ISO 3269:2019

Overview

ISO 3269:2019 - Fasteners - Acceptance inspection defines a purchaser’s incoming inspection procedure to be used when no prior agreement with the supplier exists. It provides a reference acceptance procedure for acceptance or rejection of inspection lots of bolts, screws, studs, nuts, pins, washers, rivets and related fasteners. The standard is intended for general-purpose fasteners (not those for high‑volume machine assembly, specially engineered or special‑purpose applications). It complements in‑process inspection standards (see ISO 16426).

Key topics and requirements

• Scope and purpose: A purchaser-led sampling and inspection procedure when supplier/purchaser agreements are absent or disputed.
• Inspection lots: Defined as same designation, supplier and (when available) manufacturing lot number.
• Sampling plans: Sample size is selected based on inspection lot size (Table 1). The standard introduces a layered approach including a small-sample option (N = 0) and uses sampling categories.
• Acceptance criteria: Uses acceptance number (Ac) and rejection number (Re) per characteristic; Category 1 and 2 characteristics typically have Ac = 0 (no non‑conformities tolerated), while Category 3 characteristics allow limited non‑conformities and are linked to ISO 2859‑1 sampling tables.
• Quality indices: Defines AQL (Acceptance Quality Limit) and LQ (Limiting Quality) concepts and links them to operating characteristics of sampling plans.
• Inspection modalities: Purchaser chooses which mechanical, physical, functional and dimensional characteristics to inspect (examples: hardness, tensile strength, drive geometry, dimensions, torque). Destructive tests and non‑destructive tests are treated according to the characteristic.
• Disposition and verification: If non‑conformities are found, procedures for lot disposition and purchaser options (including offering the supplier opportunity to verify) are specified; a reference acceptance procedure is provided when no agreement is reached.

Applications and users

• Practical use: incoming inspection, receiving inspection, lot acceptance/rejection decisions, dispute resolution between purchaser and supplier.
• Typical users: quality engineers, inspection and test laboratories, procurement and purchasing managers, suppliers and manufacturers of fasteners, and compliance officers responsible for incoming material control.
• Benefits: provides a standardized, defensible approach to sampling, reduces ambiguity in supplier disputes, and helps balance inspection effort with product risk.

Related standards

• ISO 2859-1 - Sampling procedures for inspection by attributes (AQL sampling)
• ISO 16426 - In‑process control and final inspection by the manufacturer (complementary)
• ISO 1891-4, ISO 3534-2 - Terminology and statistics referenced by ISO 3269
• Product and test standards referenced for specific characteristics: ISO 898‑1, ISO 3506‑2, ISO 16047, ISO 10683, ISO 6157‑1

Keywords: ISO 3269:2019, fasteners, acceptance inspection, sampling plan, AQL, incoming inspection, inspection lot, acceptance number (Ac).