1.2 Definitions
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.585 – Standards for Vapour Emission Control Systems – (Adopted on 16 April 1992) - Annex - Standards for Vapour Emission Control Systems - 1 General - 1.2 Definitions

1.2 Definitions

  1.2.1 “Diluted": the condition in which the concentration of a flammable gas in a flammable gas/air mixture is less than 50% of the lower explosive limit of the gas.

  1.2.2 “Enriched": the condition in which the concentration of a flammable gas in a flammable gas/air mixture is not less than 150% of the upper explosive limit of the gas. When flammable gases are mixed to achieve an enriched condition, the upper explosive limit of the flammable gas mixture shall be used.

  1.2.3 “Flammable cargoes" means cargoes of crude oil, petroleum products, and chemicals having a flashpoint not exceeding 60°C (closed cup test), as determined by an approved flashpoint apparatus, and a Reid vapour pressure which is below atmospheric pressure and other liquid products having a similar fire hazard.

  1.2.4 “Inerted:" the condition in which the oxygen content in a flammable gas/air mixture is 8% or less by volume.

  1.2.5 “Independent" as applied to two systems means that one system will operate with a failure of any part of the other system except power sources and electrical feeder panels.

  1.2.6 “Maximum allowable transfer rate" means the maximum volumetric rate at which a tanker may receive cargo or ballast.

  1.2.7 “Tanker vapour connection" means the point in a tanker's fixed vapour collection system where it connects to a vapour collection hose or arm.

  1.2.8 “Terminal vapour connection" means the point in a terminal's vapour collection system where it connects to a vapour collection hose or a vapour collection arm.

  1.2.9 “Vapour balancing" means the transfer of vapour displaced by incoming cargo from the tank of a tanker receiving cargo into a tank of a facility delivering cargo via a vapour collection system.

  1.2.10 “Vapour collection system" means an arrangement of piping and hoses used to collect vapour emitted from a tanker's cargo tanks and transport the vapour to a vapour processing unit.

  1.2.11 “Vapour destruction unit" means a vapour processing unit that destroys cargo vapour by a means such as incineration.

  1.2.12 “Vapour dispersion system" means a vapour processing unit which releases cargo vapour to the atmosphere through a venting system not located on the tanker being loaded or ballasted.

  1.2.13 “Vapour emission control system" means an arrangement of piping and hoses used to control vapour emissions collected from a tanker, and includes the vapour collection system and the vapour processing unit.

  1.2.14 “Vapour processing unit" means the components of a vapour control system that recovers, destroys, or disperses vapour collected from a tanker.

  1.2.15 “Vapour recovery unit" means a vapour processing unit that recovers cargo vapour by a non-destructive means such as lean oil absorption, carbon bed adsorption, or refrigeration.


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