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1、BRITISH STANDARD BS 1191-1: 1973 Specification for Gypsum building plasters Part 1: Excluding premixed lightweight plasters UDC 691.55:666.91 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1191-1:1973 This British Standard, having been a
2、pproved by the Cement, Lime and Gypsum Industry Standards Committee, was published under the authority of the Executive Board on 5 October 1973 BSI 03-1999 First published as BS 1191, December 1944 First revision November 1955 Second revision as BS 1191-1, August 1967 Third revision October 1973 The
3、 following BSI references relate to the work on this standard: Committee reference CEB/15 ISBN 0 580 07690 3 Co-operating organizations The Cement, Lime and Gypsum Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following
4、 Government departments and scientific and industrial organizations: Association of Consulting Engineers British Steel Industry British Precast Concrete Federation British Railways Board British Ready Mixed Concrete Association British Quarrying and Slag Federation Cement and Concrete Association Ce
5、ment Makers Federation* Chemical Industries Association* Concrete Society Department of the Environment* Department of the Environment Building Research Establishment* Federation of Civil Engineering Contractors Greater London Council Gypsum Products Development Association* Imperial Chemical Indust
6、ries Limited Institution of Civil Engineers Institution of Municipal Engineers* Institution of Structural Engineers Institution of Water Engineers National Federation of Building Trades Employers* Sand and Gravel Association Limited Society of Chemical Industry* The Royal Institution of Chartered Su
7、rveyors* Welwyn Hall Research Association The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Gypsum
8、Limited Modular Society National Federation of Plastering Contractors Royal Institute of British Architects Individual manufacturers Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c
9、) BSI BS 1191-1:1973 BSI 03-1999i Contents Page Co-operating organizationsInside front cover Forewordii 1General1 1.1Scope1 1.2Definitions1 1.3Classification1 1.4Purity1 1.5Composition1 1.6Marking1 1.7Samples for testing and sampling1 1.8Manufacturers certificate2 2Quality of the different classes 2
10、.1Class A. Plaster of paris2 2.2Class B. Retarded hemihydrate gypsum plaster2 2.3Class C. Anhydrous gypsum plaster3 2.4Class D. Keenes plaster3 Appendix A Determination of chemical composition and loss on ignition4 Appendix B Examination for soundness4 Appendix C Method of determining transverse str
11、ength4 Appendix D Determination of mechanical resistance by the dropping ball test6 Appendix E Determination of expansion7 Appendix F Method of stabilizing classes A and B plasters8 Appendix G Determination of freedom from coarse particles8 Appendix H Examples of typical classification markings requ
12、ired by 1.68 Figure 1 Gang mould9 Figure 2 Extensometer11 Publication referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1191-1:1973 ii BSI 03-1999 Foreword This British Standard has been revised under the author
13、ity of the Cement, Lime and Gypsum Industry Standards Committee to bring it into line with current practice. The terms used to describe the function and types of plaster accord with those given in BS 4049, “Glossary of terms applicable to internal plastering, external rendering and floor screeding”.
14、 The alphabetical classification of the plasters remains unchanged but the Class B category in this edition is restricted to undercoat and final coat plasters and their sub-divisions, while plasters in Classes C and D are for finishing purposes only. Improvements have been made to a number of test p
15、rocedures and additional test methods have been introduced. This has led to the modification of certain performance requirements. In accordance with the change to the metric system this standard has now been metricated giving values in terms of SI units. For further information on SI units reference
16、 should be made to BS 3763, “The International System of units (SI)”. Figure 1 and 1.8 have been amended and Figure 2 deleted, but otherwise the contents are the same as the previous edition which it is proposed to withdraw when this standard is published. NOTE1 N/mm2 = 1 MN/m2= 1 MPa. A British Sta
17、ndard does not purport to include all the necessary provisions 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
18、, an inside front cover, pages i and ii, pages 1 to 12, an inside back cover and 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 the inside front cover. Licensed Copy: sheffieldun sheffieldun
19、, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1191-1:1973 BSI 03-19991 1 General 1.1 Scope This British Standard specifies requirements for those plasters which have a definite set due to the hydration of calcium sulphate to form gypsum and which are intended for general bu
20、ilding operations and for the manufacture of preformed building products. Premixed lightweight building plasters are not included in this Part of the standard (see Foreword). NOTEThe British Standards referred to in this standard are listed on the inside back cover. 1.2 Definitions For the purposes
21、of this British Standard, the following definitions apply: gypsum the dihydrate of calcium sulphate, CaSO4.2H2O, is the raw material from which the gypsum plasters are commonly manufactured; it is also the final stage in the setting of gypsum plasters hemihydrate an intermediate phase in the dehydra
22、tion of gypsum by heat wherein the amount of combined water corresponds approximately to the formula 2CaSO4.H2O, calcium sulphate hemihydrate. The formula is often written CaSO4.H2O, hence the designation hemihydrate plaster of paris a form of hemihydrate without any added retarder of set. It is man
23、ufactured in several grades for various industrial uses retarded hemihydrate a form of hemihydrate which contains an addition of a retarder of set anhydrous gypsum plaster a material consisting essentially of anhydrous calcium sulphate (CaSO4), produced by the dehydration of gypsum, the set of which
24、 has been suitably accelerated keenes plaster a gypsum plaster of the anhydrous class which is characterized by being more easily brought to a smooth and true finish in continuous plastered surface, this property being associated as well with a gradual set 1.3 Classification Gypsum plaster shall be
25、of one of the following classes: 1.4 Purity No materials shall be added to gypsum plasters except such as are necessary to control the setting and working characteristics or to impart anti-corrosion or fungicidal properties. 1.5 Composition Gypsum plaster shall comply with the relevant clause on che
26、mical composition in Section 2. Materials present arising from impurities in the original gypsum used in manufacture, or from permissible additions under 1.4 shall not be of a type having deleterious effects on the set plaster. 1.6 Marking The vendor shall show clearly on each package of plaster the
27、 number of this British Standard, i.e. BS 1191-1, the class and type to which the plaster belongs (see Appendix H for examples) and the date of manufacture. In addition, it shall be clearly indicated whether the plaster is to be used as an undercoat or final coat. NOTEAttention is drawn to certifica
28、tion facilities offered by BSI: see the inside back cover of this standard. 1.7 Samples for testing and sampling Each sample shall be not less than 5 kg in weight, and shall be enclosed immediately in a clean, dry, airtight container. The process of sampling shall be carried out in as short a time a
29、s possible. Sufficient material shall be taken in approximately equal portions selected from at least twelve different positions when the plaster is loose, from not less than twelve different packages when the plaster is not loose, or, where there are fewer than twelve different packages, from each
30、package. The portions shall be thoroughly mixed and shall be quartered down to give a sample of the weight required for testing. Every care shall be taken in the selection so that a fair, average sample is obtained. The vendor shall afford every facility for the efficient sampling of the bulk and fo
31、r subsequently identifying the plaster sampled. Class A. Class B. Class C. Class D. Plaster of Paris Retarded hemihydrate gypsum plaster Anhydrous gypsum plaster Keenes plaster Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1191-1:1973 2
32、 BSI 03-1999 1.8 Manufacturers certificate At the purchasers request the supplier shall provide statistical quality control certificates, or a certificate stating that the product complies with the requirements of this British Standard. 2 Quality of the different classes 2.1 Class A. Plaster of pari
33、s 2.1.1 Compliance with tests. Plaster of Paris shall comply with the requirements of 2.1.2 to 2.1.5 when tested by the methods described in the relevant Appendix A to Appendix G. 2.1.2 Chemical composition. The chemical compositions shall be as follows when determined as described in Appendix A: 1)
34、 The sulphur trioxide content, expressed as a percentage by weight of the plaster as received, shall be not less than 35 %. 2) The calcium oxide content shall be not less than two-thirds of the sulphur trioxide content, by weight. 3) The sum of the soluble sodium salt and magnesium salt contents, ex
35、pressed as percentages of sodium oxide (Na2O), and magnesium oxide (MgO), by weight of the plaster as received, shall be not greater than 0.2 %. 4) The loss on ignition shall be not greater than 9 % and not less than 4 % by weight of the plaster as received. 2.1.3 Freedom from coarse particles. The
36、residue on a 1.18 mm sieve complying with the requirements of BS 410 shall be not greater than 5 % by weight when determined by the method described in Appendix G. 2.1.4 Soundness. The set plaster pats shall show no signs of disintegration, popping or pitting when examined by the method described in
37、 Appendix B. 2.1.5 Transverse strength. The transverse strength (modulus of rupture) of set plaster shall be not less than 2.5 N/mm2 when determined in accordance with the method described in Appendix C. 2.2 Class B. Retarded hemihydrate gypsum plaster 2.2.1 Type. Retarded hemihydrate gypsum plaster
38、s shall be of one of the following types: Type a: Undercoat plaster (plaster for use with sand) 1. Browning plaster 2. Metal lathing plaster Type b: Final coat plaster 1. Finish plaster 2. Board finish plaster 2.2.2 Compliance with tests. When tested by the methods described in Appendix A to Appendi
39、x G, retarded hemihydrate plasters shall comply with the requirements of 2.2.3 and 2.2.5. In addition, the following plasters shall comply with the subclauses indicated: 2.2.3 Chemical composition. The chemical composition shall be as follows when determined as described in Appendix A: 1) The sulphu
40、r trioxide content, expressed as a percentage by weight of the plaster as received, shall be not less than 35 %. 2) The calcium oxide content shall be not less than two-thirds of the content of sulphur trioxide by weight. 3) The sum of the soluble salt and magnesium salt contents, expressed as perce
41、ntages of sodium oxide (Na2O), and magnesium oxide (MgO), by weight of the plaster as received, shall be not greater than 0.2 %. 4) The loss on ignition shall be not greater than 9 % and not less than 4 % by weight of the plaster as received. 5) For metal lathing plaster, the free lime shall be not
42、less than 3 % by weight at the time of despatch. 2.2.4 Freedom from coarse particles. The residue on a 1.18 mm sieve complying with the requirements of BS 410 shall be not greater than 1 % by weight when determined by the method described in Appendix G. 2.2.5 Soundness. The set plaster pats shall sh
43、ow no signs of disintegration, popping or pitting when examined by the method described in Appendix B. 2.2.6 Transverse strength. The transverse strength (modulus of rupture) of the set sanded plaster shall be not less than 1.2 N/mm2 when tested in accordance with the method described in Appendix C.
44、 1) Browning plaster Type a. 1:2.2.6 2) Metal lathing plaster, Type a. 2:2.2.3 5) and 2.2.6 3) Finish plaster, Type b. 1:2.2.4 and 2.2.7 4) Board finish plaster, Type b. 2:2.2.4, 2.2.7 and 2.2.8 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:27:27 GMT+00:00 2006, Uncontrolled Copy, (c) BS
45、I BS 1191-1:1973 BSI 03-19993 2.2.7 Mechanical resistance. The mechanical resistance of the set neat plaster shall be such that the impact of the dropping ball produces an indentation having a diameter not greater than 5 mm when determined as described in Appendix D. 2.2.8 Expansion on setting. The
46、linear expansion on setting at the time of despatch shall not exceed 0.2 % in one day when tested in accordance with the method described in Appendix E. 2.3 Class C. Anhydrous gypsum plaster 2.3.1 Type. Anhydrous gypsum plasters are for finishing only. 2.3.2 Compliance with tests. Anhydrous gypsum p
47、lasters shall comply with the requirements of 2.3.3 to 2.3.6. 2.3.3 Chemical composition. The chemical composition shall be as follows when determined as described in Appendix A: 1) The sulphur trioxide content, expressed as a percentage by weight of the plaster as received, shall be not less than 4
48、0 %. 2) The calcium oxide content shall be not less than two-thirds of the sulphur trioxide content by weight. 3) The sum of the soluble sodium salt and magnesium salt contents, expressed as percentages of sodium oxide (Na2O), and magnesium oxide (MgO), by weight of the plaster as received, shall be
49、 not greater than 0.2 %. 4) The loss on ignition shall be not greater than 3 % by weight of the plaster as received. 2.3.4 Freedom from coarse particles. The residue on a 1.18 mm sieve complying with the requirements of BS 410 shall be not greater than 1 % by weight when determined as described in Appendix G. 2.3.5 Soundness. The set plaster pats shall show no signs of disintegration, popping or pitting when examined by the method described in Appendix B. 2.3.6 Mechanical resistance. The mechanical resistance of the set neat plaster shall be such that the impact of