13-8 Change A
U.S. Navy Diving Manual—Volume 3
mixed gas diving is that there be adequate quantities of the appropriate gases on
hand, as well as a substantial reserve, for all phases of the operation. The initial
determinations become critical if the nearest point of resupply is far removed from
the operation site.
13-3.10.1
Gas Consumption Rates. The gas consumption rates and carbon dioxide absor-
bent durations for various types of underwater breathing apparatus are shown in
Table 13-1. Refer to Chapter 4 for required purity standards.
13-3.10.2
Surface Supplied Diving Requirements. For surface supplied diving, the diver
gas supply system is designed so that helium-oxygen, oxygen, or air can be
supplied to the divers as required. All surface supplied mixed gas diving systems
require a primary and secondary source of breathing medium consisting of
helium-oxygen and oxygen in cylinder banks and an emergency supply of air from
compressors or high-pressure flasks. Each system must be able to support the gas
flow and pressure requirements of the specified equipment. The gas capacity of
the primary system must meet the consumption rate of the designated number of
divers for the duration of the dive. The secondary system must be able to support
recovery operations of all divers and equipment if the primary system fails. This
may occur immediately prior to completing the planned bottom time at maximum
depth when decompression obligations are the greatest. Emergency air supply is
provided in the event all mixed gas supplies are lost.
13-3.10.3
Deep Diving System Requirements. A deep diving system must be able to store
and supply enough gas to support saturation diving to the maximum certified
depth. Deep diving systems can handle and store pure gases, and mix the required
percentages of helium-oxygen as needed. When DDS type equipment is
employed, additional quantities of gas must be included for DDC and PTC
charging and for replacing losses due to leakage, transfer trunk and service lock
usage and scrubber cycling. A DDS must also have an air system capable of
supporting surface supplied air diving operations and initial pressurization of the
DDS for saturation operations.
13-4
SELECTING AND ASSEMBLING THE DIVE TEAM
Selecting a properly trained team for a particular diving mission is critical. Refer
to Chapter 6 for an expanded discussion on dive team selection, as well as the
criteria for selecting qualified personnel for various tasks. It is critical to ensure
that only formally qualified personnel are assigned. The Diving Officer, Master
Diver, and Diving Supervisor must verify the qualification level of each team
member. The size and complexity of deep dive systems reinforces the need for a
detailed and comprehensive watch station qualification program.
13-4.1
Diver Training. Training must be given the highest command priority. The
command that dives infrequently, or with insufficient training and few work-up
dives between operations, will be ill prepared in the event of an emergency. The
dive team must be exercised on a regular diving schedule using both routine and
nonroutine drills to remain proficient not only in the water but on topside support
