1 In general, the construction and type testing
should be in accordance with publication IEC 60079: Electrical Equipment
for Explosive Gas Atmospheres to a minimum requirement of EX(ia).
Where a ship is designed only for the carriage of cargoes that cannot
create a combustible or explosive atmosphere then the requirement
for intrinsically safe circuitry should not be insisted upon, provided
the operational instructions included in the Manual required by 4.1
of the appendix to the annex specifically exclude the carriage of
cargoes that could produce a potential explosive atmosphere. Any exclusion
of cargoes identified in the annex should be consistent with the ship's
Cargo Book and any Certification relating to the carriage of specifically
identified cargoes.
2 The maximum surface temperature of equipment
installed within cargo spaces should be appropriate for the combustible
dusts and/or explosive gases likely to be encountered. Where the characteristics
of the dust and gases are unknown, the maximum surface temperature
of equipment should not exceed 85ºC.
3 Where intrinsically safe equipment is installed,
it should be of a certified safe type.
4 Where detector systems include intrinsically
safe circuits, plans of the arrangements should be appraised/approved
by individual classification societies.