Ecological factors affecting efficiency and health in warships.

The environment of those who live and work in warships is closely related to the way the ships are built and employed. In stating the requirements for the atmosphere between decks the emphasis has swung during the past 50 years from the need for controlling the chemical constituents to the control of the factors which comprise the thermal environment, and now, with the advent of the nuclear-powered -submarine, to the need for achieving, as nearly as possible, complete physical, chemical, and microbiological control. Between 1944 and 1953 the thermal factors between decks were investigated in a series of studies carried out in H.M. Ships. The average effective temperatures on the mess decks and in the work places of 11 ships in the Eastern Fleet in 1944 exceeded 84°F. (28-9°C.). In compartments where radiant heat was an added factor the average corrected effective temperature levels were 10 or 2°F. (0-55-1 1 C.) higher than the corresponding effective temperatures. The effects of climatic conditions on naval personnel were investigated by psychological studies to determine the levels of warmth at which performance deteriorated; by physiological experiments to show the levels of warmth at which the collapse of men working at different work rates might be expected; by comfort surveys in ships and on shore to determine the levels of warmth at which the majority enjoyed optimum comfort; and by relating the monthly incidence of the common causes of ill-health to the average monthly upper-deck temperature as recorded at noon each day in order to determine the temperature level above which sickness increased. It was concluded that the upper desirable level of warmth to consider when designing ships for hot climates was an effective temperature of 78°F. (25 50C.). As it is usually impracticable in many compartments to achieve temperatures below 78°F. (25 5°C.) in the tropics without the generous application of air cooling, attention was then directed to the associated effects on the chemical and bacterial constituents of restricting air supplies, an unavoidable feature of most air conditioning systems, and to defining the permissible lower limits for fresh air requirements. The nuclear submarine with its capacity for remaining submerged for very long periods raises new problems relating to life in a confined space and involving very prolonged exposure to the submarine environment. These problems have still to be investigated.