.1 Enclosed spaces which contain open sections
of the mud circulating system from the final degassing discharge to
the mud pump suction connection at the mud pit.
.2 Outdoor locations within the boundaries of
the drilling derrick up to a height of 3 m above the drill floor.
.3 Semi-enclosed locations below and contiguous
to the drill floor and to the boundaries of the derrick or to the
extent of any enclosure which is liable to trap gases.
.4 In outdoor locations below the drill floor,
within a radius of 1.5 m area beyond the zone 1 area as specified
in paragraph 6.2.3.3.
.5 The areas 1.5 m beyond the zone 1 areas specified
in paragraph 6.2.3.5 and beyond the semi-enclosed locations specified
in paragraph 6.2.3.2.
.6 Outdoor areas within 1.5 m of the boundaries
of any ventilation outlet from or access to a zone 2 space.
.7 Semi-enclosed derricks to the extent of their
enclosure above the drill floor or to a height of 3 m above the drill
floor, whichever is greater.
.8 Air locks between a zone 1 and a non-hazardous
area.