EN ISO 16701:2025 PDF

Overview

EN ISO 16701:2025 (ISO 16701:2025) defines an accelerated laboratory corrosion test for metals and coatings that combines humidity cycling with intermittent spraying of a salt solution. The procedure targets environments where chloride ions (typically sodium chloride from winter road de‑icing) strongly influence corrosion. The standard is published by CEN as EN ISO 16701:2025 and supersedes the 2015 edition.

Key points:

• Two closely related test variants: Variant A (constant dew point) and Variant B (constant temperature).
• Intended to assess relative corrosion resistance under salt‑contaminated, variable‑humidity conditions.
• Results are indicative of comparative performance only and do not predict behaviour across all real service environments.

Key Topics and Requirements

• Scope of applicability: ferrous and non‑ferrous metals and alloys; metallic and chemical conversion coatings; organic coatings on metals; combinations that may include galvanic interactions or crevice conditions.
• Test variants: humidity cycling with intermittent salt spray - Variant A (constant dew point) and Variant B (constant temperature).
• Limitations and exclusions:
  • Risk of exaggerated pitting when testing some low‑alloy austenitic stainless steels.
  • Not suitable for wax or oil‑based rust protection agents due to elevated test temperatures.
• Test equipment and instrumentation: detailed requirements for climate test chambers, spray devices, and stand‑alone monitoring (see Annexes A–C).
• Quality control and calibration: procedures for climate control, salt solution precipitation monitoring, visual spray pattern checks, routine inspections, deviation handling and annual calibration (see Clause 7 and Annex D).
• Test object preparation: geometric, orientation and placement requirements and guidance for painted/scribed panels and other geometries (Clause 6).
• Reporting and evaluation: test report requirements and guidance on evaluating comparative corrosion results (Clauses 8–9; Annex E).

Practical Applications

This standard is useful for:

• Comparing corrosion resistance of metals, alloys and coatings exposed to chloride‑contaminated atmospheres.
• R&D and qualification testing of protective coatings, metallic finishes and material selections where road de‑icing salts or marine salt contamination are concerns.
• Evaluating combined material/coating systems that may exhibit galvanic or crevice corrosion interaction.

Typical users:

• Materials and corrosion engineers
• Coatings manufacturers and testing laboratories
• Automotive, rail, maritime and infrastructure product designers concerned with chloride exposure

Related information

• EN ISO 16701:2025 is the CEN‑endorsed version of ISO 16701:2025 (prepared by ISO/TC 156 and CEN/TC 262).
• The standard provides test method requirements but defers specimen dimensions, exposure durations and result interpretation to product‑specific specifications. See Annexes A–E for equipment examples, monitoring guidelines and control procedures.