Just like statistics can be presented in ways to prove different points, sometimes including completely opposite conclusions, the arc-flash risk assessment process can be skewed to one’s advantage. NFPA 70E®, Standard for Electrical Safety in the Workplace® is not pushing the industry to the incident energy analysis method over the PPE category method. You may benefit by reading my blog, A preference between the PPE Category Method and the Incident Energy Analysis Method.
Not too long ago I was an observer listening to a consultant who performs risk assessments and applies the labels required by NFPA 70E. The sales pitch went into the fact that either the PPE category or the incident energy (IE) analysis method could be used. The “facts” became fuzzy after that. It was pointed out that although both methods could be used, it is better to only use one within a facility. Since a single method is better, and not all equipment meets the PPE category method, the IE analysis method was the preferred choice. I sat there thinking there are many ways to successfully mingle both methods within a facility with no confusion by the employee. I also thought most of the equipment within the facility could be evaluated quickly under the PPE category method.
To illustrate the point that the PPE category method would be a problem, it was portrayed that employees need to use the PPE category tables each time they worked on equipment. It was pointed out that the tables rely on the clearing time of the overcurrent device and the available fault current. Not only would the employee have no way of knowing this information, they may not be able to find where to get it. How would the employee know if the equipment complied with the table parameters without this information? I am not sure why the labels would be incorrect. The sales pitch led one to believe that the employee would not have this problem with the IE analysis method. I waited to hear the reason why this was true but it did not come.
The fact that equipment maintenance plays a big part of electrical safety was presented. How it affects the arc flash hazard was illustrated. At no point was it mentioned that this is required for both risk assessment methods. It was alluded that this is only a benefit for the IE analysis method and not the PPE category tables. Based on the presentation I would have concluded that the IE analysis method was the “safer” choice because PPE category equipment might not be maintained or would no longer comply with the table parameters. After this point the PPE category method was no longer mentioned. Everything else presented was based on using the IE analysis method. I almost forgot there was another method as the presentation went on.
What the consultant failed to point out was that the risk assessment and label are necessary before the employee performs any task on the equipment regardless of the method used. The method used and details necessary to get to the information necessary for the label are often not the employee’s concern. The employee needs to be qualified for their task on that equipment and must know how to protect themselves from the hazards indicated. The affixed label, work permit and work procedure for the task provide the necessary information.
One method may have an advantage over the other for a piece of equipment or portion of the distribution network. The category method was developed to aid in PPE selection for common equipment without the need for an extensive calculation. The IE analysis method covers many more pieces of equipment. Before you make a decision remember these facts.
There is no preference for a risk assessment method.
Either method can be used within a facility but not on the same piece of equipment.
Some of the same information is necessary to use either method.
Whoever you consider should be knowledgeable in both methods and offer the use of either as applicable.
Either method results in the correct label information and the necessary protection of the employee.
If the IE analysis method is used be aware that one equation may not be applicable for all of your equipment. If a computer program is used, know what equation is used, were it came from and that it is the correct equation. Ask the right questions when making your selection of a consultant.
Determining the incident energy or PPE category for a piece of equipment is only a portion of conducting a risk assessment. Make sure you know what needs to be addressed in a risk assessments.
Risk assessments and equipment labeling have become a business of their own. After an employee injury or fatality is not the time to find out that the applied risk assessment or labelling method was flawed.
You are responsible for providing a safe work environment for your employees. Your employees trust that you are doing what is necessary for that safe environment to exist. This includes having competent and qualified people, whether your own employees or an outside organization, perform the required risk assessments.
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Next time: Four different ways to work on electrical equipment.