30.E Mixed-Gas Diving Operations.
30.E.01 A dual lock, multi-place, recompression chamber with a trained, competent operator must be available and ready for use at the dive location for any mixed-gas dive.
Mixed gas diving training.
Sufficient oxygen must be available to complete chamber operations. At extreme depth, mixed gas diving can only be done if:
- A bell is used at depths greater than 220 ft (67 m) or when the dive involves in-water decompression time of greater than 120 minutes (except when heavy gear is worn or when diving in physically confining spaces), or
- A closed bell is used at depths greater than 300 ft (91.4 m), except when diving is conducted in physically confining spaces.
30.E.02 Each diving operation must have a primary breathing gas supply sufficient to support divers for the duration of the planned dive, including decompression.
30.E.03 Each diving operation must have a reserve breathing gas supply integral or in-line with the primary air source sufficient to safely recover the diver(s) in the event of failure of the primary breathing gas supply.
30.E.04 When heavy gear is worn:
- An extra breathing gas hose capable of supplying breathing gas to the diver in the water must be available to the standby diver, and
- An in-water stage must be provided to divers in the water.
30.E.05 An in-water stage must be provided for divers without access to a bell for dives deeper than 100 ft (30.4 m) or outside the no-decompression limits.
30.E.06 When a closed bell is used, one dive team member in the bell must be available and tend the diver in the water.
30.E.07 Oxygen Enriched Air.
- The use of "Oxygen Enriched Air" (OEA) such as Nitrox (EANx) breathing mixtures by USACE in-house dive teams requires the specific initial approval of the HQUSACE Dive Safety Program Manager prior to the first use of such equipment. Requests for approval will be accompanied by a written program that identifies training, certification, and procedures for OEA use. Use of OEA by Contractors requires approval by the local DDC.
- Navy or NOAA Nitrox Dive Tables or other decompression tables designed specifically for the OEA mixture being used must be followed without exception.
- The use of OEA/Nitrox is considered mixed gas diving and requires a decompression chamber on site and ready for use.
30.E.08 Contractors must provide evidence of training and experience with OEA breathing mixtures prior to actual diving operations.
30.E.09 OEA breathing mixture must be analyzed/tested by the diver to assure proper mix prior to each use. No more than 40% OEA is allowed for normal diving operations. Higher OEA concentrations are allowable for in-water decompression at shallow safety stops.
30.E.10 Use of Surface Decompression with Oxygen (SUR-D-O2) and/or 100% oxygen in- water decompression by trained and certified dive teams, must only be authorized as a decompression methodology upon submittal of an oxygen-specific decompression plan and schedule, and only with the expressed written approval of the District Dive Coordinator or alternate.
Knowledge Check Choose the best answer for the question.
30-14. No more than _____ oxygen enriched air (OEA) is allowed for normal mixed-gas diving operations.
You forgot to answer the question!