REPEX: Development of repetitive excursions, surfacing techniques, and oxygen procedures for habitat diving. Technical Report 88-1A.

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REPEX: Development of repetitive excursions, surfacing techniques, and oxygen procedures for habitat diving. Technical Report 88-1A.

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Title: REPEX: Development of repetitive excursions, surfacing techniques, and oxygen procedures for habitat diving. Technical Report 88-1A.
Author: Hamilton Jr, RW; Kenyon, DJ; Peterson, RE; Butler, GJ; Beers, DM
Abstract: The Repex program expanded and improved on the basic technology of the NOAA OPS project, which in 1973 opened up nitrox saturation or "habitat" diving by making it possible for divers to excurse to depths both shallower and deeper than their saturation storage depth. From the beginning it was apparent that other capabilities were needed. This program has provided development of these new procedures and a modest chamber validation. Excursion tables were computed using modificatfons of the NOAA OPS algorithm, adjusted to account for a few decompression problems that have occurred; a new M-value matrix was derived. We justified basing repetitive computations on gas loading because bubble activity depends on gas loading, and ultrasound data has shown no increase, possibly a decrease, in bubbles in the second of repetitive dives having equal stress. We found the dive number in a repetitive sequence and the interval between dives were the important factors, assuming that similar repetitive excursions would be the worst case; tables are based on order and interval. For longer excursions a single stop of up to 1 hr is used, with a preliminary deeper stop of 2 min. Three week-long chamber tests covered the storage depth (50, 80, 110 fsw) and excursion depth (94-240 fsw) ranges in 252 diver-excursions with representative times and intervals. Divers ranged from 19 to 62 yr and from 100 to 235 1b, and included 4 females. No DCS resulted from excursions, and doppler monitoring found bubbles of Grade I1 or below. We had pain-only DCS at 10 fsw decompressing from 50 fsw after a 12-hr hold fol lowing the last excursion, so changed the decompression to start at a "starting depth*' deeper than the habitat; it is based on recent excursions. For example, the 80 fsw saturation started at 130 fsw; this is quicker than a 12-hr wait, which would be inadequate anyway. Subsequent saturation decompressions were okay. Two groups of divers were well above the 02 limit, but had only trivial symptoms, suggesting that the limits are quite good; the daily and total doses depend on the duration of the exposure. The Procedures are ready for provisional use at sea. [Development and validation report to the Office of Undersea Research, NOAA, U.S. Dept. of Commerce, under Contract NA-84-DGC-00152.]
Description: Reproduction in part or in whole is permitted for any purpose.
URI: http://archive.rubicon-foundation.org/4865
Date: 1988

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