TS ISO 28593

TS ISO 28593 is the Turkish edition of a standard for acceptance sampling by attributes that uses a credit-principle, accept-zero single-sampling system to control outgoing quality. Its central idea is straightforward: in lot-by-lot inspection, if the sample contains one or more nonconforming items, the lot is not accepted. The scheme is built around an average outgoing quality limit (AOQL) chosen by the user.

What AOQL and accept-zero mean in practice

In general technical terms, AOQL is a long-run ceiling for the average quality reaching the customer or marketplace. Accept-zero plans differ from conventional acceptance sampling because they do not allow any nonconforming item in the sample if the lot is to be accepted. The emphasis is therefore not only on counting defects in a lot, but on limiting the overall outgoing quality performance across a series of lots.

What this standard covers

• Single sampling schemes for lot-by-lot inspection by attributes.
• All plans are accept-zero form: one or more nonconforming items in the sample means the lot is not accepted.
• The user selects the AOQL value used by the scheme.
• No restrictions are placed on the sizes of successive lots in the series.
• The methodology is intended to keep the long-run average quality reaching the customer or market-place from exceeding the AOQL.

This makes the standard relevant wherever outgoing quality control is managed statistically and the acceptance decision must reflect the quality impact of an ongoing stream of lots, not just a single isolated shipment. It is a specialised acceptance-sampling framework rather than a general inspection rule.