ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO ۳۹۰ was prepared by Technical Committee ISO/TC ۷۷, Products in fibre reinforced cement Study group for harmonization work.
This second edition cancels and replaces the first edition (ISO ۳۹۰:۱۹۷۷), of which it constitutes a technical revision.
Annexes A and B form an integral part of this International Standard. Annexes C and D are for information only.
Scope
This International Standard establishes rules for batching, sampling and inspection of fibre-reinforced cement products.
These rules apply to all acceptance tests. In certain cases they may also apply to type tests but the sampling scheme for type tests will usually be specified in the product standards.
These rules form a uniform method for determining whether consignments of fibre-reinforced cement products can be considered as conforming to relevant product standards.
This International Standard also gives guidelines for internal sampling and inspection of finished products from a continuous production process, allowing the relaxation of the rules concerning acceptance or rejection of inspection lots providing that the appropriate conditions have been fulfilled.
The quality system of the factory is outside of the scope of this International Standard.۱)
The sampling schemes are based on ISO ۲۸۵۹-۱, ISO ۳۹۵۱, ISO ۸۴۲۲ and ISO ۸۴۲۳ with an AQL of 4 % and inspection level S3.۲)According to the results obtained on previous batches, either a reduced or a tightened control is applied in accordance with these Standards.
The methods of switching rules (normal, tightened or reduced inspection) are given in extracts of those Standards reproduced in annexes A and B.
Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
- ISO ۳۹۵:۱۹۸۳, Asbestos-cement slates.
- ISO ۸۸۱:۱۹۸۰, Asbestos-cement pipes, joints and fittings for sewerage and drainage.
- ISO ۲۸۵۹-۱:۱۹۸۹, Sampling procedures for inspection by attributes — Part1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection.
- ISO ۳۹۵۱:۱۹۸۹, Sampling procedures and charts for inspection by variables for percent nonconforming.
- ISO ۸۴۲۲:۱۹۹۱, Sequential sampling plans for inspection by attributes.
- ISO ۸۴۲۳:۱۹۹۱, Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation).
- ISO ۹۰۰۰:۱۹۸۷, Quality management and quality assurance standards —Guidelines for selection and use.
- ISO ۹۰۰۱:۱۹۸۷, Quality systems — Model for quality assurance in design/development, production, installation and servicing.
- ISO ۹۰۰۲:۱۹۸۷, Quality systems — Model for quality assurance in production and installation.
- ISO ۹۰۰۳:۱۹۸۷, Quality systems — Model for quality assurance in final inspection and test.
Definitions
For the purposes of this International Standard, the following definitions apply.
acceptable quality level (AQL)
When a continuous series of lots is considered, the quality level which for the purposes of sampling inspection is the limit of a satisfactory process average.
Note 1 to entry: A sampling scheme with an AQL of 4 % means that batches containing up to 4 % defective items have a high probability of acceptance.
order
Quantity of a product or material ordered at one time from one producer.
Note 1 to entry: An order may consist of one or more consignments. See production batch (۳.۸) and inspection batch (۳.۹).
consignment
Quantity of products or material delivered at one time covered by one set of shipment documents.
Note 1 to entry: A consignment may consist of several lots or parts of lots. See also production batch (۳.۸) and order (۳.۲).
type test
Test for approval of a new product and/or a fundamental change in formulation or method of manufacture, or both. The test is performed on the as-delivered product.
The type test is not to be taken as evidence of the conformity to specification of products subsequently produced in quantity.
acceptance test
Test to establish whether a batch of products conforms to a specification. The tests are performed on samples drawn either from continuous production or from a consignment.
Note 1 to entry: Test methods and specification limit values are defined in the individual product standard. Sampling levels and acceptance criteria are defined in this International Standard.
inspection
Activities such as measuring, examining, testing and gauging one or more characteristics of a product, and comparing the results with designated requirements.
item
Actual or conventional object that can be individually considered and separately inspected.
Note 1 to entry: The term “individual” is sometimes used as a synonym for “item”. The word “unit” is often used as a synonym for “item”.
production batch
Quantity of product or material manufactured by one supplier under conditions presumed uniform i.e. manufactured from the same formulation on the same forming machine without prolonged or abnormal interruptions and having the same acceptance requirement for the relevant test.
inspection batch
Definite quantity of some product or material collected together and submitted for examination or acceptance.
Note 1 to entry: An inspection batch may consist of several batches or parts of batches. See also “consignment” (۳.۳) and “order”(۳.۲).
inspected batch
Inspection batch that has been submitted to examination.
maximum size of inspection batch
Upper size limit of an inspection lot from which a certain sample has to be drawn to be submitted to inspection.
minimum size of inspection batch
Lower size limit of an inspection lot from which a certain sample has to be drawn to be submitted to inspection.
inspection by attributes
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 characteristic (attribute) and in counting how many items have or do not have this characteristic.
inspection by variables
Method which consists in measuring a quantitative characteristic for each item of a population or of a sample taken from this population.
sample
One or more items taken from an inspection batch at random irrespective of their quality and intended to serve as a basis for a decision on that lot.
sampling plan
Specific plan which states sample size or sizes to be used and the associated acceptance criteria. Verification of an inspection batch based upon the inspection of a sample.
single sampling
Sampling inspection in which the decision to accept or not to accept a batch is based on the inspection results obtained from a single sample of predetermined size n.
double sampling
Sampling inspection in which the inspection of the first sample of size n۱ leads to a decision to accept a batch or not to accept it or to take a second sample of size n۲ and the second sampling inspection then leads to a decision of acceptance or rejection.
sequential sampling
Type of sampling which consists in taking successively items, or sometimes groups of items, but without fixing their number in advance, the decision to accept or reject the batch being taken as soon as the results permit it, according to rules laid down in advance.
sample size
Number of items in the sample.
test specimen
Item or part of an item prepared for testing.
range
Difference between the greatest and the smallest observed values of a quantitative characteristic.
nonconformity
Non-fulfilment of a specified requirement.
nonconforming item
nonconforming unit
Item (unit) with one or more nonconformities.
acceptance
Conclusion after inspection that a batch or quantity of products satisfies the requirement criteria based on the results of the inspection.
non-acceptance
rejection
Conclusion after inspection that a batch, or quantity of products does not satisfy the requirement criteria based on the results of the inspection.
Note 1 to entry: When it is applied to the consignment from a producer, the term “rejection” means in a more liberal sense “non-acceptance of the batch under the conditions of the contract” (for example, the batch may be placed in another class, subjected to a lowering of price, etc.), and it is usual to specify the disposal of a rejected batch (e.g. return to supplier).
acceptance number
Acn
In sampling inspection by attributes, the highest number of nonconformities or nonconforming items (units) found in the sample that permits the acceptance of the batch.
rejection number
non-acceptance number
Ren
In sampling inspection by attributes, the lowest number of nonconformities or nonconforming items (units) found in the sample that requires the rejection of the batch.
منبع: ISO
نام کتاب:
ISO -Products in fibre reinforced cement
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