BS ISO 21885:2019 pdf free.Ships and marine technology一Testing specification for stairsteps using electrical resistance trace heating.
The equipment shall be tested at the temperatures agreed upon between the manufacturer and the purchaser. The test temperature shall be observed after the test-specimen temperature is stabilized according to 5.3.2.2. The temperature of the wind delivered to the test specimen shall be within +2 °C of the test condition temperature during the steady state. Where, due to the size of the test chamber, it is not feasible to maintain these tolerances, the tolerances may be widened to +3 °C down to -25 °C. A temperature sensor shall be installed between the wind generator and the test specimen to measure the ambient temperature.Spatial resolution of temperature measurements shall be sufficient to identify cold spots on the surface of the test piece. No less than 9 sample points shall be used. Technical evidence shall be provided to identify the coldest spots to be used as sample points. The sample points need not be located within 50 mm of the perimeter, however, 5 sample points shall be located within 20 mm of the leading edge. The remaining sample points shall be located at the coldest spots on the specimen. Any temperature sensor used in the testing shall be calibrated according to its manufacturers’ directions for the planned test conditions. Temperature sensors (e.g. thermal imagery or thermo couples) shall be properly adjusted for the emissivity of the material, if applicable, and verified with a secondary measurement.Lower the ambient temperature of the test chamber to 5 °C. Once temperature stabilization has been achieved for both the chamber and the test specimen, turn on the electric power of the heating media. Turn on the wind generator as required to meet the test conditions (see 5.3.3). The wind speed to the specimen shall be maintained throughout the test. The wind generator should start operating before lowering the ambient temperature of the cold room to the target temperature, because it may not start operating unless warmed up in low temperature.BS ISO 21885 pdf download.