Scuba & Nitrox Glossary: V
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 — V
- Verification Analysis
- A second confirmation of gas composition after blending or before use.
- Visual Inspection for Oxygen Service
- Inspection performed as part of maintaining cylinder or equipment suitability for specified oxygen exposure.
- Volume Blending
- Creating a mixture based on measured gas volumes, typically at low pressure before compression.
- Valve Oxygen Compatibility
- Suitability of valve materials and preparation for the intended oxygen exposure.
- Variable Nitrox Blend
- An enriched-air mixture produced at an oxygen percentage selected for the fill.
- Ventilation During Blending
- Air movement used to prevent dangerous oxygen accumulation in a fill area.
- Verified MOD
- A maximum operating depth calculated from the analyzed mix and chosen PPO2.
- Visual Oxygen Inspection
- Inspection for contamination or damage before oxygen-service preparation.
General Scuba Terms — V
- Valve Drill
- A practiced sequence for identifying and operating cylinder valves, common in technical diving.
- Valve Feathering
- Repeatedly opening and closing a valve to conserve gas after certain failures; specialized training is required.
- Vertigo
- A false sensation of motion or spinning, sometimes associated with unequal ear pressure.
- Visibility
- The distance and clarity with which objects can be seen underwater.
- Visual Inspection
- Periodic internal and external examination of a scuba cylinder under applicable standards.
- Manifold Valve Drill
- A practiced sequence for isolating and managing manifold valves and regulators.
- Vapor Barrier
- A drysuit or undergarment layer intended to reduce moisture movement.
- Vertical Visibility
- The distance a diver can see upward or downward in the water column.
- Vessel Traffic
- Boat activity that creates navigation and surfacing hazards for divers.
- Visual Reference
- An object, line, terrain feature, or teammate used for orientation.