1、BRITISH STANDARD BS 6065:1981 ISO 5022:1979 Methods for Sampling and acceptance testing of shaped refractory products ISO title: Shaped refractory productsSampling and acceptance testing UDC 666.74:620.113BS6065:1981 This British Standard, having been prepared under the directionof the Refractory Pr
2、oducts Standards Committee, was published under the authorityof the Executive Boardand comes into effect on 30April1981 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference RPE/12 Draft for comment78/71174 ISBN 0 580 11861 4 Cooperating organizations The
3、Refractory Products Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: British Ceramic Research Association* British Steel Industry* Cbmpe Chemical Industries Association Coke Oven Managers Association Combustion Engineering
4、 Association Engineering Equipment Users Association Glass Manufacturers Federation Institute of Refractories Engineers Refractories Association of Great Britain* Society of British Gas Industries Society of Chemical Industry Society of Glass Technology Society of Industrial Furnace Engineers The or
5、ganizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Ministry of Defence Amendments issued since publication Amd. No. Date of issue CommentsBS6065:1981 BSI 02-
6、2000 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Scope and field of application 1 2 Statistical terminology and symbols 1 3 General considerations and preliminary conditions for sampling 3 4 Sampling for non-destructive tests 8 5 Sampling for destructive tests
7、 10 6 Report on sampling 25 Annex A Determination of the arithmetic mean and standarddeviationofaproduction 26 Annex BComparison of the means of two samples 27 Annex CEquations used for calculating the values given in the tables 28 Annex D Bibliography 31 Figure 1 Example of operating characteristic
8、 curves when severalpropertiesare investigated simultaneously 6 Figure 2 Operating characteristic curves for single sampling plans definedinTable 4: testing for a guaranteed value of the population meanwhenthe standard deviation is known 13 Figure 3 Procedure for decision on conformity 16 Figure 4 O
9、perating characteristic curves of single sampling plans of Table 9 for AQL=1.5%: fixed unilateral limit for individualvaluesandknown standard deviation 20 Figure 5 Operating characteristic curves of single sampling plans of Table 9 for an AQL=2.5%: fixed unilateral limit for individual valuesandknow
10、n standard deviation 21 Figure 6 Operating characteristic curves of single sampling plans of Table 9 for an AQL=4.0%: fixed unilateral limit for individual valuesandknown standard deviation 22 Figure 7 Operating characteristic curves of single sampling plans of Table 9 for an AQL=6.5%: fixed unilate
11、ral limit for individual valuesandknown standard deviation 23 Table 1 Change in risks when the number of independent propertiesinspectedincreases 7 Table 2 Inspection process 9 Table 3 Single sampling plans for sampling by attributes in normal inspection 9 Table 4 Single sampling plans in the case o
12、f a guaranteed value for the mean 12 Table 5 Conformity decisions 14 Table 6 Sequential sampling plans in the case of a guaranteed value limit ( G ) for the mean and a known standard deviation 15 Table 7 Development of sequential sampling plan 15 Table 8 Development of sequential sampling plan 17 Ta
13、ble 9 Single sampling plans with a fixed unilateral limit for theindividualvalues and a known standard deviation 17 Table 10 Single sampling plans with a unilateral limit fixed for theindividualvalues and an unknown standard deviation 25 Table 11 Confidence interval of and for different sizes n 26 T
14、able 12 Values for the quantity g for the purpose of comparing themeansoftwo samples of the same size n 27 Publication referred to Inside back coverBS6065:1981 ii BSI 02-2000 National foreword This standard has been prepared under the direction of the Refractory Products Standards Committee. It is i
15、dentical with ISO5022 “Shaped refractory productsSampling and acceptance testing”, published in1979 by the International Organization for Standardization (ISO). A summary of the procedures, together with guidance on the factors to be considered when drawing up specifications and choosing sampling pl
16、ans, will be published in a future British Standard. Terminology and conventions. The text of the International Standard has been accepted as suitable for publication, as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Stand
17、ards; attention is especially drawn to the following. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on
18、the baseline as the decimal marker. NOTETextual error. When adopting the text of the International Standard the following printing error was noticed. In 5.3.2.4 “kgF/cm 2 ” should be read as “kgf/cm 2 ”. A British Standard does not purport to include all the necessary provisions of a contract. Users
19、 of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross references International Standard Corresponding British Standard ISO2859:1974 BS6000:1972 Guide to the use of BS6001. Sampling proc
20、edures and tables for inspection by attributes (Technically equivalent) BS6001:1972 Sampling procedures and tables for inspection by attributes (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1to32, an inside back cover and
21、 a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6065:1981 BSI 02-2000 1 1 Scope and field of application This International Standard gives directives for sampling sh
22、aped refractory products and for obtaining, from a sample of the smallest possible size, the most precise assessment possible, of the quality of a consignment. The methods described below make it possible to carry out an acceptance test based on an assessment of the extent to which the specification
23、s have been observed, but do not make it possible to determine whether the accepted consignment is suitable for a given application or to compare different qualities of parts for this same purpose. This International Standard applies to products manufactured from refractory materials. It may be appl
24、ied when the parties concerned have agreed to do so and have therefore, by common consent, made a choice between the various possibilities put forward in this International Standard, and have specified the various parameters (see3.2) which must be defined in order to permit the application of the me
25、thods described. It is also possible to apply the directives forming the subject of this International Standard while modifying, by prior agreement between the parties concerned, those values which, particularly in the tables, do not follow from statistical laws (see3.3). 2 Statistical terminology a
26、nd symbols 2.1 population the totality of items under consideration. Each of the batches formed in accordance with3.1 represents a population 2.2 size of the population number of items in the population (symbol: N) 2.3 sample one or more items taken from a population and intended to provide informat
27、ion on the population and possibly to serve as a basis for a decision on the population or the process which had produced it 2.4 size of the sample number of items in the sample (symbol: n) 2.5 observed value the value of a characteristic determined as a result of an observation or test (symbol for
28、the observed value having the number i : x i ) 2.6 extreme values 2.7 (arithmetic) mean the arithmetic mean of the observed values in a sample is their sum divided by the size of the sample the mean value of the population is designated by the symbol x max : largest observed value in a sample; x min
29、 : smallest observed value in a sample.BS6065:1981 2 BSI 02-2000 2.8 standard deviation the standard deviation is the quantity most commonly used in statistics to characterize dispersion. It is the square root of the variance the standard deviation of the sample is given by the formula: the standard
30、 deviation of the population is designated by the symbol in practice it is generally not convenient to computeand s using the above formulae. Computations are made easier and their results improved using equivalent but different formulae (see2) 2.9 confidence interval when it is possible to define t
31、wo functions T 1and T 2of the values observed such that, when is a population parameter to be estimated, the probability P|T 1 u u T 2 |=1 where1 is a fixed number which is positive and less than1, the interval between T 1and T 2is a confidence interval for the limits T 1and T 2of the confidence int
32、erval are random variables which, as such, may have different values for each sample in a large series of samples, the frequency of the cases in which the interval will include will be approximately equal to1 2.10 confidence level the value1 of the probability associated with a confidence interval 2
33、.11 statistical tolerance interval an interval for which it can be stated with a given level of confidence that it contains at least a specified proportion of the population when both limits are defined by statistics, the interval is two-sided. When one of the two limits is not finite or consists of
34、 the absolute boundary of the variable, the interval is one-sided 2.12 inspection by attributes a method which consists in taking note, for every item of a population or of a sample taken from this population, of the presence or absence of a certain qualitative characteristic (attribute) and in coun
35、ting how many items have or do not have this characteristic the characteristics inspected by attribute are, for example, cracks or other defects which are visible on the outside, or else defects which are revealed on sawing or by a sonic test 2.13 inspection by variables a method which consists in m
36、easuring a quantitative characteristic for each item of a population or of a sample taken from this population the measurable characteristics are, for example, the results of dimensional measurements, of chemical analysis or of physical tests 2.14 single sampling a type of sampling which consists of
37、 taking only one sample per batch xBS6065:1981 BSI 02-2000 3 2.15 sequential sampling a type of sampling which consists in taking successive items, or sometimes successive groups of items, but without fixing their number in advance, the decision to accept or reject the batch being taken, as soon as
38、the results permit it according to rules laid down in advance 2.16 acceptable quality level (AQL) a quality level which, in a sampling plan, corresponds to a specified, but relatively high, probability of acceptance it is the maximum proportion of defective units in the batch, such that batches in w
39、hich the percent defective does not exceed this values, are regarded as “good” and will very probably be accepted if a sampling plan is applied 2.17 limiting quality (LQ) a quality level which, in a sampling plan, corresponds to a specified and relatively low probability of acceptance (usually10%) i
40、t is the proportion of defective units in the batch, such that batches in which the percent defective exceeds this value are regarded as “bad” and will very probably be rejected if a sampling plan is applied 2.18 producers risk for a given sampling plan, the probability of rejecting a batch in which
41、 the proportion of defective items has a value fixed by the plan it is the probability of rejecting a batch when the proportion of defective units in this batch equals the acceptable quality level AQL (or when its mean value is equal to the guaranteed value Gfor the mean) 2.19 consumers risk for a g
42、iven sampling plan, the probability of accepting a batch in which the proportion of defective items has a value fixed by the plan it is the probability of accepting a batch when the proportion of defective units is equal to the limiting quality LQ (or when its mean value equals G +% or G %) 2.20 ope
43、rating characteristic curve (OC) a curve showing, for a given sampling plan, the probability of acceptance of a batch as a function of its actual quality 3 General considerations and preliminary conditions for sampling 3.1 Subdivision of consignments into batches Consignments which correspond to a l
44、arge tonnage shall be subdivided into batches of100 to500t made up in accordance with the objectives which are being aimed at. These batches shall be sampled and subjected to tests separately and they may be accepted separately. It will also be necessary to subdivide into batches a consignment which
45、 comprises products belonging to different classes or in which the items have been obtained by different methods of manufacture. Moreover, a consignment shall also be subdivided into batches according to sizes, masses and, if necessary, the shapes of the items, if the producer and consumer are agree
46、d in thinking that these factors influence the characteristics investigated. For the purpose of making up batches in terms of the masses of the items, it is often desirable to divide the items into the following three categories: category1: items up to15kg; category2: items ranging from15 to35kg; ca
47、tegory3: items in excess of35kg.BS6065:1981 4 BSI 02-2000 The making-up of batches from a consignment may be facilitated if the items are marked in such a way as to indicate the period during which they have been manufactured. If a batch is declared to be non-complying it is possible to sub-divide i
48、t into smaller batches by applying the criteria indicated above which might not have been taken into account when making it up, in order to ensure greater uniformity of each of the new batches made up, and these may be subjected to acceptance separately. This procedure may only be applied after a ne
49、w agreement has come into operation between the producer and the consumer, and it is expedient to make sure that the new sampling plans which will be operated provide, for both parties, similar guarantees to those which would result from the first plan used. 3.2 Properties inspected 3.2.1 Specifications relating to the properties inspected For each of the batches made up as indicated above, each of the properties inspected by attributes is characterised by a proportion of defective units in
