ISO 2859-2-2020 PDF

Full title and description

St ISO 2859-2-2020 — "Sampling procedures for inspection by attributes — Part 2: Sampling plans indexed by limiting quality (LQ) for isolated lot inspection". This part of ISO 2859 specifies an acceptance-sampling system for attribute inspection intended for isolated lots or short/unique series of lots where the switching rules of lot-by-lot schemes are not applicable.

Abstract

This document provides sampling plans indexed by a series of limiting quality (LQ) values and associated acceptance criteria for isolated-lot inspection. It is intended for inspection of nonconforming items and nonconformities per 100 units where suppliers and purchasers treat a lot as isolated (unique, resubmitted after inspection, or part of a short series). The plans give consumer protection typically with the consumer's risk at or below about 0.10 (10 %) in most cases.

General information

• Status: Published.
• Publication date: 13 February 2020.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 03.120.30 — Application of statistical methods.
• Edition / version: Edition 2 (2020).
• Number of pages: 46 pages (ISO edition listing).

(General information as published by ISO and national standards bodies.)

Scope

ISO 2859-2:2020 establishes LQ-indexed single, double and multiple sampling plans and the rules to select them for the inspection of isolated lots (an isolated lot, an isolated sequence of lots, a unique lot or a short series of lots). It is used where switching rules and inspection levels from ISO 2859‑1 are not applicable; it can be included directly in contracts or product standards when inspection must treat a lot in isolation. The standard provides procedures and tables to determine sample sizes and acceptance numbers for specified limiting qualities and shows how to handle accept-zero and other plan variants.

Key topics and requirements

• Sampling plans indexed by limiting quality (LQ) rather than AQL (Acceptance Quality Limit).
• Procedure A (default) and Procedure B for selecting plans depending on whether the lot is regarded as isolated by both parties or only by the purchaser.
• Single, double and multiple sampling plans with tabulated sample sizes and acceptance numbers for a range of LQ values.
• Tables and OC (operating characteristic) information to assess consumer's and producer's risks for selected plans.
• Guidance for using accept-zero plans and for inspection when switching rules (ISO 2859-1) are not suitable.
• Compatibility guidance to help maintain consistency with ISO 2859-1 sampling schemes where appropriate.

The procedural detail and tabulated plans are provided in the standard's tables and explanatory examples.

Typical use and users

Typical users include quality engineers, purchasing and inspection personnel, conformity assessment bodies, standards writers, contract managers and suppliers who need a statistically based, internationally recognized method for acceptance sampling of isolated lots or short production runs. Common uses are contract acceptance testing, one-off production runs, incoming inspection of special batches, and product standards that specify sampling clauses for isolated lots.

Related standards

ISO 2859-2 is part of the ISO 2859 series of attribute sampling standards. Key related parts include ISO 2859-1 (sampling schemes indexed by AQL for lot-by-lot inspection), ISO 2859-3 (skip-lot sampling procedures), ISO 2859-4 (procedures for assessment of declared quality levels), ISO 2859-5 (sequential sampling systems) and ISO 2859-10 (introduction to the ISO 2859 series). For lot-by-lot and continuing-series inspection practitioners, ISO 2859-1 is the principal complement to Part 2.

Keywords

Attribute sampling, limiting quality (LQ), lot-by-lot inspection, isolated lot, acceptance sampling, sampling plans, consumer's risk, acceptance number, sample size, ISO 2859.

FAQ

Q: What is this standard?

A: ISO 2859-2:2020 is an international standard that specifies acceptance-sampling procedures by attributes for isolated-lot inspection, using sampling plans indexed by limiting quality (LQ).

Q: What does it cover?

A: It covers the selection and use of single, double and multiple sampling plans indexed by specified LQ values, provides tables of sample sizes and acceptance numbers, and gives rules for acceptance/rejection and examples of application where switching rules are not appropriate.

Q: Who typically uses it?

A: Quality and inspection staff, procurement and contract managers, standards developers, and conformity assessment bodies that need statistically based acceptance decisions for isolated or unique lots. It is also used where suppliers and purchasers agree the lot should be treated in isolation.

Q: Is it current or superseded?

A: ISO 2859-2:2020 is the current edition (published February 2020) and replaces the earlier 1985 edition. Users should confirm they hold the 2020 edition for current tables and text.

Q: Is it part of a series?

A: Yes — it is part of the ISO 2859 series. Part 1 (AQL-indexed plans) and Part 3 (skip-lot procedures), among others, are commonly used alongside Part 2 depending on whether inspection is for continuing series of lots or isolated lots.

Q: What are the key keywords?

A: Limiting quality (LQ), acceptance sampling, isolated lot inspection, sample size, acceptance number, consumer's risk, ISO 2859.