Quality control · acceptance sampling
AQL inspection for China sourcing
AQL is not a percentage of defects the buyer agrees to receive. It is one input to a defined acceptance-sampling scheme. The purchase order must still say what counts as a defect, how the lot is formed, how units are selected, what happens after failure, and which safety checks sit outside visual sampling.
Standard
Name edition and plan
Execution
Protect random selection
Decision
Write accept, reject and escalation
- Editorial status
- Source-checked buyer guide
- Last reviewed
- Prepared by
- AllForSourcing Editorial Desk
Research basis: The current ISO 2859-1:2026 standard record, current ASQ acceptance-sampling material, and CPSC guidance on representative samples and regulatory testing.
Boundary: This guide does not reproduce licensed sampling tables, select AQL values, create a product-safety test plan, or decide whether a specific lot is legally compliant or commercially acceptable.
2026 standard update
ISO 2859-1:2026 is now the current edition
ISO lists the third edition as published in January 2026 and shows ISO 2859-1:1999 and its amendments as withdrawn. The new edition adds updated application guidance and skip-lot procedures. If a supplier, inspector or template still says only “ISO 2859-1,” record the edition and sampling scheme before relying on the plan.
Direct answer
An AQL number alone is not an inspection plan
“AQL 2.5” leaves most of the decision undefined. It does not identify the lot, inspection level, normal/tightened/reduced state, single/double/multiple plan, sample-size code, sample size, acceptance and rejection numbers, defect classes, random-selection method or disposition after a failed result. A usable instruction binds those choices to one product revision and one lot.
What AQL means—and the common misreading
Useful meaning
ISO 2859-1 uses an acceptance quality limit to index sampling schemes for a continuing series of lots. The standard combines that index with lot size, inspection level and plan rules to produce a sampling decision.
Misleading shortcut
“AQL 2.5 means up to 2.5% defective units are acceptable in this shipment.” That sentence turns a scheme parameter into a promise about one lot. It also ignores how defects are counted and how the sample was selected.
The twelve fields an inspector needs
- 01
Product + revision
SKU, drawing/specification revision, approved sample reference and packaging version.
- 02
Lot definition
Quantity presented as one lot, production dates, line/site, variant mix and completion status.
- 03
Sampling standard
Named standard and edition, such as ISO 2859-1:2026, or the contractually selected alternative.
- 04
Scheme choices
Inspection level, normal/tightened/reduced state, and single/double/multiple plan.
- 05
AQL by defect class
Buyer-selected values for defined classes; do not let a generic inspector template silently choose them.
- 06
Sample size + Ac/Re
Taken from the licensed standard or approved sampling tool after all plan inputs are fixed.
- 07
Random-pull method
Access across cartons, pallet positions, production times and variants—not units staged by the factory.
- 08
Inspection checklist
Observable criteria, measurement method, equipment, tolerance and sample count per test.
- 09
Defect catalogue
Photographs or unambiguous descriptions showing how each failure is classified.
- 10
Reporting evidence
Lot photos, carton selection, serial/batch details, readings, defect photos and counts.
- 11
Disposition
Who may accept, reject, sort, rework, reinspect or grant a written concession.
- 12
Payment/shipment gate
Whether goods may ship or balance may release before the named approver closes the report.
Define defects in product language
“Critical, major and minor” are labels until the buyer connects them to the product, use and market. The same scratch can be cosmetic on an internal bracket and unacceptable on a retail-facing polished surface. The same loose part can be a functional failure or a safety hazard depending on intended users.
| Field | Weak instruction | Controlled instruction |
|---|---|---|
| Appearance | No scratches | Viewing distance, light, surface zone, allowed size/count and reference photo |
| Dimension | Check size | Named characteristic, nominal, tolerance, instrument and units tested |
| Function | Works normally | Defined cycle, load/input, duration and pass/fail observation |
| Packaging | Export packing | Pack count, materials, labels, barcode data, carton dimensions and closure |
Random selection is a control, not a courtesy
The inspector should choose units from the defined lot. Record how many cartons were available, which were opened, where they sat, and how variants were represented. If the supplier presents a table of preselected “inspection samples,” the result describes that table, not necessarily the shipment.
CPSC’s laboratory guidance makes the broader point plainly: test samples need to be representative, and material substitution or manufacturing variability can make apparently identical units different. AQL execution therefore depends on lot integrity and change control before the sample is drawn.
AQL inspection does not replace compliance testing
Visual and functional sampling cannot establish chemical composition, electrical safety, flammability, migration, microbiological status or every regulated characteristic. Some tests are destructive; some require accredited or regulator-accepted laboratories; some compliance duties sit with the importer or manufacturer.
Keep three decisions separate: product acceptance sampling, laboratory/regulatory evidence, and the legal market-access determination. A passing inspection report does not merge them into one approval.
Decide the failed-lot path before the inspection
The supplier must know
- Who owns containment and sorting
- Whether rework changes the product revision
- What corrective evidence is required
- Who pays for reinspection under the contract
The buyer must know
- Who can issue a written concession
- Whether critical findings block release
- Whether a new random sample is required
- Which payment and shipment holds apply
Do not automatically “add more samples until it passes.” That changes the decision after seeing the result. Follow the selected scheme or document a separate investigation and disposition.
Audit the report before accepting the result
- Correct supplier, factory, product, revision, PO and lot quantity
- Production completion and packing status recorded
- Sampling standard, edition, level, plan, AQL, sample and Ac/Re visible
- Carton and unit selection evidence supports randomness
- Defect counts reconcile with photographs and final decision
- Measurements include units, instruments and actual readings
- Open tests, unavailable documents and inspector limitations remain visible
- Buyer approval is recorded separately from the inspector’s finding
Public source citations
ISO 2859-1:2026 — Sampling procedures for inspection by attributes
iso.org | current international standard record | checked 2026-07-15
AQL-02ASQ/ANSI Z1.4 and Z1.9 sampling plan standards
asq.org | official standards organization guidance | checked 2026-07-15
AQL-03CPSC: Selecting a Third Party Laboratory
cpsc.gov | official product-safety guidance | checked 2026-07-15
AQL-04CPSC: Third Party Testing Guidance
cpsc.gov | official regulatory testing guidance | checked 2026-07-15