TS ISO 3951-2

TS ISO 3951-2 is the part of the standard that sets out the general rules for single sampling plans indexed by acceptance quality limit (AQL) in inspection by variables. It focuses on lot-by-lot inspection of independent quality characteristics, where each measurable characteristic in a lot is assessed separately and the sampling plan is selected on an AQL basis.

How inspection by variables works

The technical approach here relies on numerical measurements rather than a simple pass/fail classification. In practice, that means the decision is based on the relationship between the sample measurements, the process variation, and the specification limits. Sampling by variables can provide more information from fewer observations, but it is best suited to users who are already familiar with statistical concepts and data interpretation.

Single plans indexed by AQL

This part specifies an acceptance sampling system of single sampling plans and organizes it in terms of the acceptance quality limit (AQL). The AQL serves as a reference quality level for lots intended to be accepted at a given statistical threshold, creating a common framework for producer’s risk and buyer expectations. The standard is aimed at users with prior experience in variables sampling or those with more complex requirements.

In general technical use, standards of this kind support consistent lot acceptance, quality control, and statistical decision-making in production and receiving inspection. Measurement uncertainty, process spread, and the choice of a suitable sample size are important practical considerations; in this listing, however, the scope is the general specification for single sampling plans within a broader acceptance sampling system.