1、BRITISH STANDARD BS 8449:2005 Building and construction sealants with movement accommodation factors greater than 25 % Method of test for determination of adhesion/cohesion properties at variable temperatures ICS 91.100.50 BS 8449:2005 This British Standard was published under the authority of the S
2、tandards Policy and Strategy Committee on 11 February 2005 BSI 11 February 2005 The following BSI references relate to the work on this British Standard: Committee reference B/547 Draft for comment 04/30101494 DC ISBN 0 580 44831 2 Committees responsible for this British Standard The preparation of
3、this British Standard was entrusted to Technical Committee B/547, Sealants for building and construction, upon which the following bodies were represented: Association of Sealant Applicators BRE Building Research Establishment British Adhesives and Sealants Association Flat Glass Manufacturers Assoc
4、iation Glass and Glazing Federation Institution of Civil Engineers Water UK Amendments issued since publication Amd. No. Date CommentsBS 8449:2005 BSI 11 February 2005 i Contents Page Committees responsible Inside front cover Foreword ii 1S c o p e 1 2 Normative references 1 3T e r m s a n d d e f i
5、 n i t i o n s 1 4 Principle 1 5M a t e r i a l s 1 6E q u i p m e n t 1 7 Preparation of test specimens 4 8 Conditioning of test specimens 4 9 Procedure 4 10 Test specimen examination and definition of failure 5 11 Test report 6 Bibliography 7 Figure 1 Test specimen with mortar substrates 2 Figure
6、2 Test specimen with aluminium or glass substrates 3 Table 1 Test amplitudes 5BS 8449:2005 ii BSI 11 February 2005 Foreword This British Standard has been prepared by Technical Committee B/547. The scope of this British Standard is relevant to a group of sealants with high movement accommodation fac
7、tors (MAFs) not covered by any other existing or provisional, British or International Standard. Experience has shown that extending the method described in BS EN ISO 9047 to test sealants with a MAF greater than 25 % does not accurately reflect the behaviour of the sealant in service. This standard
8、 addresses this issue by using a definition of MAF that takes into account the difference in behaviour between compression and extension. The test method anticipates such properties. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for it
9、s 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 7 and a back cover. The BSI copyright notice displayed in this document indic
10、ates when the document was last issued.BS 8449:2005 BSI 11 February 2005 1 1 Scope This British Standard specifies requirements for sealants with a movement accommodation factor (MAF) greater than 25 %, which are selected according to the procedures in BS 6213 and BS 6093 and are installed according
11、 to the procedures in BS 8000-16. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) a
12、pplies. BS EN 26927, Building construction Jointing products Sealants Vocabulary. BS ISO 13640, Building construction Jointing products Specifications for test substrates. 3 Terms and definitions For the purposes of this British Standard, the terms and definitions given in BS EN 26927 apply. 4 Princ
13、iple Test specimens are prepared, in which the sealant to be tested adheres to two parallel contact surfaces. After submission to cycles of compression and extension under defined conditions, the test specimens are examined for evidence of loss of adhesion or cohesion. 5 Materials 5.1 Substrate mate
14、rials The substrates used shall conform to BS ISO 13640. Select the substrate material(s) from mortar, and/or aluminium, and/or glass, or from other substrate materials as agreed by the parties concerned. Two substrate pieces of the same material shall be used for each test specimen. These shall hav
15、e a cross-section of dimensions as shown in Figure 1 or Figure 2, depending on the material. Test substrates and spacers (see 5.2) of other dimensions may be used, but the dimensions of the sealant bead and the area of adhesion shall be the same as those shown in Figure 1 and Figure 2 (12 1) mm and
16、(12 1) mm (50 1) mm respectively. 5.2 Spacers Spacers for the preparation of the test specimens shall be rigid and of dimensions (12 1) mm (12 1) mm (12 1) mm with an anti-adherent surface. 5.3 Anti-adherent material The test specimens shall be prepared upon a non-adhesive material, e.g. polyethylen
17、e film. NOTE The choice of material should follow the advice of the sealant manufacturer. 6 Equipment 6.1 Ventilated convection type oven, capable of being maintained at (70 2) C. 6.2 Refrigerated enclosure, capable of being maintained at (20 2) C. 6.3 Container for water immersion of the specimens
18、for conditioning according to method B (8.2). 6.4 Test machine, capable of extending and compressing the test specimens at a rate of (5.5 0.7) mm/min. 6.5 Measuring device, capable of measuring the depth of cracks and tears, in the sealant bead, to a resolution of 1 mm.BS 8449:2005 2 BSI 11 February
19、 2005 All dimensions are in millimetres Key 1 Mortar substrate 2S e a l a n t u n d e r t e s t 3 Spacers Figure 1 Test specimen with mortar substrates 12 12 50 12 25 12 25 1 1 2 3 3 3BS 8449:2005 BSI 11 February 2005 3 All dimensions are in millimetres Key 1 Aluminium or glass substrate 2 Sealant u
20、nder test 3S p a c e r s Figure 2 Test specimen with aluminium or glass substrates 12 50 12 66 12 1 1 2 3 3 3BS 8449:2005 4 BSI 11 February 2005 7 Preparation of test specimens 7.1 For each substrate material, prepare three test specimens. 7.2 For each specimen, assemble two substrates (5.1) and two
21、 spacers (5.2), as described by Figure 1 or Figure 2, upon the anti-adherent material (5.3). 7.3 Follow the instructions of the sealant manufacturer concerning, for instance, whether a primer should be used and the mixing procedure for multi-component sealants. Fill the hollow volume formed by the s
22、ubstrates and spacers with the sealant, taking the following precautions: a) avoid the formation of air bubbles; b) press the sealant in order that it makes good contact with the substrates; c) tool the sealant surface so that it is flush with the top faces of the substrates and spacers. 7.4 Keeping
23、 the pieces in the arrangement described in Figure 1 or Figure 2, set the test specimens on the edge of one of the substrates. 7.5 Remove the anti-adherent surface as soon as practicable. Store the specimens in this position during pre-conditioning. Keep the spacers in place during pre-conditioning
24、and conditioning. 7.6 Pre-condition the sealant and the substrate material for 24 h at (23 2) C. 8 Conditioning of test specimens 8.1 Conditioning method A Condition the test specimens for 28 days at (23 2) C and (50 5) % relative humidity. 8.2 Conditioning method B First condition the test specimen
25、s according to method A and subsequently subject them three times to the following storage cycle: a) 3 days in the oven (6.1) at (70 2) C; b) 1 day in distilled water (6.3) at (23 2) C; c) 2 days in the oven (6.1) at (70 2) C; d) 1 day in distilled water (6.3) at (23 2) C. Alternatively, this cycle
26、may be carried out in the sequence: c) d) a) b). Store the test specimens for a further period of 24 h at (23 2) C and (50 5) % relative humidity before testing. NOTE Conditioning method B is a normal conditioning procedure using the influence of heat and water. It is not intended to give informatio
27、n on the durability of the sealant. 9 Procedure 9.1 Pre-examination After preparation and conditioning, the sealant test pieces shall be examined for defects. Any test specimens deemed unsuitable for testing shall be rejected. Remove the spacers. 9.2 Calculation of test parameters The speed of exten
28、sion and compression used in the test procedure shall be (5.5 0.7) mm/min. The amplitudes of movement to be used during testing, depending on the expected MAF, shall be as shown in Table 1.BS 8449:2005 BSI 11 February 2005 5 Table 1 Test amplitudes If a sealant is to be tested for a MAF value other
29、than those shown in Table 1, then the following equations give the extension and compression required: where: 9.3 Test 9.3.1 First week Day 1: Place the test specimens in the refrigerated enclosure (6.2) at (20 2) C. After three hours, extend the test specimens in the test machine (6.4) to the requi
30、red extension. Maintain the extension at (20 2) C for 21 h. Day 2: Release the extension. Place the test specimens in the oven (6.1) at (70 2) C. After three hours compress the test specimens in the test machine (6.4) to the required compression. Maintain the compression for 21 h at 70 C. Day 3: Rel
31、ease the compression and follow the procedure of Day 1. Day 4: Follow the procedure of Day 2. Days 5 to 7: Release the compression, store at (23 2) C and (50 5) % relative humidity without applying any mechanical force. 9.3.2 Second week Repeat the procedure of the first week. 10 Test specimen exami
32、nation and definition of failure 10.1 After the test specimens have been submitted to the above cycles, examine them for loss of cohesion and/or adhesion. Measure the depth of any adhesive or cohesive failures using the measuring device (6.5). 10.2 Record the maximum depth of adhesion loss or cohesi
33、on loss and the position of that maximum for each test specimen. 10.3 If loss of adhesion or loss of cohesion exceeds two millimetres anywhere on the sealant surface, the sealant test piece shall be reported as having failed. 10.4 If two or more of the test specimens fail, the sealant shall be repor
34、ted as having failed. 10.5 If only one test specimen fails then the complete test shall be repeated. If, after the repeated test, one or more test specimens fail, the sealant shall be reported as having failed. Movement accommodation factor (MAF) Extension Compression Width after extension Width aft
35、er compression %m mm m 35 35 26 16.2 8.8 50 50 34 18.0 7.9 70 70 42 20.4 6.9 100 100 50 24.0 6.0 (1) (2) E is the extension (%); C is the compression (%); k MAF is the movement accommodation factor. Ek MAF = C 100k MAF 100 k MAF + - =BS 8449:2005 6 BSI 11 February 2005 11 Test report The test report
36、 shall contain the following information: a) laboratorys name and date of test; b) reference to this British Standard, i.e. BS 8449; c) name and type of sealant; d) identification of the sealant batch from which the test specimens were produced; e) substrates used (see 5.1); f) primer(s) used, if ap
37、plicable; g) method of conditioning; h) MAF tested for and the extension/compression cycle used (see Clause 9); i) location and maximum value of the depth of adhesion loss or cohesion loss for each test specimen; j) which test specimens, if any, have passed; k) which test specimens, if any, have fai
38、led; l) whether the sealant has passed or failed; and m) any deviation from the procedure specified in this standard.BS 8449:2005 BSI 11 February 2005 7 Bibliography Standards publications BS 6093, Code of practice for design of joints and jointing in building construction. BS 6213, Selection of con
39、struction sealants Guide. BS 8000-16, Workmanship on building sites Code of practice for sealing joints in buildings using sealants. BS EN ISO 9047, Building construction Jointing products Determination of adhesion/cohesion properties of sealants at variable temperatures.BS 8449:2005 BSI 389 Chiswic
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