1.3.1
Inert gas means a gas or a
mixture of gases, such as flue gas, containing insufficient oxygen
to support the combustion of hydrocarbons.
1.3.2
Inert condition means a condition
in which the oxygen content throughout the atmosphere of a tank has
been reduced to 8% or less by volume by addition of inert gas.
1.3.3
Inert gas plant means all equipment
specially fitted to supply, cool, clean, pressurize, monitor and control
delivery of inert gas to cargo tank systems.
1.3.4
Inert gas distribution system means
all piping, valves, and associated fittings to distribute inert gas
from the inert gas plant to cargo tanks, to vent gases to atmosphere
and to protect tanks against excessive pressure or vacuum.
1.3.5
Inert gas system means an inert
gas plant and inert gas distribution system together with means for
preventing backflow of cargo gases to the machinery spaces, fixed
and portable measuring instruments and control devices.
1.3.6
Inerting means the introduction
of inert gas into a tank with the object of attaining the inert condition
defined in 1.3.2.
1.3.7
Gas-freeing means the introduction
of fresh air into a tank with the object of removing toxic, flammable
and inert gases and increasing the oxygen content to 21% by volume.
1.3.8
Purging means the introduction
of inert gas into a tank already in the inert condition with the object
of:
-
.1 further reducing the existing oxygen content;
and/or
-
.2 reducing the existing hydrocarbon gas content
to a level below which combustion cannot be supported if air is subsequently
introduced into the tank.
1.3.9
Topping up means the introduction
of inert gas into a tank which is already in the inert condition with
the object of raising the tank pressure to prevent any ingress of
air.