Government of New Brunswick

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- V -

Vacuum Distillation Tower. A tower-like device where liquid distillation occurs under less than atmospheric pressure. This process is used to lower boiling temperatures and lessen the risk of thermal degradation during distillation. Typically found in the Oil Refining Industry.

Vanadium (V). A parameter that may be required to be analysed for in the air waste stream particulate matter, and effluent discharge at specific industrial facilities. Vanadium may be a constituent of particulate matter emissions as a result of fossil fuel combustion (typically coal or heavy fuel oils). A silvery-white ductile metal that is highly resistant to corrosion. It is used in alloy steels and as an x-ray target.

Vapour Pressure. The pressure exerted by a liquid as determined by ASTM D5191-96, Standard Test Method for Vapour Pressure of Petroleum Products (Mini Method).

Vapour Recovery System. A system to catch vapourized materials (usually fuels or solvents) as they are vented from the storage vessel. In petroleum refining, it means a process unit to which gases and vaporized gasoline from various processing operations are charged, separated and recovered for further use. In the petroleum product storage sector, significant amount of vapours are emitted from storage tanks during dispensing and filling operations and require vapour recovery during these petroleum product transfer activities.

Vent. Includes the intake, piping, and exhaust equipment through which gases enter and exit a unit operation. The gases going through the vent may contain air contaminants.

Ventilation Process Gas Flow. The gas flow, usually measured in cubic feet per minute, of the ventilation system. Can be represented by the intake gas flow, the exhaust gas flow or both.

Venturi. A short tube that is inserted in a pipeline, that has flaring ends connected by a constricted middle, whose operation is dependent on the fact that as the velocity of flow of a fluid increases in the constricted part, the pressure decreases.

Venturi Scrubber. A proven air pollution control technology that is widely used as a gas-cleaning device in which liquid injected at the throat of a venturi is used to scrub dust and mist from the gas flowing through the venturi.

Vertical Temperature Sounding Device. A device capable of measuring low-level mixing heights at or nearby the facility. Also see Minisonde.

Veterinary Powder Wound Sprays. An antiseptic used to treat animal wounds. The propellant used in the spray may contain an ozone depleting substance.

Visible Coloured Plume. A visible or measurable discharge of a contaminant from a given source. It can be visible in the air like a plume of smoke.

Volatile Compound. A substance or combination of substances having a vapour pressure of 10.34 kilopascals absolute or greater under actual handling, transporting or storage conditions.

Volatile Organic Compounds (VOCs). A term used to refer to a group of substances, many of which are natural that participate in atmospheric photochemical reactions. Volatile means that it tends to evaporate readily at ordinary temperatures. For purposes of environmental protection, only those VOCs which cause some kind of problem, are significant. Everyday examples of VOCs include gasoline, solvents, varsol, nail polish remover (acetone), chloroform, rubbing alcohol, dry cleaning fluids, butane, propane and naphthalene.

Volumetric Flowrate (m3/s or ACFM). The volume of a fluid that passes a fixed point per unit of time. The typical units that are used to represent the volume of fluid per unit of time is cubic metres per second, or actual cubic feet per minute.