Overview - EN ISO 3269:2019 (Fasteners - Acceptance inspection)
EN ISO 3269:2019 defines a purchaser-focused procedure for acceptance inspection of fasteners when no prior inspection agreement exists between buyer and supplier. It provides a reference acceptance procedure to resolve disputes or when no supplier–purchaser agreement can be reached. The standard applies to inspection lots of bolts, screws, studs, nuts, pins, washers, rivets and related fasteners, but excludes fasteners intended for high‑volume machine assembly or specially engineered applications requiring advanced in‑process control and lot traceability.
Key topics and technical requirements
- Purpose: Sets a standard incoming inspection procedure for the purchaser and a reference procedure for lot acceptance/rejection.
- Scope of parts: Bolts, screws, studs, nuts, pins, washers, rivets and other related fasteners.
- Inspection timing: Applied to fasteners “as delivered” - inspection occurs after receipt and before release to further processing.
- Sampling and acceptance criteria:
- Sample sizes are selected based on inspection lot size (see Table 1 in the standard).
- If required sample size exceeds lot size, 100% inspection is required for non‑destructive tests.
- Acceptance and rejection numbers (Ac and Re) are determined per characteristic.
- Introduces a layered approach including an Ac = 0 (zero accepted defects) option for smaller sample sizes.
- Quality indices:
- AQL (Acceptance Quality Limit) - percentage of non‑conforming fasteners corresponding to a 95% chance of acceptance under the sampling plan.
- LQ (Limiting Quality) - percentage corresponding to a 10% chance of acceptance (consumer’s risk).
- Inspection categories: Characteristics to be inspected are listed (Table 2) and selection is at the purchaser’s discretion based on form, fit and function.
- Dispute resolution: Provides a reference acceptance procedure when purchaser and supplier disagree, and requires supplier opportunity to verify alleged non‑conformities.
- Normative references: ISO 2859‑1 (sampling by attributes), ISO 1891‑4 (fastener vocabulary), ISO 3534‑2 (statistics).
Applications and who uses it
- Purchasers and quality engineers who receive fasteners without prior inspection agreements.
- Procurement teams and receiving inspection departments in manufacturing, maintenance, and repair operations.
- Suppliers and manufacturers can use it as a baseline for buyer expectations when no contract specifies inspection rules.
- Useful for industries using standard fasteners where lot traceability and advanced in‑process control are not required (e.g., general assembly, repair parts).
Related standards
- ISO 16426 - in‑process control and final inspection by the manufacturer (see for manufacturer-side inspection).
- ISO 2859‑1 - attribute sampling schemes (used for sample plan basis).
- ISO 1891‑4, ISO 3534‑2 - terminology and statistics referenced by EN ISO 3269:2019.
Keywords: EN ISO 3269:2019, fasteners acceptance inspection, AQL, sampling plan, inspection lot, bolts screws nuts washers, purchaser inspection, fastener standards.