Canadian Occupational Safety

22 Canadian Occupational Safety www.cos-mag.com A rc flash, a type of electrical explosion, is one of the most complex workplace risks that exists. It is often described using technical terminology and several acronyms. But beneath the alphabet soup of letters and numbers associated with workplace electrical safety, there is a simple explanation for arc fl ash. Firstly, it's important to understand arc fl ash has nothing to do with welding; it's an electrical hazard. There are three general categories of electrical hazards defi ned within the applicable standards: shock, arc fl ash and arc blast. Within a millisecond, the temperature produced by an arc fl ash, at its core, can be up to four times hotter than the surface of the sun. Other secondary hazards related to an arc fl ash include intense light emissions, pressure wave (arc blast), fl ying debris, toxic fumes and damaging sound levels. Workers perform tasks that put them at risk for exposure to an arc fl ash every day, including voltage testing, removing bolted-on panel covers and inserting or removing circuit breakers. An arc flash hazard can be an extremely violent event that may result in worker fatalities. Workplace injuries and fatalities resulting from electrical hazards, including arc fl ash and shock, are considered low frequency, high severity events. Arc fl ash accidents are rare, but they do happen — and often with catastrophic results if workers are not wearing arc fl ash personal protective equipment (PPE). Specifi c to arc fl ash and shock, the electrical safety industry reports the ratio of deaths to incidents as being about one in 10. A typical arc fl ash is caused when a conductive object gets too close to an energized conductor or circuit part and ground. An electric arc super heats and ionizes the air, allowing for a path for electrical current to fl ow. Provided there is suffi cient voltage, usually above 208 V, the arc can sustain itself and transform into an arc fl ash. An arc fl ash can be caused by equipment failure and human interaction. However, under normal operating conditions, enclosed energized electri- cal equipment that has been properly installed and maintained poses a negligible risk of an arc fl ash hazard. Anyone working with energized electrical equipment should be knowledgeable and competent to assess normal versus abnormal condi- tions to be permitted to perform any routine operation of that equipment. The acceptable occupational health and safety hierarchal approach to eliminate or reduce risk related to an arc fl ash hazard is similar to any other workplace hazard. Within the context of electrical safety, these steps include: • de-energize, isolation and lockout/ tagout • substitution with safer systems or processes • engineering "safety by design" including effective equipment maintenance • warning signs and barricading • administrative controls, training and procedures • electrical specifi c PPE, tools and equipment with proper care, use and maintenance. The most effective way to manage electrical hazards, including arc fl ash, is to implement an electrical safety program as part of an overall occupa- tional health and safety management system. An electrical safety program Beneath all the acronyms and of this complex By Jim Pollard 4552 THE NATURAL ADVANTAGE An industry-leader in general purpose hand protection, SHOWA's 4552 provides superior defense against oils, dirt and grime, grease and abrasion, with optimal long- lasting grip. Engineered with Eco Best Technology®, this planet-friendly milestone in glove innovation is ideal for multi-use applications across a range of industries. SHOWAgroup.com [T: 800.565.2378]

• Cover