Overview
ISO 22987:2020 - Ships and marine technology - Laboratory test method for skin friction of antifouling paints by rotating drum - defines a controlled laboratory procedure to measure the skin friction of antifouling paints applied to cylindrical drums. The method uses a dynamic ageing system and a friction test system (rotating drum) to generate hydrodynamic conditions and directly measure torque, which represents the coating’s friction against seawater. This standard is applicable to both biocidal and biocide‑free antifouling paints and is intended primarily for laboratory screening and comparative characterization, not as a full prediction of in-service ship performance.
Key topics and technical requirements
- Test systems: Two main subsystems - a dynamic ageing system to condition/age specimens and a friction test system to measure torque. Each requires motors, a cylindrical test chamber, temperature control, and sensors (temperature, pH, salinity).
- Testing solution: Filtered natural seawater or artificial seawater prepared to ASTM D1141; specified pH, salinity and temperature ranges are given for repeatability.
- Drum specification: Corrosion‑resistant, deformation‑resistant materials (e.g., acrylic, PVC); minimum dimensions and tight tolerances are specified to ensure consistent flow conditions.
- Specimen preparation: Sampling and surface preparation per ISO 15528 and ISO 1513; conditioning at 23 °C ± 2 °C and 50 % ± 5 % RH for 7 days; dry film thickness of the topcoat specified at 175 µm ± 25 µm (ISO 2808).
- Measurement and accuracy: Torque sensors with adequate range and accuracy (no larger than 0.1 % of reading); single‑specimen testing per friction compartment for accuracy.
- Test design: Minimum test cycles (six cycles minimum) and use of at least two samples with mean values reported.
- Flow regime: Test chamber and drum geometry are defined to produce fully developed turbulent flow (Reynolds number threshold stated in the standard).
Practical applications and users
- Who uses it: Antifouling paint manufacturers, coating R&D and QA laboratories, shipowners evaluating coating options, naval architects assessing drag implications, and test facilities conducting pre‑field screening.
- Why use it:
- Screening and ranking antifouling formulations for skin‑friction performance.
- Characterizing how friction of coatings evolves during simulated ageing.
- Comparing biocidal vs. biocide‑free products under repeatable lab conditions.
- Supporting product development and quality control prior to patch tests and full‑scale trials.
- Limitations: ISO 22987:2020 provides laboratory characterization but does not by itself validate in‑service hull performance or predict full‑scale fuel consumption impacts.
Related standards
Normative references for specimen preparation, thickness and surface assessment include: ISO 1513, ISO 2808, ISO 3270, ISO 4287, ISO 4288, ISO 15528, and ASTM D1141 (artificial seawater). Use these referenced standards alongside ISO 22987:2020 for a complete test program.