Electrical Safety Stories Blog

What Goes into an Arc Flash Risk Assessment?

What Goes into an Arc Flash Risk Assessment?

By: Rich Gojdics


In the event of a fatal or nonfatal electrical incident—arc flash, electrocution, or otherwise—many employees injured never return to their pre-incident state. Further, the costs for an employer who fails to take preventive or risk mitigation steps are exponential—the Electrical Power Research Institute (EPRI) estimates direct and indirect costs to an employer from a fatal electrical accident in the millions of dollars.

Today, we would like to explore the basics of these assessments, discussing the importance of completing an arc flash risk assessment, the process of completing one, and the steps to mitigating risk after one is completed.

Arc Flash Risk Assessments

Knowing this, it’s imperative to recognize hazards, take steps to reduce risk, and take steps to minimize harm in the event that an incident takes place. One of the most important processes to recognize, measure, and mitigate is to complete an Arc Flash Risk Assessment.

Part of a much larger safety program and culture of safety, assessments provide insight into the steps a workplace needs to take to protect workers. With the results of these analyses, employers can follow the recently highlighted hierarchy of controls central to update of the 2018 Edition Of NFPA 70E, which is to eliminate or substitute risk (de-energization), raise awareness (labeling), provide training, or select the proper equipment for the job.

These assessments should be completed every five years or any time a major modification is made to the facility that may result in increased risk or severity in the event of an incident. Today, we will explore the basics of arc flash risk assessments as part of a much larger electrical safety initiative.

NFPA 70E: Three Steps to Completing a Risk Assessment

While risk assessments can be completed for any process and/or hazard; for arc flash, these studies are guided by NFPA 70E and IEEE 1584, which in turn inform NEC Article 110 and OSHA 1910.132(d). NFPA 70E states that the goal of an arc flash risk assessment is a three-step process:

  1. Identify a Hazard
  2. Estimate the Likelihood of Occurrence and the Potential Severity of Injury
  3. Determine If Additional Protective Measures are Needed

Arc Flash studies take approximately four to six weeks to complete depending on the size of the facility and must be completed before any person is exposed to electrical hazards.

Step 1: Identify Hazards

The first step in a risk assessment is to identify a hazard. Hazards differ from risks; a hazard is a source of potential injury or damage to health while a risk represents the likelihood and severity of injury. Step 1 pertains to the hazard identification (i.e. determining if something may pose a risk when a worker is completing a task).

In regular operation and for certain tasks, properly maintained equipment will pose no risk, despite the fact that a hazard does exist. For example, non-contact inspections such as infrared thermography do not pose high risk, but can’t be completed until hazards are identified.

Table 130.5(C): A Reference Guide for Hazard Identification

As input from engineers, companies, and workers has continued to refine and improve the NFPA 70E Standard, this guiding body has introduced more and more tables to help facilitate decision making. Table 130.5(C) is one such table designed to provide quick reference whether a given task or piece of equipment poses a hazard, although it is no replacement for a complete risk assessment.

Section 130.5(C) of the 2018 standard states that “Table 130.5(C) shall be permitted to be used to estimate the likelihood of occurrence of an arc flash event to determine if additional protective measures are required.”

An additional note, table 130.5(C) only applies to equipment in “normal operating condition,” defined as the following:

  • The equipment is properly installed in accordance with the manufacturer's recommendations and applicable industry codes and standards.
  • The equipment is properly maintained in accordance with the manufacturer's recommendations and applicable industry codes and standards.
  • The equipment is used in accordance with instructions included in the listing and labeling and in accordance with manufacturer's instructions.
  • Equipment doors are closed and secured.
  • Equipment covers are in place and secured.
  • There is no evidence of impending failure such as arcing, overheating, loose or bound equipment parts, visible damage, or deterioration.”

Step 2: Estimating the Likelihood of Occurrence and the Potential Severity of Injury (Assessing Risks)

While hazard identification is one part of the equation, the second step is to identify the likelihood that an adverse event may occur and the severity of injury if it does. Known as assessing risks, this process involves determining how much energy would be released in an arc flash and understanding the severity of injury in such an event.

In completing a risk analysis, NFPA 70E provides two ways to approach this risk: Incident Energy Analysis and PPE Tables.

Incident Energy Analysis and Labeling

One method for assessing arc flash risk is to complete an incident energy analysis. This analysis takes into consideration the technical details of the equipment in order to calculate the expected incident energy at a various distances.

Often incident energy analysis is a much more complex way of identifying the potential for risk and severity of injury and is used to determine labeling for the equipment. Completing an incident energy analysis can be completed in multiple ways and a recent article on OHS Online looked at the steps to complete such an analysis, noting the following:

The Reverse-Study (Table) Method

Check a few things in the field at each location (such as upstream transformer kVA); select and apply a pre-printed label using a table.

Engineering Study

The alternative method used when an engineering study is still required. In this, someone well-versed in the electrical code will complete data collection, noting any potential violations or situations in which operation isn’t considered “normal.” From here, the engineering study will create a one-line from the engineering software, creating reports so that step three (printing and applying labels) can be completed.

PPE Table Approach

The alternative to the incident energy analysis is the use of the PPE Tables, which offer recommendations for a set of common tasks based on the equipment and voltage.

NFPA 70E (2018) reduced the number of PPE Categories from five to four, a topic we discussed in our recent blog. Learn more about the four PPE Categories here.

Step 3: Choosing Protective Measures and Developing a Safety Program

With the information in hand and the risks assessed, you can in turn take this information into consideration while developing a much larger safety program. NFPA 70E (2018) brought into the spotlight the Hierarchy of Controls—a systematic view of a workplace safety program that provides six levels of protection in order of effectiveness.

Hierarchy of Controls

As we discussed in our blog, the hierarchy of controls starts at the source, starting with the protections considered to be immune to human error and moving to the controls that are often the most feasible at any facility. The six steps are as follows:

  1. Elimination: Removing the hazard entirely
  2. Substitution: Replacing a severe hazard with a less severe one
  3. Engineering Controls: Replacing equipment or changing the work environment to separate workers from a hazard.
  4. Awareness: Educating workers on the hazards and providing information on making safe decisions.
  5. Administrative Controls: Developing formal procedures and processes for working safely under anticipated conditions.
  6. Personal Protective Equipment: Equipping workers with clothing and equipment designed to reduce risk and limit the severity of injuries.

PPE: A Necessary Part of a Safety Program and Your Last Line of Defense

A necessary part of any electrical operation, the completion of an arc flash risk assessment is not only an important part of determining the effective measures to protect workers, it is required. The new NFPA 70E standard has leveraged years of engineering knowledge to develop the reverse-study method, PPE tables, and more and has made it easier and more affordable than ever to calculate incident energy and select the proper equipment for the job.

As discussed in our blog on the hierarchy of controls, personal protective equipment is your last line of defense—a required part of a larger safety program used to mitigate damage to workers.

At Enespro PPE, we designed a complete line of 8, 12, 20 and 40 CAL Arc-Rated flame-resistant suits for PPE CAT 2 & 4 exposures. We also offer Class 00, 0 and 2 rubber voltage rated glove & leather protector kits. We travelled the country to gain a deeper understanding of the needs of workers in the electrical industry with the goal of transforming the industry with greater comfort, functionality and safety for a wide range of work requirements. Learn more about our complete range of innovative electrical safety products and read our blog for all of the latest Arc Flash safety news.

Higher Incident Energy? See Why More Companies Are Opting for the One-Suit Approach

In the wake of new IEEE 1584-2018 Standards, you may notice that incident energy levels are higher than initially expected. Paired with a conservative approach that exists in the NFPA 70E PPE tables, and you may see that your CAT 2 suits are getting less and less use. But did you know that a one-suit approach is now a reality?

Thanks to innovations in the electrical PPE market, companies are finding that they can cover all four PPE categories with a single suit—without sacrificing the satisfaction of workers.

But don’t just take our word for it. LidCo Electrical Contractors, a safety-conscious organization with over 35 years serving commercial and industrial customers in Central Massachusetts recently opted to do just that, replacing their legacy PPE with Enespro’s 40 CAL AirLite™ kits in each service van.

The results were astounding. Not only did it increase use among workers, employees found the suit so lightweight, breathable, and comfortable that the company was able to move to a one suit approach. Ready to learn more? Read the entire case study below.

<<Back to Electrical Safety Stories Blog