Arc Flash Study

Each year, more than 10,000 burn injuries occur due to arc flashes, 3,000 of which are severe cases and 500 of which result in a fatality. An Arc Flash hazard is the danger of excessive heat exposure and serious burn injury due to arcing faults in electrical power systems. Arc flash energy is dangerous because it can cause severe injuries or fatalities to workers who are exposed to it. It is the thermal energy released by an electric arc that occurs when a fault occurs in an electrical system and can produce temperatures up to 35,000 degrees Fahrenheit, which is hotter than the surface of the sun. This can also create a blast pressure of up to 2,000 pounds per square foot, which can knock workers off their feet and damage equipment.

Arc flash Hazard Analysis is the process of identifying and assessing the arc flash hazard at different points in the facility and recommending practices and methodologies to reduce the likelihood and severity of arc flash incidents. Some of the mitigation techniques include installing current-limiting devices and breakers with arc flash reduction modes, arc-resistant switchgear, arc flash relays, and performing regular maintenance and inspection of the equipment. These techniques can help to lower the fault currents, clear the faults faster, contain and redirect the arc energy, and prevent arcing faults from occurring.

Why perform Arc Flash Hazard Analysis?

Arc Flash incidents have prompted OSHA and other organizations to develop and enforce regulations and standards for arc flash safety. One of the most important regulations is the OSHA 29 CFR 1910.269, which applies to electric power generation, transmission, and distribution. This regulation requires employers to estimate the incident energy of any arc flash hazard and provide workers with appropriate personal protective equipment (PPE) and training. NFPA 70E recommends the practice to calculate the arc flash hazard, mark the safe distances, and select the right PPE.

NFPA 70E Article 130 specifies electrical safety work practices including the selection and use of PPEs for the workers exposed to electrical hazards. The article defines the methods and tables for arc flash risk category, the arc flash boundary, and incident energy levels. It also emphasizes the importance of following OEMs instructions and recommendations for the use and selection of PPEs.

Assessing Arc Flash Hazards and Reducing Incident Energy Levels

By performing arc flash analysis, the incident energy and arc flash boundary can be calculated for each piece of equipment. The incident energy is the amount of thermal energy that a worker would receive at a certain distance from the arc source, measured in calories per square centimeter (Cal/cm2). The arc flash boundary is the distance from the arc source where the incident energy is 1.2 Cal/cm2, which is the threshold for the onset of a second-degree burn. These values can be used to determine the appropriate personal protective equipment (PPE) for workers, such as gloves, helmets, and clothing.

To assess the arc flash hazards and reduce incident energy levels based on NFPA 70E, the first step is to develop and audit electrical safe work practices policy. Then we perform an Arc Flash Study to evaluate the likelihood of occurrence and assess the severity of arc flash hazards. The mitigative strategies to reduce arc flash hazards include the use of PPE to reduce the risk of injury in case of an arc flash. Adequate Arc Flash Training and the proper use of PPEs is also required for the personnel.

To perform the Arc Flash Study, we first gather system and installation data, including the system voltage, available short-circuit current, protective devices and other equipment characteristics. We model the facility based on the data collected by using the latest simulation software. We determine the system scenarios, such as normal, maintenance, and emergency operation. The three-phase arcing current is then calculated using the IEEE 1584 equations and the three-phase bolted fault current determined from the short circuit study. The time duration of the arc flash is determined from the TCC curves of the protective devices and the calculated arcing fault current. The incident energy and arc flash boundary are then calculated from the arcing fault current and the IEEE 1584 equations for each location under study. The results are used to determine the minimum PPE requirements for each electrical point in the system.

Experienced and Qualified Engineers:

Giving engineering recommendations about the causes of exceptions, the integrity of the system, or recommendations for corrective actions requires knowledge and skills beyond those of power systems engineering. Our team of certified professional engineers have the expertise to investigate arc flash hazards, evaluate risk severity and provide innovative engineering solutions for your facility. We work closely with our clients in gathering data, modeling the system, simulating faults, identifying arc flash hazards, and employing mitigative strategies in compliance with the latest standards and owner’s requirements.

AllumiaX, LLC delivers independent consulting and third-party engineering support by presenting comprehensive deliverable reports backed by the latest industry standards and best practices. Analysis is performed based on industry-leading software: SKM, ETAP and Easy Power and proven results based on correct modelling and calculations. The reports are expected to include the following deliverables:

1. A comprehensive electrical model of the facility
2. Evaluation of the equipment under short circuit conditions for normal and emergency scenarios
3. Identification of the hazardous areas in the system
4. Calculations of the incident energy levels for each electrical point within the facility.
5. PPE Recommendations for the safety of the working personnel
6. Arc Flash Labels on service entrance equipment as well as electrical distribution equipment such as panelboards, switchboard, MCC, etc.
7. Recommendations to increase the overall reliability and safety of the equipment and personnel.
8. Tabulated results of the study in compliance with OSHA, NEC, IEEE, ANSI & NFPA standards in a high-quality Power System Study report
9. Arc flash labels include the safety critical information for each bus.
10. Our Certified and Qualified Electrical Technician delivers Arc Flash training to the personnel.

What is the customer/client responsible for?

OSHA states that it is the owner’s responsibility to set up, document, and implement the safety-related work practices and procedures as required by NFPA 70E. They are also required to train their employees on safety work-related practices and procedures.

At AllumiaX, we evaluate the power system and flag potential problems and high-risk situations while also recommending various options for resolutions and best-in-the-market practices to our customers for a safe, regulated, reliable, and well-designed power system. Clients who choose not to perform the study misses out on a huge value proposition.

What to Expect?

Arc flash study is performed as per the latest standards IEEE, NEC, ANSI & NFPA and a regulatory body (OSHA). Study outcomes and recommendations are expected to improve your facility in the following areas:

1. Recommended PPE levels for working personnel are expected to provide increased protection against arc flashovers.
2. Safety and protection of the electrical system can be expected to increase.
3. Complete documentation of the energy levels at all electrical points in the system
4. Arc flash labels will provide the necessary safety information for maintenance work.
5. Increased reliability of the electrical distribution system.
6. A safe work environment is ensured in compliance with the OSHA & NEC requirements.