Static Electricity 2000 Edition

9.3 Spray Application.
9.3.1
Processes that involve spray application of liquids or
powders (e.g., paints, coatings, lubricants, and adhesives) can
cause accumulation of static electric charges on the spray
apparatus and on the surfaces of the objects being sprayed and
other objects in the spray area. If the material sprayed is
ignitible, then static electric discharge can result in ignition.
9.3.2*
Personnel involved in operating or servicing electro-
static spray application equipment should be trained in the
operating procedures recommended by the manufacturer of
the equipment and in the control of hazards associated with
the materials being sprayed and their residues.
9.4 Belts and Conveyors.
9.4.1 General.
Flat or “V”-shaped rubber or leather belts
used for transmission of power or belts used for the transpor-
tation of solid materials can generate static electric charges
that warrant corrective measures if a possibility exists that
ignitible concentrations of flammable gases or vapors or com-
bustible dusts or fibers might be present. The amount of
charge generated will increase as any of the following increase:
(1) Belt speed
(2) Belt tension
(3) Width of the contact area
9.4.2 Flat Belts.
9.4.2.1*
Synthetic, rubber, or leather flat belts are usually
good insulators because they are dry when operated and
because they operate at elevated temperatures due to friction.
Generation of static electric charge occurs where the belt
leaves the pulley and can occur with either conductive or non-
conductive pulleys.
9.4.2.2*
Accumulation of static electric charge on belts can be
prevented by using belts made of conductive materials or by
applying a conductive dressing to the belt. If a dressing is used,
it should be reapplied frequently or the conductivity of the