TS ISO 2859-5

TS ISO 2859-5 is the part of the acceptance sampling framework for lot-by-lot inspection by attributes that adds sequential sampling schemes to the ISO 2859 system. It presents a structured way to use sequential plans indexed by acceptance quality limit (AQL) and to complement the base acceptance sampling approach defined in ISO 2859-1.

What sequential sampling means

Sequential sampling is an acceptance sampling method in which inspection results are evaluated step by step rather than only after a fixed sample size has been reached. At intermediate stages, a lot may be accepted, rejected, or inspection may continue. This can make the inspection effort more responsive to the apparent quality of the lot. In attribute inspection, the results are typically categorical, such as conforming/nonconforming or pass/fail, rather than measured values.

How it relates to ISO 2859-1

This part supplements the ISO 2859-1 acceptance sampling system, so it should be understood as a companion to the main lot-by-lot sampling framework rather than a standalone quality philosophy. The AQL is the key indexing concept used to organize the plans and balance producer’s and consumer’s risks in a practical inspection system. For that reason, the standard is useful wherever an organisation needs to understand which sequential plan family applies to a given inspection situation.

In general technical terms, sequential plans are often attractive in incoming inspection, production control, and shipment release because they can reduce unnecessary inspection effort when quality is clearly good or clearly poor. Here, however, the standard is about the plan system itself, not about declaring any particular product acceptable; the actual decision boundaries follow the rules of the standard edition.