APPENDIX 7 Definition of Terms

Air sharing – The sharing of an air supply between divers.

Altitude Diving – Diving conducted in excess of 1,000 feet above sea level.

Bottom Time/Dive Time – The total time underwater.

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

Buddy Breathing – The sharing of a single air source between divers.

Buddy Diver – Second member of the dive team.

Buddy system -Two comparably equipped scuba divers in the water in constant communication.

Buoyant Ascent – An ascent made using some form of positive buoyancy.

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

Certified Diver – A diver who holds a recognized valid certification from a MBL campus, an AAUS organizational member, or recognized certifying agency.

Controlled Ascent – Any one of several kinds of ascents including normal, swimming, and air sharing ascents where the diver(s) maintain control so a pause or stop can be made during the ascent.

Cylinder – A pressure vessel for the storage of gases.

Decompression Chamber – A pressure vessel for human occupancy. Also called a hyperbaric chamber or recompression chamber.

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. (Also called dive tables.)

Dive – A descent into the water, an underwater diving activity utilizing compressed gas, an ascent, and return to the surface.

Dive Computer- A microprocessor based device which computes a diver’s theoretical decompression status, in real time, by using pressure(depth) and time as input to a decompression model, or set of decompression tables, programmed into the device.

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

Dive Site – The physical location of a diver during a dive.

Diver – An individual in the water who uses apparatus, including snorkel, which supplies breathing gas at ambient pressure.

Diver-In-Training – An individual 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 independent 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 another diver.

Diving Mode – A type of diving required specific equipment, procedures, and techniques, for example, snorkel, scuba, surface-supplied air, or mixed gas.

Diving Control Board (Diving Control Board). The group of individuals who act as the official representative of the campus in matters concerning the scientific diving program (see Section 1.24).

Diving Safety Officer (DSO) – The individual responsible for the safe conduct of the scientific diving program of the campus (see Section 1.23).

Emergency Ascent – An ascent made under emergency conditions where the diver exceeds the normal ascent rate.

FSW – Feet of seawater, or equivalent static head.

Hookah Diving – A type of shallow water surface-supplied diving where there is no voice communication with the surface.

Hyperbaric Chamber – See decompression chamber.

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

Lead Diver – The certified diver with experience and training to conduct the diving operation.

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

No-Decompression Limits – The depth-time limits of the “no-decompression limits and repetitive dive group designations table for no-decompression air dives” at a rate specified by the tables or computers used.

Normal Ascent – An ascent made with an adequate air supply at a rate specified by the table or computer being used by the diver.

Organizational Member – An organization which is a current member of the AAUS, and which has a program which adheres to the standards of the AAUS as set forth in the AAUS Standards for Scientific Diving Certification and Operation of Scientific Diving Programs.

Pressure-Related Injury – An injury resulting from pressure disequilibrium within the body as the result of hyperbaric exposure. Examples include: decompression sickness, pneumothorax, mediastinal emphysema, air embolism, subcutaneous emphysema, or ruptured eardrum.

Pressure Vessel – See cylinder.

Psig – pounds per square inch gauge.

Recompression Chamber – see decompression chamber.

Scientific Diving – Scientific diving is defined (29 CFR 1910.402) as 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.

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 assistance to a diver in the water.

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

Umbilical – The composite hose bundle between a dive location and a diver or bell, or between a diver and a bell, which supplies a 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.