Arc Flash Hazard Analysis

By R.W. Hurst, The Electricity Forum

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An arc flash hazard analysis is a critical component of electrical safety in the workplace. By identifying and assessing potential hazards, developing safety procedures and protocols, and providing appropriate PPE to workers, employers can significantly reduce the chance of arc flash (AF) incidents and ensure the safety of their workforce. In addition, working with trained professionals and complying with industry standards and regulations is essential to ensure that AF hazards are properly identified and mitigated.

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To prevent such accidents, employers must investigate and comprehensively evaluate electrical equipment and systems to identify and assess potential AF hazards.

The first step in an analysis is to gather data about the electrical equipment and system, including line diagrams, equipment specifications, and system configurations. This data is then used to perform a short circuit study, determining the maximum available fault current at each point in the system.

The next step is to determine the AF boundary, the distance from the source of a potential AF at which the incident energy is equal to or greater than 1.2 calories per square centimetre. This boundary is critical in determining the level of personal protective equipment (PPE) required for workers.

After determining the AF boundary, engineers and safety professionals must perform an analysis which considers factors such as equipment type, operating conditions, and the proximity of workers to potential AF hazards. This analysis helps identify specific areas of concern and potential hazards that require mitigation.

Based on the results of the analysis, employers must then develop safety procedures and protocols to mitigate potential arc hazards. These procedures may include de-energizing equipment before performing maintenance, providing PPE to workers, and implementing lockout/tagout procedures to prevent accidental energization of equipment.

Additionally, AF hazard warning labels must be placed on electrical equipment to warn workers of potential hazards. These labels must include information such as the nominal system voltage, the incident energy at the boundary, and the required PPE.

One of the most important resources for conducting an analysis is the Institute of Electrical and Electronics Engineers (IEEE) 1584 standard, which provides a methodology for calculating the incident energy and AF boundary at various points in an electrical system. This standard also provides guidance on selecting appropriate PPE based on the incident energy level and AF boundary.

In addition to IEEE 1584, employers must also comply with the National Fire Protection Association's (NFPA) 70E standard, which establishes workplace electrical safety requirements. This standard includes guidelines for training workers, selecting and using PPE, and conducting regular equipment inspections and maintenance.

Protective devices like circuit breakers are critical in mitigating hazards. These devices are designed to quickly interrupt the flow of electrical current in the event of a fault, limiting the amount of energy released and reducing the chance. Therefore, it is important to ensure that protective devices are properly selected, installed, and maintained to ensure they function as intended.

It is essential to emphasize that conducting an analysis is not a one-time event. As electrical equipment and systems are modified or replaced, it is critical to reassess potential hazards and update safety procedures accordingly. Additionally, workers must be trained regularly to identify and avoid potential hazards, use PPE correctly, and follow established safety procedures.

An analysis is typically conducted by a qualified engineer or technician who will assess the electrical equipment, its configuration, and operating conditions to determine the likelihood of an AF occurring. In addition, the analysis will consider factors such as available fault current, protective device settings, and the distance from the worker to the equipment.

The purpose is to identify potential hazards, estimate the incident energy levels, and determine the required personal protective equipment (PPE) for workers. The study will also identify any additional safety measures that need to be implemented, such as equipment upgrades or modifications, to reduce the likelihood and severity of an AF incident.

This kind of investigation is critical to ensuring the safety of workers involved in electrical work. It helps to identify the chances associated with electrical equipment and to take appropriate measures to prevent serious injuries or fatalities from AF incidents.


What is the difference between an arc flash hazard analysis and an AF study?

An analysis and an AF study are sometimes used interchangeably, but they can have slightly different meanings depending on the context.

An AF study generally refers to a more comprehensive analysis of an electrical system's hazard and may include several components, including an analysis. In addition, an AF study may consist of a short circuit study, a protective device coordination study, and other electrical system performance and safety evaluations.

On the other hand, analysis focuses on identifying the AF hazards and chances associated with an electrical system or piece of equipment and recommending the appropriate measures to reduce those hazards. The analysis typically includes calculating incident energy levels, selecting appropriate PPE, and recommending equipment upgrades or modifications to reduce the likelihood and severity of an AF  incident.


The Nine Steps for Conducting an Arc Flash Hazard Analysis?

The steps for conducting an investigation typically include the following:


  1. Identify the equipment and systems that need to be evaluated: Begin by determining which electrical equipment and systems need to be included in the analysis. This may include switchgear, circuit breakers, motor control centers, and transformers.
  2. Collect data: Gather and review all available electrical data for the equipment, including electrical drawings, system configuration, protective device settings, fault current levels, and equipment specifications.
  3. Conduct a visual inspection: Inspect the equipment to identify any visible signs of damage, wear, or corrosion that could affect the electrical system's safety and reliability.
  4. Calculate the available fault current: Determine the maximum available fault current at each point in the electrical system using appropriate modelling software and calculations.
  5. Determine the protective device settings: Determine the settings for all protective devices, such as fuses, circuit breakers, and relays, designed to protect the electrical system from overcurrent and short circuit conditions.
  6. Analyze the incident energy: Use specialized software to calculate the incident energy level at each point in the electrical system, which is the amount of energy that could be released during an incident. This information is used to determine appropriate PPE and warning labels.
  7. Select appropriate PPE: Determine the appropriate level of personal protective equipment (PPE) required for workers based on the calculated incident energy levels and other relevant factors, such as distance from the equipment and the task duration.
  8. Develop and document recommendations: Based on the results of the analysis, develop and document recommendations for reducing the hazards associated with incidents, such as equipment upgrades, modifications, or replacement, as well as any additional training or procedures needed to reduce the likelihood and severity of an AF incident.
  9. Review and update the analysis: Periodically review and update to ensure that it reflects any electrical system or equipment changes and remains current with the latest safety standards and regulations.

Following these steps is critical in ensuring the safety of workers who operate or maintain electrical equipment and systems. The analysis helps identify potential hazards, evaluate hazards, and develop safety procedures and protocols to mitigate those hazards. Working with trained professionals and complying with industry standards and regulations is essential to ensure that hazards are properly identified and addressed. In addition, conducting an AF hazard analysis is not a one-time event, and employers must regularly reassess potential hazards and update safety procedures to ensure continued safety in the workplace.


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