Christopher Coache

NFPA 70E Series: Minimum arc rating, PPE Category, incident energy or site specific PPE

Blog Post created by Christopher Coache Employee on Apr 20, 2017

NFPA 70E® allows you to put one of four things on the equipment label when it comes to arc-flash PPE. You can mark it with the incident energy, a PPE category, a minimum required rating or a site specific designation. Some confusion comes with the requirement’s wording that the label must include at least one of these. Several NFPA 70E users ask about using both the incident energy and PPE category on a label. The first thing that enters my mind when that comment is made is that this person does not fully understand how to use NFPA 70E.

That statement is made because the standard only allows one method of conducting an arc-flash risk assessment on a single piece of equipment. This would mean that either the incident energy analysis (arc-rating) or a PPE category would be used. Since PPE category is not an incident energy and an incident energy is not a PPE category, these two should never appear on a label together. Redefining a PPE category as a site specific rating could be done but then why put both on the label if they are exactly the same thing? Calculating the incident energy (arc-rating) then changing it to a site specific rating is common. A facility could use this method label all the equipment with a few PPE levels when the incident energy analysis method calculated dozens or hundreds of energy levels. It's not clear on why someone would simplify the method then make it more complex and confusing by including both. Another common method is specifying the calculated incident energy but require a minimum PPE rating above that energy level.

NFPA 70E is about protecting the worker and confusing the worker when safety is at risk is a dangerous thing. If the equipment is labeled with the incident energy or minimum required arc-rating, the worker can utilize equipment with at least that rating. Equipment labeled with a PPE category provides specifics on what the worker can use. With site specific ratings, the worker is likewise provided with specific gear or rating necessary for protection. So why not include them all? Worker safety.

Assume that equipment has been determined to have an incident energy of 1.1 cal/cm2, 1.5 cal/cm2, 3.5 cal/cm2, 4.7 cal/cm2 and 8.9 cal/cm2. If these were placed on the equipment labels as the minimum arc-rating necessary for PPE, anything rated higher for each piece of equipment would be acceptable. Now, assume that the facility safety system intends to use site-specific category BLUE for 4 cal/cm2 or less and ORANGE for over 4.0 cal/cm2 up to 12 cal/cm2. Three pieces are also marked BLUE and two are marked ORANGE. Now the employer also decides to require a minimum rating that is 2 cal/cm2 above the incident energy to increase the probability of successfully preventing a thermal injury. For the last one, assume that NFPA 70E is incorrectly used and the equipment is also labeled as no PPE Category, PPE Category 1, PPE Category 1, PPE Category 2 and PPE Category 3. The labels would look like:

Equipment #

Incident energy

Required gear

PPE rating

PPE Category

1

1.1 cal/cm2

BLUE

3.1 cal/cm2

 

2

1.5 cal/cm2

BLUE

3.5 cal/cm2

1

3

3.5 cal/cm2

BLUE

5.5 cal/cm2

1

4

4.7 cal/cm2

ORANGE

6.7 cal/cm2

2

5

8.9 cal/cm2

ORANGE

10.9 cal/cm2

3

                                               

Can you train your employee on how to follow all four ratings on the label? Could they comply with all four or are they following the one that results in the highest rated gear? Would you permit them to select the lowest rated gear for specific equipment? Does your package for ORANGE contain specific equipment? What happens when the worker is wearing a 1.8 cal/cm2 shirt because they did not want to put on a heavier one for Equipment #1? Which piece of equipment would you let your employee work on while wearing a 2.1 cal/cm2 shirt? Which piece of equipment specifies PPE rated for at least 25 cal/cm2? Is it confusing what to wear based on these applied labels?

Maybe now you see why clearly stating the appropriate PPE, as well as using the standard correctly, is critical. The common labeling methods which include the incident energy require clear procedures so that employees understand that the specified required gear or specified minimum rating, not the incident energy, defines the only permitted PPE rating. It is often best to simplify matters to make compliance easier for the employee. Pick something for clarity. Training and enforcement will be easier. NFPA 70E is about worker safety. Why confuse the issue?

Next time: Something you don’t consider yourself to be the authority having jurisdiction for but you really are.

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