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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 8221-1:2000 ICS 91.040
2、.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Code of practice for cleaning and surface repair of buildings Part 1: Cleaning of natural stones, brick, terracotta and concrete Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:01:49 G
3、MT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Sector Committee for Building and Civil Engineering, was published under the authority of the Standards Committee and comes into effect on 15 April 2000 BSI 04-2000 The following BSI refe
4、rences relate to the work on this standard: Committee reference B/209/7 Draft for comment 96/18388 DC ISBN 0 580 33135 0 BS 8221-1:2000 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this British Standard was entrusted by
5、Technical Committee B/209, General building codes to Technical Subcommittee B/209/7, Cleaning and surface repair of buildings, upon which the following bodies were represented: Chartered Institute of Building Construction Confederation Department of the Environment, Transport and the Regions Constru
6、ction Directorate National Council of Building Material Producers National House-Building Council Royal Institute of British Architects Royal Institution of Chartered Surveyors The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Brick Develop
7、ment Association British Ceramic Research Ltd. Concrete Society Council for Aluminium in Building Council for the Care of Churches Department of the Environment, Transport and the Regions Represented by the Building Research Establishment Ecclesiastical Architects and Surveyors Association English H
8、eritage Historic Scotland London Transport Mortar Producers Association Limited National Grp Construction and Engineering Federation Society for Protection of Ancient Buildings Stone Federation UK Steel Association Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08
9、 06:01:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8221-1:2000 BSI 04-2000i Contents Page Committees responsibleInside front cover Forewordii Introduction1 1Scope1 2Normative references1 3Definitions1 4Considerations affecting external cleaning decisions2 5Stonework5 6Clay and calcium silicate
10、brickwork8 7Terracotta and faience8 8Concrete9 9Removal of specific deposits9 10Cleaning methods12 11Safety15 12Consolidants for porous building materials15 Annex A (informative) Precautions for hand cleaning16 Annex B (informative) Precautions for water cleaning16 Annex C (informative) Precautions
11、with abrasive cleaning16 Annex D (informative) Further information on chemical cleaning17 Bibliography20 Table 1 Factors affecting choice of cleaning method3 Table 2 Geological groups of rocks and examples of building materials5 Table 3 Types of sandstone and their potential resistance to weathering
12、 and soiling6 Table 4 Sandstone matrices and their potential resistance to weathering and soiling6 Table 5 Operating pressures13 Table 6 Hardness of abrasives14 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:01:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI i
13、i BSI 04-2000 BS 8221-1:2000 Foreword This British Standard has been prepared by Subcommittee B/209/7. Together with Part 2, it supersedes BS 6270-1:1982 and BS 6270-2:1985, which are withdrawn. This part of BS 8221 gives guidance on selection and application of cleaning methods for external facades
14、 of buildings. It has been prepared in parallel with BS 8221-2, which provides guidance on surface repairs. This code of practice covers removal of deposits, including graffiti, from the surface of natural stones, clay brick, calcium silicate brick, glazed and unglazed terracotta/faience, and concre
15、te products for building. Guidance is given on the characteristics of deposits and susceptibilities of substrates to various cleaning materials and processes, and a procedure is given for carrying out investigations into suitable and safe cleaning. Consideration is given to some problems that may be
16、 encountered. This code of practice takes the form of guidance and recommendations. It should not be quoted as if it were a specification and care should be taken to ensure that claims of compliance are not misleading. WARNING This British Standard calls for the use of substances and/or procedures t
17、hat may be injurious to health or damaging to the environment, if adequate precautions are not taken. It refers only to technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage. A British Standard does not purport to include all the necess
18、ary 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, an inside front cover, pages i and ii, pages 1
19、 to 20, an inside back cover and a back cover. The BSI copyright 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 06:01:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 04-20001 BS 82
20、21-1:2000 Introduction This code of practice is intended to give building owners, architects, surveyors, engineers, and contractors general information on cleaning. Buildings are cleaned either to enhance their appearance or to assist maintenance and/or conservation. Reasons for wanting to enhance a
21、ppearance include: removal of disfigurements (e.g. stains, graffiti); revealing the nature, colour or details of a building; unification of the appearance of a building that has been altered, extended or repaired. Reasons for cleaning a building prior to maintenance and/or conservation include: remo
22、val of harmful or undesirable deposits or applied materials from the fabric in order to arrest decay; exposure of concealed defects, where surfaces are very thickly soiled, in order to establish the extent and nature of repairs required; preparation of a surface for additional treatments; to fulfil
23、the terms of a lease that requires periodic cleaning of a building. Buildings have a variety of surfaces and materials and types of soiling. Each should be cleaned with appropriate methods and materials. It is essential to identify, in advance, the type, properties, and condition of masonry (in part
24、icular, whether limestone or sandstone) and jointing materials. NOTEIf features of artistic or historic importance are to be cleaned, specialist guidance should be sought. Each project should be considered carefully, taking into account previous experience with the building (or similar buildings) an
25、d available materials and methods. If treatment of one material or surface can harm other materials or surfaces, proper protection should be provided. 1 Scope This standard provides guidance on removal or partial removal of deposits from the original surface or substrate of a building. Advice is giv
26、en on the principal cleaning methods in use and the characteristics of surface deposits. Guidance is given on cleaning natural stones, clay brick, calcium silicate brick, glazed and unglazed terracotta/faience, and cast concrete and concrete products such as cast stone, concrete brick and concrete b
27、lockwork. 2 Normative references The following normative documents contain provisions that, through reference in this text, constitute provisions of this British Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references,
28、 the latest edition of the publication referred to applies. BS 1139 (all parts), Metal scaffolding. BS 2482:1981, Specification for timber scaffold boards. BS 3761:1995, Specification for solvent-based paint remover. BS 5973:1993, Code of practice for access and working scaffolds and special scaffol
29、d structures in steel. BS 6037:1990, Code of practice for permanently installed suspended access equipment. BS 6100-5, Glossary of building and civil engineering terms Masonry. BS 6100-6, Glossary of building and civil engineering terms Concrete and plaster. BS 8221-2, Code of practice for cleaning
30、and surface repair of buildings Surface repair of natural stones, brick and terracotta. 3 Definitions For the purposes of this code of practice, the definitions given in BS 6100-5 and -6 apply, together with the following. 3.1 Coade stone proprietary off-white terracotta body produced from a kaolini
31、tic clay, containing titanium dioxide, feldspar as flux and quartz as glass-forming agent, and a grog of powdered prefired clay NOTECoade stone was manufactured by the Coade family between 1769 and 1820. 3.2 conservation stabilizing and preventing or retarding deterioration of masonry 3.3 cleaning r
32、emoval or partial removal of surface deposits (e.g. grease, organic growth, paint, stains) and mineral deposits that chemically combine with the surface (iron and carbon deposits, gypsum skins, etc.) 3.4 crazing fine, hair-line stress relief cracks caused by inability of a glazed surface and underbo
33、dy to accommodate thermal and moisture movement NOTECrazing is also known as poor glaze fit. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 06:01:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 04-2000 BS 8221-1:2000 3.5 engobe surface application by brush
34、or spray of liquid clay, before firing, to provide an opaque, unglazed coloured finish on some forms of terracotta 3.6 faience masonry, similar to terracotta, with some surfaces covered with a clear or coloured glaze 3.7 fired-clay unit masonry unit formed from brick-earth, clay or shale, dried and
35、burned NOTEFired-clay should not be confused with fireclay, which is used for making refractory bricks. 3.8 fireskin thin, smooth, outer layer on unglazed terracotta, containing a high proportion of fines NOTEIn traditional firing processes, fireskin is vitrified to a greater degree than the body of
36、 the clay beneath. Fireskin is protective and retention of it should be a priority in cleaning and repair works. 3.9 glaze mixed paste of fluxes and colouring ingredients that, applied to a surface and fired, fuses with the open-pored underbody to form a thin, vitreous, transparent, or coloured coat
37、ing of glassy, opaque or translucent consistency NOTEGlazes can be plain, mottled or textured and can range from high-gloss to egg-shell finish. Craze resistance should conform to BS 6431-17. 3.10 terracotta fired clay, fine textured and unglazed, usually yellow to brownish-red 4 Considerations affe
38、cting external cleaning decisions 4.1 General The following should be understood prior to carrying out a cleaning programme: a) the type and properties of masonry and jointing material; b) the condition of the masonry units and joints; c) the types, extent and nature of surface deposits; d) the susc
39、eptibility of substrates to various cleaning materials and processes. All cleaning operations present different criteria to consider, including a suitable method, the materials of construction, and their condition. Previous experience with a building or similar buildings may be useful but should not
40、 be assumed to apply fully. It should be recognized that some deposits are not fully removable from surfaces without causing damage. Residual or uneven marks can remain, but should not be mistaken for poor quality cleaning. Apart from cost, the factors listed in Table 1 should be considered prior to
41、 selecting a cleaning progamme. 4.2 Inspection and identification of substrate A comprehensive survey should be carried out, in the presence of advisors with expertise in the type of building, before cleaning a masonry facade. The nature and condition of masonry materials and the types of surface de
42、posits should be assessed before an appropriate cleaning method can be decided. Masonry facades should be inspected closely using the following procedure. Each material should be identified in sufficient detail so that cleaning can proceed without risk to the fabric. The condition of the masonry and
43、 its joints and associated materials should be assessed and recorded, as well as the effects of previous cleaning operations. The extent and nature of surface deposits should be identified. Tests to identify a stone type for susceptibility to various cleaning processes and the effects of deposits sh
44、ould be carried out if appropriate. 4.3 Identification of surface deposits Deposits on external facades of buildings can vary from a few microns to as much as 50 mm in thickness and cleaning may involve removal of one or more of the following deposits: a) atmospheric particulates, often bound togeth
45、er as well as to the masonry surface with either calcium sulfate or silica, depending on the substrate; b) mortar splashes and runs; c) encrustations of calcium carbonate from lime-rich masonry; d) efflorescent salts; e) bird fouling; f) paint and graffiti; g) anti-pigeon gel; h) heavy and light oil
46、s; i) biological growth; j) metallic stains. It is essential at the investigation stage to distinguish between the layer of soiling and the altered surface of the substrate, so that the level of cleaning can be decided. Licensed Copy: London South Bank University, London South Bank University, Fri D
47、ec 08 06:01:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 04-20003 BS 8221-1:2000 Table 1 Factors affecting choice of cleaning method FactorRemarks Type and condition of surfaceExtent of deterioration, nature of joints, extent of ornamentation and other surfaces should be considered Type and con
48、dition of materialStonework (see clause 5); clay and calcium silicate brickwork (see clause 6); terracotta and faience (see clause 7); and concrete (see clause 8) should be identified Amount and type of depositsSee clause 9 Construction ab Type and use of building cd Location of building efghi Healt
49、h and safety risk assessment jk Environmental assessment ek Availability of servicesSee 4.11 Weather conditions l Interior workAdditional protective measures should be taken to contain the effect of cleaning processes a Some buildings may contain embedded ferrous cramps or steel frame supports. These may require cleaning that restricts or eliminates water use. b Mortar in joints can entrap and be dissolved by cleaning chemicals, or can be eroded by abrasives. c Buildings of architectural or historic interest require special consideration
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