Overview - ISO 21539:2019 (Ships and marine technology)
ISO 21539:2019 specifies a standardized test method for heated walkways using electrical resistance trace heating to provide anti-icing for exterior shipboard and marine applications in low-temperature environments. The standard defines the required test facility, environmental and wind conditions, specimen dimensions and installation, detailed test procedures (two options), stabilization criteria, pass/fail rules and mandatory reporting content for laboratory testing.
Key topics and technical requirements
- Test purpose: Verify that heated walkways prevent ice formation and function correctly under low-temperature conditions.
- Test facility: Cold chamber capable of holding specified temperatures and controlled wind; wind from refrigeration must not affect specimen; all sensors calibrated.
- Test conditions:
- Ambient temperature control within ±2 °C of the target (±3 °C permitted down to −25 °C in large chambers).
- Wind-speed control maintaining flow within 10%.
- Temperature stabilization: ambient ±2 °C over 30 min; specimen ±2 °C over 60 min.
- Specimen requirements: Standard test surface area is 1 000 mm × 1 000 mm; installed parallel to wind flow; test with airflow above and below (flush-mounted tested with upper surface airflow only).
- Measurements: Minimum 9 sample points located at identified cold spots (not within 50 mm of the perimeter); sensors (thermocouples or thermal imaging) adjusted for material emissivity and verified by secondary measurement.
- Test procedures: Two procedural options cover sequence differences (when to energize heating and when to start wind): both include visual/electrical checks, calibration verification, controlled temperature/wind ramps and repeated measurements.
- Pass/fail criterion: The stabilized specimen temperature (excluding the single lowest and highest of the 9 sample points) must remain constantly above 0 °C.
- Reporting: Test report must capture laboratory ID, test conditions, sensor data, thermal images, stabilization graphs and pass/fail assessment.
Applications and practical value
- Ensures reliable anti-icing performance for exterior walkways on ships, offshore platforms and other marine structures operating in cold climates.
- Supports design validation, procurement acceptance testing, regulatory and classification society certification, and comparative evaluation of trace-heating solutions.
- Helps manufacturers and shipyards reduce slip/accident risk and demonstrate compliance with buyer specifications.
Who should use this standard
- Shipbuilders, naval architects, marine engineers
- Trace-heating and heated-walkway manufacturers
- Test laboratories and certification bodies
- Classification societies and purchasers specifying anti-icing requirements
Related standards
- IEC/IEEE 60079-30-1 and 60079-30-2 (Electrical resistance trace heating - general/testing and application guide) - referenced for hazardous-area installations and trace-heating compliance.