1-28 Publication: 0028607
SAFETY
1
Static Charge Dissipation
When picking up potential explosive materials (either
hydrocarbons with flash points below 300°F, or explosive
dust), it is necessary to safely dissipate static charges by
completely grounding the vacuum truck, intake hose, and
container from which the material is being removed. Only
a static dissipating vacuum hose supplied by Super
Products should be used. There should be a grounding
strap run from the truck frame to a grounding stake.
All grounding cables should be a minimum of 1/0 in size.
Grounding lugs should be welded onto the male and
female couplings of all hose sections so that grounding
straps (min. #10 gauge wire) can be run from the male
coupling to the female coupling at all connection points. A
grounding reel should be installed on the vacuum loader
with the ground cable run to the container from which the
material is being removed.
When material is being transferred by a pneumatic
conveying system, static electricity is generated. If this
electricity is not dissipated through an electrical ground,
arcing can occur. The resulting spark can cause a dust
explosion or a hydrocarbon explosion either within the
unit or within a building that the conveying line enters.
The following safeguards are recommended to dissipate
static charge caused by operation of the unit:
• Truck tires can insulate the unit; therefore, an
electrical wire should be connected between the
body and a known electrical ground such as a water
pipe, plant ground loop system, or metal stake driven
into the ground sufficiently deep to ensure an
electrical ground. Bolt wire to truck frame — do not
weld.
• The electrical resistance from the truck to the
electrical ground must be at 10 ohms or less for the
duration of the material transfer process. Some
companies, such as Newson Gale, provide a ground
verification system to enable operators to establish
safe grounding of their vehicle.
• Supertube and hose couplers have rubber sealing
gaskets. The presence of dirt and corrosion can
prevent electrical conduction from tube to tube
through the tube clamps. It is recommended to weld
a bolt or a threaded stud to each end of each tube or
hose coupler, and connect a wire of sufficient length
from tube to tube after installation of the clamp. Wing
nuts could assist in making these connections
quickly.
• Standard Super Products material handling hoses
are specially designed to conduct static electricity. Do
not substitute hoses of unknown construction,
particularly plastic hoses, which may not be static
conducting.
• Never operate the unit inside a building that has a
dust-laden atmosphere, such as inside of a grain
elevator. The unit's electrical system and electrical
components will arc in normal operation. Sparks and
flame could also be emitted from the engine exhaust.
Any of these conditions could cause a dust explosion
within the building.
• Before operation, ensure that all ground wire
connections are tight and free from corrosion and
paint.
Failure to comply with the recommendations for
static charge prevention could result in
equipment failure, personal injury, or death.
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