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On-land trials. On-land trials simulated a scenario in which a TEMPSC has become immobilized due to entrapment in an ice oe or a lack of fuel. e trials were carried out in an indoor loading bay with a mean daily temper- ature of 18°C. Random, incremental loading of participants in groups of 1, 3, 5, 7, 9, 11, 13, and 15 showed signicant increases in the rate of CO 2 accumulation within the TEMPSC. In turn, this led to a decrease in the time required to reach the 8-hour CO 2 exposure limit of 5000 ppm as prescribed by the Health and Safety Executive. ree occupants produced a rate of CO 2 accumulation of 77 ppm/min, requir- ing 58 minutes to reach the 8-hour exposure limit, while 15 occupants produced a rate of 517 ppm/min and required only 12 minutes to reach the exposure limit. A complete summary of the dataset is shown in Table 1. Open hatches e results indicate that occupant habitability within a TEMPSC is compromised due to the accumulation of CO 2 gas. During the dry land trials it took only 12 minutes for 15 occupants to produce CO 2 levels that approached, and exceeded, the 8-hour exposure limit. Having the lifeboat hatches closed decreases the func- tionality of the passive ventilation system, thereby creating the potential for CO 2 accu- mulation at dangerous levels. It may seem obvious to suggest that oper- ating the TEMPSC with the hatches open would be an e ective mitigating step in terms of preventing CO 2 build-up within the vessel. Although this may be true, it may not always be possible or safe to do so. Operating with the hatches open compromises the watertight integrity of the TEMPSC, and doing so in a high sea state would greatly increase the risk of tak- ing on water. Also, if the TEMPSC were forced to navigate through res or clouds of sour gas, having the hatches open would directly expose the occupants to these dangers. Emergency escape rescue (EER) events are often very fast-paced and stressful situa- tions that involve many cognitive tasks, such as decision making and navigation. It would be very dicult to e ectively carry out EER protocols and operate the TEMPSC while undergoing the respiratory distress and cen- tral nervous system e ects that can be brought on by exposure to high levels of CO 2. Ironically, the TEMPSC, a safety appliance that has been designed to increase safety in harsh climates, is capable of creating an internal environment that is harmful to human life. It is recommended that the TEMPSCs pas- sive ventilation system be replaced with an active one if the possibility of regular ush- ing? of ambient air is not possible. It is not unrealistic to expect that the occupants of a TEMPSC located in arctic waters may have to wait 24 hours, or more, for rescue vessels to arrive. While in these stationary states, the passive ventilation system within the TEMPSC is rendered relatively ine ective, and thus it is highly probable that CO 2 levels will climb to levels that are dangerous to human health. However, if an active ventilation system were implemented that constantly exchanged air between the internal and external environ- ment of the vessel, occupant habitability within the TEMPSC would be greatly improved and, in turn, the likelihood of a successful EER event would be increased. MTScott N. MacKinnon is professor, associate dean, and direc- tor of the Interdisciplinary PhD Program, School of Graduate Studies at Memorial Univer sity of Newfoundland. Andrew Baker is a graduate student at the School of Human Kinetics and Recreation at Memorial University of Newfoundland. April 2012www.sname.org/sname/mt (mt notes) e Intersection of Habitability and Survival continued LEARN MORE To learn more about the issues described in this article, check out the following resources. Health and Safety Executive, Control of Substances Hazardous to Health: EH40 Workplace Exposure Limits,? www.hse. gov.uk/coshh/table1.pdf International Maritime Organization, International Convention for the Safety of Life at Sea (SOLAS),? 1997 Consolidated Edition and subsequent amendments. International Maritime Organization, International Life-Saving Appliance Code,? 2003 edition. Power, J., and Simões Ré, A., Lifeboat Habitability and Eects on Human Subjects,? IceTech 2010. Robson, J., Overview of TEMPSC Performance Standards,? research report 599 for Health and Safety Executive, www. hse.gov.uk/RESEARCH/rrpdf/rr599.pdf Scott, J., Kraemer, D., and Keller, R., Occupational Hazards of Carbon Dioxide Exposure,? Journal of Chemical Health and Safety, 2008. Taber, M., Simões Ré, A., and Power, J., A preliminary ergonomic assessment of piloting a lifeboat in ice. Safety Sci , 2009. Xu, F., Uh, J., Brier, M., Hart, J., Yezhuvath, U., Gu., H., Yang, Y., and Lu, H., The in?uence of carbon dioxide on brain activity and metabolism in conscious humans,? Journal of Cerebral Blood Flow & Metabolism , 31.On-land trials simulated a scenario in which a TEMPSC has become immobilized due to entrapment in an ice oe or a lack of fuel.