Electrical hazards such as arc flashes are always a possibility, whether in massive manufacturing plants or a small-space office, putting workers safety at risk. To mitigate this risk and avoid damaging equipment and the workplace, it is important for organizations to implement arc flash assessments when designing and setting up power grid and other electrical systems.
What is an Arc Flash Assessment?
The arc flash, also known as flashover or electric arc, is an incident involving a rapid succession of energy release caused by a dangerous arc fault. An arc flash can happen in milliseconds and is described as a low impedance connection that permits unwanted electric discharge to move through the air to the ground or across voltage phases. It causes temperature and pressure to rise, resulting in an explosion called the arc blast.
To mitigate dangerous arching faults, a thorough arc flash assessment should be performed. It is a compliance-type analysis required by the National Fire Protection Association Standard for Electrical Safety in the Workplace (NFPA70E). It determines the specific arc electric arc hazard and provides an estimation of the possible occurrence and risk of damage or injury. The assessment will also reveal whether the workplace requires added protective measures.
Human errors commonly cause an arc flash. Careless practices such as letting a test probe touch the wrong surface or improper installation tools and techniques can all heighten the risk for an electric arc incident. It can also be caused by equipment failure, breaks in insulation integrity or corrosion, dust, and other debris on the conductor surface.
Ensuring that an arc flash assessment is completed before operating any equipment or process is crucial to protect employees and property from accidents. These circumstances don’t choose the time and place; as it happens in milliseconds, there’s no time to duck or hide to avoid it. The best course of action is to find and mitigate arc flashes before they become a real threat.
How to Apply Safety by Design in the Assessment
An electric arc hazard analysis lays the groundwork for safety design to be accomplished by a dedicated electrical engineer who has technical expertise and familiarity with the electrical systems found in the facility. The law states that along with the arc flash assessment, all employees and people who will likely be exposed to electrical components of the workplace should undergo safety training, as stated in article 110.2 of the NFPA70E.
Applying the safety by design approach even in existing systems is possible, with solutions varying from one case to another. It determines how much potential arc flash exposure a worker may get and what kind of personal protective equipment (PPE) they are required to wear to combat heat, blast, and light that may occur during an arching fault.
Safety by design is fulfilled in an arc flash risk assessment through the design layout, choice of equipment, and options to achieve electrical safety.
Here are some safety points to implement when performing the assessment:
- Keeping workers away from hazard zones and identifying the protection boundaries
- Providing arc flash warning labels with clear PPE and boundary requirements
- Using control systems and remote monitoring to perform tasks like opening breakers, metering functions, or checking the log of events
- Remote racking systems to enable workers to keep a distance from the breaker racking operation
- Employing a switch that reduces the duration and energy of an arc flash incident
- Enabling smart circuit breakers combined with sensors, software, and remote diagnostics and monitoring functionalities
Designing the Arc Flash Assessment
Based on the NFPA70E standards, arc flash risk assessments need to be performed every five years or when the facility undergoes a significant change or modification. It’s crucial to evaluate external factors, such as new facilities built around existing ones, which could affect the fault current.
The assessment may last anywhere from 4-6 weeks, varying based on the facility size. The IEEE1584 provides the governing standards such as calculations and techniques to be applied by the engineer when identifying the hazard distance and incident energy exposure any worker will be subjected to. The measurements enable operators to wear the proper PPE to mitigate the arc flash incident.
To start, a data collection phase should be implemented through on-site inspection of the electrical equipment and facility. It’s nearly impossible to determine arc flash incidence via drawings, so it is necessary that an expert technician gather details about the equipment and furnishing a report to be used for the next steps.
Based on the collated information, a qualified engineer should proceed with the engineering solutions phase. It is where professional knowledge, experience, and software are utilized to short-circuit analysis, interrupt rating analysis, protective device coordination analysis, and incident energy analysis.
Lastly, the results must be thoroughly interpreted and evaluated to provide arc flash energy labeling. Arc flash hazard labels are essential in the safety policies of a facility to comply with the NFPA70E standard.
Unparalleled Electrical Engineering Experience
Conducting an arc flash risk assessment is a crucial component of the Electrical Safe Workplace Practices (ESWP) policy of any facility. When industries take advantage of the latest technologies and ensure that internal processes are done correctly, both the workforce and facility are protected and safe at all times. Present Group has over two decades of experience in providing specialist electrical engineering services, including arc flash studies. Contact us today to learn how we can help you.