Air contaminants in a submarine equipped with air independent propulsion.

The Swedish Navy has operated submarines equipped with air independent propulsion for two decades. This type of submarine can stay submerged for periods far longer than other non-nuclear submarines are capable of. The air quality during longer periods of submersion has so far not been thoroughly investigated. This study presents results for a number of air quality parameters obtained during more than one week of continuous submerged operation. The measured parameters are pressure, temperature, relative humidity, oxygen, carbon dioxide, hydrogen, formaldehyde and other volatile organic compounds, ozone, nitrogen dioxide, particulate matter and microbiological contaminants. The measurements of airborne particles demonstrate that air pollutants typically occur at a low baseline level due to high air exchange rates and efficient air-cleaning devices. However, short-lived peaks with comparatively high concentrations occur, several of the sources for these have been identified. The concentrations of the pollutants measured in this study do not indicate a build-up of hazardous compounds during eight days of submersion. It is reasonable to assume that a substantial build-up of the investigated contaminants is not likely if the submersion period is prolonged several times, which is the case for modern submarines equipped with air independent propulsion.

Atmospheric changes and physiological responses during a 6-day "disabled submarine" exercise.

BACKGROUND: Survival time within a disabled submarine (SUBSUNK) is dependant on atmospheric composition and proper design and use of emergency atmospheric control systems. The objective of this study was to investigate atmospheric changes and physiological responses during a SUBSUNK trial. METHODS: There were 18 volunteers who were restrained within a 250 m3 front compartment of an Ula-class submarine submerged in 8 degrees C seawater for 6 d, 18 h. Atmospheric control was maintained according to emergency procedures using non-electrically powered chemical CO2 absorption, and O2 was replenished using chlorate candles. Atmospheric parameters, skin and body temperatures, weight, urine, and drinking volume were measured. Subjective responses to cold were measured on a visual analog scale (VAS), and symptoms were logged on the environmental symptoms questionnaire (ESQ). RESULTS: Atmospheric temperature gradually decreased to a minimum of 14.1 degrees C. Toe, heel, and finger temperatures decreased significantly. Subjects reported inferior subjective thermal comfort on the VAS and increased cold stress on the ESQ. Except for CO2, no inorganic or volatile organic compounds exceeded occupational exposure limits. The PO2 and PCO2 ranged from 17.4-20.3 and 1.9-2.8 kPa, respectively, during the first 5 d. During the last 2 d, PO2 and PCO2 were deliberately maintained at about 15.8 and 3.1 kPa, respectively. Mean oxygen consumption and CO2 production were 23.8 and 19.8 L standard temperature and pressure (STP) x man(-1) x h(-1), respectively. Soda lime and lithium hydroxide CO2 absorption capacities were 126 and 405 L STP x kg(-1) respectively. CONCLUSIONS: Atmospheric conditions can be controlled acceptably for 6 d, 18 h within the front compartment of an Ula-class submarine operating according to emergency SUBSUNK procedures.