1、BS 6073-2:2008Precast concrete masonry units Part 2: Guide for specifying precast concrete masonry unitsICS 91.100.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates
2、 when the document was last issued. BSI 2008ISBN 978 0 580 59366 6The following BSI references relate to the work on this standard:Committee reference B/519/1Draft for comment 08/30168066 DCPublication historyFirst published July 1981Second edition, November 2008Amendments issued since publicationAm
3、d. no. Date Text affectedBS 6073-2:2008 BSI 2008 iBS 6073-2:2008ContentsForeword ii1 Scope 12 Normative references 13 Terms and definitions 14 General 25 Basic characteristics (BS EN 771-3:2003+A1, 6.1, and BS EN 771-4:2003+A1, 6.1) 26 Additional characteristics (BS EN 771-3:2003+A1, 6.1, and BS EN
4、771-4:2003+A1, 6.1) 67 Other properties 68 Manufacturing control 7Bibliography 8List of tablesTable 1 Work sizes of aggregate concrete blocks (BS EN 771-3) 3Table 2 Work sizes of aggregate concrete coursing units (BS EN 771-3) 3Table 3 Work sizes of aircrete blocks (BS EN 771-4) 3Table 4 Work sizes
5、of aircrete coursing units (BS EN 771-4) 3Table 5 Limit deviations in millimetres for aggregate concrete units (BS EN 771-3) 4Table 6 Limit deviations in millimetres for aircrete units (BS EN 771-4) 4Table 7 Grouping of units volume limits 5Table 8 Commonly available unit strengths of aggregate conc
6、rete and aircrete units (BS EN 771-3 and BS EN 771-4) 5Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, an inside back cover and a back cover.BS 6073-2:2008ii BSI 2008ForewordPublishing informationThis part of BS 6073 is published by BSI and
7、 came into effect on 30 2008. It was prepared by Subcommittee B/519/1, Masonry units, under the authority of Technical Committee B/519, Masonry and associated testing. A list of organizations represented on these committees can be obtained on request to its secretary.SupersessionThis part of BS 6073
8、 supersedes BS 6073-2:1981, which is withdrawn.Relationship with other publicationsThis part of BS 6073 was originally developed as a method for specifying masonry units in accordance with BS 6073-1, which has been withdrawn and superseded by BS EN 771-3 and BS EN 771-4.This new edition of BS 6073-2
9、 is intended to provide a guide to the understanding and application of BS EN 771-3 and BS EN 771-4 for specifiers.Use of this documentAs a guide, this part of BS 6073 takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be
10、taken to ensure that claims of compliance are not misleading.Any user claiming compliance with this part of BS 6073 is expected to be able to justify any course of action that deviates from its recommendations.Presentational conventionsThe provisions in this standard are presented in roman (i.e. upr
11、ight) type. Its recommendations are expressed in sentences in which the principal auxiliary verb is “should”.Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.Contractual and legal considerationsThis publication
12、does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.November BSI 2008 1BS 6073-2:20081 ScopeThis British Standard gives guidance for specifying preca
13、st concrete masonry units conforming to BS EN 771-3 and BS EN 771-4.2 Normative referencesThe 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 docu
14、ment (including any amendments) applies.BS 5628-3:2005, Code of practice for the use of masonry Part 3: Materials and components, design and workmanshipBS EN 771-3:2003+A1:2006, Specification for masonry units Part 3: Aggregate concrete masonry units (dense and lightweight aggregates)BS EN 771-4:200
15、3+A1:2005, Specification for masonry units Part 4: Autoclaved aerated concrete masonry unitsBS EN 1996-1-1, Eurocode 6: Design of masonry structures Part 1-1: Common rules for reinforced and un-reinforced masonry structures3 Terms and definitionsFor the purposes of this part of BS 6073, the followin
16、g terms and definitions apply.3.1 masonry unitpre-formed component intended for use in masonry construction3.2 common masonry unitmasonry unit normally intended for use with no faces left visible3.3 close textured masonry unitmasonry unit with a texture suitable for direct decoration3.4 facing mason
17、ry unitmasonry unit intended for use with one or more faces left visible and which may or may not be exposed to external climatic conditions3.5 exposed masonry unitfacing masonry unit exposed to external climatic conditions without render or other equivalent protection3.6 aggregate concrete masonry
18、unitmasonry unit manufactured from cementitious binder, aggregates and water and which may contain admixtures and additions and colouring pigments and other materials incorporated or applied during or subsequent to unit manufactureBS 6073-2:20082 BSI 20083.7 autoclaved aerated concrete (AAC) masonry
19、 unitmasonry unit manufactured from hydraulic binders such as cement and/or lime, combined with siliceous-based fine material, cell-generating material and waterNOTE AAC is commonly known as aircrete in the UK.3.8 coursing unitmasonry unit, commonly of brick size, used to assist in achieving the sto
20、rey height of a wall in conjunction with full height blocks3.9 blockmasonry unit which when used in its normal aspect exceeds the length or width or height specified for a coursing unit3.10 accessory unitmasonry unit which is shaped to provide a particular function3.11 work sizesize of masonry unit
21、specified for its manufacture, to which the actual size conforms within permissible deviations4GeneralWhen specifying masonry units, the basic characteristics listed in items a) to e) of both BS EN 771-3:2003+A1, 6.1, and BS EN 771-4:2003+A1, 6.1, should be included. Where relevant, additional chara
22、cteristics from those listed should also be specified.NOTE BS EN 771-3:2003+A1, 6.1, and BS EN 771-4:2003+A1, 6.1, specify requirements for the description and designation on masonry units.5 Basic characteristics (BS EN 771-3:2003+A1, 6.1, and BS EN 771-4:2003+A1, 6.1)5.1 GeneralIt is important to s
23、pecify that the masonry units conform to BS EN 771-3 or BS EN 771-4, as appropriate, and to further specify: the type of unit (see Clause 3); the work size dimensions (see 5.2); the tolerance category (see 5.3); the configuration (see 5.4); the mean compressive strength (see 5.5); the dry density (s
24、ee 5.6). BSI 2008 3BS 6073-2:20085.2 Work size dimensionsThe work size of masonry units should be specified in terms of length, width (thickness) and height, e.g. 440 mm 100 mm 215 mm. NOTE 1 Previous UK practice called for work size to be specified in terms of length, height and thickness. Table 1
25、and Table 2 show the work sizes of aggregate concrete masonry units commonly supplied in the UK. Tables 3 and 4 show the work sizes of aircrete masonry units commonly supplied in the UK.NOTE 2 To obtain the coordinating size of a masonry unit, add the nominal joint width, which is normally 10 mm, to
26、 the length and height of the unit.NOTE 3 Other widths might be available and in use. No single manufacturer necessarily produces the complete range of face sizes and widths given in Table 1 to Table 4.Table 1 Work sizes of aggregate concrete blocks (BS EN 771-3)Length mmWidthmmHeight mm75 90 100 14
27、0 190 215390 190440 215Table 2 Work sizes of aggregate concrete coursing units (BS EN 771-3)Length mmWidthmmHeight mm90 100290 90215 65190 90190 65440 140440 65Table 3 Work sizes of aircrete blocks (BS EN 771-4)Length mmWidth mmHeight mm440 Available in a range from 50 mm to 350 mm215610 215620 215N
28、OTE Other heights are available for foundation blocks and for thin layer mortar construction.Table 4 Work sizes of aircrete coursing units (BS EN 771-4) Length mmWidth mmHeight mm215 Available in a range from 90 mm to 150 mm65215 70BS 6073-2:20084 BSI 20085.3 Tolerance categoryBS EN 771-3 permits fo
29、ur tolerance categories to be declared by the manufacturer for regular shaped units, non-regular shaped units and accessory units. NOTE Alternative tolerances for non-regular shaped units and accessory units may be as declared by the manufacturer. The majority of units manufactured in the UK conform
30、ing to BS EN 771-3 are supplied to tolerance categories D1 or D2. Tolerance categories D3 and D4 are for use with thin joint mortar and not currently used in the UK. The tolerance category for aggregate concrete units should therefore be specified in accordance with Table 5.For regular shaped units,
31、 BS EN 771-4 has one tolerance category for general purpose mortar or lightweight mortar (GPLM) and two tolerance categories for thin layer mortar. The tolerance category for aircrete units should therefore be specified in accordance with Table 6.Table 5 Limit deviations in millimetres for aggregate
32、 concrete units (BS EN 771-3)Dimensions Tolerance categoryD1 D2Length +3p5+1p3Width +3p5+1p3Height +3p52NOTE BS EN 771-3 permits closer tolerances to be declared for one or more dimensions.Table 6 Limit deviations in millimetres for aircrete units (BS EN 771-4)Dimensions Mortar typeGeneral purpose a
33、nd lightweight mortarThin layer mortar(GPLM) (TLMA) (TLMB)Length +3p53 1.5Width 3 2 1.0Height +3p52 1.5Flatness of bed faces n/a n/a u1.0Plane parallelism of bed facesn/a n/a u1.0NOTE BS EN 771-4 permits closer tolerances to be declared for one or more dimensions. BSI 2008 5BS 6073-2:20085.4 Configu
34、rationBS EN 1996-1-1 categorizes units according to their void size, void percentages and shell and web dimensions and permits the manufacturer to either:a) provide the purchaser with detailed information on void percentages, number of voids, volume of largest void, thickness of shells and webs etc.
35、, to enable the purchaser to establish the appropriate grouping to BS EN 1996-1-1; or b) declare the unit grouping. In the UK the unit grouping is declared by the manufacturer and the specifier should request the appropriate unit grouping, if other than Group 1 is needed. Units are generally either
36、Group 1 or Group 2. NOTE 1 All aircrete units conforming to BS EN 771-4 are Group 1 units.NOTE 2 Volume limits for each unit grouping are given in Table 7.5.5 Compressive strengthThe compressive strength of masonry units should generally be specified in accordance with Table 8. These values correlat
37、e with the values given in BS 5628-1:2005, Table 2, and BS 5628-2:2005, Table 3, and with those given in BS 8103-2 and UK Building Regulations relating to structure.NOTE Other compressive strengths might be available and in use. No single manufacturer necessarily produces the complete range of stren
38、gths given in Table 8.Table 7 Grouping of units volume limitsUnit grouping Limits for voids (by volume)Group 1 u25% formed voidsGroup 2 25% u60% formed vertical voidsGroup 3 25% u70% formed vertical voidsGroup 4 25% u50% formed horizontal voidsTable 8 Commonly available unit strengths of aggregate c
39、oncrete and aircrete units (BS EN 771-3 and BS EN 771-4)Compressive strengthN/mm22.93.67.38.7 A)10.4 B)17.5 B)22.5 B)30.0 B)40.0 BA)Only for aircrete units to BS EN 771-4.B)Only for aggregate concrete units to BS EN 771-3.BS 6073-2:20086 BSI 20085.6 Dry densityThe gross dry density of the units shou
40、ld be specified in kg/m3. The permitted tolerance for aggregate concrete units is 10% and for aircrete units it is 50 kg/m3.Aggregate concrete units are generally in the gross density range of 650 kg/m32 400 kg/m3. Aircrete units are generally in the gross density range of 300 kg/m31 000 kg/m3.NOTE
41、The net dry density of masonry units is not generally needed.6 Additional characteristics (BS EN 771-3:2003+A1, 6.1, and BS EN 771-4:2003+A1, 6.1)6.1 Thermal propertiesWhere the masonry units are intended to be used in applications where thermal properties are relevant, either the thermal conductivi
42、ty of the concrete should be specified in W/mK or the thermal resistance of the units in m2K/W.6.2 DurabilityWhere the units are intended to be used in applications exposed to frost, the durability of the units should be specified in accordance with BS 5628-3:2005, Table 12.7 Other properties7.1 Gen
43、eralInformation might be available from manufacturers for the following properties, which are not generally needed for specification in the UK:water absorption; moisture movement; water vapour permeability; reaction to fire; shear bond strength.7.2 Water absorptionWhere the units are intended to be
44、used as exposed units, the water absorption in g/m2s may be specified. In cases where water absorption is specified, it should be specified: for a period of 10 min for aggregate concrete units; for a period of 10, 30 or 90 min for aircrete units. BSI 2008 7BS 6073-2:20087.3 Moisture movementIt is ve
45、ry difficult to calculate the likely amount of moisture movement in masonry and hence, when masonry is designed, an allowance is generally made instead for a small amount of moisture movement to take place.Where the units are intended to be used in structural applications, the reference test moistur
46、e movement in mm/m may be obtained from the manufacturer. NOTE Different methods are used to assess moisture movement in units conforming to BS EN 771-3 and BS EN 771-4 so the resulting values are not directly comparable.7.4 Water vapour permeabilityWhere the units are intended to be used in externa
47、l applications, the water vapour diffusion coefficient may be specified in accordance with tabulated values given in BS EN 1745 or alternatively in accordance with BS EN ISO 12572.7.5 Reaction to fireWhere the units are intended to be used in applications that are expected to be non-combustible, rea
48、ction to fire may be specified. NOTE UK Building Regulations relating to fire regard masonry units as being non-combustible.7.6 Shear bond strengthWhere the units are intended to be used in structural applications, the shear bond strength of the unit in combination with mortar may be specified in N/
49、mm2.BS EN 998-2:2003 specifies values for general purpose and lightweight mortar (0.15 N/mm2) or thin layer mortar (0.3 N/mm2).8 Manufacturing controlMasonry units should be specified as either: Category I units, which have a declared mean compressive strength with a probability of failure to reach this strength not exceeding 5%; or Category II units, which are not intended to conform to the level of confidence of Category I units.NOTE Masonry unit
