17-22
U.S. Navy Diving Manual—Volume 4
NOTE
Surface decompression is not authorized for MK 16 operations.
Appropriate surface decompression tables have not been developed for
constant 0.7 ata ppO2 closed-circuit diving.
17-10.3
Rules for Using 0.7 ata Constant ppO2 in Nitrogen and in Helium Decompres-
sion Tables.
NOTE
The rules using the 0.7 ata ppO2 tables are the same for nitrogen and
helium; however, the tables are not interchangeable.
These tables are designed to be used with MK 16 UBA (or any other constant
ppO2 closed-circuit UBA) with an oxygen setpoint of 0.7 ata or higher.
When using helium as the inert gas, the amount of nitrogen must be minimized
in the breathing loop. Flush the UBA well with helium-oxygen using proper
purge procedure in the MK 16 UBA O&M manual.
Tables are grouped by depth and within each depth group is a limit line. These
tables are designed to be dived to the limit line. Schedules below the limit line
provide for unforeseen circumstances when a diver might experience an inad-
vertent downward excursion or for an unforeseen reason overstay the planned
bottom time.
Tables/schedules are selected according to the maximum depth obtained dur-
ing the dive and the bottom time (time from leaving the surface to leaving the
bottom).
General rules for using these tables are the same as for standard air tables:
1.
Enter the table at the listed depth that is exactly equal to or is next greater
than the maximum depth attained during the dive.
2.
Select the bottom time from those listed for the selected depth that is
exactly equal to or is next greater than the bottom time of the dive.
3.
Never attempt to interpolate between decompression schedules.
4.
Use the decompression stops listed for the selected bottom time.
5.
Ensure that the diver's chest is maintained as close as possible to each
decompression depth for the number of minutes listed.
6.
Maximum ascent rate is 30 feet per minute.
7.
Begin timing each stop on arrival at the decompression stop depth and
resume ascent when the specified time has elapsed. Do not include ascent
time as part of stop time.
