TS ISO 2859-2

TS ISO 2859-2 is a standard for acceptance sampling by attributes for isolated lots, using sampling plans indexed by limiting quality (LQ). It is aimed at situations where lots are independent, short-run, or otherwise not suitable for switching-rule systems such as those used in ISO 2859-1. In practical terms, it helps define how a single lot is sampled and judged when the lot stands on its own rather than as part of a continuing production stream.

How limiting quality frames the decision

In this document, LQ is the quality level used to index the sampling plans and to relate the plan to consumer risk. The supplied scope states that the probability of acceptance at the LQ is usually below 0.10, with some exceptions. Conceptually, this means the plans are designed to be more conservative at poor quality levels, which is especially relevant when a lot is unique, resubmitted, or part of only a very short sequence of lots. The standard does not provide inspection levels like ISO 2859-1; instead, it is built around the isolated-lot use case.

Typical contexts and technical meaning

• Attribute inspection where each item is classified as conforming or nonconforming
• Inspection expressed either in nonconforming items or nonconformities per 100 items
• Job lots supplied in varying quantities from different sources
• Lots treated as isolated or too short in sequence for switching rules to apply

From a general quality-engineering perspective, acceptance sampling is used when full inspection is impractical, costly, or unnecessary. The key technical distinction here is between continuous lot-based control and isolated-lot decision making: the former may use switching rules and inspection levels, while the latter needs a plan indexed directly to limiting quality. TS ISO 2859-2 serves that narrower but important context for making statistically grounded accept/reject decisions on discrete lots.