AQL is a sampling-plan index, not permission to ship a known percentage of defective clamps. The useful procurement decision is whether the delivery is a continuing series or an isolated lot, which characteristics are inspected by attributes, which dimensions require measurement, and what happens after a sample fails.
Use an ISO 2859 plan only after defining a homogeneous lot, inspection level, AQL, defect class and acceptance/rejection numbers. Do not copy a sample size from another order. Critical characteristics, mixed revisions, failed traceability or a rejected sample can justify project-specific 100% inspection.
- Best for
- Buyers and supplier-quality teams releasing repeat lots of pipe clamps, cable cleats, inserts, plates and fastener kits.
- Not suitable for
- A universal sample-size table, a substitute for the purchased ISO tables, or permission to sample a safety-critical feature that the contract requires to be checked on every item.
- Decision checks
- lot identity, drawing revision, random sample, defect classes, inspection level, AQL or LQ, Ac/Re, measurement uncertainty, escalation rule
- RFQ inputs
- lot size, production source, part and revision, critical characteristics, defect definitions, inspection history, certificate list and disposition authority
§ 01 Define the lot before choosing a sample
A sample is meaningful only when the lot represents one part number, revision, material route and reasonably consistent production process. Mixed revisions, reworked pieces or products from different sources should not be hidden inside one statistical lot.
§ 02 Choose ISO 2859-1 or ISO 2859-2 by lot context
ISO 2859-1:2026 is designed around lot-by-lot inspection and switching rules for continuing series. ISO 2859-2:2020 addresses isolated or short series where those switching rules do not apply. Selecting between them is a procurement decision that precedes sample-size selection.
§ 03 Classify defects in the purchase specification
Critical, major and minor are contractual classes, not universal labels supplied by ISO 2859. Define each observable nonconformity: wrong part or revision, missing traceability, damaged body, wrong insert, coating defect, missing fastener, dimensional failure or packaging damage.
§ 04 Keep attribute sampling separate from dimensional measurement
Attribute sampling records conforming or nonconforming results. A measured bore, plate thickness or hole spacing also needs a tolerance, calibrated equipment and a decision rule near the limit. ISO 14253-1 addresses conformity decisions when measurement uncertainty matters.
§ 05 Do not invent Ac/Re numbers
The inspection level, AQL or LQ and lot size lead to a code letter, sample size and acceptance/rejection numbers in the selected standard. Record the edition and exact plan. This page deliberately does not reproduce copyrighted tables or prescribe one AQL for every clamp order.
§ 06 Define 100% inspection triggers before receipt
Project-specific triggers can include a critical defect, a rejected sample, mixed revisions, broken batch traceability, first delivery after a process change, repeated supplier deterioration or an explicit customer requirement. Full inspection does not erase the need for root-cause action and lot disposition.
§ 07 Release the lot with an auditable record
The report should identify lot, sample selection, inspected characteristics, results, Ac/Re decision, nonconformance references, reinspection status and release authority. Keep certificates and measurement records linked to the same lot identity.
§ 08 Evidence levels
| Evidence level | Use | Boundary |
|---|---|---|
| TESTED | Result matches the tested configuration. | Does not cover changed components or installation. |
| BATCH-TRACEABLE | Record links to the delivered lot. | Does not prove unrecorded system performance. |
| STANDARD-BASED | Official scope defines a method or decision system. | Does not select project criteria or prove this product passed. |
| PROJECT-SPECIFIC | Customer risk and drawings close the decision. | Cannot be generalized to another project. |
| INDICATIVE | Example or early screening logic. | Not an acceptance plan or guaranteed value. |
§ 09 Decision matrix
| Decision | Use | Boundary |
|---|---|---|
| Continuing lots | ISO 2859-1 scheme with documented switching history. | Requires a stable series and consistent application of switching rules. |
| Isolated lot | ISO 2859-2 or another contract-approved isolated-lot plan. | Do not pretend prior supplier history creates switching rules. |
| Critical characteristic | 100% or special control when specified by project risk. | The standard does not define which clamp feature is critical. |
| Measured dimension | Tolerance plus calibrated method and decision rule. | AQL alone does not resolve measurement uncertainty. |
| Rejected sample | Quarantine and disposition under the agreed quality plan. | Sorting or resampling needs prior rules; it is not automatic acceptance. |
§ 10 Official sources and evidence boundary
These official sources define sampling, measurement or cable-cleat test scope. They do not select project acceptance criteria or certify a Weique product by themselves.
- ISO 2859-1:2026 — AQL-indexed sampling for continuing series of lots
- ISO 2859-2:2020 — LQ-indexed sampling for isolated lots
- ISO/TR 8550-2:2007 — Guidance for attribute sampling of discrete items
- ISO 14253-1:2017 — Measurement decision rules and uncertainty
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