6.1. Explosion prevention measures
The risk of an explosion is removed when one of the following
measures is taken:
6.1.1. An explosible dust cloud is never allowed to form
6.1.1.1. Control of fuel. There are two main methods of ventilation
for eliminating or controlling the spread of explosible atmospheres
(fuel):
6.1.1.1.1. Dilution ventilation. Dilution ventilation provides
a flow of fresh air into and out of the building. This normally
results in a reduction of the background concentration of the
flammable atmosphere in the working area, but there is no
control of the flammable atmosphere at the source of release.
This method is not effective in controlling the concentration of
dust cloud atmospheres but is often used to control flammable
vapor concentrations.
6.1.1.1.2. Local exhaust ventilation, LEV. Local exhaust ventilation
is designed to intercept the fuel at the source of release, dilutes the
atmosphere and directs it into a system where the material is
recovered or destroyed. Correctly designed local exhaust ventilation
systems are very effective in limiting the spread of dust cloud
atmospheres beyond the source of release.