1、BRITISH STANDARD BS7308:1990 ISO7737: 1986 Method for Presentation of dimensional accuracy data in building constructionsBS7308:1990 This British Standard, having been prepared under the directionof the Basic Data andPerformance Criteria for CivilEngineering and Building Structures Standards Policy
2、Committee, was published underthe authority of the Board ofBSI and comes into effect on 28 September1990 BSI08-1999 The following BSI references relate to the work on this standard: Committee reference BDB/4 Draft for comment 84/13860 DC ISBN 0 580 18494 3 Committees responsible for this British Sta
3、ndard The preparation of this British Standard was entrusted by the Basic Data and Performance Criteria for Civil Engineering and Building Structures Standards Policy Committee (BDB/-) to Technical Committee BDB/4, upon which the following bodies were represented: Association of County Councils Brit
4、ish Standards Society Building Employers Confederation Chartered Institution of Building Services Engineers Concrete Society Department of Education and Science Department of the Environment (Building Research Establishment) Department of the Environment (Property Services Agency) Incorporated Assoc
5、iation of Architects and Surveyors Institute of Building Control Institute of Clerks of Works of Great Britain Inc. Institution of Civil Engineers Institution of Structural Engineers Institution of Water and Environmental Management Royal Institute of British Architects Royal Institution of Chartere
6、d Surveyors The following body was also represented in the drafting of the standard, through subcommittees and panels: Chartered Institute of Building Amendments issued since publication Amd. No. Date of issue CommentsBS7308:1990 BSI 08-1999 i Contents Page Committees responsible Inside front cover
7、National foreword ii 0 Introduction 1 1 Scope 1 2 Field of application 1 3 References 1 4 Dimensional variability 1 5 Dimensional accuracy data expressed in terms of standard deviation and systematic deviation 1 6 Items to be measured 2 7 Assessment and presentation of accuracy data 2 8 Publication
8、of accuracy data 2 Table 1 List of types of dimension to be measured 3 Table 2 Example of form on which measurements are to be recorded (for1 to3 measurements on one product or item) 4 Table 3 Format for the presentation of generalized accuracy data (for one or several building projects) 5 Table 4 E
9、xample of Table 2 filled in 8 Table 5 Example of Table 3 filled in 9 Table 6 Example of a format for the presentation of accuracy data relating to a specific manufacturer 12 Table 7 Example of a format for the presentation of accuracy data relating to a specific manufacturer 12 Publications referred
10、 to Inside back coverBS7308:1990 ii BSI 08-1999 National foreword This British Standard, which has been prepared under the direction of the Basic Data and Performance Criteria for Civil Engineering and Building Structures Standards Policy Committee, is identical with ISO7737 “Tolerances for building
11、 Presentation of dimensional accuracy data” published by the International Organization for Standardization (ISO). This standard is referred to in BS5606, “Code of practice for accuracy in buildings” as a means of presenting dimensional accuracy data, and will aid the collection of further data, for
12、 future incorporation into BS5606. The information given in BS5606 can therefore be extended and updated. Readers of this standard are encouraged to record measured data in the manner recommended, and to forward it to the Secretary of BDB/4, BSI,2Park Street, London W1A2BS. The Technical Committee h
13、as reviewed the provisions of ISO1803-1, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A related standard to ISO1803-1:1985 is BS6100 “Glossary of building and civil engineering terms” Subsection1.5.1:1984 “Coordination of
14、 dimensions; tolerances and accuracy”. Reference is made in the text to ISO3443-4, which provides an alternative calculation procedure to that given in BS6954-3. The procedure given in BS6954-3 is considered to be preferable and can be used without reference to ISO3443-4, which has not been adopted
15、by the UK. Cross-references International Standard Corresponding British Standard ISO1791:1983 BS6100 Glossary of building and civil engineering terms Subsection1.5.1:1984 Coordination of dimensions; tolerances and accuracy (Technically equivalent) BS6954 Tolerances for building ISO3443-1:1979 Part1
16、:1988 Recommendations for basic principles for evaluation and specification (Identical) ISO3443-2:1979 Part2:1988 Recommendations for statistical basis for predicting fit between components having a normal distribution of sizes (Identical) ISO3443-3:1987 Part3:1988 Recommendations for selecting targ
17、et size and predicting fit (Identical) ISO/DIS5479 BS2846 Guide to statistical interpretation of data Part7:1984 Tests for departure from normality (Technically equivalent) BS7307 Building tolerances. Measurement of buildings and building products ISO7976-1:1989 Part1:1990 Methods and instruments (I
18、dentical) ISO7976-2:1989 Part2:1990 Position of measuring points (Identical)BS7308:1990 BSI 08-1999 iii A British Standard 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 Stand
19、ard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1to12, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated.
20、This will be indicated in the amendment table on the inside front cover.iv blankBS7308:1990 BSI 08-1999 1 0 Introduction The aim of this International Standard is to state how measured data on observed dimensional accuracy shall be presented as feedback from the building site. Information describing
21、 the accuracy of constructed work (and possible sources of error) obtained from measurement surveys is of value to building designers, component manufacturers and contractors. Presentation of data in accordance with the principles laid down in this InternationalStandard gives the following advantage
22、s. Building designers are able to use the data directly in standard calculation procedures designed to determine the appropriate reference sizes of components and to choose the appropriate jointing techniques with a “known” probability of satisfactory fit and performance. Component manufacturers, wh
23、ose products are used in conjunction with a variety of constructed work, are able to establish target sizes which will have the widest ranges of application. Contractors are able to predict the need for, and type of, remedial measures and to assess the economic consequences of any predicted misfit a
24、t an early stage. Construction managers are in a better position to plan the level of supervision available and can exercise closer control on the execution. 1 Scope This International Standard lays down the principles on which the collection of dimensional accuracy data in building construction wor
25、k shall be based and the format in which this data shall be presented for defined items of construction and manufactured components. 2 Field of application This International Standard is for use in all types of building construction. 3 References ISO1803-1, Tolerances for building Vocabulary Part1:
26、General terms. ISO3443-1, Tolerances for building Part1: Basic principles for evaluation and specification. ISO3443-2, Tolerances for building Part2:Statistical basis for predicting fit between components having a normal distribution of sizes. ISO3443-3, Tolerances for building Part3:Calculation of
27、joint clearance and prediction of fit 1) . ISO3443-4, Tolerances for building Part4:Methods for predicting deviations of assemblies and for allocation of tolerances 1) . ISO5479, Normality tests 1) . ISO7976-1, Tolerances for building Methods of measurement of buildings and building products Part1:
28、Instruments and accuracy 1) . ISO7976-2, Tolerances for building Methods of measurement of buildings and building products Part2: Position of measuring points 1) . 4 Dimensional variability In order to achieve an increased expectation of satisfactory fit during construction, it is necessary at the d
29、esign stage to make a realistic assessment of the way fit is affected by dimensional variability at the design stage. The different parts of ISO3443 provide procedures for making such assessments. These procedures require descriptions of the dimensional variability that occurs during construction or
30、 assembly for defined items of construction and manufactured components. Subjective estimates are unlikely to describe variability sufficiently accurately and do not have the statistical basis that is strictly required for the determination of data describing dimensional variability. It is important
31、 therefore that such descriptions which are associated with any process are based entirely on measured information. Dimensional variability shall be taken into account by the designer at the design stage and should refer to the standards of workmanship that are normally achievable. At this stage the
32、 contractor and the component manufacturer may not be known. 5 Dimensional accuracy data expressed in terms of standard deviation and systematic deviation The spread of the sizes of a dimension about a mean value is given by the term “standard deviation”. Some feature of the construction or producti
33、on process may cause the mean value to be systematically displaced from the target. This displacement is given by the term “systematic deviation” (see ISO3443-2). Ideally the dimensional variability observed for a given process should be based on the measurement of all construction or production res
34、ulting from that process but this is rarely possible. However, if a representative sample is measured, a reliable estimate of the dimensional variability can be established. 1) At present at the stage of draft.BS7308:1990 2 BSI 08-1999 6 Items to be measured For all types of construction and types o
35、f manufactured components, the dimensions relevant to fit shall be measured. The list of items is given in Table 1. As its contents are not exhaustive, the items and types of dimension given are only to be considered as examples. The measurement methods to be adopted when obtaining dimensional accur
36、acy data and the preferred positions of measuring points are covered by ISO7976-1 and ISO7976-2. The survey should include measurements of overall dimensions that are of practical significance, for example verticality over a single storey height and verticality over building height. For buildings wh
37、ich are to be clad with a wholly external envelope, deviations of the structural face from a theoretical vertical plane shall be measured. Measurements made on site or in the factory should be recorded on a copy of Table 2, or on a form based on Table 2. 7 Assessment and presentation of accuracy dat
38、a 7.1 Assessment of accuracy data For each item of construction and type of component, the associated dimensional variability shall be given as a set of two parameters, standard deviation and systematic deviation. In order to assess whether the dimensional variability is significantly influenced by
39、one or more factors, it should initially be determined for each set of observed accuracy data included in the total sample of measurements and then compared statistically. The necessary background information required to compare and assess this data for each item or product should include the indivi
40、dual sample size of each set of data; the reference size or sizes; the specified permitted deviation or deviations; the descriptions of the items or products being measured and the descriptions of the measurement methods adopted and the accuracy in use of each method. Where the data for an item or p
41、roduct is shown to be significantly related to a particular factor, for example the use of jigs for positioning elements, the data related to this factor should be considered separately and a separate statement of the associated dimensional variability determined. Where no variable exerts a signific
42、ant effect on the individual dimensional variabilities, variability for each set of data should be combined statistically to give one overall statement of observed dimensional variability. 7.2 Presentation of accuracy data For each item of construction and type of component, the accuracy data shall
43、be presented as values of standard deviation and systematic deviation. Where analysis of the data for any dimension indicates that no given variable is significant, only one statement of the dimensional variability shall be given. For those dimensions where a particular factor has been shown to be s
44、ignificant, a separate statement of dimensional variability should be given as a sub-division of the type of dimension measured. In addition (for each statement), the following information should be given for each item of construction or type of component: a) the number of sets included in the repre
45、sentative sample; b) the overall sample size; c) a description of the type of item or product measured such that any significant variables are identified; d) where necessary, a drawing of the item or product which should include an indication of the positions of the measuring points; e) the results
46、of any test carried out to investigate normality; f) where no test of normality is made or when the test of normality indicates the distribution of measured data is not normal, a histogram giving the actual deviations about the reference size. For any item of construction or type of component, the m
47、easured accuracy data can be either “generalized” accuracy data in which the data collected relates to a representative sample drawn from all contractors or manufacturers, or “specific” accuracy data in which the data relates to a particular contractor or manufacturer. Generalized accuracy data shal
48、l be presented in the form shown in Table 3. Specific accuracy data concerned with items of construction shall be presented in the form shown in Table 6 and for manufactured components in the form shown in Table 7. 8 Publication of accuracy data For each item of construction or general component typ
49、e, the generalized accuracy data should preferably be presented to and published by the national standards organization.BS7308:1990 BSI 08-1999 3 The publication of specific accuracy data should be the responsibility of the particular contractor or manufacturer concerned who, for each item of construction or type of component, should publish the observed dimensional variability in his appropriate literature. Table 1 List of types of dimensions to be measured 1 Dimensions of setting out Size: distance between primary, secondary and positio
