To more accurately convey the hazards presented by gases, the
classification required by Regulation 2, Chapter VII of the
Convention for Safety of Life at Sea (SOLAS) 1974 must be
supplemented by the additional description of the subclass.
The IMDG code gives general information concerning the properties of
gases, plus guidelines on means of packing, stowing, and segregating
them.
The schedules themselves include the UN number and the chemical
formula of each gas. Also, if the gas is flammable, the range of its
explosive limits (that is, the percentage of gas required in a gas
air atmosphere to make the mixture explosive) is given.
Thus, the
schedule for acetylene, the first entry in Class 2, shows that a
mixture of acetylene and air is explosive when it contains from 2.1
percent to 80 percent acetylene.
The schedules then describe properties of specific gases, including
appropriate
additional
information
and
details
on
packing
requirements, stowage, and segregation.
Class 3 - Inflammable* Liquids
Class 3 is divided into three subclasses according to the flashpoint
(the lowest temperature at which the vapor of a combustible liquid
can be made to ignite momentarily in air) of the liquid.
Class 3.1 covers liquids with a low flashpoint (below -18C)
(0F).
Class 3.2 covers liquids with an intermediate flashpoint (-18C
and up to, but not including, 23C)(73F).
Class 3.3 covers liquids with a high flashpoint (23C and
above, up to 61C)(141F).
NOTE:
Transporting liquids with flashpoints up
to
100C (212F) is regulated within Europe.
The IMDG code sets out the various methods which
can be used to
establish the flashpoint of inflammable liquids, an
important factor
as far as safety is concerned. Packing and stowage
requirements for
liquids with low flashpoints are stricter than for
those with high
flashpoints.
The introduction to Class 3 includes information on packing, stowage,
and segregation. The individual schedules are arranged
*Flammable has the same meaning.
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TR1029
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