{"data":{"id":"us/46-cfr-197.204","jurisdiction":"us","citation":"46 CFR 197.204","heading":"Definitions.","body":"As used in this subpart:\nACFM means actual cubic feet per minute.\nANSI Code1 means the B31.1 American National Standards Institute “Code for Pressure Piping, Power Piping.”\nASME Code means the American Society of Mechanical Engineers “Boiler and Pressure Vessel Code.”\nASME PVHO-1 means the ANSI/ASME standard “Safety Standard for Pressure Vessels for Human Occupancy.”\nATA means a measure of pressure expressed in terms of atmosphere absolute (includes barometric pressure).\nBell means a compartment either at ambient pressure (open bell) or pressurized (closed bell) that allows the diver to be transported to and from the underwater work site, allows the diver access to the surrounding environment, and is capable of being used as a refuge during diving operations.\nBottom time means the total elapsed time measured in minutes from the time the diver leaves the surface in descent to the time to the next whole minute that the diver begins ascent.\nBreathing gas/breathing mixture means the mixed-gas, oxygen, or air as appropriate supplied to the diver for breathing.\nBursting pressure means the pressure at which a pressure containment device would fail structurally.\nCommercial diver means a diver engaged in underwater work for hire excluding sport and recreational diving and the instruction thereof.\nCommercial diving operation means all activities in support of a commercial diver.\nCylinder means a pressure vessel for the storage of gases under pressure.\nDecompression chamber means a pressure vessel for human occupancy such as a surface decompression chamber, closed bell, or deep diving system especially equipped to recompress, decompress, and treat divers.\nDecompression sickness means a condition caused by the formation of gas or gas bubbles in the blood or body tissue as a result of pressure reduction.\nDecompression table means a profile or set of profiles of ascent rates and breathing mixtures designed to reduce the pressure on a diver safely to atmospheric pressure after the diver has been exposed to a specific depth and bottom time.\nDepth means the maximum pressure expressed in feet of seawater attained by a diver and is used to express the depth of a dive.\nDive location means that portion of a vessel or facility from which a diving operation is conducted.\nDive team means the divers and diver support personnel involved in a diving operation, including the diving supervisor.\nDiver means a person working beneath the surface, exposed to hyperbaric conditions, and using underwater breathing apparatus.\nDiver-carried reserve breathing gas means a supply of air or mixed-gas, as appropriate, carried by the diver in addition to the primary or secondary breathing gas supplied to the diver.\nDiving installation means all of the equipment used in support of a commercial diving operation.\nDiving mode means a type of diving requiring SCUBA, surface-supplied air, or surface-supplied mixed-gas equipment, with related procedures and techniques.\nDiving stage means a suspended platform constructed to carry one or more divers and used for putting divers into the water and bringing them to the surface when in-water decompression or a heavy-weight diving outfit is used.\nDiving supervisor means the person having complete responsibility for the safety of a commercial diving operation including the responsibility for the safety and health of all diving personnel in accordance with this subpart.\nFacility means a deepwater port, or an artificial island, installation, or other device on the Outer Continental Shelf subject to Coast Guard jurisdiction.\nFsw means feet of seawater (or equivalent static pressure head).\nGas embolism means a condition caused by expanding gases, which have been taken into and retained in the lungs while breathing under pressure, being forced into the bloodstream or other tissues during ascent or decompression.\nHeavy-weight diving outfit means diver-worn surface-supplied deep-sea dress.\nHyperbaric conditions means pressure conditions in excess of surface atmospheric pressure.\nInjurious corrosion means an advanced state of corrosion which may impair the structural integrity or safe operation of the equipment.\nLiveboating means the support of a surfaced-supplied diver from a vessel underway.\nMaximum working pressure means the maximum pressure to which a pressure containment device can be exposed under operating conditions (usually the pressure setting of the pressure relief device).\nNo-decompression limits means the air depth and bottom time limits of appendix A.\nPressure vessel means a container capable of withstanding an internal maximum working pressure over 15 psig.\nPsi(g) means pounds per square inch (gage).\nPVHO means pressure vessel for human occupancy but does not include pressure vessels for human occupancy that may be subjected to external pressures in excess of 15 psig but can only be subjected to maximum internal pressures of 15 psig or less (i.e., submersibles, or one atmosphere observation bells).\nSaturation diving means saturating a diver's tissues with the inert gas in the breathing mixture to allow an extension of bottom time without additional decompression.\nSCUBA diving means a diving mode in which the diver is supplied with a compressed breathing mixture from diver carried equipment.\nStandby diver means a diver at the dive location available to assist a diver in the water.\nSurface-supplied air diving means a diving mode in which the diver is supplied from the dive location or bell with compressed breathing air including oxygen or oxygen enriched air if supplied for treatment.\nSurface-supplied mixed-gas diving means a diving mode in which the diver is supplied from the dive location or bell with a compressed breathing mixture other than air.\nTimekeeping device means a device for measuring the time of a dive in minutes.\nTreatment table means a depth, time, and breathing gas profile designed to treat a diver for decompression sickness.\nUmbilical means the hose bundle between a dive location and a diver or bell, or between a diver and a bell, that supplies the diver or bell with a life-line, breathing gas, communications, power, and heat as appropriate to the diving mode or conditions.\nVessel means any waterborne craft including mobile offshore drilling units required to have a Certificate of Inspection issued by the Coast Guard or any waterborne craft connected with a deepwater port or within the deepwater port safety zone, or any waterborne craft engaged in activities related to the Outer Continental Shelf.\nVolume tank means a pressure vessel connected to the outlet of a compressor and used as an air reservoir.\nWorking pressure means the pressure to which a pressure containment device is exposed at any particular instant during normal operating conditions.","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER V—MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS","PART 197—GENERAL PROVISIONS","Subpart B—Commercial Diving Operations"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"a57df7bea718564abdb817df3badad35a63c458d305c0a501b835dc0d3ed87f4","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-197.203","next":"us/46-cfr-197.205"},"notice":"GroundRules: Original legal text. Not legal advice."}