Standard drives technology developments that include risk-reduction tools and strategies for improved workplace safety and productivity.
By Phil Allen, president, Grace Engineered Products, Inc.
Safety is the reduction of risk, not the absence of risk. This risk reduction defines true safety innovation. In 1979, the National Fire Protection Association (NFPA) published its first edition of NFPA® 70E to address the growing number of electrical shock injuries and fatalities. Over the years, NFPA 70E has developed a track record of minimizing incident energy in power distribution systems, thus reducing arc-flash and shock injuries.
The organization continues to further improve safety; the 2000 edition included quantifying the poorly understood physics of arc-flash incident energy and began to define methods and procedures for reducing risks to workers. A recent study showed that 57% of facilities reported noticeable safety improvements following their implementation of an NFPA 70E electrical safety program.
The upcoming NFPA 70E 2018 edition aims to further enhance electrical safety in the workplace. Its emphasis on risk management will continue to drive electrical safety innovation and keep the floodgates open for better risk reduction in the future.
Standard Sparks Innovation
Since 2000, NFPA 70E has inspired almost two decades of rapid-fire innovations, including arc-rated equipment, smarter circuit breakers, arc-flash software tools and innovative training techniques. Each innovation has contributed to electrical safety risk reduction. Safety innovations can move the risk-reduction needle only if they rest solely on the unchanging principles of electrical safety. Here are some ways NFPA 70E has contributed to worker safety through new standards and advances in technology.
Energized Electrical Work Permit. The inclusion of the live work permit in the 2004 NFPA 70E, for the most part, eliminated high-risk live work tasks. Getting an approved live work permit requires a full job risk analysis, a job plan and approval of several layers of management.
Most often, the high risk associated with live work is deemed unacceptable and can wait until the system is de-energized. The result is better planning and a more robust predictive maintenance program to avoid unplanned shutdowns.
Incident Energy Mitigation. Before NFPA 70E, power system designs focused primarily on short-circuit coordination. Now these designs include incident energy values for the system, which helps facility engineers “pre-engineer” out the risk of arc flash. NFPA 70E also inspired the development of the arc-flash relay that reduces the intensity and damage caused during arc incidents.
Another new technology finds hot spots in electrical equipment before they can cascade into arc flashes. Hot spots within electrical equipment should be found early, especially when located on a bus with high incident energy, and this early detection can help to prevent catastrophic equipment failures. One solution deploys a nonconductive light-based technology continuously to monitor potential hot spot locations within electrical equipment.
This hot spot monitoring technology is immune to voltage and allows sensors to be bolted directly to the bus-bar or potential failure point. Infrared thermography provides a similar functionality but is only a snapshot in time with a limited ability to direct and impact day-to-day maintenance activities. Partially loaded conditions during scanning can affect infrared reading accuracy. Additionally, many of these inspections are performed with the equipment doors open, which exposes workers to the risk of arc flash.
Safety by Design
The concept of permanent electrical voltage testers installed into electrical panels is a true safety-by-design innovation.
Fundamental to mechanical lockout/tagout (LOTO) is the bump test. The U.S. Occupational Safety and Health Administration (OSHA) requires this test to make sure all energy sources are in a safe state. However, many technicians began mistrusting the bump test because of sophisticated control and machine safety systems, so in most cases it was rendered irrelevant and ineffective.
To address this, voltage indicators installed on the load side of isolators provide a simple way for frontline workers to see firsthand that electrical energy is off. By opening the isolator, the voltage indicator changes state (illumination to no illumination), which helps determine that the right isolator is open and that there is a low residual risk of the electrical energy causing hazardous motion.
In addition, NFPA 70E determined that opening electrical panels was risky, so even a simple voltmeter test for electrical isolation in mechanical LOTO was not practical and added more, not less, risk. The end result was that workers were more productive and reported saving an average of 13 minutes per LOTO.
Voltage indicators installed on isolators brought an unexpected safety dividend to electrical LOTO. Voltage indicators essentially engineer out risk by increasing the likelihood that workers are exposed to zero voltage when performing the OSHA-required absence-of-voltage voltmeter test on the disconnect switch after opening the enclosure. The reliability record of voltage indicators coupled with the statistical improbability of a combined, simultaneous failure of both the voltage indicator and isolator have made their use widespread within many Fortune 500 facilities.
The Voltmeter Test
Will permanent voltage testing instruments ever supersede the practice of test-before-touch by qualified electrical workers? Ironically, this practice does not diminish the voltmeter’s importance in LOTO but rather elevates it in becoming the worker’s personal electrical safety tool. Exposure to voltage comes with a high risk of death and therefore essentially converts the voltmeter into an electrician’s primary personal safety device during LOTO.
For certain occupations such as pilots, high-rise window washers or electricians, safety failures may result in death. In these workplace scenarios, workers personally verify proper equipment operation and suitability before starting their work tasks: pilots don’t fly unless they perform a thorough preflight check, and electricians never touch conductors without checking for voltage with their voltmeters. Therefore, the voltmeter test always will be a nonnegotiable safety step before an electrician works on conductors.
New Technology and Safety Fundamentals
Technology will continue playing a role in providing novel risk-reduction tools and strategies resulting in more safety and productivity for employees working on and around electrical energy. However, fundamental electrical safety principles, such as test-before-touching electrical conductors, will remain intact for some time. Future innovations eventually will rewrite the rules of electrical safety, but until then some safeguards will stay the same.
Encompass™ Product Partner Grace Engineered Products, Inc. provides personnel safety products including programming interface ports for controllers, SafeSide permanent electrical safety devices and IR viewing windows.
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