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October 01, 2008— St. John's, Newfoundland and Labrador

A new research initiative underway at NRC facilities in St. John's, Newfoundland, aims to help people survive when forced to abandon ship in cold waters. Thanks to NRC's Marine Safety Program, Canada will soon provide the data needed to strengthen international standards for thermal protection in life rafts, immersion suits and other marine safety equipment.

Transport Canada follows the current International Maritime Organization (IMO) standards for life rafts. According to Lawrence Mak, a mechanical and ocean engineer at the NRC Institute for Ocean Technology (NRC-IOT), thermal protection is required in life rafts, but IMO standards provide no specific thermal performance requirements or assessment criteria.

"Marine operators, survival training organizations and regulatory agencies have no information to help them select life rafts that are better suited to certain geographic locations," says Mak. This is a serious shortcoming, since what might be sufficient thermal protection in the Caribbean could be completely inadequate off Canadian shores.

"With solid data about human heat loss over time and in specific temperatures, Transport Canada will be well positioned to recommend more stringent thermal protection requirements," he adds.

NRC researchers have evaluated life rafts of various sizes to assess their operational performance in diverse weather conditions.
NRC researchers have evaluated life rafts of various sizes to assess their operational performance in diverse weather conditions.

Simulating various sea conditions, Mak and his team used the tank facilities at NRC-IOT to assess the thermal protection of a 16-person, commercially available SOLAS life raft. The researchers compared heat loss in volunteers and manikins exposed to cool (16°C water temperature and 19°C air temperature) and cold conditions (5°C water temperature and 5° C air temperature). To facilitate certification testing, Transport Canada needs assurance that manikins can provide equivalent data to humans.

One of their objectives was to develop a life raft occupancy heat loss model that could interface with the "Cold Exposure Survival Model" developed by Defence Research and Development Canada, one of Mak's research partners. The project was designed to help develop methods for testing the thermal performance of life rafts and survival prediction tools for search and rescue planners and training providers.

In a related study, Mak's colleague, Jonathan Power, is measuring the effect of wind and waves on the heat loss of humans wearing certified and commercially available immersion suits.

"People with no thermal protection who are suddenly immersed in cold water could suffer from cold shock response and drown within just a few minutes," says Power. "Or they could experience hypothermia, which takes longer."

An immersion suit can greatly reduce the risk of cold shock response and delay hypothermia, while providing buoyancy. To be certified, immersion suits must be tested for material strength and thermal protective properties, and must prevent a drop in core body temperature of no more than 2°C in six hours.

"Although this testing provides baseline data, there's a significant difference between the data you'll collect from people monitored in a calm indoor pool and people exposed to real ocean conditions," says Power. "We need to measure body temperature loss over time when people are buffeted by high wind and waves. So far, we've measured skin temperature, core body temperature, heat flow and heart rates in different wind, wave and water temperature conditions to determine how each factor affected the participants."

Power and his team are being funded by Transport Canada and the Program for Energy Research and Development (PERD). Both of these sponsors will benefit from the data NRC will produce on the thermal regulatory response of people wearing immersion suits.

Mak's project on life rafts was sponsored by Transport Canada and financed by the National Search and Rescue Secretariat. The team also had the support of Memorial University, the Marine Institute Offshore Safety and Survival Centre, Defence Research and Development Canada, Helly Hanson Canada, Brock University, Waterloo University, Safety Net and the Canadian Coast Guard.

Although NRC's objective was to recommend changes to the international standards for this equipment, the results of this research will help marine industry stakeholders understand how humans fare in realistic conditions in the life rafts and immersion suits now being certified.

Enquiries: Media relations
National Research Council of Canada

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