To remove from the application of Clause 5.3.1.2.(1)(c) and permit the use of compressed air or similar
methods if:
vacuum methods are impracticable, and
measures are taken to eliminate all possible sources
of ignition from the dust removal area where hazardous conditions
are created by the displacement of dust.
This is to limit the probability that
the dust will be ignited by sources of ignition, which could lead
to harm to persons.