Statistically Based Decompression Tables. 2. Equal Risk Air Diving Decompression Schedules

摘要

Several sets of equal risk air decompression tables were calculated using a new methodology. Empirical decompression risk models were used to predict the probability of decompression sickness (DCS) for a given pressure exposure. These probabilistic models, earlier shown to have a considerable ability to separate tabulated experimental air dives according to DCS risk, were used to choose decompression schedules with an acceptable risk. The levels of risk used were 1% and 5% for standard air dives with an additional set of 0.5% no-decompression limits. As the new method calculates risk according to an integral over the dive and postdive period, many possible decompression schemes will have the same risk. The best schedules are defined as those requiring minimal total decompression time for the specified risk and subject to operational constraints. The constraints used here are decompression stops at even 10-ft intervals of depth for whole minutes. An algorithm was developed to obtain schedules in a partially optimal manner. The methodology can be used directly to produce tables for other operational constraints or risk levels. Because of the known limitations of source data and risk models, these tables represent considerable extrapolation from known procedures and should not be considered for use without testing.