1、BRITISH STANDARD BS 7243-1: 1989 ISO 8656-1: 1988 Refractory raw materials Part 1: Method of samplingBS7243-1:1989 This BritishStandard, having been prepared under the directionof the Refractory Products Standards Policy Committee, was published underthe authority of the BoardofBSI and comes into ef
2、fect on 31October1989 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference RPM/12 Draft for comment 87/35421 DC ISBN 0 580 17846 3 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Refractory Prod
3、ucts Standards Policy Committee (RPM/-) to Technical Committee RPM/12, upon which the following bodies were represented: British Cement Association British Ceramic Research Ltd. British Metallurgical Plant Constructors Association British Steel Industry Department of Trade and Industry Refractories
4、Association of Great Britain Society of Glass Technology Amendments issued since publication Amd. No. Date of issue CommentsBS7243-1:1989 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 General rules 2 5
5、Sampling and sample preparation 3 6 Composition and number of laboratory samples and test portions for analysis 7 7 Precision of the determination of a property 7 8 Example 8 Annex A (normative) Methods for taking increments 9 Figure 1 Example of a sampling scheme 8 Figure A.1 Examples of sampling f
6、rom wagons 10 Table 1 Minimum mass of increment depending on the maximum grain size 3 Table 2 Minimum number of increments and sampling precision 5 Table 3 Variation class depending on the selected oxide 6 Publications referred to Inside back coverBS7243-1:1989 ii BSI 12-1999 National foreword This
7、BritishStandard has been prepared under the direction of the Refractory Products Standards Policy Committee. It is identical with ISO8656-1:1988 “Refractory products Sampling of raw materials and unshaped products Part1: Sampling scheme”, published by the International Organization for Standardizati
8、on (ISO). This International Standard was prepared by Technical Committee ISO/TC33, Refractories, with the active participation of the UK. Additional information. Where this sampling scheme is used for prepared unshaped refractory products (e.g.castables, gunning materials and ramming mixes), unacce
9、ptably large amounts of material may be required. For reduced sampling rates, see BS1902-7.1 The scheme is unsuitable for mouldables (seenote to clause1). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their c
10、orrect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding BritishStandard ISO3534:1977 BS5532 Statistical terminology Part1:1978 Glossary of terms relating to probability and general terms r
11、elating to statistics (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in t
12、he amendment table on the inside front cover.BS7243-1:1989 BSI 12-1999 1 1 Scope This part of ISO8656 specifies methods and conditions of sampling for raw materials and prepared unshaped refractory products, in order to indicate the mean values of a consignment and the interval of sampling. It does
13、not apply to products in the form of large static quantities or cargoes from which reliable samples cannot be taken. The type of sampling equipment, and the preparation and reduction of the samples, which should not alter the properties to be tested, are to be agreed between the interested parties.
14、NOTEDifficulties may be encountered when sampling certain types of unshaped products, for example mouldables. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO8656. At the time of publication, the editio
15、ns indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO8656 are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid Inter
16、national Standards. ISO3534:1977, Statistics Vocabulary and symbols. ISO8656-2:, Refractory products Sampling of raw materials and unshaped products Part2:Determination of the coefficient of variation 1) . 3 Definitions NOTESee also ISO3534. 3.1 lot defined quantity of a particular material manufact
17、ured or produced in conditions which can be considered as being uniform 3.2 consignment quantity of material supplied at one time. A consignment may consist of one or several lots or parts of a lot 3.3 test lot specific quantity subjected to inspection (checking), manufactured normally by a supplier
18、 in conditions which can be assumed to be uniform 3.4 packaged unit packaged part of a lot (for example, in a sack or small container) 3.5 sample quantity of material taken from a consignment or a lot, intended to supply information, and possibly serve as a basis for a decision concerning the consig
19、nment or lot or the process by which it has been produced 3.6 increment quantity of material taken at one time from a larger quantity of material 3.7 standard deviation of sampling standard deviation of the random variations introduced into the measurement of a chosen property by sampling 1) To be p
20、ublished.BS7243-1:1989 2 BSI 12-1999 3.8 bulk sample the aggregation of the increments 3.9 partial sample sample obtained by dividing the bulk sample 3.10 laboratory sample sample intended to be used for an inspection or for laboratory tests 3.11 test sample; final sample, analytical sample sample t
21、aken from the laboratory sample and prepared in a suitable manner for subjection to particular tests (for example, determination of grain size distribution, humidity, chemical composition, physical or other properties) 3.12 coefficient of variation ratio of the standard deviation to the absolute val
22、ue of the arithmetic mean (this ratio may be expressed as a percentage) 4 General rules Because of the diversity of ceramic raw and unshaped materials, the method of delivery and packaging and the conditions and circumstances under which sampling and sample preparation are carried out, rigid rules f
23、or sampling cannot be specified in all cases (see Annex A), and interested parties should agree on the preferred sampling plan. 4.1 The sampling and sample preparation procedures shall be performed under the supervision of a person having adequate experience of sampling. 4.2 Where required, the cons
24、ignment may be sub-divided into individual test lots, for example, if it is clear that the consignment consists of various lots or should be treated in separate partial quantities. 4.3 Sampling should preferably be carried out on material in movement during loading or unloading of the consignment or
25、 while filling the packaged units. 4.4 In the case of certain prepared unshaped materials (for example, concrete) delivered in sacks which may, at the time of packaging, have been filled with successive layers of unmixed components, or where materials have become separated to some extent during tran
26、sportation, it is necessary to take the increment(s) after mixing the various components. This sampling method is expensive as it results in large quantities of materials being handled. For this reason the sampling method described in4.3 shall be preferred. 4.5 The increment shall be taken on the ba
27、sis of a periodic systematic sampling method with a random starting point and a systematic procedure, on the basis of time, or on the basis of uniform intervals between samplings and/or on the basis of mass. 4.6 The minimum mass of the increment shall be determined, taking account of the maximum gra
28、in size of the material in order to avoid systematic errors during sampling (see Table 1). 4.7 The number of increments to be taken from a test lot shall be determined taking account of deviations in the properties of the material and the desired precision of sampling( 1 ) (see Table 2). 4.8 During
29、sampling, sample division, and preparation and storage of the samples, the samples shall be protected against any changes in the properties to be tested. 4.9 The use of a sample to determine several properties is allowed, provided that the result(s) of the test is (are) not changed by the test or th
30、e preceding tests.BS7243-1:1989 BSI 12-1999 3 5 Sampling and sample preparation 5.1 Procedure 5.1.1 Identify the test lot, i.e.of the consignment or part of the consignment to be sampled (nature of product, mass, transport conditions, etc.). 5.1.2 Estimate the maximum grain size of the material. 5.1
31、.3 Determine the mass of the increment in accordance with Table 1, taking account of the minimum quantities required for the tests provided for (see note3 to Table 1). 5.1.4 Classify the test lot in a quality variation class (see Table 2,5.3 and5.4). 5.1.5 Determine the number of increments to be ta
32、ken (in accordance with Table 2). 5.1.6 Calculate the minimum mass of the bulk sample and verify that it is in conformity with the tests provided for (see5.5). 5.1.7 Determine the sampling point(s) and the methods for sampling and combining increments. 5.1.8 Take the required number of increments in
33、 accordance with5.5. 5.1.9 If necessary, before making up the bulk sample, the increment(s) may be divided in order to have a reserve sample which may be used in case of dispute. 5.1.10 Make up laboratory samples, as agreed between the interested parties, from the increments or bulk sample in accord
34、ance with the sampling and sample preparation plan. NOTECare should be exercised not to alter the material when testing properties in the “as-received” condition. 5.1.11 Make up the test samples necessary to carry out the specified programme. 5.2 Mass of the increment 5.2.1 The minimum mass of the i
35、ncrement is determined in accordance with Table 1 from the maximum grain size of the material. 5.2.2 When the mass of the increment has been determined, take samples in such a way that all have approximately the same mass. Table 1 Minimum mass of increment depending on the maximum grain size Maximum
36、 grain size mm Minimum mass of increment 100 100 50 20 10 3 1 30kg 15kg 5kg 2kg 500g 200g 50g NOTE 1The masses of the increments relate to a bulk density greater than1g/cm 3 . For lower bulk densities, the mass of the increment may be determined by multiplying the numerical value in the table by the
37、 bulk density of the material. NOTE 2Special agreements should be made in the case of very lumpy products. In the case of pre-ground or pre-homogenized material, the minimum mass of the increment can be determined, not from the grain size of the coarsest aggregate, but from the maximum size of the g
38、rains of the material before aggregating. NOTE 3The actual increment masses should depend on the sampling equipment and the tests to be performed. This is the case for unshaped products if the physico-mechanical properties of specimens taken from these products are to be determined.BS7243-1:1989 4 B
39、SI 12-1999 5.3 Classification of a property according to the range of its variations 5.3.1 The mean value and the standard deviation of a given property, designated respectively by and , define the coefficient of variation / of this property. Expressed in practice as a percentage v=100 / this is use
40、d in this International Standard to assign and define the classes of variation of the property. 5.3.2 The values of the coefficient of variation are divided into three classes: 0 u vu5% small variation, class1 5%vu 15% medium variation, class2 15%vu 30% large variation, class3 5.3.3 The estimation o
41、f the coefficient of variation requires the estimation of the standard deviation of sampling, which is obtained from the appropriate test results, applying the variance method or analysis. When this is done, a property is immediately assigned to a class of variation. It may be that the most critical
42、 coefficient of variation of the property is used for selecting the number n of increments in Table 2. 5.3.4 If nothing is known about the coefficient of variation or if it is greater than30, use the class3 values (large variations) of Table 2 (seeexamplesin5.6). 5.4 Number of increments and samplin
43、g precision 5.4.1 Determine the number n of increments from a property of the material. For example, this may be, depending on the agreements reached, the most important property or the property which is affected by the highest coefficient of variation v. The coefficient of variation of the determin
44、ation of a property using the bulk samples and resulting from the sampling is expressed by means of the sampling coefficient of variation between increments v: The relative precision of sampling for this property is defined as: 5.4.2 The number n of increments shall be such that for the property cho
45、sen a specific sampling precision 1is obtained: 5.4.3 The number of increments needed to achieve the desired precision of sampling is determined from the class of quality variation of the property and the mass of the test lot as specified in Table 2. The value of n given in Table 2 is a minimum and
46、generally the actual number should not be less than that specified in the table. For example: if a lower sampling precision is considered sufficient for economic reasons; or because the relative precisions of the sampling preparation and the test method are too great; or if a greater precision is re
47、quired, then the number of increments for the required precision can be determined from equation(3) (seealsoclause7). If other properties which are being determined by forming a bulk sample have coefficients of variation different from that of the selected property, their relative sampling precision
48、s 1differ from the values given in Table 2 and can be calculated from equation(2). If the test lot is delivered by separate means of transport, for example railway wagons or trucks, at least one increment shall be taken from each of these means of transport. . . .(1) . . .(2) . . .(3) v 1 v n - = 1
49、2v 1 2v n - = n 4v 2 2 1 - =BS7243-1:1989 BSI 12-1999 5 If the test lot is delivered in smaller packaged units such as bags, sacks, etc., the n increments as specified in Table 2 shall be taken from different packaged units. If the number of packaged units in the test lot is less than n, the same number of samples shall be taken from each of the packaged units giving a total at least equal to n. The number of increments per packaged unit shall be reported. NOTEThe coefficient of variation of the material in any fi
