Overview
ISO 2808:2019 - Paints and varnishes - Determination of film thickness - defines standardized methods for measuring the thickness of coatings applied to substrates. It covers procedures for wet‑film thickness, dry‑film thickness and the thickness of uncured powder layers, and reports on the field of application and precision for each method. The standard also includes guidance for measuring on rough surfaces (Annex B) and wooden substrates (Annex C), plus requirements for the test report.
Keywords: ISO 2808, film thickness, coating thickness measurement, paints and varnishes, wet-film thickness, dry-film thickness, powder coatings.
Key topics and technical scope
- Scope and definitions: Terms and definitions used in film thickness measurement.
- Wet‑film measurement methods:
- Mechanical gauges (comb, wheel, dial)
- Gravimetric (mass difference)
- Photothermal techniques
- Dry‑film measurement methods:
- Mechanical thickness difference and depth gauging
- Surface profile scanning and cross‑sectioning
- Optical methods (white‑light interferometry, wedge cut)
- Magnetic methods (magnetic pull‑off, magnetic‑flux, magnetic‑induction, eddy‑current)
- Radiological (beta backscatter)
- Photothermal and acoustic (ultrasonic reflection)
- Electromagnetic (terahertz)
- Uncured powder layer methods:
- Gravimetric, magnetic, photothermal approaches adapted for powder films
- Precision and field of application: For each method ISO 2808 provides an overview of suitable substrates, limitations and expected precision.
- Annexes and reporting:
- Annex A: overview of methods
- Annex B: measurement on rough surfaces
- Annex C: factors affecting measurements on wood
- Section on test report content and documentation
Practical applications and users
- Quality control and acceptance testing in coating manufacture, automotive, marine, industrial, architectural and wood coatings sectors.
- Process control on production lines (wet or dry measurements) and laboratory R&D for new paint systems.
- Inspection and compliance checks for corrosion protection and regulatory specifications.
- Typical users: coating formulators, QC technicians, inspection bodies, third‑party testing labs, specifiers and contract applicators.
Related standards (if applicable)
- ISO 2808 is part of a family of paint and coating test standards. Users often consult complementary national or international standards (for example, ASTM methods and other ISO coating test standards) for cross‑reference and additional procedural detail.
ISO 2808:2019 helps organizations select appropriate coating thickness measurement methods, understand limitations for different substrates, and document results consistently for reliable quality assurance and compliance.
