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Subchapter 7. General Industry Safety Orders
Group 26. Diving Operations
Article 152. Diving Operations

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§6051. Definitions.

As used in this Article, the listed terms are as follows:

Acfm. Actual cubic feet per minute.

ASME Code or Equivalent. ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code, Section VIII, or an equivalent code which the employer can demonstrate to be equally effective.

ATA. Atmosphere absolute.

Agricultural Diving. All diving operations (including maricultural and aquacultural diving) performed by agricultural employees necessary to a farming activity including but not limited to maintenance planting, cultivation, growing or harvesting not conducted by a commercial diver.

Aquaculture (Mariculture). The culture and husbandry of aquatic organisms.

Bell. An enclosed compartment, pressurized (closed bell) or unpressurized (open bell), which allows the diver to be transported to and from the underwater work area which may be used as a temporary refuge during diving operations.

Bottom Time. The total elapsed time measured in minutes from the time when the diver leaves the surface in descent to the time that the diver begins ascent.

Breath-hold Diving. A diving mode in which the diver uses no self-contained or surface-supplied air or oxygen supply.

Bursting Pressure. The pressure at which a pressure containment device would fail structurally.

Commercial Diver. A diver hired for underwater work who is engaged in commercial diving operations.

Commercial Diving Operations. All diving operations in which construction, demolition, repair, maintenance, shipbuilding, shipbreaking or ship repair, work is performed.

Cylinder. A pressure vessel for the storage of gases.

Decompression Chamber. A pressure vessel for human occupancy such as a surface decompression chamber, closed bell, or deep diving systems used to decompress divers and to treat decompression sickness.

Decompression Sickness. A condition with a variety of symptoms which may result from gas and bubbles in the tissues of divers after pressure reduction.

Decompression Table. A profile or set of profiles of depth-time relationships for ascent rates and breathing mixtures to be followed after a specific depth-time exposure or exposures.

Dive Location. A surface or vessel from which a diving operation is conducted.

Dive-Location Reserve Breathing Gas. A supply system of air or mixed gas (as appropriate) at the dive location which is independent of the primary supply system and sufficient to support divers during the planned decompression.

Diver. An employee working in water who using apparatus, including snorkels, which supplies breathing gas at ambient pressure.

Diver-in-Training. An employee gaining experience and training in additional diving activities under the supervision of a dive team member experienced in those activities.

Diver-Carried Reserve Breathing Gas. A diver-carried supply of air or mixed gas (as appropriate) sufficient under standard operating conditions to allow the diver to reach the surface, or another source of breathing gas, or to be reached by a standby diver.

Dive Site. The physical location of a diver during a dive which may be on the surface or underwater.

Dive Team. Divers and support employees who are exposed to or control the exposure of others to hyperbaric conditions, including the designated person-in-charge.

Diving Mode. A type of diving requiring specific equipment, procedures and techniques (SCUBA, surface-supplied air, or mixed gas).

Fsw. Feet of seawater (or equivalent static pressure head).

Heavy Gear. Diver-worn, deep-sea dress including but not limited to helmet, breastplate, dry suit.

HOOKAH Diving. A type of shallow water surface-supplied diving where the diver uses the second stage of a SCUBA regulator connected to a non-return valve and hose to a surface air source.

Hyperbaric Conditions. Pressure conditions in excess of normal atmospheric pressure at the dive site.

Inwater Stage. A suspended underwater platform which supports a diver in the water.

Liveboating. The practice of supporting a surface-supplied air or mixed gas diver from a vessel which is underway.

Maximum Working Pressure. The maximum pressure to which a containment device may be exposed under standard operating conditions.

Mixed-Gas Diving. A diving mode in which the diver is supplied in the water with a breathing gas other than air.

Msw. Meters of seawater (or equivalent static pressure head).

No-Decompression Limits. The depth-time limits of the “no-decompressions limits and repetitive dive group designations table for no-decompression air dives.” U.S. Navy diving Manual or equivalent limits which the employer can demonstrate to be equally effective.

Pressure-Related Injury. Any injury resulting from pressure disequilibrium within the body as the result of hyperbaric exposure such as: decompression sickness, pneumothorax, mediastinal emphysema, air embolism, or subcutaneous emphysema.

Psi(g). Pounds per square inch (gauge).

Scientific Diving. All diving performed solely as a necessary part of a scientific research, or educational activity by employees whose sole purpose for diving is to perform scientific research tasks. Scientific diving does not include performing any tasks usually associated with commercial diving such as: placing or removing heavy objects underwater, inspection of pipelines and similar objects; construction; demolition; cutting or welding; or the use of explosives.

SCUBA Diving. A diving mode independent of surface supply in which the diver uses open circuit self-contained underwater breathing apparatus.

Standby Diver. A diver at the dive location capable of rendering immediate assistance to a diver in the water.

Surface-Supplied Air Diving. A diving mode in which the diver in the water is supplied from the dive location with compressed air for breathing.

Technical Diving. All diving other than scientific or commercial diving performed by employees in making or performing observations, measurements, adjustments, underwater photography or special effects and related activities, etc., which require technical expertise and are not an integral part of an ongoing construction, demolition, repair, maintenance, shipbuilding, shipbreaking, or ship repair job.

Treatment Table. A depth-time and breathing gas profile designed to treat decompression sickness.

Umbilical. The composite hose bundle between a dive location and a diver or bell, or between a diver and a bell, which supplies the diver or bell with breathing gas, communications, power, or heat as appropriate to the diving mode or conditions, and includes a safety line between the diver and the dive location.

Volume Tank. A pressure vessel connected to the outlet of a compressor and used as an air reservoir.

Working Pressure. The normal pressure at which the system is designed to operate.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment filed 9-11-80; designated effective 1-1-81 (Register 80, No. 37).

2. Amendment filed 6-10-83; effective thirtieth day thereafter (Register 83, No. 24).

3. Change without regulatory effect amending definition of “Liveboating” filed 11-7-2011 pursuant to section 100, title 1, California Code of Regulations (Register 2011, No. 45).

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