Overview
EN ISO 20567-1:2017 - Paints and varnishes: Determination of stone‑chip resistance of coatings - Part 1: Multi‑impact testing - specifies laboratory methods to evaluate how automobile finishes and other coatings resist damage from small stones. The standard defines multi‑impact tests that project chilled‑iron grit onto coated test panels to simulate stone‑chip impacts and quantifies coating damage against pictorial reference standards.
Key topics and technical requirements
- Scope and purpose: Defines three multi‑impact methods for assessing stone‑chip resistance of coatings (automotive and similar finishes).
- Test material: Uses chilled‑iron grit as the projectile; particle size distribution is addressed in the revised edition.
- Apparatus and performance: Describes a multi‑impact tester with a vibrating conveyor and grit‑accelerating nozzle. The apparatus shall be capable of projecting 500 g of grit in 10 s and maintaining a working pressure (example nominal working pressure is 200 kPa) for the test duration. Figures and dimensional specifications (nozzle, pipe, angles and distances) are provided for reproducible testing.
- Test panels and preparation: Refers to standard panels and coating thickness requirements (see ISO 1514 and ISO 2808). Conditioning and environmental requirements follow ISO 3270.
- Procedure and evaluation: After projection, loose fragments are removed and damage is evaluated by comparison with pictorial reference standards (ISO 21227‑2). The document includes informative annexes: Annex A (example procedures for removing loose paint) and Annex B (recommended calibration procedure for the apparatus).
- Normative references: Includes ISO 565 (sieves), ISO 11124‑2 and ISO 11125‑2 (chilled‑iron grit specification and particle size), among others.
Applications and who uses this standard
- Automotive OEMs and tier suppliers for assessing and specifying stone‑chip performance of factory and aftermarket coatings.
- Coatings and paint formulators developing multi‑layer finishes to meet durability targets.
- Independent testing laboratories performing quality control and comparative evaluations.
- R&D teams validating new primer/topcoat systems and protective coatings for transportation and infrastructure.
- Procurement and compliance teams referencing stone‑chip resistance in technical specifications.
Related standards
Use EN ISO 20567‑1:2017 when you need a reproducible laboratory method for multi‑impact stone‑chip testing - essential for specifying, comparing and validating coating durability under simulated road‑stone bombardment.