Arc flashes are a constant and potentially fatal threat to railroad workers. Arc flashes are concentrated bursts of energy that explode outward from electrical equipment. They are caused by a broad range of incidents including insulation failures and corrosion. The Occupational Safety and Health Administration (OSHA) and National Fire Protection Association (NFPA) both recommend standards to prevent arc flashes.
How Do Arc Flashes Happen?
An arc flash occurs when two or more energized conducting surfaces connect an electrical current through the air or a medium not meant to conduct an electrical charge. Ar flashes can occur in a variety of situations, including, but not limited to:
- Birds, flies, bees, rodents, and other animals snapping leads at connections;
- Insulation failures;
- Equipment failure due to wear and tear, improper installation, or substandard parts;
- Human errors, including dropped tools, accidental contact with conducting surfaces, or improper work procedures; and
- The build-up of impurities or dust, and corrosion on insulation surfaces which can create a path for electrical currents.
Common Arc Flash Injuries
An arc flash is a concentrated release of radiant energy which can cause significant injuries. For example, arc flashes can cause a pressure wave that fractures ribs, can knock a worker off a ladder, blow someone across a room, collapse lungs, and damage hearing. The pressure waves can also send loose material, such as tools and other objects, flying more than 700 mph. Arc flashes also release a superheated ball of gas which can burn at temperatures higher than 5,000 degrees which can ignite clothing and cause serious burns. Finally, the high-intensity flash point can damage eyesight or even blind a worker.
These injuries can occur even if the worker is standing en feet or more from the center of the arc. Moreover, arc flashes can occur in high- and low-voltage areas. According to OSHA, more than 2,000 workers are injured every year in arc flash incidents.
OSHA requires employers to provide signs, warning tags, and symbols to alert workers that they are in an arc flash danger area. NEPA also recommends employers perform analyses of potential arc flash areas before allowing workers to work on energized equipment. NEPA also recommends workers wear personal protective equipment and restrict access to areas where arc flashes can occur.