First agree with the supplier and inspector which lot will be inspected, whether each garment is one inspection unit, the checks and the criteria for nonconformity. Then choose a sampling plan suitable for that lot and record sample size, selection method, acceptance and non-acceptance decisions, and exception handling. AQL does not mean “this many defective items are permitted in every lot.” Acceptance by sampling is not proof that the whole lot has zero defects or meets every safety requirement. Shipment authorisation must be confirmed separately according to the order.
This guide helps buyers prepare an inspection agreement; it does not prescribe an AQL value for every order or look up standard tables on your behalf. Qualified inspection or quality personnel must determine the actual plan from the applicable standard, lot circumstances and agreement. Product safety, regulations, particular performance tests and contract requirements need separate confirmation.
Understand the limits of the lot and AQL first
The American Society for Quality glossary describes acceptance sampling as inspecting a sample from a lot to decide whether to accept that lot. Its definition of AQL concerns the limit of a satisfactory process average for sampling a continuing series of lots. It is not a guarantee that the actual nonconforming proportion of an individual lot may reach a given percentage, nor the number of nonconforming items allowed in the sample. The responsible person should select the plan using the complete standard; writing “AQL” in an order alone does not ensure shared understanding.
The public page for ISO 2859-1:2026 describes attribute sampling schemes indexed by acceptance quality limit for lot-by-lot inspection and switching rules; application includes continuing submitted lots. The public scope of ISO 2859-2:2020 describes another kind of plan indexed by limiting quality (LQ), for isolated lots or short series where switching rules do not apply. State first whether the order is one lot or a continuing series, then have the inspector determine scope, standard edition and complete rules. Do not interchange the schemes automatically. This guide does not reproduce standard tables or claim that WTBF has applied a particular standard.
Define the goods and counting unit
Identify purchase order, style, colour, size, production batch, packing state, location and quantity available for inspection. Confirm with the inspector which goods form one acceptance lot and whether different style-colour combinations, sizes or production batches are combined. The total order quantity is not necessarily one acceptance lot. List unfinished goods or goods unavailable for selection so unsubmitted goods are not counted as inspected. Check against the packing list, record carton numbers and quantities, and agree how all submitted goods can be available for selection before inspection.
Define counting first too. For example, a sweater with an open seam and a stain can be one nonconforming garment, while two nonconformities can also be recorded; these are not the same number. Confirm the unit, defect classification, decision rules and recording of multiple issues on one item for the plan, then have the inspector check the corresponding count and decision. Label the number inspected, affected garments and defect occurrences separately; do not interchange them.
| Decision | What to agree or record | Why |
|---|---|---|
| Acceptance lot | Order, style-colour-size, production batch, location, quantity submitted and exclusions | Identify the goods covered by the result |
| Inspection unit | Garment or other agreed unit and how nonconforming garments and defect occurrences are counted | Avoid mixing different counts |
| Sampling plan | Applicable standard and edition, lot circumstances, inspection level or other plan parameters where applicable, sample size and acceptance/non-acceptance rules | Let both parties review the decision basis |
| Selection and inspection | Selection method, carton numbers, quantities, checks, reference and measurement conditions | Record what was actually inspected |
| Result and treatment | Inspected and uninspected quantities, findings, decision and responsibility for holds or reinspection | Prevent goods being released without a decision |
Align the plan with the actual inspection
Before inspection, confirm who selects the sample, how selection follows the plan, whether cartons or goods are inaccessible, how checks are allocated and which identifiers and photos must be retained. Do not let the supplier pick a few attractive samples and call that random sampling. If the agreed selection method cannot be used on site, record the limitation and have the responsible person decide whether to adjust or reschedule; do not silently use the original plan's conclusion.
Link appearance, dimensions, labels, packing and other agreed checks to the relevant approved reference, revision and measurement conditions. Quantity reconciliation, fit review, care performance or safety tests may use different methods and samples; one appearance sample cannot be assumed to cover all requirements. The inspection report should state actual checks, samples, observations, defect classifications and the decision under agreed rules. The production sample guide addresses approval of garments selected from a production batch; production sample approval and final acceptance sampling are different decisions.
Read the sample result without turning it into a whole-lot guarantee
Suppose the parties agree an illustrative single-sampling plan of 20 garments, counting nonconforming garments. Under this hypothetical plan, accept if no more than 1 garment is nonconforming and do not accept if 2 or more are nonconforming. If 1 garment has both an open seam and a stain, count 1 nonconforming garment and separately record 2 defects. The plan permits an acceptance decision, but does not establish that unselected goods have no problems or precisely estimate the entire lot's nonconforming proportion from 1 ÷ 20. This is not an ISO table, recommended plan, WTBF inspection record or acceptance limit.
Sampling decisions have risks: a lot at a given quality level may not be accepted, and a poorer lot may be accepted. If a lot is not accepted under the plan, do not simply change the decision to pass or resample indefinitely before agreeing disposition. Buyer, supplier and inspector should confirm review, sorting, correction, resubmission and cost responsibility under applicable rules. Even when sampling leads to acceptance, handle identified nonconforming items and unresolved safety or specification issues under the agreement. Acceptance is not an exemption from legal obligations.
Separate the inspection result from release
Keep inspection date, location, lot composition, quantities submitted and selected, selection method, standard edition, plan parameters, checks, results, photos, uninspected items and decision-maker. Identify covered style-colour-size combinations and quantities, those awaiting assessment and any sampling limitations. The buyer should also review contract, packing and delivery documents and other required tests before an authorised person decides shipment for the relevant scope.
If an issue is found only after arrival at the warehouse, separately record inspected and uninspected quantities, preserve evidence and agree treatment with the supplier. The receiving quality issue guide covers that later process. A sampling report can be one record but cannot replace investigation and decisions on the actual issue.
What to send with an inquiry
Browse the knitwear range and use the inquiry page to provide the style and approved specification, size range and estimated quantity per style and colour, planned inspection location, sales market, delivery location and target arrival date. Describe proposed lot divisions, checks, whether third-party inspection is needed, applicable standards or customer requirements and release rules still to be agreed. Ask the supplier to confirm samples, inspection cooperation, costs and timing for the project.