1、BRITISH STANDARD BS3712-3: 1974 Incorporating Amendment Nos. 1 and2 Building and construction sealants Part3: Methods of test for application life, skinning properties and tack-free time UDC 691.58:620.1BS3712-3:1974 This British Standard, having been approved by the Building Divisional Council, was
2、 publishedunder the authority ofthe Executive Board on 31January1974 BSI 03-1999 The following BSI references relate to the work on this standard: Committee references B/89, B/89/1 Draft for comment68/26713 ISBN 0 580 07828 0 Co-operating organizations The Committee, under whose supervision this Bri
3、tish Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: British Association of Synthetic Rubber Manufacturers British Rubber and Resin Adhesive Manufacturers Association British Rubber Manufacturers Association Br
4、itish Tar Industries Association British Whiting Federation Chemical Industries Association Limited Confederation of British Industry Department of the Environment Department of the Environment Building Research Establishment Flat Glass Manufacturers Association Greater London Council Institution of
5、 Civil Engineers Insulation Glazing Association Mastie Asphalt Council and Employers Federation Metal Window Federation of Great Britain National Association of Putty and Building Mastics Manufacturers National Council of Building Material Producers National Federation of Building Trades Employers N
6、ational Rubber Producers Association Royal Institute of British Architects Sealant Applicators Association Sealant Manufacturers Conference Society of Chemical Industry Welwyn Hall Research Association Whiting and Industrial Powders Research Council Individual manufacturers Amendments issued since p
7、ublication Amd. No. Date of issue Comments 4860 August 1985 6819 September 1991 Indicated by a sideline in the marginBS3712-3:1974 BSI 03-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 General 1 1.1 Scope 1 1.2 Definition 1 1.3 Sampling 1 2 Tests and methods 1 2.1 A
8、pplication life 1 2.2 Text deleted 1 2.3 Skinning properties 1 2.4 Tack-free time 2 2.5 Text deleted 2 Appendix A Text deleted 4 Figure 1 Figure deleted 2 Figure 2 Figure deleted 2 Figure 3 Figure deleted 2 Figure 4 Figure deleted 2 Figure 5 Tack-free time test specimen 3 Figure 6 Figure deleted 2 F
9、igure 7 Figure deleted 2 Publications referred to Inside back coverBS3712-3:1974 ii BSI 03-1999 Foreword This British Standard was originally issued under the authority of the Building Divisional Council, B/-, in 1974 and has been amended and confirmed under the direction of the Elements and Compone
10、nts (of Diverse Materials) for Buildings Standards Committee in1985. For further information see the foreword in BS3712-1:1991 and the following standards: BSEN27390, BSEN28394, BSEN29046, BSEN29048 and ISO9047. A British Standard does not purport to include all the necessary provisions of a contrac
11、t. 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, pages1 to4, an inside back cover a
12、nd a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS3712-3:1974 BSI 03-1999 1 1 General 1.1 Scope This Part of BS3712 describes test methods for the following propertie
13、s of building and construction sealants. 1) Application life. 2) Skinning properties. 3) Tack-free time. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 1.2 Definition For the purposes of this Part of this British Standard the following definition
14、 applies: building sealant a joint sealant for buildings, applied by hand, gun, knife, or trowel, or in strip form, or by pouring, and intended to maintain a seal between the sides of a joint which is subject to some degree of movement. The strip form materials covered by this definition are plastic
15、 at the time of application, i.e.readily deformable but not capable of reverting to their original shape 1.3 Sampling The samples of building sealants to be used in the following determinations and methods of test shall be taken as follows: Select at random sufficient original unopened packages to p
16、rovide material for the tests. Alternatively, select sufficient material at random from the bulk supply. Report any skin formation (which should be removed), any separation of components or foreign matter, and any variability between one sample and another. In special circumstances it may be appropr
17、iate to take single samples from a gun for specific tests. The method of sampling shall be reported. 2 Tests and methods 2.1 Application life 2.1.1 General. This test is applicable to multi-part sealants. The object of the test for application life is to provide an indication of the useful life of t
18、he sealant taken from freshly opened containers and mixed in accordance with the manufacturers instructions. 2.1.2 Apparatus. The following apparatus is required: 1) A clean cylindrical container65mm diameter and50mm height (approx.). 2) Aluminium alloy surface mill finished, of grade6063 T6 or6082
19、T6 as specified in BS1474 or grade6082 T6 as specified in BS1470. 3) A flat bladed spatula or power stirrer. 4) Containers for storing components and sealant. 5) Enclosure maintained at25 2 C and50 5% r.h. 2.1.3 Preparation of specimen. The container shall be thoroughly cleaned. Suitable quantities
20、of the components in closed containers, together with clean cylindrical container, shall be conditioned for at least16h at in the enclosure. Appropriate amounts of the base component and of the curing component shall be mixed thoroughly in the cylindrical container at25 2 C, either by hand for10min,
21、 using a spatula or by using a power stirrer until uniform mixing is achieved. It is essential that the curing component is evenly dispersed throughout the base component. Particular care shall be taken when mixing the parts to avoid or eliminate all air bubbles. 2.1.4 Cleaning of test surface. The
22、aluminium test piece shall be cleaned with water, detergent solution or solvents to remove major contamination. The surface shall then be cleaned using butanone (ethyl methyl ketone) or similar solvent and washed with a dilute detergent solution. Finally the surface shall be rinsed in industrial met
23、hylated spirits and air dried. 2.1.5 Procedure. The mixed samples shall be stored uncovered at in the enclosure. Not lessthanh before the expected expiry time of the application life, and thereafter at10min intervals, tests shall be performed to check that the sample is capable of being applied by a
24、 spatula without difficulty on to the aluminium surface. 2.1.6 Reporting. The application life is reported as the total time between the completion of mixing and the last test in which the sealant is easily applied to and readily adheres to the aluminium surface. 2.2 Change in consistency (usingthec
25、onstantload penetrometer) Clause 2.2 Text deleted 2.3 Skinning properties 2.3.1 General. This test is particularly applicable to sealants which are intended to form a skin but remain soft underneath. The object of the test is to establish the presence of a skin on the surface.BS3712-3:1974 2 BSI 03-
26、1999 2.3.2 Apparatus. A shallow tin50mm diameter and10mm deep approximately. 2.3.3 Preparation of specimen. The tin shall be filled with the sealant and be exposed at room temperature. Other conditions of exposure may be specified. 2.3.4 Procedure. The surface of the sealant is gently drawn back at
27、intervals with a probe or needle. The skin will be indicated as a rupture in the displaced surface. 2.3.5 Reporting. Report the time taken for the skin to form to the nearest12h and the conditions under which it was exposed. The specimen may be left for a period and the condition of the skin reporte
28、d e.g.smooth, wrinkly, thick, thin, oily or readily detached. 2.4 Tack-free time 2.4.1 General. The object of this test is to determine the time required for the surface of the sealant to become tack-free. The test is applicable to sealants which are intended to develop tack-free surfaces within a l
29、imited period when exposed to normal atmospheric conditions. 2.4.2 Apparatus. A flat base plate (e.g.aluminium) with a non-absorbent surface175mm 75mm. Aflat sheet of metal50mm 25mm weighing approximately15g. Pieces of polyethylene sheet85mm 30mm 0.025mm. A constant temperature enclosure unless othe
30、rwise agreed controlled at25 1 C and805% relative humidity. Care should be taken to provide ample volume when dealing with solvent release sealants. 2.4.3 Preparation of specimen. The metal base plate shall be clean and dry. The polyethylene shall be clean, dry and free from cuts or wrinkles. The se
31、alant or its components shall be conditioned in closed containers at25 1 C for not less than16h. 2.4.4 Procedure. Spread the sealant (after mixing for multi-part sealants) on to the non absorbent surface and draw a template across the sealant to produce a layer of sealant with a smooth surface measu
32、ring 150mm 65mm 3mm. The sealant shall then be exposed in the constant temperature enclosure or under other conditions as specified. After a specified interval of time place a piece of polyethylene upon the surface of the sealant. Following this, place the metal plate (weight15g) upon the polyethyle
33、ne for not less than10s, and not more than20s. (seeFigure 5). Remove the plate and slowly peel back the polyethylene at90 from the surface. The test is repeated at suitable intervals after further periods of exposure using fresh pieces of polyethylene on the undisturbed areas of the sealant. 2.4.5 R
34、eporting. Report the tack-free time as the time between the application of the sealant to the non-absorbent surface and the time when there is no transfer of sealant to the polyethylene. NOTEWith pouring grade sealants a mask or frame to contain the sealant may be necessary. 2.5 Text deleted Figure
35、1 Figure deleted Figure 2 Figure deleted Figure 3 Figure deleted Figure 4 Figure deleted Figure 6 Figure deleted Figure 7 Figure deletedBS3712-3:1974 BSI 03-1999 3 Figure 5 Tack-free time test specimenBS3712-3:1974 4 BSI 03-1999 Appendix A. Text deletedBS3712-3:1974 BSI 03-1999 Publications referred
36、 to BS1470, Wrought aluminium and aluminium alloys for general engineering purposes. Plate, sheet and strip. BS3712, Building and construction sealants. BS3712-1, Methods of test for homogeneity, relative density and penetration. BSEN27390, Building constructionJointing productsDetermination of resi
37、stance to flow 1) . BSEN28394, Building constructionJointing productsDetermination of extrudability of one-component sealants 1) . BSEN29046, Building constructionSealantsDetermination of adhesion/cohesion properties at constant temperature 1) . BSEN29048, Building constructionJointing productsDeter
38、mination of extrudability of sealants using standardized apparatus 1) . ISO9047, Building constructionSealantsDetermination of adhesion/cohesion properties at variable temperature 1) . 1) Referred to in the foreword only.BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | |
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