During the pneumatic transfer of fine flour into an industrial storage silo, the plastic delivery pipes and the metal frame of the silo can become electrostatically charged. Before commencing the flour transfer, a copper bonding strap is connected between the silo frame and a metal rod driven deep into the ground.
Explain how the flour and the delivery system become electrically charged during the transfer process.
Describe a major hazard associated with a highly-charged silo during the transfer of fine flour dust.
What type of electrical connection is made by using this copper bonding strap?
Explain how connecting this strap before starting the pneumatic transfer reduces the risk of an explosion.