AQL inspection: what it is and how it works

Accepting or rejecting an order of thousands of units by checking every one is unfeasible. That's why quality control in importing relies on statistical sampling, and the worldwide benchmark is the AQL.

In this guide we explain what AQL is, how an inspection is applied and how to interpret its results to make sound decisions before paying.

What AQL is

AQL stands for Acceptable Quality Limit. It's a statistical method set out in the ISO 2859-1 standard that defines, for a given batch size, how many units to inspect and how many defects can be tolerated before rejecting the order. Instead of checking everything, a representative sample is inspected and the result extrapolated to the batch.

The three types of defect

• Critical: they compromise user safety or break the law. Tolerance is usually zero.
• Major: they affect the product's function or sale (it doesn't work, a significant visible defect).
• Minor: small imperfections that don't prevent use or sale.

Each level has its own limit. For consumer goods, an AQL of 0 / 2.5 / 4.0 (critical / major / minor) is common, though it's adjusted to the product and the customer's requirements.

How the sample size is decided

From the batch size and an inspection level (usually general level II), the standard assigns a code letter and, with it, how many pieces to inspect. For example, a batch of 3,200 units may require checking about 125 pieces. The AQL table then states the maximum acceptable number of defects and the number that causes rejection.

When the inspection is carried out

• During production (DUPRO): at 20-80% manufactured, to correct in time if something goes wrong.
• Before shipment (PSI, Pre-Shipment Inspection): the most common, with production finished and packed.
• Container loading inspection: checks the packaging and stowage condition.

What a good inspection report includes

A complete report covers the AQL result (accepted or rejected), photographs, measurements, quantity checks, function tests, labelling and packaging review, and a list of the defects found classified by severity. It's the document that lets you negotiate with the supplier if something doesn't comply.

How R'S WARE helps you

We carry out the AQL inspection at the factory before shipment and give you a detailed report with photos before you authorise the final payment. So you decide with objective data whether to accept the order and avoid receiving defective goods when there's no room left to act.