514 EM 385-1-1 Chapters 30-37

Sections

30-8. General Requirements.

Mixed-Gas Diving Operations

Ensure a functional dual lock, multi-place recompression chamber with a trained Competent Person is provided for mixed-gas dives. The chamber must be capable of following U.S. Navy decompression tables and have enough oxygen for operations. Avoid extreme depth, mixed-gas diving.
Equip each diving operation with a primary breathing gas supply sufficient to support divers for the duration of the planned dive, including decompression.
Equip each diving operation with 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.
Allow SUR D O2 or 100% oxygen in-water decompression only with a specific plan, schedule, and written approval from the DDC or ADC.
When heavy gear is used, ensure an extra hose for standby divers and an in-water stage for divers are provided. For dives deeper than 100 feet or outside no-decompression limits without a bell, provide an in-water stage. If a closed bell is used, assign one team member inside to tend the diver.

Oxygen Enriched Air (OEA)

The USACE National Dive Safety Program Manager must approve the use of OEA such as Nitrox (EANx) by in-house teams, and the DDC must approve its use by contractors. A written program detailing training, certification, and OEA procedures is required for approval.
Clearly mark bottles for OEA breathing mixtures and adhere strictly to U.S. Navy or NOAA Nitrox Dive Tables for the specific OEA mixture. More conservative decompression tables may be used after DDC acceptance.
The use of OEA/EANx is considered mixed-gas diving and requires a decompression chamber onsite and ready for use.
Require divers to show training and experience with OEA mixtures before diving. Test OEA mixtures before each use, ensuring proper mix and adhering to the maximum allowable OEA concentration for normal and shallow safety stop operations.

Knowledge Check Choose the best answer for the question.

30-8. The use of OEA/EANx is considered mixed-gas diving and requires a decompression chamber _____.

available for prompt use

onsite and ready for use

located within 15 minutes of the dive operation

suitable for use with at least two divers

You forgot to answer the question!

EM 385-1-1 Paragraph 30-8 (d.–e.).

30-8. General Requirements. (d.–e.).

d.  Mixed-Gas Diving Operations.  (30-8.d)

(1)  For mixed-gas dives, provide a fully functioning dual lock, multi-place, recompression chamber with a trained, competent operator.  Provide sufficient oxygen to complete chamber operations.  The recompression chamber must be capable to conduct decompression following the mixed-gas decompression tables in the U.S. Navy
    Diving Manual.  Do not perform extreme depth, mixed-gas diving.

(2)  Equip each diving operation with a primary breathing gas supply sufficient to support divers for the duration of the planned dive, including decompression.

(3)  Equip each diving operation with 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.

(4)  The primary and reserve breathing gas supply must be capable of delivering the mixed-gas requirements.  For example, when performing mixed-gas helium-oxygen according to the U.S. Navy Surface-Supplied Helium-Oxygen Decompression Tables, the diving system must be capable of suppling the diver’s umbilical with four different breathing gasses: Bottom Mixture; 50% Helium 50% Oxygen; 100% Oxygen; and Air.

(5)  SUR D O2 and/or 100% oxygen in-water decompression by trained and certified dive teams, may only be authorized as a decompression methodology upon submittal of an oxygen-specific decompression plan and schedule as part of the dive operations plan, and only with the expressed written approval of the DDC or ADC (see para 30-7.c).

(6)  When heavy gear is worn provide the following:

(a)  Provide each standby diver with an extra hose capable of supplying breathing gas to the diver in the water.

(b)  Provide each diver with an in-water stage.

(7)  For divers without access to a bell for dives deeper than 100 feet (30.5 m) or outside the no-decompression limits, provide an in-water stage.

(8)  When a closed bell is used, one dive team member in the bell must be available to tend the diver in the water.

e.  Oxygen Enriched Air (OEA).  (30-8.e)

(1)  USACE National Dive Safety Program Manager must approve any use of OEA such as Nitrox (EANx) breathing mixtures, and the associated equipment, by USACE in- house dive teams. Provide a written program that identifies training, certification, and procedures for OEA use with the request for approval.  The DDC must approve use of OEA by contractors.

(2)  Properly mark bottles used for OEA breathing mixtures.

(3)  Follow, without exception, the U.S. Navy or NOAA Nitrox Dive Tables for the OEA mixture being used.  Other more conservative decompression tables may be used after acceptance by the DDC.

(4)  The use of OEA/EANx is considered mixed-gas diving and requires a decompression chamber onsite and ready for use.

(5)  All divers must provide evidence of training and experience with OEA breathing mixtures prior to actual diving operations (see para 30-3).

(6)  Test OEA breathing mixtures 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.