test frame, constructed from standard scaffolding components (see Figures A.2 and A.3), of a construction suitable for the test specimen to be attached in the same manner as it would be fixed on site and in accordance with the manufact
49、urers recommendations. A.4.2 A bag, of (501) kg capacity, the largest diameter of which, when hanging at rest, is not more than 25 mm from the surface of the test specimen and which is suspended from an overhead support. A.4.3 An overhead support, the length of which is to be adjusted so that the bag, at its greatest diameter, is of equal distance from the top and bottom eyelets of the test specimen and equal distance from each side eyelet. A.4.4 Means to prop up the bag at an angle to the test specimen, to allow a calculated im