ISO 2859-1:1999
Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
- Статус документа:
- Отменён
- Формат:
- Электронный (PDF)
- Количество страниц:
- 87
- Дата публикации:
- 18 ноября 1999 г.
- Издание:
- ISO IS 2859 edition 2 version 1
- ICS:
- 03.120.30
1.1 This part of ISO 2859 specifies an acceptance sampling system for inspection by attributes. It is indexed in terms of the acceptance quality limit (AQL). Its purpose is to induce a supplier through the economic and psychological pressure of lot non-acceptance to maintain a process average at least as good as the specified acceptance quality limit, while at the same time providing an upper limit for the risk to the consumer of accepting the occasional poor lot. Sampling schemes designated in this part of ISO 2859 are applicable, but not limited, to inspection of ¾ end items, ¾ components and raw materials, ¾ operations, ¾ materials in process, ¾ supplies in storage, ¾ maintenance operations, ¾ data or records, and ¾ administrative procedures. 1.2 These schemes are intended primarily to be used for a continuing series of lots, that is, a series long enough to allow the switching rules (9.3) to be applied. These rules provide: a) a protection to the consumer (by means of a switch to tightened inspection or discontinuation of sampling inspection) should a deterioration in quality be detected; b) an incentive (at the discretion of the responsible authority) to reduce inspection costs (by means of a switch to reduced inspection) should consistently good quality be achieved. Sampling plans in this part of ISO 2859 may also be used for the inspection of lots in isolation but, in this case the user is strongly advised to consult the operating characteristic curves to find a plan that will yield the desired protection (see 12.6). In that case, the user is also referred to the sampling plans indexed by limiting quality (LQ) given in ISO 2859-2.
Abstract
Overview
ISO 2859-1:1999 specifies an acceptance sampling system for inspection by attributes, indexed by the Acceptance Quality Limit (AQL) for lot-by-lot inspection. Its purpose is to provide a standardized framework that pressures suppliers (economically and psychologically) to maintain process quality at or above a specified AQL while bounding consumer risk of accepting poor lots. The standard supports inspection of end items, components, in‑process materials, stored supplies, maintenance operations, records and administrative procedures.
Key topics and requirements
- AQL-based sampling schemes: Plans are indexed by AQL to determine sample sizes and acceptance numbers for lot acceptance decisions.
- Inspection modes: Defines normal, tightened and reduced inspection with formal switching rules to move between modes based on lot history.
- Sampling plan types: Includes single, double and multiple sampling schemes (master tables for normal/tightened/reduced inspection).
- Risk and performance tables: Tables and curves for producer’s risk, consumer’s risk quality, average outgoing quality limits (AOQL) and operating characteristic (OC) curves to assess plan performance.
- Sample size code letters and extensive tabulated plans: Code letters map lot sizes to sample sizes; auxiliary and fractional acceptance number plans are included for smoother progression between acceptance numbers.
- Optional features: Fractional acceptance number plans, skip‑lot sampling as an alternative to reduced inspection, and guidance for non‑constant sampling plans (informative Annex A).
- Use context: Primarily intended for a continuing series of lots (so switching rules can be applied), but tables and OC curves are provided for isolated-lot use with caution.
Practical applications
- Incoming inspection and supplier control: standardized lot acceptance criteria for purchased parts and materials.
- Production and in‑process quality control: sampling instead of 100% inspection when attributes (conforming/nonconforming) are measured.
- Storage, maintenance and administrative audits: periodic lot checks using attribute sampling.
- Quality contracts and procurement specifications: a common, internationally recognized method to define inspection obligations and acceptance criteria.
- Statistical quality practitioners use OC curves and risk tables to select plans that meet organizational tolerance for consumer/producer risk.
Who should use it
- Quality engineers, QA/QC managers and inspection teams
- Procurement and supplier quality professionals
- Regulatory bodies and auditors specifying acceptance criteria
- Statisticians designing sampling schemes for manufacturing or service processes
Related standards
- ISO 2859-0: Introduction and illustrative examples (recommended companion)
- ISO 2859-3: Skip‑lot sampling procedures (alternative to reduced inspection)
- ISO 3534 series: Vocabulary and symbols for statistics and quality control
Keywords: ISO 2859-1, AQL, acceptance sampling, lot-by-lot inspection, sampling plans, OC curves, producer’s risk, consumer’s risk, single sampling, double sampling, multiple sampling.
Технические детали
- Технический комитет
- ISO/TC 69/SC 5 - Acceptance sampling
- SKU
- ISO 2859-1:1999
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