The importance of arc flash protection was not assumed to be of great importance until the early 1980s. An article by Ralph Lee, published in the IEEE Transactions on Industry Applications, first brought the seriousness of arc flash burns and injuries to the attention of general public. This started deeper studies into the problem. The studies showed that far too many workers, especially those in the petrochemical industry, were suffering serious electrical burns and accidents. This urged companies to establish safety practices to better protect their laborers and electricians (and apprentices) working on live electrical equipment.
The Oil Industry Led the Way
Petrochemical companies were among the first to recognize the potential dangers and the need for better electrical safety procedures and safety clothing. Others soon followed their example. Even though a greater amount of energy is released in high voltage electrical explosions, the vast number of low voltage equipment in industrial and commercial facilities results in many more electrical accidents. The wittiest and easiest way to prevent injuries is to disconnect the power from equipment You are working on before You actually begin. In a few situations, turning off the power can create a greater hazard than leaving it on. Standards have been in place to prevent this; according to which responsibility was put on employers to establish safe practices and procedures designed to protect laborers from arc flash traumas. The standards are intended to keep workers safe from any potential hazards such as shock, burns, electrocution and arc blasts. This makes acknowledging the standards crucial for all sorts of employers, as well as employees working with or around electrical hazards. It is essential to understand:
- The requirements outlined in the standard
- The importance of following an electrical safety program
- Your duties and responsibilities
- The responsibilities of Your employer
- The best practices and processes to follow as described in the various regulations and industry standard guidelines
Industry Standards for Arc Flash Protection
There are 3 main industry standards for arc flash protection:
- Federal Regulation code OSHA 29 – it implies that safety practices at work shall be implemented to prevent electrical shock or other injuries that may result from direct or indirect contact with electricity. The standard specifies that workers must be qualified to work with electrical equipment and that provisions must be in place to ensure the appropriate safety gear is used to perform the work. Safety practices are enforced by the OSHA.
- National Electrical Code – it states that companies must clearly mark electrical equipment that has the potential to create a calamity. The markings may be general or extremely specific, as determined by the company. It is speculated that future revisions to this standard may demand companies to label the equipment with detailed information.
- NFPA 70E-2000 – This is basically a “how to” standard explaining the OSHA enforcement. Details of the actions a business have to take to comply with federal regulations are provided. Specifically:
- Defined responsibilities of the safety program
- Precise calculations as to the degree of hazard present
- Personal protective equipment suitable for the situation
- In depth training for all employees
- Proper tools to work safely
- Proper warning labels on all equipment
Arc Flash Protection Equipment
Guide For Electrical Safety Regulation, IEEE Standard – For warning labels to be effective, they must hold enough information to clearly show the exact danger zones. Companies must define the electrical safety zone and the areas to be entered only by qualified workers, also regarded to as the protection boundary. This regulation provides companies with a method of calculating incident energy rates to define the level of PPE workers require in order to work safely in the particular area.
Many companies now offer special arc flash protection equipment. The materials used are thoroughly tested for specific arc ratings. The ratings classify the maximum energy resistance the material will withstand before it breaks, or the point where second degree burns will occur.
Selecting the proper PPE for the task is normally done in one of two ways. In most cases you or your employer will consult the hazard classification table, such as the NFPA 70E. Table 130.7(C)(9)(a). Particular table lists several possible electrical working scenarios by voltage level and recommends the appropriate PPE You should use when performing these tasks. To illustrate, if You are working on a 600V switchgear and the task is to remove the bolted cover exposing bare, energized components, the table suggests Category 3 arc flash protective gear. This includes PPE that offers a combined protection level of up to 25 cal/cm2. The minimum PPE required in any category protects against the maximum level of risk for that particular job.
The second way of how an appropriate PPE may be selected is by performing an arc flash hazard calculation. This calculation defines the potential incident arc energy. The IEEE 1584 has a guide to help You do these calculations as long as the bolted fault current, length of faults and other general information about the equipment is in place.
After You have calculated the incident energy potential, You can choose the PPE ensemble that provides greater protection than the potential hazard.
Arc Flash Protection Equipment is Your Ally
Personal protective equipment (see the Safety Clothing for more information) ensures protection in case an arc flash accident occurs and should be considered the last line of defense. Reducing the number and seriousness of incidents should be everyone’s primary concern. As with all other factors of electricity safety, the best arc flash protection is prevention.