Scuba & Nitrox Glossary: Q
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 — Q
- Quality-Control Gas
- A known reference gas used to check analyzer or blending-system performance.
- Quick Disconnect
- A coupling sometimes used on analyzer, inflator, or breathing-gas systems; suitability depends on pressure and gas service.
- Quality-Control Reference Gas
- A verified mixture used to test analyzer or blending performance.
- Quick-Disconnect Analyzer Fitting
- A fitting allowing controlled connection of a sample line to an analyzer.
- Quick Oxygen Calculation
- A simplified planning estimate that must be confirmed with proper formulas or tools.
- Quiescent Sample
- A stable, nonpulsating gas sample presented to an oxygen sensor.
- Qualified Gas Blender
- A person trained and authorized to prepare breathing-gas mixtures.
General Scuba Terms — Q
- Quadrat
- A frame used in underwater scientific surveys to define a sample area.
- Quarter-Turn Back
- A common valve check in which a fully opened valve was historically turned slightly closed; many current operators instead leave valves fully open and verify position.
- Quick Release
- A buckle or connection designed for rapid opening.
- Quarry Diving
- Diving in a flooded quarry, often used for training but still subject to visibility, depth, temperature, and access hazards.
- Quadrant Search
- A search pattern dividing an area into sections for systematic coverage.
- Quarry Dive
- A dive conducted in a flooded excavation, often used for training.
- Quarter-Turn Valve Practice
- Opening a valve fully and then slightly closing it, an older practice not universally recommended.
- Quick Buckle
- A buckle designed for rapid fastening or release on dive equipment.
- Quiet Breathing
- Slow, controlled breathing that supports comfort and gas efficiency without skip breathing.