ISO 2859 is an internationally recognized standard that specifies an acceptance sampling system for inspection by attributes. It is indexed in terms of the acceptable quality level (AQL).
The objective is to induce suppliers to maintain a quality level that is at least as good as the AQL specified by the buyer. At the same time, the system minimizes the statistical risk for a buyer of accepting an occasional poor lot.
Sampling schemes designated in this part of ISO 2859 are applicable, but not limited, to the inspection of:
components and raw materials
materials in process
supplies in storage
These schemes are intended primarily to be used for a continuing series of lots, i.e. a series that is long enough to allow switching rules to be applied. These rules provide:
Consumer protection (by means of a switch to tighten inspection) if a deterioration in quality is detected;
An incentive (at the discretion of buyer) to reduce inspection costs (by means of a switch to reduce inspection) if consistently good quality is achieved.
Sampling plans in this section of ISO 2859 may also be used for the inspection of lots in isolation; however, the user is strongly advised to consult the operating characteristics curves to find a plan that will yield the desired protection. In which case, the user is referred to the sampling plans indexed by limiting quality (LQ) given in ISO 2859-2.This instruction indicates partial tables of the standard ISO 2859-1.