1、BRITISH STANDARD BS4255-1: 1986 Rubber used in preformed gaskets for weather exclusion from buildings Part 1: Specification for non-cellular gaskets UDC 678.074:62762.4:699.83BS4255-1:1986 This British Standard, having been prepared under the directionof the Rubber StandardsCommittee, was published
2、under the authority ofthe Board of BSI and comes intoeffect on 30 May1986 BSI 07-1999 First published December 1967 First revision May 1986 The following BSI references relate to the work on this standard: Committee reference RUM/35 Draft for comment83/37993 DC ISBN 0 580 15077 1 Committees responsi
3、ble for this British Standard The preparation of this British Standard was entrusted by the Rubber Standards Committee (RUM/-) to Technical Committee RUM/35, upon which the following bodies were represented: British Rubber Manufacturers Association British Structural Bearings Manufacturers Associati
4、on Building Employers Confederation Concrete Society Department of the Environment (Building Research Establishment, Princes Risborough Laboratory) Department of Transport (Highways) Flexible Roofing Association Institute of Medical Laboratory Sciences Institution of Structural Engineers Malaysian R
5、ubber Producers Research Association Ministry of Defence Royal Society of Chemistry Amendments issued since publication Amd. No. Date of issue CommentsBS4255-1:1986 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Classification 1 3 Testing 1 4 General re
6、quirements 1 5 Requirements for black and non-black rubber gaskets 2 6 Marking 2 Table 1 Hardness classification 1 Table 2 Requirements for black rubber gaskets 2 Table 3 Requirements for silicone rubber and white and coloured gaskets 2 Publications referred to Inside back coverBS4255-1:1986 ii BSI
7、07-1999 Foreword This Part of BS4255 has been prepared under the direction of the Rubber Standards Committee. It is a revision of the 1967 edition which is withdrawn. The major changes incorporated in this revision are as follows: a) chlorosulphonated polyethylene and silicone rubbers have been incl
8、uded in the field of application; b) the classification of rubbers by hardness and application has been modified; c) various changes have been introduced into the values specified for the physical property requirements. The requirements of ISO3934 and ISO5892, published by the International Organiza
9、tion for Standardization (ISO), were taken into account during the preparation of this Part of BS4255, but the standard is substantially different from those two documents. This standard is a material specification and does not cover the design of gaskets nor their application to building constructi
10、on nor their performance in service. Attention is drawn, however, to the following standards. BS4315, Methods of test for resistance to air and water penetration Part1:Windows and structural gasket glazing systems. BS6093, Code of practice for design of joints and jointing in building construction.
11、BS6262, Code of practice for glazing for buildings. Attention is also drawn to BS3734 which specifies dimensional tolerances for rubber products. The appropriate classes of tolerance for gaskets should be agreed between the user and the manufacturer. A test for the determination of ozone resistance
12、after simulated ageing and leaching is to be developed and it is hoped that a requirement for this property will eventually be included in this Part. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correc
13、t 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, pagesi andii, pages1 and2, an inside back cover and a back cover. This standard has been updated (see copyright
14、date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4255-1:1986 BSI 07-1999 1 1 Scope This Part of BS4255 specifies requirements for the classification, physical properties and marking of solid (non-cellular) rubber used in prefor
15、med gaskets for sealing applications in buildings where resistance to weathering, ozone and permanent deformation under load are of prime importance. This Part applies to chloroprene, butyl, halobutyl, ethylene propylene, chlorosulphonated polyethylene and silicone rubbers used in the gaskets. Five
16、classes of material, defined according to the hardness of the rubber, are specified. NOTEThe titles of the publications referred to in this Part of BS4255 are listed on the inside back cover. 2 Classification The rubber shall be classified according to its hardness, as given in Table 1. The hardness
17、 shall be determined in accordance with the appropriate method in BS903-A26. Method M shall be used for small components; otherwise method N or method H shall be used, according to the expected hardness value. Table 1 Hardness classification 3 Testing Tests shall normally be carried out on test piec
18、es taken from the actual gasket. But if the gasket is too narrow for a particular test piece to be cut from it, that test shall be carried out using test pieces taken from a specially moulded sheet, vulcanized under conditions which shall achieve the same state of cure as that of the actual gasket;
19、this shall be reported in the documentation that accompanies the gaskets supplied to the purchaser. 4 General requirements 4.1 Appearance and finish When examined visually, all surfaces (including the cross sections) shall be homogeneous and free from porosity and grit. Gaskets shall be cut so that
20、the cross section can be examined. 4.2 Accelerated ageing After ageing in an air oven at100 C for a period ofh, in accordance with either of the methodsdescribed in BS903-A19, the rubber shall comply with the following requirements. a) The tensile strength, compared with the unaged value, shall not
21、be reduced by more than15% of the unaged value when determined in accordance with BS903-A2. b) The elongation at break, compared with the unaged value, shall not be reduced by more than40% of the unaged value when determined in accordance with BS903-A2. c) The hardness shall not be below the unaged
22、value and shall not be more than10IRHD above the unaged value when determined in accordance with BS903-A26. 4.3 Static ozone resistance When tested in accordance with BS903-A43, at a test elongation of 20% at40 C and at an ozone concentration of 100p.p.h.m. 1) , the test pieces shall show no crackin
23、g after96h. 4.4 Low-temperature hardness change When tested in accordance with BS5294, the hardness afterh at 10 C shall be not more than12IRHD above the initial value atp10 C. 4.5 Staining When tested in accordance with method A1 of BS903-A33, the rubber shall not cause migration staining. Test pie
24、ces shall be placed between two painted panels and the assembly shall be heated forh at 70 C in an air circulating oven. The panels, without the test pieces, shall then be exposed for2h under a mercury arc lamp and the presence of migration staining shall be assessed by visual examination. Class Har
25、dness A B C D L IRHD 75 4 NOTEClasses A, B, C and D are used for U channel types of gasket. Class L is intended for lock-strip type (“zipper” type) structural gaskets but class D is normally used for the actual locking strip for such gaskets. 50 +5 4 60+5 4 70+5 4 80+5 4 1) Parts per hundred million
26、 by volume. 70 +20 166 +20 24+20 BS4255-1:1986 2 BSI 07-1999 5 Requirements for black and non-black rubber gaskets 5.1 Black rubber gaskets 5.1.1 General. The requirements given in Table 2 shall apply to all rubbers listed in clause1, with the exception of silicone rubber. (see5.2) 5.1.2 Tensile pro
27、perties. The tensile strength and elongation at break, when determined in accordance with BS903-A2, using type2 dumb-bell test pieces, shall comply with the requirements given in Table 2. 5.1.3 Compression set. When determined in accordance with BS903-A6, using type1 test pieces maintained at70 C fo
28、rh with lubrication of the faces of the compression plates, the compression set shall comply with the requirements given in Table 2. Table 2 Requirements for black rubber gaskets 5.2 White and coloured rubber gaskets and all silicone rubber gaskets 5.2.1 General. The requirements given in Table 3 sh
29、all apply to all non-black gaskets and to all gaskets made of silicone rubber. Grey shall be regarded as a non-black colour. 5.2.2 Tensile properties. The tensile strength and elongation at break, when determined in accordance with BS903-A2, using type2 dumb-bell test pieces, shall comply with the r
30、equirements given in Table 3. 5.2.3 Compression set. When determined in accordance with BS903-A6, using type1 test pieces maintainedat100 C forh for silicone rubber and at70 C forh for all other rubbers, with lubrication of the faces of the compression plates, the compression set shall comply with t
31、he requirements given in Table 3. 5.2.4 Tear strength. When determined in accordance with method C of BS903-A3, the tear strength shall comply with the requirements given in Table 3. 6 Marking Each gasket, or each container if it is not possible to mark the actual gasket, shall be marked in a suitab
32、le position with the following: a) the manufacturers name or trademark; b) the month and year of manufacture; c) the class and type of rubber; d) the colour of the gasket; e) the number and date of this British Standard, i.e.BS4255-1:1986 2) . Table 3 Requirements for silicone rubber and white and c
33、oloured baskets Class Nominal hardness Tensile strength (minimum) Elongation at break (minimum) Compression set (maximum) A B C D L IRHD 50 60 70 80 75 MPa 8.5 8.5 10.5 10.5 12.0 % 300 250 200 150 150 % 25 25 25 25 25 22+20 2) Marking BS4255-1:1986 on or in relation to a product is a claim by the ma
34、nufacturer that the product has been manufactured to the requirements of the standard. The accuracy of such a claim is therefore solely the manufacturers responsibility. Enquiries as to the availability of third party certification should be addressed to the appropriate certification, body. 22+2 0 2
35、2+2 0 Class Nominal hardness Tensile strength (minimum) Tear strength (minimum) Elongation at break (minimum) Compression set (silicone rubber) (maximum) Compression set (rubbers other than silicone) (maximum) A B C D L IRHD 50 60 70 80 75 MPa 6.0 6.0 6.0 6.0 6.0 kN/m 15 15 15 15 15 % 300 200 150 10
36、0 125 % 30 30 30 30 30 % 25 25 25 25 25 NOTEThe compression set requirements in Table 3 differ in recognition of the use of silicone rubber in non-black gaskets. A minimum tear strength is specified because, in general, silicone rubber and non-black rubbers are weaker than rubbers containingcarbon b
37、lack.BS4255-1:1986 BSI 07-1999 Publications referred to BS903, Methods of testing vulcanized rubber. BS903-A2, Determination of tensile stress-strain properties. BS903-A3, Determination of tear strength (trouser, angle and crescent test pieces). BS903-A6, Determination of compression set after const
38、ant strain. BS903-A19, Heat resistance and accelerated air ageing tests. BS903-A26, Determination of hardness. BS903-A33, Methods of test for staining in contact with organic materials. BS903-A43, Determination of resistance to ozone cracking (static strain test). BS3734, Specification for dimension
39、al tolerances of solid moulded and extruded rubber products 3) . BS4315, Methods of test for resistance to air and water penetration 3) . BS4315-1, Windows and structural gasket glazing systems. BS5294, Method of test. Determination of crystallization effects in rubbers by hardness measurements. BS6
40、093, Code of practice for design of joints and jointing in building construction 3) . BS6262, Code of practice for glazing for buildings 3) . ISO3934, Rubber building gaskets Materials in preformed solid vulcanizates used for sealing glazing and panels Specification 3) . ISO5892, Rubber building gas
41、kets Materials for preformed solid vulcanized structural gaskets Specification 3) . 3) Referred to in the foreword only.BS4255-1: 1986 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents
42、the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to im
43、prove the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:020
44、89967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel:020899690
45、01. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and int
46、ernational standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members of BSI are k
47、ept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyr
48、ight, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwi
49、se without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
