1、BRITISH STANDARD BS 1902-3.1: 1981 Methods of testing Refractory materials Part 3: General and textural properties Section 3.1 Guidance on sampling NOTEThis Section is to be read in conjunction with BS1902-3.0 “Introduction” which shows the general arrangement of BS1902 and lists the Sections of Par
2、t 3. UDC 666.76.017:620.113BS1902-3.1:1981 This British Standard, having been prepared under the direction of the Refractory Products Standards Committee, was published under the authority of the Executive Board and comes into effect on 27 February 1981 BSI 06-1999 The following BSI references relat
3、e to the work on this standard: Committee reference RPE/1 Draft for comment 79/74383 DC ISBN 0 580 11710 3 Cooperating organizations The Refractory Products Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: British Ceramic
4、Research Association* British Steel Industry* Cbmpe Cement Makers Federation Chemical Industries Association Coke Oven Managers Association Combustion Engineering Association Engineering Equipment Users Association* Glass Manufacturers Federation Institute of Refractories Engineers Refractories Asso
5、ciation of Great Britain* Society of British Gas Industries Society of Chemical Industry Society of Glass Technology* Society of Industrial Furnace Engineers The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee
6、 entrusted with the preparation of this British Standard: British Cast Iron Research Association Electricity Supply Industry in England and Wales Institute of Petroleum Amendments issued since publication Amd. No. Date of issue CommentsBS 1902-3.1:1981 BSI 06-1999 i Contents Page Cooperating organiz
7、ations Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Definition 1 4 Random samples and representative samples 1 5 Availability for sampling 1 6 Size of sample 1 7 Exclusion and substitution of samples 2 Publications referred to Inside back coverBS1902-3.1:1981 ii BSI 06-1999 Foreword Thi
8、s Section of this British Standard has been prepared under the direction of the Refractory Products Standards Committee. This Section supersedes clauses2 and3 of BS1902-1A:1966, “Sampling and physical tests”, which have been deleted by amendment. The contents of clause4 have been omitted in view of
9、the preparation of standards specific to sampling methods, and the contents of clause5 have been transferred to the separate Sections dealing with the tests concerned. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsibl
10、e 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, pagesi andii, pages1 and2, an inside back cover and a back cover. This standard has been updat
11、ed (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS1902-3.1:1981 BSI 06-1999 1 1 Scope This Section of this British Standard gives guidance on the taking and use of samples of refractory materials and products.
12、2 References The titles of the standards publications referred to in this Section of this British Standard are listed on the inside back cover. 3 Definition For the purposes of this British Standard, the following definition applies. sample a group of units (e.g.bricks) or a portion of material that
13、 is taken from a consignment or from a quantity of material with a view to its being used to give information on the quality of that larger quantity 4 Random samples and representative samples 4.1 Samples may be “random” or “representative”. Random samples are taken without bias so that each item ha
14、s an equal chance of inclusion. Representative samples are drawn in a systematic way so that each portion of the sample represents a corresponding portion of the bulk. The sampling of each portion of a representative sample will probably need to be random. 4.2 Each of these methods is used, as appro
15、priate, in the sampling of refractory products. Representative samples may be taken by the manufacturer from a kiln to check the uniformity of firing; random samples may be taken by the user from a consignment of bricks to check the quality of the material. 5 Availability for sampling Sampling can o
16、nly be properly carried out when the whole of the batch from which the sample is required is accessible to the sampler. In general, this is only practicable when the material is being moved from one position to another. A stockpile cannot be adequately sampled under practical conditions. 6 Size of s
17、ample 6.1 When a supplier and purchaser have agreed that a transaction is to be based on a defined scheme for sampling and subsequently accepting or rejecting the consignment concerned, the size of the sample (bricks and units) will be laid down by the scheme 1) . It generally depends on the nature
18、of the sampling and inspection to be carried out, e.g.sampling for an inspection by attributes (non-destructive) or sampling for the measurement of properties (usually destructive), on the size of the batches into which the consignment has been divided and on whether or not the standard deviation of
19、 each property value is known. 6.2 The following guidance is offered for the formulation of a sampling programme when there has been no agreement on the use of a standard sampling scheme. a) Stock size bricks. When sampling for an inspection by attributes, where the ordered quantity of bricks is les
20、s than 1000 pieces, the minimum sample should consist of 20 bricks; where the ordered quantity is greater than 1 000 but less than 5000, the minimum sample should consist of 80 bricks; and between 5001 and 10000 the minimum sample should be 125 bricks. An agreement should be made on which attributes
21、 are to be subject to control, and the maximum permissible level of defectives should be agreed before any batch of bricks can be declared to be not in conformity with the requirement. When sampling for an inspection by properties, where the ordered quantity of bricks is less than 1000 pieces, the m
22、inimum sample should consist of 4bricks; where the ordered quantity is greater than 1000 but less than 5000, the minimum sample should consist of 6 bricks; and between 5001 and 10000 the minimum sample should be10 bricks. An agreement should be made on which properties are to be subject to control,
23、with a maximum of three properties. 1) BS . which implements ISO5022 without deviation, describes a scheme of this nature for the sampling of shaped refractories. Schemes for the sampling of unshaped refractories and of refractory materials are being prepared by the International Organization for St
24、andardization. Each of these will be considered for implementation as a British Standard when completed.BS1902-3.1:1981 2 BSI 06-1999 Simple and inexpensive control tests should be performed on the samples outlined above. When compliance with a specified value of the average or extreme limit of a co
25、ntrol property is in question, a larger sample may be taken, by agreement between the purchaser and supplier. Other properties, which may not be suitable for control, may be tested at a reduced rate, but the results cannot then be treated statistically. b) Special shapes and sizes. For the reasons o
26、utlined above, no general rules can be given, but it is suggested that, whenever convenient, the procedure for stock size bricks should be followed. c) Ground clay, cements and granular materials. In the case of materials with a maximum grain size below 10mm, a minimum representative sample of 5kg s
27、hould be taken and for batches of more than 5t, the sampling rate should be not less than 1kg/t. 7 Exclusion and substitution of samples 7.1 In general, samples should be selected in accordance with an agreed standard sampling scheme (see6.1). Subject to that scheme, a sample selected in accordance
28、with the agreed procedure cannot be excluded from use in the tests without invalidating the statistical control effected by the scheme. 7.2 The general principle set out in7.1 is applicable to a selected sample that has a flaw likely to affect the value of the variable being measured; for example, a
29、 pronounced crack in a test piece would be likely to affect the result of any test carried out under an applied stress. In other cases, however, a flaw in a selected test piece might affect, not the value of the property, but the accuracy with which it could be determined; for example, the same crac
30、k would not affect the density or the porosity of the material on either side of the crack but might, by affecting the measurement of the volume of the test piece, lead to false results in the determination of density and porosity. 7.3 In the second of the cases in7.2, it might be correct to exclude
31、 the flawed test piece from the tests and to substitute another one for it. If a selected test piece is so excluded the fact should be mentioned in the test report. 7.4 Whether or not it would be correct, in any particular case, to exclude such a test piece is a matter of judgement, and perhaps for
32、agreement between the parties interested in the tests. The purpose of this clause is to ensure that any such situation is recognized and due consideration given to it.BS1902-3.1:1981 BSI 06-1999 Publications referred to BS . . . ., Sampling and acceptance testing of shaped refractory products 2) . I
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