| Abstract | The ISO Thermal Manikin Working Group has been tasked to assess the suitability to include thermal manikins in the standard for the current immersion suit approval testing. Five international laboratories were involved in a round robin test to measure the thermal resistance of immersion suits. The objectives are (1) to assess the uniformity of thermal resistance of suits derived from different manikins, to attempt to quantify the errors caused by methodology, tools and calculation methods; and (2) to evaluate the difference in thermal resistance output between manikin and human for the same immersion suit. The results of the tests conducted at National Research Council Canada, Institute for Ocean Technology (NRC-IOT) are documented in this report. In air, the thermal resistance of a manikin wearing only test clothing was determined to be 1.408 clo. The thermal resistance of a manikin wearing a non-insulated immersion suit and an insulated suit, with SOLAS RTD lifejacket over test clothing were 2.442 clo and 2.574 clo, respectively. In water, under uniform cooling conditions, the thermal resistance for a non-insulated immersion suit and an insulated immersion suit were 0.532 clo and 1.355 clo, respectively. Under non-uniform cooling conditions, the results can be up to 25% different from those conducted in uniform cooling conditions. It is concluded that under uniform cooling conditions, the constant temperature control mode of thermal manikins and the parallel method can be used to determine thermal resistance. Further research and development are needed before thermal manikins could be used with confidence for suit evaluation under non-uniform cooling conditions. To provide the scientific evidence that manikins can be used as an evaluation tool for immersion suits, it is also important to assess the thermal resistance of humans and manikins in the same environmental conditions, concurrently, in the same laboratory. |
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