ISO 3549:2024

Overview

ISO 3549:2024 - "Zinc dust pigments for paints - Specifications and test methods" defines requirements and laboratory methods for zinc dust pigments intended for use in protective coatings. The third edition updates compositional tolerances, particle-size testing and analytical techniques to support consistent quality, performance and regulatory compliance for zinc-rich paints and corrosion-protection systems.

Key topics and technical requirements

• Scope and purpose: Specifies essential characteristics, tolerances and corresponding test methods for zinc dust pigments used in protective coatings.
• Types and composition: Introduces three pigment types (Type I, II and III) with differing requirements for metallic zinc content, impurities and particle characteristics. Composition and tolerances are given in normative tables.
• Particle size and sieve analysis: Nominal sieve sizes are now 125 µm, 75 µm and 45 µm. The maximum residue on the 45 µm sieve has been tightened (previously 5% mass fraction, now 0.5% mass fraction).
• Analytical methods: Covers a broad suite of test procedures, including:
  • Determination of residue on sieve (particle-size distribution)
  • Determination of total zinc and metallic zinc content
  • Determination of contaminants: lead, cadmium, iron, arsenic and chloride
  • Determination of matter insoluble in acid
• Modern instrumentation: Adds ICP‑OES (inductively coupled plasma–optical emission spectroscopy) as an accepted technique for elemental analysis.
• Sampling and reporting: Aligns sampling with ISO 15528 and requires standardized test reporting to ensure traceability and reproducibility.
• Updated normative references: References ISO 565 (test sieves) and ISO 3696 (water for analytical use) among others; CAS numbers for reagents are included.

Practical applications

• Quality control of zinc dust pigments during manufacture and before shipment.
• Raw‑material acceptance testing by paint and coatings manufacturers.
• Verification of pigment suitability for zinc‑rich, sacrificial corrosion‑protection coatings (e.g., primers for steel structures).
• Regulatory and safety screening for heavy-metal contaminants (lead, cadmium, arsenic).
• Laboratory method standardization for contract testing and supplier audits.

Who should use ISO 3549:2024

• Pigment manufacturers and suppliers
• Paint and coatings formulators and quality managers
• Third‑party testing laboratories and accreditation bodies
• Procurement specialists preparing material specifications
• Regulatory and compliance officers in protective coatings sectors

Related standards

• ISO 565 - Test sieves (nominal opening sizes)
• ISO 3696 - Water for analytical laboratory use
• ISO 15528 - Sampling of paints, varnishes and raw materials

ISO 3549:2024 provides a practical, up‑to‑date framework for ensuring zinc dust pigments meet performance, safety and consistency expectations in protective coatings applications.