1、PUBLICLY AVAILABLE SPECIFICATION PAS 70:2003 HD clay bricks Guide to appearance and site measured dimensions and tolerance ICS 91.100.25 PAS 70:2003 This Publicly Available Specification comes into effect on 28 October 2003 BSI 28 October 2003 ISBN 0 580 42783 8 Amendments issued since publication A
2、md. No. Date CommentsPAS 70:2003 BSI 28 October 2003 i Contents Page Foreword ii Introduction 1 1S c o p e 1 2 Normative references 1 3T e r m s a n d d e f i n i t i o n s 1 4A p p e a r a n c e 2 4.1 General 2 4.2 Principle 3 4.3 Construction of the reference panel 3 4.4 Construction of the sample
3、 panels 3 4.5 Assessment 4 5 Dimensions and tolerances 4 5.1 Principle 4 5.2 Apparatus 4 5.3 Preparation of specimens 4 5.4 Procedure A Tolerances for mean dimensions (T1, T2 or Tm) 4 5.5 Procedure B Tolerance category for dimensional range (R1, R2 and Rm) 5 5.6 Practical considerations of Procedure
4、s A and B 6 5.7 Test report 6 Annex A (informative) Example report format for Procedure B 7 Bibliography 9 Figure 1 Arrangement of bricks for measurement of dimension 4 Figure 2 Brick measurement positions 5PAS 70:2003 ii BSI 28 October 2003 Foreword This Publicly Available Specification, PAS 70, wa
5、s developed through the British Standards Institution (BSI). Acknowledgement is given to the following groups and organizations that were consulted in the development of this Publicly Available Specification: Brick Development Association Ltd. Ceram Building Technology Kingston University National B
6、uilding Specification Ltd. National House Building Council Office of the Deputy Prime Minister This Publicly Available Specification has been prepared and published by BSI, which retains its ownership and copyright. BSI reserves the right to withdraw or amend this PAS on receipt of authoritative adv
7、ice that it is appropriate to do so. This PAS will be reviewed at intervals not exceeding two years, and any amendments arising from the review will be published as an amended PAS and publicised in Update Standards. This publication does not purport to include all the necessary provisions of a contr
8、act. Users are responsible for its correct application. This Publicly Available Specification (PAS) is not to be regarded as a British Standard. It will be withdrawn upon publication of its content in, or as, a British Standard. Compliance with a Publicly Available Specification does not of itself c
9、onfer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.PAS 70:2003 BSI 28 October 2003 1 Intro
10、duction Where disputes over the appearance of clay brickwork arise they have traditionally been resolved with the assistance of Appendix F to BS 3921 which includes some general guidance and a means of comparing the appearance of sample panels built from a consignment of bricks with that of an agree
11、d reference panel at the start of the contract. When BS 3921 is withdrawn, Appendix F will no longer be available. This Publicly Available Specification is intended to supersede Appendix F by continuing to provide authoritative guidance, whilst removing reference to contractual arrangements and reta
12、ining a sample and reference panel approach to acceptability. Similarly, where disputes over the size or tolerance of clay bricks arise they have traditionally been resolved using the procedure in BS 3921 which will be superseded by BS EN 771-1 in due course. The BS 3921 procedure was to place 24 br
13、icks in a row and to measure the overall length, width or height of the row using a tape. This overall dimension was required to be within certain upper and lower limits. Although the bricks-in-a-row test was very practical and helpful and had been in use for some 50 years, the practice in the major
14、ity of European countries has been to control the dimensional tolerances of individual masonry units and it is this procedure that has been adopted as the reference in BS EN 771-1. The BS EN 771-1 measurement procedure is complex and the measuring equipment not readily amenable to site use. Conseque
15、ntly this Publicly Available Specification has been produced to give a simple site test that is intended to resolve most disputes without recourse to off site measurements and the use of long jaw callipers. In cases of dispute that cannot be resolved by these simple site procedures, it is recommende
16、d that the clay bricks are sampled in accordance with BS EN 771-1 and tested in accordance with BS EN 772-16, using the reference measuring procedure identified in BS EN 771-1. 1 Scope This Publicly Available Specification gives guidance on assessing the appearance of facing bricks, and the determin
17、ation of on-site measurements of work size dimensions, for all high density (HD) type clay bricks as defined by BS EN 771-1. It includes a procedure for comparing sample panels with reference panels in order to assess the appearance acceptability of consignments of clay facing bricks. It is not inte
18、nded to apply to common and engineering HD type clay bricks. It also provides a method of determining the overall dimensions of all clay bricks. The limits for the tolerance categories for the mean and range are those that apply to HD type clay bricks where the manufacturers declared work sizes are
19、those traditionally known as British Standard dimensions (UK standard format clay bricks). If clay bricks are supplied with other work sizes, the limits for these categories will need to be calculated in accordance with BS EN 771-1. 2 Normative references The following referenced documents are indis
20、pensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS 4035:1966, Specification for linear measuring instruments for use on building and civil en
21、gineering constructional works Steel measuring tapes, steel bands and retractable steel pocket rules. BS EN 771-1:2003, Specification for masonry units Part 1: Clay masonry units. 3 Terms and definitions For the purpose of this Publicly Available Specification, the following terms and definitions ap
22、ply. 3.1 brickwork masonry of bricks bonded and solidly put together with mortar BS 6100-5.1:1992PAS 70:2003 2 BSI 28 October 2003 3.2 HD (high density) clay brick clay masonry unit with a high gross dry density for use in unprotected masonry as well as in protected masonry BS EN 771-1:2003 with Nat
23、ional Annex NOTE These relate most closely to facing units in BS 6100-5.3 although, as the BS EN is performance related, the requirements are written in terms of durability rather than appearance. 3.3 brick masonry unit that does not exceed 338 mm in length, 225 mm in width or 113 mm in height BS 61
24、00-5.3:1984 3.4 facing unit masonry unit specially made or selected to give an attractive appearance BS 6100-5.3:1984 3.5 common unit masonry unit suitable for general construction work, with no special claim to give an attractive appearance BS 6100-5.3:1984 3.6 engineering brick brick sized fired-c
25、lay unit that has a dense and strong semi-vitreous body, that conforms to defined limits for water absorption and compressive strength BS 6100-5.3:1984 3.7 recessed joint mortar joint with its face finished back from the arrises and face of the adjacent masonry units 3.8 flush joint mortar joint wit
26、h its face finished level with the face of adjacent masonry units BS 6100-5.1:1992 3.9 reference panel trial panel built as brickwork and usually constructed at the start of a project for the purpose of establishing the visual characteristics of the brick, which is to be representative of the appear
27、ance of the brick to be used in the executed work 3.10 sample panel panel of brickwork or mortarless laid bricks erected adjoining the reference panel during the ongoing project works for the purpose of assessing the visual characteristics of bricks taken from subsequent project deliveries, to ensur
28、e a consistency of appearance in the executed work 4 Appearance 4.1 General The definitions in Clause 3 are taken from, or based on, the relevant parts of BS 6100. In practice, the term in common usage and of the greatest relevance to the appearance of clay brickwork is facing brickwork, which is br
29、ickwork as defined in 3.1 made from facing units as defined in 3.4. In practice it is not possible to write a universally applicable definition of acceptable appearance of facing brickwork, as this will vary significantly with the type of clay brick chosen. The appearance of brickwork is additionall
30、y dependent on the choice of brick, mortar, joint profile and workmanship.PAS 70:2003 BSI 28 October 2003 3 The characteristics of the surface of the clay brick are relevant only in so far as they prohibit the achievement of the specified required appearance. Consequently cracks or chips in the expo
31、sed face or arrises of a smooth faced regular shaped brick used with a recessed mortar joint may be unacceptable, but a similar number of such features may be quite acceptable on a handmade product used with a flush joint. To illustrate the variety that can be achieved, some examples of different ap
32、pearances produced by different bricks and mortars are: a) smooth faced wire-cut brick with recessed joint and a flush joint; b) stock brick with recessed joint and a flush joint; c) effect of mortar variation; d) effect of not blending bricks; e) textured surfaces/multi-coloured facing bricks. 4.2
33、Principle The acceptability of minor defects such as cracks, chips or surface blemishes of clay facing bricks when delivered to site is assessed. Sample panels from the brick deliveries are compared with a previously constructed reference panel, which is representative of what may reasonably be expe
34、cted to be delivered, and is large enough to encompass known and acceptable variations in bricks. This method can be used to assess consistency of supply in respect of colour and texture. The panels are viewed from a distance of 3 m, which is sufficient to reliably compare their aesthetic characteri
35、stics. 4.3 Construction of the reference panel Erect the reference panel on a level, firm foundation in a dry location, having good natural daylight. It should be sited so that it can be retained for further inspection and reference and should, therefore, be protected from damage and adverse weather
36、 conditions. If necessary, provision should be made for ensuring lateral stability of the panel. The reference panel should be of a size agreed by all parties but not less than 1 m 2and the clay bricks should be: a) supplied by the manufacturer or supplier so that they are reasonably representative
37、of the average quality of the whole order to be delivered; or b) randomly sampled in accordance with BS EN 771-1. Build the reference panel to the specification and contract requirements of the finished work and so that it exposes for assessment those faces that will be visible in the finished work.
38、 Lay bricks to the bond selected for the finished work to the horizontal and vertical gauge proposed and using mortar of the same class and colour, and finished with the same joint profile. 4.4 Construction of the sample panels Either: a) construct sample panels representing individual batches in th
39、e same way and of the same size as the reference panel (see 4.3). Allow the mortar sufficient time to cure so that the appearance can be fairly judged, in a protected environment; NOTE Seven days is usually sufficient curing time. or b) construct a dry bonded sample panel using no mortar between the
40、 bricks. Comparison of this dry stacked sample panel to the reference panel (see 4.3) should take no account of the mortar profile, colour and texture. In the event of dispute, a mortared sample panel should be used for comparison purposes. The clay bricks used for each panel should be randomly samp
41、led from the batch delivered to the site in accordance with BS EN 771-1 prior to subsequent handling on site.PAS 70:2003 4 BSI 28 October 2003 4.5 Assessment Inspection of the sample panel should be carried out at any time prior to subsequent handling on site. When the sample panel is viewed at the
42、same distance as the reference panel, which is usually 3 m and without close scrutiny of individual bricks, the two panels should not differ significantly. It is important that the reference panel is agreed by all parties as having the appearance required of subsequent sample panels. In particular,
43、if the clay bricks are being supplied through a third party, the manufacturer should agree to supply bricks equivalent in appearance to those of the reference panel. 5 Dimensions and tolerances 5.1 Principle This guide includes two procedures for assessment of dimensions and tolerance, A and B. Proc
44、edure A is a rapid method for determining the tolerance category for the mean length, width and height dimension. The overall dimension for ten clay bricks laid together in a row is measured and the average value determined. The difference between this average value and the declared work size is com
45、pared with tabulated values for the two tolerance categories for mean dimensions, T1 and T2 in BS EN 771-1. Procedure B is used to determine the range class. Ten clay bricks are individually measured and the difference between the largest and the smallest for each dimension is compared to tabulated
46、values for the two tolerance categories for the range, R1 and R2 in BS EN 771-1. NOTE Although both procedures in this PAS are only calibrated for use with UK standard format clay bricks, other clay unit work dimensional formats can be dealt with in a similar way if tolerance recalibration is undert
47、aken. 5.2 Apparatus 5.2.1 Retractable steel pocket rule, meeting the requirements of BS 4035. 5.3 Preparation of specimens 5.3.1 Sampling Sample ten clay bricks in accordance with BS EN 771-1, unless otherwise agreed. 5.3.2 Surface treatment Remove any superfluous material adhering to the clay brick
48、s as a result of the manufacturing process before taking measurements. 5.4 Procedure A Tolerances for mean dimensions (T1, T2 or Tm) 5.4.1 Determination of mean dimensions Place the clay bricks in contact with each other in a straight line along a level surface, using the appropriate arrangement for
49、 each dimension as shown in Figure 1. Measure the overall dimension (length, width and height) to the nearest millimetre, using a retractable rule (5.2.1), and record the result. Divide each respective overall measurement by 10 to obtain a mean value to the nearest millimetre. Figure 1 Arrangement of bricks for measurement of dimensionPAS 70:2003 BSI 28 October 2003 5 5.4.2 Tolerance category Determine the absolute values of the differences between the measured mean length, wi
