1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 8221-1:2012Incorporating corrigendum No. 1Code of practice for cleaningand surface repair ofbuildings Part 1: Cleaning of natural stone,brick, terracotta and concretePublishin
2、g and copyright informationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 80052 8ICS 91.040.01The following BSI references relate to the work on this standard:
3、Committee reference B/560Draft for comment 11/30241242 DCPublication historyFirst edition April 2000Second (current) edition July 2012Amendments issued since publicationDate Text affectedJuly 2012 C1- See forewordBS 8221-1:2012 BRITISH STANDARDContentsForeword iiIntroduction 11 Scope 12 Normative re
4、ferences 13 Terms and definitions 24 Considerations affecting cleaning decisions 25 Stonework 106 Clay and calcium silicate brickwork 157 Terracotta and faience 178 Concrete 179 Removal of specific deposits 1810 Cleaning methods 2211 Health and safety 29AnnexesAnnex A (normative) Precautions for han
5、d cleaning 31Annex B (normative) Precautions for water cleaning 31Annex C (normative) Precautions with abrasive cleaning 32Annex D (informative) Further information on chemical cleaning 33Bibliography 38List of tablesTable 1 Factors affecting choice of cleaning method 4Table 1 Factors affecting choi
6、ce of cleaning method 5Table 2 Geological groups of rocks and examples of building materials 11Table3Types of sandstone and their potential resistance to weathering andsoiling 12Table 4 Sandstone matrices and their potential resistance to weathering andsoiling 12Table 5 Operating pressures 24Table 6
7、 Hardness of abrasives 26Summary of pagesThis document comprises a front cover, an inside front cover, pages i to ii,pages 1 to 40, an inside back cover and a back cover.BRITISH STANDARD BS 8221-1:2012 The British Standards Institution 2012 iForewordPublishing informationThis part of BS 8221 is publ
8、ished by BSI Standards Limited, under licence fromThe British Standards Institution, and came into effect on 31 July 2012. It wasprepared by Technical Committee B/560, Conservation of tangible culturalheritage. A list of organizations represented on this committee can be obtainedon request to its se
9、cretary.Information about this documentThe start and finish of text introduced or altered by Corrigendum(a) No. 1 (andNo. 2) is indicated in the text by tagsg33andg34.Supersessiong33This part of BS 8221 supersedes BS 8221-1:2000, which is withdrawn.g34Hazard warningsWARNING. This British Standard ca
10、lls for the use of substances and/orprocedures that can be injurious to health if adequate precautions are nottaken. It refers only to technical suitability and does not absolve the userfrom legal obligations relating to health and safety at any stage.Use of this documentAs a code of practice, this
11、part of BS 8221 takes the form of guidance andrecommendations. It should not be quoted as if it were a specification andparticular care should be taken to ensure that claims of compliance are notmisleading.Any user claiming compliance with this part of BS 8221 is expected to be able tojustify any co
12、urse of action that deviates from its recommendations.Presentational conventionsThe provisions in this standard are presented in roman (i.e. upright) type. Itsrecommendations are expressed in sentences in which the principal auxiliaryverb is “should”.Commentary, explanation and general informative m
13、aterial is presented insmaller italic type, and does not constitute a normative element.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard can
14、not confer immunity from legalobligations.BRITISH STANDARDBS 8221-1:2012ii The British Standards Institution 2012IntroductionThis British Standard is intended to give building owners, architects, surveyors,engineers, and contractors general information on cleaning.Buildings are cleaned either to enh
15、ance their appearance or to assistmaintenance and/or conservation.Reasons for wanting to enhance appearance include:a) removal of disfigurements (e.g. stains, graffiti); revealing the nature, colouror details of a building; andb) unification of the appearance of a building that has been altered, ext
16、endedor repaired.Reasons for cleaning a building prior to maintenance and/or conservationinclude:1) removal of harmful or undesirable deposits or applied materials from thefabric in order to slow down the rate of decay;2) exposure of concealed defects, where surfaces are very thickly soiled, inorder
17、 to establish the extent and nature of repairs required;3) preparation of a surface for additional treatments; and4) to fulfil the terms of a lease that requires periodic cleaning of a building.Buildings have a variety of surfaces and materials and types of soiling that eachneed to be cleaned with a
18、ppropriate methods and materials. It is essential toidentify, in advance, the type, properties, and condition of masonry (inparticular, whether it is limestone or sandstone) and jointing materials.1 ScopeThis part of BS 8221 gives recommendations on the removal or partial removalof deposits from the
19、 original surface or substrate of a building.It includes the principal cleaning methods in use and the characteristics ofsurface deposits. It is applicable to the cleaning of natural stones, clay brick,calcium silicate brick, glazed and unglazed terracotta/faience, and cast concreteand concrete prod
20、ucts such as cast stone, concrete brick and concrete blockwork.2 Normative referencesThe following referenced documents are indispensable for the application ofthis document. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (i
21、ncluding anyamendments) applies.BS 1139-2 Metal scaffolding Part 2: Couplers Aluminium couplers and specialcouplers in steel. Requirements and test methodBS 1139-4 Metal scaffolding Part 4: Specification for prefabricated steelsplitheads and trestleBS 2482, Specification for timber scaffold boardsBS
22、 6037 (all parts), Code of practice for permanently installed suspended accessequipmentBS 6100-5, Building and civil engineering Vocabulary Part 5: Civil engineering Water engineering environmental engineering and pipe linesBS 6100-6, Building and civil engineering Vocabulary Part 6: Constructionpar
23、tsBRITISH STANDARD BS 8221-1:2012 The British Standards Institution 2012 1BS 8221-2, Code of practice for cleaning and surface repair of buildings Part 2:Surface repair of natural stones, brick and terracottaBS EN 39, Loose steel tubes for tube and coupler scaffolds. Technical deliveryconditionsBS E
24、N 1004, Mobile access and working towers made of prefabricated elements.Materials, dimensions, design loads, safety and performance requirementsBS EN 12811-1, Temporary works equipment. Part 1: Scaffolds. Performancerequirements and general designBS EN 15898, Conservation of cultural property. Main
25、general terms anddefinition3 Terms and definitionsFor the purposes of this part of BS 8221, the terms and definitions given inBS 6100-5, BS 6100-6 and BS EN 15898 the following apply.3.1 faiencemasonry, similar to terracotta, with some surfaces covered with a clear orcoloured glaze3.2 fireskinthin,
26、smooth, outer layer on unglazed terracotta, containing a high proportionof finesNOTE In traditional firing processes, fireskin is vitrified to a greater degree thanthe body of the clay beneath. Fireskin is protective and retention of it is a priority incleaning and repair works.3.3 glazemixed paste
27、of fluxes and colouring ingredients that, applied to a surface andfired, fuses with the open-pored underbody to form a thin, vitreous,transparent, or coloured coating of glassy, opaque or translucent consistencyNOTE Glazes can be plain, mottled or textured and can range from high-gloss toegg-shell f
28、inish.3.4 historic masonarymasonry that forms an integral part of a building or structure which is listed,scheduled or in a conservation area or is of acknowledged historic merit3.5 specialist contractorcontractor who has demonstrable expertise that is based upon knowledge andexperience of best prac
29、tice3.6 terracottafired-clay, fine textured and unglazed, usually yellow to brownish-red4 Considerations affecting cleaning decisionsCOMMENTARY ON Clause 4All cleaning operations present different criteria to consider, including a suitablemethod, the materials of construction, and their condition.4.
30、1 GeneralThe following should be determined prior to carrying out a cleaningprogramme:BRITISH STANDARDBS 8221-1:20122 The British Standards Institution 2012a) 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
31、surface deposits;d) the susceptibility of substrates to various cleaning materials and processes;e) any effects that the cleaning methods and processes could have on theinterior of the building; andf) the likelihood of any historic polychromy surviving beneath the soiling.Information on current pene
32、trating dampness problems or other problemscaused by such dampness should be taken into account when deciding upon thecleaning method and processes.Each project should be considered carefully, taking into account previousexperience with the building (or similar buildings) and available materials and
33、methods which might be useful but should not be assumed to apply fully.If treatment of one material or surface could harm other materials or surfaces,these areas should be protected.If features of artistic or historic importance are to be cleaned, specialist guidanceshould be sought.Historic buildin
34、gs sometimes have a conservation management plan, in whichcase the Conservation Policies contained therein should be followed. In theabsence of a conservation management plan, the impact that cleaning andsurface repair of the building has on the significance of the building should beunderstood and a
35、ny detrimental consequences mitigated as appropriate.Some deposits are not fully removable from surfaces without causing damage.Residual or uneven marks can remain, but should not be mistaken for poorquality cleaning.Apart from cost, the factors listed in Table 1 should be taken into account priorto
36、 selecting a cleaning programme.Where it is determined that surface repairs are required as part of the cleaningprocess these should be done in accordance with BS 8221-2.BRITISH STANDARD BS 8221-1:2012 The British Standards Institution 2012 3Table 1 Factors affecting choice of cleaning methodFactor
37、RemarksType and condition of material Stonework (see Clause 5); clay and calcium silicatebrickwork (see Clause 6); terracotta and faience(see Clause 7); and concrete (see Clause 8) shouldbe identifiedType and condition of surface Extent of deterioration, nature of joints, extent ofornamentation and
38、other surfaces should beconsidered (see 4.2)Amount and type of deposits See 4.3ConstructionA) B)Type and use of buildingC) D)Location of buildingE) F) G) H) I)Health and safety risk assessmentJ) K)Environmental assessmentE) K)Availability of services See 4.12Weather conditionsI)Interior work Where p
39、ossible an inspection of the interior of thebuilding should be made and if necessaryappropriate additional protective measures shouldbe taken to contain the effect of cleaning processesRisk of re-soiling Likelihood of re-soiling occurring and timescale forre-soiling should be taken into account.Risk
40、 to other parts of the building fabric Some methods pose greater risk to the buildingfabric than others, for example due to run-off ofsoiled water or chemical cleaning media, or waterpenetration into the fabric leading to corrosion ofembedded metals, rotting of embedded timbers,salt mobilization or
41、mobilization of iron-basedminerals.A)Some buildings might contain embedded ferrous cramps or steel frame supports. These can require cleaning thatrestricts 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 archi
42、tectural or historic interest require special consideration and permission might be required toclean these.D)The use or contents of a building can limit the cleaning process or add to preparatory and support measures.E)The proximity of a building to vegetation and waterways and the position of the w
43、ater table can prevent use ofcertain chemical agents. Biodegradable proprietary products should be used. Alternatively, special collection orcontainment measures might be required.F)The height and position of a building can make water, abrasive or chemical use hazardous, particularly in verywindy co
44、nditions.G)The position, use and condition of adjoining buildings (especially listed buildings) can affect selection of acleaning method.H)Noise nuisance can restrict working methods or times.I)Dust nuisance can affect selection of a cleaning method.BRITISH STANDARDBS 8221-1:20124 The British Standa
45、rds Institution 2012Table 1 Factors affecting choice of cleaning methodJ)Health and safety considerations might restrict use of certain processes.K)All lead-containing and other toxic debris, including masks and filters should be collected in plastic bags andsealed with tape.NOTE 1 Attention is draw
46、n to the Environmental Protection (Duty of Care) Regulations 1991 1. It is advisable toverify appropriate disposal routes with the local waste regulator.NOTE 2 Consent to discharge waste water from chemical cleaning and from other wet processes might berequired from the local authority or the local
47、water authority.NOTE 3 Where cleaning interiors are concerned any reports on decorative surfaces need to be soughtprior to any decisions being made.4.2 Inspection and identification of substrateA comprehensive survey should be carried out, in the presence of advisors withexpertise in the type of bui
48、lding, prior to carrying out a cleaning programme.The nature and condition of substrate materials and the types of surfacedeposits should be assessed before an appropriate cleaning method is selected.Building and structures to be cleaned should be inspected closely ,using thefollowing procedure.a) E
49、ach material should be identified in sufficient detail so that cleaning canproceed without risk to the fabric.b) The condition of the construction and its joints and associated materialsshould be assessed and recorded, as well as the effects of previous cleaningoperations.c) The extent and nature of surface deposits should be identified (see 4.3).d) Tests to identify a substrate type for susceptibility to various cleaningprocesses and the effects of deposits should be carried out if appropriate.NOTE In some cases, it might be necessar
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