[abstract] REPEX: SIMULATION OF HABITAT DIVING PROCEDURES INVOLVING REPETITIVE AND TIMED EXCURSIONS AND MANAGEMENT OF OXYGEN EXPOSURE.

Abstract

We have developed a new set of decompression tables for excursing from undersea habitats having a nitrox (nitrogen-oxygen) atmosphere. The process of reviewing past experience and devising the "tables" has been reported; this report covers a modest laboratory simulation to validate the tables for initial carefully monitored use at sea. The tables are derived from the NOAA OPS procedures included in the NOAA Diving Manual, but are expanded to include repetitive dive capability, excursions with decompression stops, management of oxygen exposure, and saturation decompression. Three saturations at IUC for 6, 5, and 5 days at storage depths of 50, 80, and 110 fsw involved 21, 23, and 19 descending excursions for a total of 252 man-dives, and a11 were without problems. Each saturation had 4 divers; the 12 (8 male, 4 female) ranged in age from 19 to 62 and in weight from 100 to 235 lb. The excursions as much as possible covered the depth-time range of the tables, were all carried to the full time, and were separated by habitat (i.e., surface) intervals timed to be the minimum allowed. Most exposures matched or exceeded the oxygen limits allowed by the procedures; very minor symptoms in one diver indicated the oxygen rules are right on target. Pain-only DCS in one diver at 10 fsw in Repex I forced revision of the saturation procedures to include a recompression based on recent excursions before starting ascent; they were trouble free thereafter. Supported by Contract NA-84-DGC-00152, NOAA Undersea Research Program.