Executive Summary

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 arching faults in electrical power systems. Electric arcs produce intense heat, sound blast and pressure waves. They have extremely high temperatures, radiate intense heat, can ignite cloths and cause severe burns that can be fatal. These arc flashovers occur due to dust on the conductor surface, condensation of vapor, corrosion of equipment parts and even accidental contact with live conductors.

The need for continuous power is expected from a utility company and demanded by the customers. There is a need to perform electrical and maintenance work on exposed live parts of electrical equipment. It is for this reason that an arc flash study is critical for the protection of all working personnel within the facility.

Objective

The main objective of an arc flash hazard analysis is to identify the arc flash hazards at each electrical point and quantify their intensity levels.

Study Methodology

To perform an arc flash hazard analysis, a comprehensive data collection procedure is performed for the facility. The information includes the arrangement of components & protective devices on a one-line model with nameplate specifications of every device. The utility is contacted for data regarding the minimum and maximum fault currents available at the entrance point. Once the data collection procedure is finalized, a short circuit analysis followed by a coordination study is performed which act as pre-requisites to the arc flash study.

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.

Study Outcomes & Recommendations

Arc flash studies are 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:

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

Study Deliverables

The proven expertise of our team of certified professional engineers will assist in the evaluation of your system and deliver state-of-the-art recommendations and arc flash solutions for your power system’s protection. We work closely with our clients in collecting the data, modeling the system, identifying the hazards, simulating the incident energy levels & providing solutions in compliance with the latest industrial standards including OSHA, NEC, IEEE & NFPA.

AllumiaX, LLC provides independent and third-party engineering support by presenting comprehensive deliverable reports backed by industry standards and best practices, analysis work based on industry-leading software (ETAP), and proven results based on accurate modelling and calculations. The reports are expected to include the following deliverables:

• A comprehensive model of the facility in modern power systems software
• Evaluation of the system for normal and emergency scenarios
• Identification of the hazardous areas in the system
• Calculations of the incident energy levels for each electrical point within the facility
• PPE Recommendations for the safety of the working personnel
• Arc flash labels including the safety critical information for each bus
• General recommendations for the overall reliability of the network
• Tabulated results of the study in compliance with OSHA, NEC, IEEE ,ANSI & NFPA standards

References

• NFPA 70, “National Electric Code” ,2017
• NFPA70E, “Standard for Electrical Safety in the Workplace”, 2017
• IEEE Std 1584b, “IEEE Guide for Performing Arc Flash Hazard Calculations”, 2013