9.1 Spaces that have not been tested should be
considered unsafe for persons to enter. If the atmosphere in an enclosed
space is suspected or known to be unsafe, the space should only be
entered when no practical alternative exists. Entry should only be
made for further testing, essential operation, safety of life or safety
of a ship. The number of persons entering the space should be the
minimum compatible with the work to be performed.
9.2 Suitable breathing apparatus, e.g. of the
air-line or self-contained type, should always be worn, and only personnel
trained in its use should be allowed to enter the space. Air-purifying
respirators should not be used as they do not provide a supply of
clean air from a source independent of the atmosphere within the space.
9.3 Persons entering enclosed spaces should be
provided with calibrated and tested multi-gas detectors that monitor
the levels of oxygen, carbon monoxide and other gases as appropriate.
9.4 Rescue harnesses should be worn and, unless
impractical, lifelines should be used.
9.5 Appropriate protective clothing should be
worn, particularly where there is any risk of toxic substances or
chemicals coming into contact with the skin or eyes of those entering
the space.
9.6 The advice in paragraph 8.5 concerning emergency
rescue operations is particularly relevant in this context.