Last Monday, as I drove to work, my business attire included a new pair of suede shoes with crepe rubber soles. As I exited my vehicle at the office there was a sudden snap, crackle and pop followed by my shout of "YOWEEE"! Contact with the door handle resulted in a static shock that "lit up" the parking garage and left me wide-awake well before my first cup of coffee. What happened to there? Were my shoes somehow involved? Was the cold winter air a culprit? Or, was it simply the effect of my electric personality? Regardless, I thought it would be a good time to talk about the nature and potential hazards of static electricity.
Static electricity is generated through the physical contact and separation of materials. Examples include the flow of gasses, liquids or pulverized materials through pipes, hoses, chutes or pneumatic conveyors; by blending, mixing and agitation operations; by rubber tires on vehicles, and by fast moving belts. Greater electrical charges are developed in cold and dry atmospheres.
The principal hazards created by static electricity are fires and explosions caused by sparks igniting vapors, gases or dusts.
Static sparks are dangerous ignition sours wherever the air contains and ignitable mixture. Hazardous areas include near the nozzles of flammable liquid fill pipes and delivery hoses, open containers of flammable liquids, and around tank trucks fill openings, barrel bungholes, and chutes or pneumatic conveyors containing pulverized materials.
Flammable liquid containers should be bonded and grounded to prevent spark ignited fires and explosions.
Bonding equalized static electricity by creating a conductive connection between drums and receivers. A flexible conductor such as a bonding strap or wire is adequate. Solid metal contacts between containers can also be used.
Grounding dissipates
static electricity into the earth to eliminate its buildup. Grounding
straps, cables or wires should be connected to known grounds such as water
pipes, grounded metal structural parts of buildings and metal underground
gas pipes. All grounding equipment should be tested periodically
for effectiveness.
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