Scuba & Nitrox Glossary: B
Nitrox and breathing-gas terminology is prioritized first. General scuba terms follow below. Definitions are educational summaries and do not replace formal training, manufacturer instructions, or an operational dive plan.
Nitrox & Gas Terms — B
- Banked Nitrox
- Premixed Nitrox stored in larger cylinders or banks for later transfer into scuba cylinders.
- Best Mix
- A gas selected to maximize oxygen content for a planned depth while staying within the chosen PPO₂ limit.
- Blending
- The controlled process of producing a breathing-gas mixture.
- Blender
- A trained person who prepares breathing-gas mixtures.
- Booster Pump
- Equipment that increases gas pressure for transfer or filling; commonly used with oxygen and helium in technical operations.
- Breathing-Gas Analysis
- Verification of gas composition before use.
- Banked Enriched Air
- Premixed Nitrox stored in larger cylinders for later fills.
- Blend Accuracy
- How closely the measured oxygen fraction matches the intended mixture.
- Blend Log
- A record of cylinder, oxygen fraction, pressure, date, analyzer, and blender details.
- Blending Panel
- Valves and gauges arranged to control gases during cylinder filling.
- Boost Pump
- Equipment used to transfer or raise the pressure of oxygen or mixed gas.
General Scuba Terms — B
- Back Gas
- The primary breathing gas carried on the diver’s back, often in a single cylinder or doubles.
- Backplate and Wing
- A modular buoyancy system consisting of a rigid plate, harness, and inflatable wing.
- Bar
- A metric unit of pressure; approximately equal to one atmosphere at the surface.
- BC or BCD
- Buoyancy compensator device used to establish positive, neutral, or negative buoyancy.
- Bottom Time
- Elapsed time used to describe the underwater or working portion of a dive; exact definitions vary by table or computer.
- Buddy Check
- A pre-dive verification of each diver’s equipment, gas, releases, and plan.
- Buoyancy
- The tendency to float, sink, or remain suspended.
- Primary Back Gas
- The main breathing supply carried on a diver's back.
- Backplate
- A rigid plate supporting a harness, wing, and cylinders.
- Boat Entry
- A procedure for entering the water from a dive vessel.
- Bottom Composition
- The material covering a dive site's floor, such as sand, rock, or silt.
- Buoyancy Swing
- The change in buoyancy caused by gas use, exposure suit compression, or depth.