Diving Abbreviations “E – F – G”

EAD – Equivalent Air Depth, or Effective Air Depth

EAR – Expired Air Resuscitation…. superceded by AV

EANX – Enriched Air Nitrox

ECM – External Cardiac Massage (term superceded by CC)

Equivalent Narcotic Depth. A measure of the narcosis expected by a Trimix diver – the dive “feels” like an air dive to that depth. END Equivalent Narcotic Depth

EO – Equipment Officer

EPIRB – Emergency Position Indicating Radio Beacon

ERC – European Resuscitation Council

ERD – Extended Range Diver (BSAC)

ESDA – Emergency Services Diving Association


FAD – First Aid for Divers

FCD – First Class Diver (BSAC)

FCD – Freeflow Control Device

FEDAS – Federacion Espanola De Actividades Subacuaticas

FEV(1) – Forced Expiratory Volume (in one second)

FFESSM – Federation Franchise d’Etudes et de Sports Sous Marins

FSSS – Federation Suisse de Sports Subaquatiques

FQAS – Federation Qubecoise des Activites Subaquatiques


GMDSS – Global Maritime Distress and Safety System

GPS – Global Positioning System

GUE – Global Underwater Explorers

Diving Abbreviations “D”

DAN – Diver’s Alert Network

DCI – Decompression Illness

DCIEM – Defence and Civil Institute of Environmental Medicine(Canadian tables)

DC or DCC – Decompression Computer

DCS – Decompression Sickness

DCS – Dive Control Specialist (SSI)

This qualification can be accepted as fully covering the BSAC Rescue First Aid qualification. As such any MOD personnel who has a DDEMS qualifications can apply to HQ for an alternative sticker in the normal fashion, by enclosing a photocopy of their DDEMS certificate and 3 for administration.

DDEMS – Defence Diver Extended Medical Skills (British Forces Qualification)

DDRC – Diving Diseases Research Centre

DEMA – Diving Equipment and Marketing Association

DER – Depth Experience Record

DIN – Deutsches Institut fur Normung e.V. (German Institute for Standardization)

DIR – Do(ing) It Right

DIW – Doing It Wrong

DL – Dive Leader (BSAC)

DM – Divemaster (PADI)

DM – Dive Marshal

DO – Diving Officer

DOD – Department of Defense (US)

DOT – Department of Transportation

DOWR81 – Diving Operations at Work Regulations 1981 (superceded by DWR97)

DPM – Dive Planning & Marshalling

DPV – Diver Propulsion Vehicle

Danger (Assess that it is not dangerous to approach caualty) Response, (Any response from possible casualty, and if so, what), Airway, Breathing, Circulation. DRABC – Danger, Response, Airway, Breathing, Circulation (casualty assessment)

DRI – Dive Rescue International

DS – Decompression Sickness

DSAT – Diving Science and Technology(PADI)

DSC – Digital Selective Calling

DSF – Dansk Sportsdykker Forbund (Danish Sport Diving Federation)

DSMB – Delayed Surface Marker Buoy

DT – Dive Time

DTR – Digital Time Recorder

DUI – Divers Unlimited International

DV – Demand Valve

DWR97 – Diving at Work Regulations 1997 (UK legislation)

Gas Pressure

Gases Under Pressure

Much has been said about how the 300bar, higher pressure diving cylinders actually have less gas in them than the gauge suggests, and there’s a need to understand why this is.
Any cylinder with a pressure of 232 bar or more is effectively holding less gas per bar of pressure than a lower pressurised cylinder.

The gases we use in diving cylinders work as ‘ideal gases’ under lower working pressures, but start to react differently under pressures over a certain point. (we’ll ignore temperature for this explanation).

A layman’s explanation.

The best way is to explain each term as if the reader knows nothing, and build upon that.


Of stable shape, usually rigid at normal temperatures.


Having a consistency like that of water or oil, incompressible, but not resistant to change of shape, neither solid or gaseous.


Any air-like or completely elastic fluid, especially not liquid or solid at ordinary temperatures. A gas will expand to fill the container it is enclosed in.


Consisting of particles that move freely among themselves and yield to slightest pressure. Not solid or rigid or stable. Gases and liquids can both be described as ‘fluid’, or being in a fluid state.

For the ease of explanation we will describe all diving gases, regardless of the mixture, as simply ‘Gas’.

Ideal gases:

As far as divers are concerned, an ideal gas behaves in this fashion. When you compress it into a limited space, ie: a diving cylinder, for the most part it just gets ‘thicker’.

Up to pressures of around 200 bars this is fine, and when the gauge reads 200 bars, then the cylinder actually contains 200 times the amount of gas that cylinder would hold at normal atmospheric pressure.

If the capacity of the cylinder is 10 litres, then this cylinder at 200 bars pressure contains 2000 litres (10 x 200 = 2000).


When a gas is placed under greater pressures than say, 232 bars, then the ideal gases theory starts to become a little hazy.

The differences aren’t really that noticeable until the pressure starts to approach 300 bars, when the gauge is really quite inaccurate.

To put it into the simplest terms, the gas now starts to behave more like a liquid than a gas because it’s so ‘thick’, and as we’ve already said, liquids are virtually incompressible, so you just can’t pack any more gas into the cylinder, because it has got so ‘thick’ that there’s hardly any room left.

However, the gauge climbs more quickly than it would normally, because even a small amount added squeezes the pressure far higher than it normally would.


Imagine trying to get 2000, or even 3000 litres of water into a 10 litre cylinder. No one would try, because it’s obvious that it wouldn’t work.


Transporting Diving Equipment Abroad

Air Cylinders

When travelling abroad and taking your diving cylinders with Airline companies, we’d like to offer the following advice: (which you should check with your airline first, preferably before booking your flight)

For Scheduled airline travel:

Contact the airline and get their terms & conditions for transporting cylinders.

Get the agent to put a notation into the PNR to indicate that cylinders are being taken and the required state of cylinders.

Follow their rules.

At check in, when they see the cylinder, tell them that the PNR has info regarding the carriage of the cylinders.

Immediately prior to boarding, check with dispatcher that cylinders are loaded.


For Charter airline travel:

Contact the airline and get their terms & conditions for transporting cylinders.

Get confirmation of the agents name/position and get this issued in writing.

Follow their rules.

Check in normally, but only show your written confirmation of their rules

if they dispute any of the procedure (Always pays to keep your ammo in reserve).

Immediately prior to boarding, check with the dispatcher that cylinders are loaded.


Further general advice:

Always make sure you arrive at the recommended check in time or earlier as sometimes there may be problems with loading your cylinders and you’ll need to check that they are actually loaded, and if not, allow yourself time to sort out why not, and speak to the people in charge of handling, and show them your paperwork to confirm that prior arrangements were made and confirmed that transporting your cylinders would be OK with the Airline company.

We would not expect people to have problems if they followed these steps when travelling with a scheduled carrier. They have extremely good audit trails in the PNR.

And finally, make sure that you have all the relevant paperwork of your confirmation with you just in case.

Disclaimer: This information is valid in February 2002.

It may have changed slightly by the time you book your flights, which makes it all the more important that you get the Current information at the time of booking from your airline company. Furthermore, each airline may have their own rules as to their exact procedure, so it’s vital that you find this out and check with them first before proceeding with your plans.

(PNR – Passenger Name Record)

Regulators, Gauges and Computers

When taking Regulators, Gauges and Dive Computers it might be an idea to take them with your hand luggage for the following reasons:

These items may be damaged by reduced pressure in the aircraft holds

[not on regular flights in large aircraft, these holds are usually pressurised and sometimes heated, the problems arise when in a smaller (say 30 seater) aircraft that might not have a pressurised hold]

They may also be easily damaged by rough handling by baggage staff. You’ll find out as you kit up for the dive, or even worse, at depth, when it’s a little late.

They are valuable items and are worth keeping close by you, items are regularly stolen from luggage, and dive kit bags with flashy stickers are a good target for thieves wanting to steal small but valuable items.

Some other points to remember:

If you get a small regulator bag, place the relevant bits of kit inside it, and carry this packed in the top of your hand luggage bag, then if there’s a query as to what the items are, then it’s easy to get to them and satisfy the flight staff that they’re safe to carry in the cabin. If they’re packed in the bottom of, or in amongst your hand luggage, then it’s a bind having to dig around for them, plus they may get tangled up, and damaged by other items in your hand luggage (food getting in the regulator mouthpiece for example)

As always, it would be advisable to confirm that these items are OK to carry as hand luggage with the airline first. [see cylinder advice above for the relevant people to contact regarding this]

Some airlines don’t allow any hand luggage at all, so it’s a good idea to check first.

A good idea is also to put the rest of your dive gear into a hard sided suitcase rather than use a dive bag. This makes it far less susceptible to damage from handling and makes it less obvious that there is dive gear in it.

Diving Abbreviations “C”

CADC – Canadian Association of Diving Contractors

A condition characterized by bubble(s) of air from a ruptured lung segment under pressure; the bubbles enter the pulmonary circulation and travel to the arterial circulation, where they may cause a stroke. (AGE or CAGE). CAGE – Cerebral Arterial Gas Embolism

A means of lifting yourself, or another diver, to the surface under control, using a buoyancy control device to provide the lift. CBL – Controlled Buoyant Lift

CBPDS – Conf. Brasileanos de Pesca e Desportos Subaquaticos

CC – Cardiac Compressions

CCCM – Closed Chest Cardiac Massage…. superceded by ECM, and eventually CC

Closed Circuit Rebreather. An item of breathing apparatus that allows maximum efficiency of gas use by recirculating and purifying exhaled gas. CCR – Closed Circuit Rebreather

CD – Club Diver (BSAC)

CD – Course Director (PADI)

CDAA – Cave Divers Association of Australia

CDG-GB – Cave Diving Group of Great Britain

CEDIP – European Committee of Professional Diving Instructors

CEN – Comite Europenne de Normalization (The European Committee for Standardisation)

CESA – Controlled Emergency Swimming Ascent

An Instructor who is considered to have a good knowledge of practical and theoretical teaching methods. CI – Club Instructor (BSAC)

CIE – Club Instructor Exam (BSAC)

CIPP – Compagnie des Instructeurs Professionnels de Plongee

CMAS – Confederation Mondiale des Activities Subaquatiques (World Underwater Federation)

CNS – Central Nervous System

An odourless, tasteless, highly poisonous gas given off by incomplete combustion of hydrocarbon fuels.   CO – Carbon Monoxide,

CO – Cardiac Output

An odorless, tasteless gas that is a byproduct of metabolism; is excreted by the lungs in exhaled air. Important in the control of respiration.   CO2 – Carbon Dioxide

CPF – Chartwork & Position Fixing

CPR – Cardio Pulmonary Resuscitation

Meaning ‘Secure’, onomatopoeic in origin from the word ‘secure’, ie: CQR – See-Cu-R – (sounds like secure). CQR – Security Patent Anchor

CTC – Current Tissue Code

CTC – Canadian Transportation Commission

CWDI – Canadian Working Divers Institute

Diving Abbreviations “B”

BA – Breathing Apparatus

BAR – Buoyancy Air Releases (BSAC)

BARF: Buoyancy, Air, Releases, Fins

BARZ – Buoyancy Air Releases ZIPS! (Drysuits)

BC – Buoyancy Control

BCD – Buoyancy Control Device

BDO Branch Diving Officer

BH – Boat Handling (BSAC)

BHA – British Hyperbaric Association

BMA – British Medical Association

BMJ – British Medical Journal

BP – Backplate, also Blood Pressure

BPM – Beats Per Minute (heart/pulse rate)

BW – Backplate and Wing

BRA – Buoyancy Releases Air

BS – British Standard

BSI British Standards Institute

BSAC – British Sub Aqua Club

BSOUP – British Society Of Underwater Photographers

BT – Bottom Time

BWRAF – Begin, With, Review And Friend. (PADI)

BWRAF – Buoyancy Weights Releases Air Final OK (PADI)

Diving Abbreviations “A”

These pages are provided by the DIVEInstruct web site as a guide to the abbreviations and terminology, used in diving and diving forums, purely as a guide.


It is not complete, and indeed never could be, as terminology changes and is added to all the time.  No responsibility is taken for any inaccuracies, although every care has been taken to make sure that the information is correct.


AA – Assisted Ascent


AAS – Alternative Air Source

ABC – Airway, Breathing, Circulation (casualty assessment)

ABT – Actual Bottom Time

ABLJ – Adjustable Buoyancy Life Jacket

ABI – Approved Boathandling Instructor (BSAC)


ACI – Assistant Club Instructor (BSAC)

ACUC – American Canadian Underwater Certification

AD – Advanced Diver (BSAC)

AD – Adventure Diver (PADI)


AED – Automatic Emergency Defibrillator

AI – Assistant Instructor (PADI)

AI – Advanced Instructor (BSAC)

AIC – Advanced Instructor Course (BSAC)

AIE – Advanced Instructor Exam (BSAC)

AISE – Association of Independent Scuba Educators

AIW – Advanced Instructor Workshop

AND – Advanced Nitrox Diver

ANDI – American Nitrox Divers International

AOW – Advanced Open Water (PADI)

AP – Ambient Pressure

AR – Ascent Rate

ASDA – Advanced Scuba Diving Association

ATA – Atmospheres Absolute

ATM – Atmosphere

AV – Artificial Ventilation

AVPU – Alert, Voice, Pain, Unresponsive (simplified consciousness assessment)