At 8:41 a.m. on August 3, 2020, two employees were working as electricians for an electric power utility. They and a third employee were working at a coal-fired generating station. The two electricians, were troubleshooting the generating station's pulverizer and pulverizer fan number 6 breaker. The breaker would not rack out from an energized 4,000-volt buss. The two electricians opened up the breaker cabinet door to access the breaker and to visually inspect the racking mechanism. The two employees unbolted and removed the front interphase barrier cover. One employee started to unbolt the horizontal steel barrier plate directly below the exposed primary side of the breaker in order to view the back portion of the lower racking mechanism. As he was doing this, an arc flash occurred. He received arc flash burns to his upper body. The second electrician, located behind his co-worker, also received burns. The third employee responded to the incident and received an injury to his leg. The two electricians were hospitalized with serious burn injuries. The electrician who received arc flash burns to his upper body died on August 26, 2020, as a result of the injuries he had received. The second electrician was hospitalized with serious burns. The third employee was treated for a contusion to his left leg. — OSHA Fatality Report
Electrical-related fatalities and serious injuries (FSI)* are among the noted FSIs. FSIs represent a safety and health challenge that has gained increasing visibility in the past decade as even organizations with elite environment, health and safety programs struggle to reduce FSI numbers.
*The acronym FSI is also known as SFI – serious injuries and fatalities. The author uses FSI believing fatalities, with their devastating effects, should precede serious injuries.
- In 2001, the U.S. Bureau of Labor Statistics (BLS) reported employers suffered 5,915 work-related fatalities. In 2019, the most recent year reported, 5,333 occupational fatalities occurred – a two percent increase above the previous year.
- In 20 years, the recordable case rate of injuries and illness per 100 full-time workers has declined from 6.7 in 1999 to 2.8 in 2019. Fatalities have increased from 4,836 in 2015 to 5,333 in 2019. That total represents the largest annual number since 2007, according to the BLS.
- The fatal work injury rate per 100 full-time workers was 3.5 in 2009. A decade late it remains at 3.5 in 2019. Industry cannot get off this plateau.
- In 2019, the BLS reported 166 fatalities due to exposure to electricity. Electrical exposure is one of OSHA’s fatal four – leading causes of workplace fatalities.
- A multiplier effect exists between the number of fatalities and serious injuries, perhaps as high as 20 times or greater, according to estimates. Therefore, approximately 3,000 – 5,000 employees annually suffer life-altering injuries (permanent disfigurement, amputations, significant permanent limited body function, etc.) due to unintended exposure to electricity.
Three factors determine the severity of an arc flash incident, according to the Workplace Safety Awareness Council (WSAC):
- Proximity of the worker to the hazard
- Temperature, which is a function of available energy
- Time for circuit to break
The National Fire Protection Association standard 70E, Electrical Safety in the Workplace® (2021 is the most recent edition) sets the bar for voluntary requirements to prevent violent, costly arc flash exposures (extended medical care is often required, sometimes costing more than $1 million, according to the WSAC). NFPA 70E has specific approach boundaries designed to protect employees working on or near energized equipment: flash protection boundary (the outer boundary); limited approach; restricted approach; and prohibited approach.
And so some equipment will have a greater flash protection boundary while other equipment will have a lesser boundary, according to the WSAC. The most common areas where arc flashes occur are:
- Electrical panels
- Motor control centers
- Damaged wires
- Metal clad switch gears
- Fused disconnects
NFPA 70E methods of protection
NFPA 70E requirements offer methods for protecting qualified, specifically-trained employees doing work on electrical circuit, and other methods for protecting non-qualified employees who work nearby energized equipment.
If it has been determined that deenergizing a circuit is not feasible (say a circuit feeding a hospital surgical room) and the employee must work “hot,” 70E requires the employer to develop and enforce safety-related work practices to prevent electric shock and burns resulting from either direct or indirect electrical contacts. Practices include: energized electrical work permits; personal protective equipment (PPE); insulated tools; written safety program; employee training; and pre-task job briefings.
Each piece of equipment operating at 50 volts or more that is not put into a zero energy state must be evaluated for arc flash and shock protection. The evaluation determines the various protective boundaries and informs workers what level of PPE must be worn. After the evaluation is complete, an arc flash hazard warning label must be affixed to the equipment and easily accessible to employees who may work on the energized equipment.
Note: OSHA standard 1910.333 mandates that all employees, regardless of industry, provide electrical safety in the workplace for all employees and contractors. OSHA states the law. NFPA 70E demonstrates how an electrically safe working environment is implemented.
Barriers to reducing FSIs
FSI research dating back more than a decade and an FSI literature search reveal well-documented precursors to FSIs, including:
- Work with electricity and energized equipment
- Confined space entry
- Work when pinched between in the line of fire and the release of significant energy
- Driving a vehicle
- Work at elevation
- Work that involves barriers & machine guards
- Work with potential arc flash exposure
- Work under a suspended load
“Follow the Energy” to reduce FSIs
We can see that many precursors involve energy. One critical aspect of FSI prevention is to train all workers on the types of potentially dangerous energy they may encounter. A white paper on FSIs by the author, titled, “Follow the Energy,” describes examples of kinetic energy as a fall from a height; fan blades and rollers; and vehicles moving at high speeds. Steam in a pipe and molten steel have thermal energy. Power conduits, power lines, and numerous equipment assets are charged with electrical energy. A wound spring contains stored energy. Ingredients of a combustible compound contain chemical energy.
Sometimes the least obvious hazards are those where energy sources interact, often invisibly or at different times. For example, the energy of strong vibrations from nearby excavation work weakened the mountings and welds on a conveyor to a silo. When the conveyor jammed and two workers climbed up to fix it, the interaction of that long-ceased vibrational energy and the men’s gravitational energy killed them and several people below when the mountings and welds gave way.
Not all FSIs result from high-energy causes. Our need for oxygen can kill us in low-energy, oxygen-deficient confined spaces, or when we are deprived of heat energy in an industrial freezer.
The first variable in accident prevention, the factor that matters most and most often, is identifying and channeling energy into production and away from workers.
There are eight steps to the “Follow the Energy” methodology:
1. Locate the sources of energy.
Every audit begins by comprehensively identifying all the major sources of energy throughout the facility, especially those powerful enough to injure or kill a worker.
2. Calibrate the energy levels.
Managing the flow or containment of energy in a facility is not just knowing what, but how much. Energy that has been sufficiently reduced, whether electricity that has been stepped down or pallet loads no longer stacked as high, cuts the odds of a tragedy.
3. Assess the human proximities.
FSIs most likely occur in the areas where people are working with machine controls or are closest to moving or electrically-charged components. We must understand where people go (or can go) to allow us to predict where serious accidents are most likely to happen and to focus our attention on those areas.
4. Identify the modes of failure.
To imagine worst-case scenarios is one of the most crucial aspects of systems thinking. Considering what would happen if a pipe burst, a key part suffered metal fatigue, or power bled into the metal frame is the essence of preventing those breakdowns. This approach is an effective tool in hazard elimination.
5. Calculate the probabilities.
Managing a process well includes knowing how likely each of its components is to fail. For most machines or their parts, there are established “potential failure” curves that are invaluable to help to focus attention in those areas where a problem is most likely to occur and most likely to result in severe injury. Even without established or easily calculated statistics to guide us, estimating the odds is a highly productive exercise that always brings up issues that otherwise would have gone unanticipated.
6. Focus on the middle of the hierarchy of controls.
When the sources and levels of energy, their proximity to workers, modes of failure, and probabilities are fully surveyed, the traditional hierarchy of controls becomes a strategic tool – with the focus especially on the middle of the hierarchy. Energy can rarely be eliminated and only modestly more often be substituted, because it is usually a necessary input to the manufacturing process. PPE is rarely enough to stop FSI-level forces. We must methodically consider engineering and administrative controls that lead to targeted, cost-effective means of isolating the hazards or keeping workers clear of them. Matching the severity of the energy release against the best engineering and administrative controls allows us to have a high degree of confidence that we has prevented the majority of potential FSIs.
7. Optimize the inspection and maintenance regimen.
Improved inspection and maintenance is the best way to control incident probabilities and not get blindsided by a break in the system. Combine current thermo-imaging technologies with an insistence on removing panel covers to get at the connections and it is stunning the problems we can discover and correct before things get potentially tragic. Thorough, frequent inspections allow an enterprise to pivot from reactive to predictive.
8. Involve the front line.
In proximity to lethal levels of energy, ignorance can often get someone killed. Involve frontline workers in assessing electrical safety. They are fully cognizant of the systems they work with and the specific means of how work gets done. Frontline workers can help identify energy sources and system and process improvements that can mitigate FSI potential.
Using this eight-step methodology allows leaders, managers, supervisors, and frontline workers to understand the precise nature of the surrounding energy and its risks. It delivers crucial information, warnings, and guidance for optimal interventions at every level. These types of innovations, focused on hazardous energy, are now and will be in the future a vital part of our collective strategy to diminish the FSI numbers.
We must note that FSI prevention approaches are not organized around human factors or human behaviors. Most of the energy forces involved and the ways energy comes into proximity of frontline workers exceeds their authority to change processes, change their perceptions to anticipate, and exceed their physical ability to withstand those forces if unleashed. Unlike the causes of less serious incidents, FSI prevention focuses more on the design, condition and maintenance of the working environment (equipment, systems, assets) into which the employees are placed.
More importantly, we should consider FSI prevention a moral imperative. Fatality and serious injury numbers can’t convey the grief of family members when someone dies on the job. Nearly every FSI is predictable and within the scope of a rigorous, risk-based, systemic approach. This strategy is within the control of a facility’s leadership team. Those in charge have within their ability the means to prevent tremendous suffering.
“Follow the Energy” methodology can be applied to organizations that are thinking about electrical safety broadly and arc flash prevention narrowly. There are technologies available that can all but eliminate many arc flash hazards. They require retrofitting and incur a cost – though the cost is a tiny faction compared to the loss of a life.