13-2 Change A
U.S. Navy Diving ManualVolume 3
they may affect his performance and safety. Mixed gas diving procedures that
minimize the effects of these changes are described in this and the following chap-
ters. Every mixed gas diver must be thoroughly familiar with these procedures.
Typical medical problems in mixed gas and oxygen diving include decompression
sickness, oxygen toxicity, thermal stress, and carbon dioxide retention. Deep satu-
ration diving presents additional concerns, including high pressure nervous
syndrome (HPNS), dyspnea, compression arthralgia, skin infections, and perfor-
mance decrements. These factors directly affect the safety of the diver and the
outcome of the mission and must be addressed during the planning stages of an
operation. Specific information concerning medical problems particular to various
mixed gas diving modes are contained in Volume 5.
ESTABLISH OPERATIONAL TASKS
Preparing a basic outline and schedule of events for the entire operation ensures
that all phases will be properly coordinated. This chapter gives specific guidelines
that should be considered when analyzing the operational tasks. Mixed gas diving
requires additional considerations in the areas of gas requirements, decompres-
sion, and medical support.
Mixed gas diving requires a predetermined supply of breathing gases and carbon
dioxide absorbent material. Operations must be planned thoroughly to determine
usage requirements in order to effectively obtain required supplies in port or at sea
prior to the start of the mission. See paragraph 13-3.10 and Table 13-1 for specific
gas/material requirements. Logistic requirements may include planning for on-site
resupply of mixed gases and other supplies and for relief of diving teams from
Fleet units. Consult unit standing operating procedures for resupply guidance and
personnel procurement (refer to OPNAVINST 3120.32 [series]).
SELECT DIVING METHOD AND EQUIPMENT
Selecting the appropriate diving method is essential to any diving operations plan-
ning. The method will dictate many aspects of an operation including personnel
Table 13-1. Average Breathing Gas Consumption Rates.
MK 21 MOD 0 UBA
MK 21 MOD 1 UBA
EXO BR MS UBA
MK 22 MOD 0 UBA
1.4 acfm (demand)
6.0 acfm (free flow)
2.5 acfm (demand)
6.0 acfm (free flow)