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5 Minimum Arc Flash Label Requirements from NFPA 70E 2018

There are many different examples of Arc Flash Labels. Also called Arc Flash Stickers.

And there are also many opinions on what should be on an Arc Flash Label.

Most of them are probably correct because there is no legally enforced arc flash label standard.

The NFPA 70E standard by the National Fire Protection Association in the USA is generally used. However, it is not enforced by the OSH Act of 1970 in the USA. It is considered a Consensus Standard. And in most countries, it is used as a guideline only.

So, what should be on the label?

This article explains the minimum label requirements according to NFPA 70E.

Note that NFPA 70E specify exceptions so that you can customize your labels, or use no labels at all! If you have the necessary controls in place.

This article also includes Arc Flash Label Examples, based on NFPA 70E requirements. And I have included my recommendations at the end.

NFPA 70E specifies two types of labels. They are based on the two official Arc Flash Study Methods in NFPA 70E. That is:

  1. The Incident Energy Method: The Incident Energy and arc Flash Boundary is calculated with a set of equations.
  2. The PPE Category Method: The PPE Category and Arc Flash Boundary is selected from pre-defined tables.

For more detail about the two methods, see What is an Arc Flash Study? Two Official Methods Described

The exact text for the arc flash label requirements from NFPA 70E is:

  1. Nominal system voltage
  2. Arc flash boundary
  3. At least one of the following:
    1. Available incident energy and the corresponding working distance, or the arc flash PPE category in Table 130.7(C)(15)(a) or Table 130.7(C)(15)(b) for the equipment, but not both
    2. Minimum arc rating of clothing
    3. Site-specific level of PPE

There are 5 minimum requirements. The next section goes through each one. Followed by Arc Flash Label Examples based on NFPA 70E. And finally my My Personal Arc Flash Label Recommendation.

The 5 Minimum Arc Flash Label Requirements

5 Mimimum Arc Flash Label Requirements NFPA USA

1. Arc Flash WARNING or DANGER Sign

A clear WARNING or DANGER sign must be displayed on the label.

In the USA, a WARNING or DANGER sign is used according to ANSI Z535, "Series of Standards for Safety Signs and Tags". The choice between a WARNING and DANGER sign is not clear. The guidelines from ANZI Z535 are in the table.

Most sites in the USA use a WARNING sign.

USA DANGER vs WARNING sign
DANGER A hazard which, if not avoided, will result in death or serious injury.
WARNING A hazard which, if not avoided, could result in death or serious injury.

In Australia, a DANGER sign is typically used, according to AS 1319-1994, "Safety signs for the occupational environment". The choice between a WARNING and DANGER sign is also not clear. The guidelines from AS 1319 are shown below.

Most sites in Australia use a DANGER sign.

Australia DANGER vs WARNING sign
DANGER A hazard which, if not avoided, will result in death or serious injury.
WARNING A hazard which, if not avoided, could result in serious injury.

The difference between the USA and Australia is in the description of a WARNING sign. In Australia, the WARNING contains only "serious injury". In the USA it contains "death or serious injury".

2. Arc Flash Hazard Description

This is just a short text that describes the hazard. In can be Arc Flash Hazard. Or just Arc Flash.

3. Nominal Voltage

The nominal voltage of the equipment. For example, 480 VAC, 600 VAC, 15,000 VAC, 15 kV, etc.

4. Arc Flash Boundary

The Arc Flash Boundary is the distance at which the incident energy equals 1.2 cal/cm2. At 1.2 cal/cm2 an operator is likely to receive second-degree burns if arc-rated PPE is not used.

With the Incident Energy Method, the Arc Flash Boundary is calculated with a set of equations.

With the PPE Category Method, the Arc Flash Boundary is selected from predefined tables in NFPA 70E.

For more information about the Arc Flash Boundary, see What is an Arc Flash Study? Two Official Methods Described

5. Minimum PPE requirements

One of the following must be on the label:
  1. 5A: Incident Energy at the working distance in cal/cm2
  2. 5B: Minimum PPE Rating in cal/cm2
  3. 5C: PPE Category from 1 to 4.

You are allowed to have both 5A Incident Energy (5A) and Minimum PPE Rating (5B) on the label.

But, you are not allowed to have PPE Category (5C) with Incident Energy (5A) or 5B Minimum PPE Rating (5B).

Note that there is also an option in NFPA 70E for Site-Specific PPE Requirements. Most sites just use a variation of 5C. I give an example in section My Personal Arc Flash Label Recommendation.

5A. Incident Energy at the working distance in cal/cm2

The calculated incident energy in cal/cm2 at the specified working distance. This is only applicable when the Incident Energy Method is used. It is calculated with a set of equations specified in IEEE 1584.

5B. Minimum PPE rating in cal/cm2

The Minimum PPE rating in cal/cm2. This is only applicable when the Incident Energy Method is used. There is no specific requirements in NFPA. However, table Table 130.5(G) in NFPA specifies the following two ranges for when the incident energy method is used.
  1. Between 1.2 cal/cm2 and 12 cal/cm2.
  2. Greater than 12 cal/cm2.

More specific PPE requirements are covered in NFPA 70E.

5C. PPE Category

The Arc Flash PPE Category from Table 130.7(C)(15)(c) in NFPA 70 must be shown on the label. This is only applicable when the Incident Energy Method is used.

As mentioned, only the Arc Flash PPE Category from Table 130.7(C)(15)(c) in NFPA 70 must be used when the Arc Flash PPE Category method is used. You are not allowed to display the Incident Energy as well.

However, it is a bit confusing, because you are allowed to use your Site-Specific PPE requirements. And a lot of sites define their own PPE Categories, which are based on the NFPA categories anyway. See section My Personal Arc Flash Label Recommendation for an example.

These sites typically calculate the energy with the Incident Energy Method and then select the relevant PPE Category based on the cal/cm2 value. If you do this, I suggest you display only the PPE Category on the label.

The 4 Arc Flash PPE Categories from NFPA are summarized below. The detail PPE clothing requirements are specified in NFPA 70E.

Category Minimum arc rating of PPE
1 4 cal/cm2
2 8 cal/cm2
3 25 cal/cm2
4 40 cal/cm2

Arc Flash Label Examples showing the Minimum NFPA 70E Requirements

Arc Flash Label Example for the USA and Australia is shown for the Incident Energy Method and the PPE Category Method.

USA

Incident Energy Method

Arc Flash Label Example Incident Energy Method USA

PPE Category Method

Arc Flash Label Example PPE Category Method USA

Australia

Incident Energy Method

Arc Flash Label Example Incident Energy Method Australia

PPE Category Method

Arc Flash Label Example PPE Category Method Australia

My Arc Flash Label Recommendation

This is my personal recommendation. Applicable for large industrial sites. Yes, you may completely disagree with me. And that is fine. Because, as mentioned, there are many correct ways.

However, I would really appreciate it if you can email me your comments. So that I can learn and improve.

Recommended Arc Flash Label
Arc Flash Label Example jCalc.NET Recommendation

1. WARNING or DANGER Label

Use a WARNING label in the USA and a DANGER label in Australia.

2. Hazard Description

Use "Arc Flash Hazard" or "Arc Flash".

3. System Voltage

Show the Nominal System Voltage.

4. Standardized Arc Flash Boundaries

I suggest you standardize the Arc Flash Boundaries, based on worse case scenarios. You can use the pre-defined Arc Flash Boundaries in NFPA 70E Table 130.7(C)(15)(a) or Table 130.7(C)(15)(b). They are specified for the PPE Category Method. Or you can define your own, based on your own calculations. For example:

Cat Voltage Arc Flash Boundary
2 400-1000 VAC 20 ft (6 m)
4 400-1000 VAC 40 ft (12 m)
4 1kV to 15kV 40 ft (12 m)

I find it confusing when the Incident Energy Method is used, and every label has a different Arc Flash Boundary. I prefer to use only one or two worse case values everywhere. It is easy to remember.

Note that, at the Arc Flash Boundary, you will theoretically still receive first-degree burns. Not second-degree burns though. So there is no harm in extending short distances to standardize.

5. Site-specific PPE Category

I suggest you define 2 Site-Specific PPE Categories, based on NFPA 70E Table 130.7(C)(15)(c). See the example below.

This will allow you to define exactly what PPE is required per category. NFPA 70E provides options which may be confusing to interpret.

You can use either the incident Energy Method or PPE Category Method to determine the required PPE. However, it is best to use one method for consistency. If you use the PPE Category method, you find that some of your equipment does not fit into the PPE Category tables, with respect to fault level and clearing time. In these cases, NFPA 70E suggests that you use the Incident Energy Method.

Whichever method you choose, I recommend that you display only the Site-Specific PPE Category on the label.

I believe, this approach is simple, clear and less ambiguous.

Example of Site-Specific PPE Categories
Cat. Rating PPE
2 8 cal/cm2
  • Arc-rated long-sleeve shirt and pants.
  • Arc-rated flash suit hood.
  • Safety glasses.
  • Ear canal inserts.
  • Arc rated gloves.
  • Leather safety boots.
4 40 cal/cm2
  • Arc-rated arc flash suit jacket.
  • Arc-rated arc flash leg covers.
  • Arc-rated arc flash suit hood.
  • Arc-rated gloves.
  • Safety glasses.
  • Hearing protection.
  • Leather safety boots.