The 2015 edition of NFPA 70E®, Standard for Electrical Safety in the Workplace introduced a requirement that risk controls be implemented during the course of the risk assessment. That edition included a possible hierarchy of risk controls as an informational note. The 2018 edition will move that specific hierarchy into mandatory text. This is a minor change since a hierarchy had to be applied already. If you have been using another hierarchy of controls you will need to modify your risk assessment process to include these new controls.
What is surprising is how often this requirement is overlooked. Everyone wants to jump into the tables or to just calculate the incident energy. To do either is not following the requirements in addition to possibly putting the employee at greater risk. It cannot be stated enough times, PPE is the last line of defense which may minimize the injury to the employee. PPE should never be the first or only risk control used. It does not necessarily prevent injury nor does it prevent an incident from occurring.
A risk assessment is not simply the determination that a hazard is present and that PPE will be used to protect from that hazard. Risk assessment is an overall process that identifies hazards, estimates the potential severity of injury or damage to health, estimates the likelihood of occurrence of injury or damage to health, and determines if protective measures are required. If additional protective measures are necessary, the hierarchy of risk controls must be implemented. A risk assessment is not justification to perform energized electrical work. Regardless of the use of hierarchy of risk controls the primary work procedure must be establishing an electrically safe work condition.
The hierarchy of risk controls must be used whether the PPE category method or the incident energy analysis method is used for an arc-flash risk assessment. The hierarchy of risk controls applies not only to arc-flash risk assessments but also to shock risk assessments. The hierarchy is used to minimize the risk to the employee when establishing an electrically safe work condition. When energized work is justified, the hierarchy is used to minimize the risk during the performance of the assigned task. The required hierarchy of risk controls in descending order of effectiveness is:
(3) Engineering controls
(5) Administrative controls
(6) Personal protective equipment (PPE)
Being a hierarchy, the risk assessment must start with elimination then work its way down the list until the hazard or risk of injury is brought down to an acceptable level. The risk assessment is not a onetime step through the risk controls. For example, a substitution should be revaluated to determine its effectiveness. It may be possible to apply a subsequent substitution to further minimize the risk. A risk assessment may get down to administrative controls but may still present an unacceptable level of risk thereby requiring another run through the entire hierarchy. A risk assessment that results in a hazard or unacceptable risk of injury to the employee should be reassessed and the hierarchy of risk controls applied again. Once the risk assessment process has minimized the hazard or risk, PPE should be selected for any residual hazard and risk. The ability to use PPE should never be employed as justification to skip the first five control methods.
There are many methods of conducting risk assessments and the process is not detailed in NFPA 70E since one method may not be appropriate for all risks or hazards. You must select and document the procedure you use. You are required to run through the hierarchy of risk controls as part of your risk assessment. The process may need to be repeated to achieve the best result. Controls that you employ may or may not remove or lower the hazard. Others may only lower the risk to the employee. The result may not be that the employee can wear lower rated PPE or use fewer pieces of PPE. What it will mean is that you have done everything possible to protect your employee when you have decided to put them at risk while performing justified energized electrical work.
Next time: The most effective risk control.