OXYGEN-CONSUMPTION AND VENTILATION DURING SIMULATED ESCAPE FROM AN OFFSHORE OIL PLATFORM

Twenty-six male workers from the North Sea offshore oil industry took part in a simulated escape exercise at the Offshore Fire Training Cent re. The course was 370 m long and had 19.4 m of vertical ascent and de scent using the stairs on simulated offshore structures. Inspired vent ilation and oxygen consumption were measured using the P. K. Morgan 'O xylog' and subjects breathed through the apparatus by mouthpiece and o ne-way valve assembly while wearing a nose clip. On comparison with an thropometric data from larger studies, this sample of the offshore wor k-force was thought to be representative. The mean duration of the exe rcise period was 371 s (SD = 24 s, range = 325-424 s). Mean oxygen con sumption standing still at the start of the trial was 0.421 min(-1) (S D = 0.101 min(-1), max. = 0.611 min(-1)) and mean ventilation 12.351 m in(-1) (SD = 4.251 min(-1), max. = 22.271 min(-1)). During exercise, t he mean oxygen consumption rose to 2.711 min(-1) (SD = 0.641 min(-1), max = 4.051 min(-1)) and mean ventilation reached 46.341 min(-1) (SD = 15.831 min(-1), max = 87.361 min(-1)) during the fifth minute of exer cise. At the end of the exercise period, oxygen consumption returned t o resting values after 2 min and ventilation after 3 min. There was no indication of an oxygen debt. Oxygen consumption and ventilation were related to body weight and the maximum figures for ventilation and ox ygen consumption were seen in individuals of over the 95th centile for weight who completed the exercise more quickly than other subjects. D raft standards for respiratory protective equipment for use during esc ape from fire do not specify the breathing volumes identified in this study, and which are considerably higher than those being currently co nsidered. Additionally, the atmospheric conditions near a fire are lik ely to stimulate ventilation to considerably higher levels than those identified here. Accordingly, such equipment is likely to limit physic al performance if a similar intensity of exercise is necessary during an escape. The architecture of offshore installations and protocols fo r escape from them should be structured to minimize exercise, and stai r climbing should be avoided if emergency respirators are to be used. Workers should be trained in the use of escape breathing equipment and instruction should include information regarding its limitations and the need to limit exercise to an appropriate level.