Insulated Tents for Cold Weather Operations

摘要

Analyses of the insulation requirements and ventilation rates for small, insulated tents were made and compared with both laboratory and field observations on two proto-type tents used during a winter trial. Predicted values of thermal resistance were in good agreement with measured values, although it was found that construction techniques could significantly alter the value of thermal insulation for the tent. Two analyses of the ventilation rate were made, one based on the conservation of thermal energy and the second based on a buoyancy driven pipe flow analysis. Predicted ventilation rates agreed with measured values to within a factor of two under calm conditions. An estimate of the minimum acceptable ventilation rate was made based on a stoichiometric combustion analysis of a generalized hydrocarbon fuel. It was found that, for the insulated tents studied, this minimum ventilation rate could be achieved by natural convection alone. This may not be the case for uninsulated tents as resulting tent air temperatures may be insufficient to produce adequate natural convection ventilation. Observations of carbon monoxide levels, made while heating the tents during the winter trial, indicated that the levels where well within acceptable occupational levels and often within acceptable public exposure levels. The use of insulated tents may indirectly help reduce the hazards of carbon monoxide by providing a more comfortable environment within the tent thereby reducing the incentive to restrict the ventilation of the tent. Water accumulation by the tents was found to be larger than expected, possibly due to the warmer than expected weather during field trial.