Pre-shipment inspection for a towel order — what an AQL inspection checks and how to read the result

A pre-shipment inspection is an independent person opening a random sample of your finished, packed order before it leaves the factory, checking it against the specification and the approved sample, and writing down what they find. Its value is timing: it is the last point at which a problem can be fixed by the supplier and not by you. It is also easy to misread, because a sample result describes the sample, and an inspector can only pass or fail a lot against rules you agreed before they arrived.

This guide sets out what an inspection checks on towels, how the AQL sampling numbers work, and what to agree in advance.

What an inspection is, and what it is not

An inspection looks at the goods in their cartons: quantity, packing, labels, colour against the approved sample, size and weight against the specification, and visible workmanship. It is not a laboratory test. Whether a towel shrinks by more than your limit, or holds its colour in a wash, is measured by a lab, and our guide on reading a towel test report covers that. Nor is it the earlier check on a sample, which our guide to reading a pre-shipment sample covers, or the check on arrival, which our guide to receiving a container covers.

When it happens, and who arranges it

Inspect when production is finished and most of the order is packed, so the inspector can draw cartons from across the whole lot and not from whatever is nearest the door. A buyer normally appoints an independent inspection company or its own representative and tells the supplier the date. The supplier should not choose the inspector, and should not be the one who selects the cartons.

Agree before the order is confirmed that the inspection will take place, which specification it is judged against, and what happens if the lot fails. A buyer who raises it for the first time on the day of the inspection is negotiating, not checking.

How AQL sampling works

AQL stands for acceptance quality limit. An inspection plan under ISO 2859-1 turns the size of the lot into a sample size, and the AQL into two numbers: the most defective pieces the sample may contain for the lot to pass (the acceptance number) and the number at which it fails (the rejection number).

There are three things to agree:

The AQL figures themselves are not set by the standard. Many buyers start with no critical defects, 2.5 for major defects and 4.0 for minor ones, but those are choices, and your product and customer may justify tighter or looser values.

Worked example

The figures below come from the standard's single-sampling table for normal inspection. Ask your inspection company which plan it applies, because they can differ.

An order of 12,000 towels, inspected at general level II, is a lot in the 10,001 to 35,000 range, which gives a sample of 315 pieces.

• Critical defects, AQL 0: any critical defect found fails the lot.
• Major defects, AQL 2.5: the sample may contain up to 14 pieces with a major defect. At 15 the lot fails.
• Minor defects, AQL 4.0: the sample may contain up to 21 pieces with a minor defect. At 22 the lot fails.

Suppose the inspector finds 3 pieces with major defects and 18 with minor ones, and none critical. 3 is below 15 and 18 is below 22, so the lot passes. If the inspector had found 16 pieces with major defects, the lot would fail on that class alone, however clean the rest of the sample was.

Read the result with its limits in mind. Fourteen defective pieces in 315 is 4.4 per cent of the sample, and the other 11,685 pieces were never opened. A pass says the sample met the plan. It does not say the rest of the lot is free of defects.

What an inspector checks on towels

Colour matching and weight are the two checks to specify in detail. Tell the inspector which approved sample is the reference and how weight is to be measured, or each of them will choose a method of their own.

Agreeing the defect list

The inspector can only class a defect that you have defined. These are typical examples of how buyers split them, and you should agree your own:

• Critical: anything unsafe or unusable, such as a broken needle or metal fragment in the product.
• Major: a defect that makes the towel unsellable or noticeably worse, such as a hole, a stain that does not come off, the wrong colour, or size or weight outside the agreed tolerance.
• Minor: a small defect that does not stop the towel being sold, such as a loose thread or a slight unevenness in a hem within tolerance.

Ask also whether the report counts defective pieces or individual defects, since a piece with two faults would count once in one method and twice in the other.

What the report should show

• Who inspected, and on what date and at which site
• The lot size, the inspection level, the sample size and the AQL used
• The defects found, by class, with photographs
• The measured size and weight against the specification
• The result, and any comment on the packing and the cartons drawn

A report with a "pass" and no numbers cannot be checked, in the same way as a test report with no limit.

What this guide does not cover

It does not set an AQL for your product, give pass limits for size or weight, or replace a laboratory test. It does not say who bears the cost of a re-inspection or rework, which belongs in your contract. The standard is revised from time to time, so confirm the edition your inspection company applies.

What to ask a supplier

• Can an independent inspector visit before the goods ship, and with what notice?
• When will the order be packed, so the inspection can be set for that date?
• If the lot fails, what happens: rework, replacement or a price adjustment, and in what time?
• Can the balance payment be tied to a passed inspection report?

Our guide on payment terms compares T/T, letter of credit and collection, and the risk each leaves with the buyer. Send us the specification, the quantity and whether you plan an independent inspection, and our export team will reply to your enquiry.