Arc Flash Analysis/Assessment
Many companies in North America are coming to grips with a new electrical safety consideration – Arc Flash Safety. Often, the initial question that is raised by management is – does this even apply to our facility? In short, the answer is a resounding YES!
In the United States, the Occupations Safety & Health Administration (OSHA) can and does cite companies who do not provide protection for their employees against arc flash/blast hazards. Although the OSHA 1910 standard does not specifically define all of the procedures and PPE necessary for a sufficient arc flash safety program, it does recognize the NFPA 70E standard as the best practices for implementation of a comprehensive electrical safety program.
In Canada, the equivalent standard, Z462 is being developed in order to provide arc flash/blast protection for electrical workers. Z462 is based on NFPA 70E with some modifications so that it is in harmony with the Canadian Electric Code, but in principal is very similar to the US standard.
Many companies do not have the expertise or do not wish to expend valuable resources required to interpret, assess and implement an energized electrical safety program. That’s were a specialty consultant such as the Jacman Group can provide assistance in helping to establish the required elements of an electrical Arc Flash Safety Program.
Training is the key element of any effective program because even experienced electricians or maintenance personnel are not familiar with the hazards associated with electrical arc flash. Implementing the Jacman Group’s Arc Flash safety program will enable everyone trained to recognize hazards they’re exposed to daily and protect them in the event that an arc flash should occur. The Jacman Group’s unique training methodologies will leave each and every employee with a new respect for electricity, which in turn will make a safety environment for everyone.
The arc flash assessment is the process that is undertaken to determine the level of hazard that exists at each electrical enclosure such as a control panel, panelboard, disconnect switch or switchgear. There are several steps required to complete the assessment.
There is a variety of information which is required in order to correctly document the power distribution system. This information includes data on circuit breakers, fuses, cabling, and end loads. At first glance, the data collection step sounds straightforward; however, most clients do not want to de-energize in order to collect this data. Therefore, this task requires an experienced, skilled and qualified individual or team. However, due to the level of skill required to do this work effectively and safely, this activity is costly. Often the data collection phase accounts for 40-55% of the overall project cost.
Most engineers/consultants conduct the arc flash analysis by utilizing specialized software such as SKM PowerTools. Although the software has become more user friendly in the last decade, many companies find that the initial investment ($10,000 is typical) and the annual licensing fees of $1,000 or more eases the decision to outsource the arc flash analysis. In this phase, the engineer models the power distribution system based on the data collected. From this model, Hazard Risk Category (HRC) levels, incident energy levels (calories/cm^2), and the arc flash boundaries for the electrical distribution system are determined.
From the study results, most reputable consultants will analyze points in the system where the Hazard Risk Category is Category 3 or above and make recommendations for possible system changes which would reduce the HRC to an acceptable level. This is standard procedure for our group as is a review of the system for any major system coordination issues and insufficient fault bracing of electrical system components. We will identify problems and report them as a part of the arc flash report.
The system model will allow for the addition of future information and study of the expanded power distribution system, if desired. We recommend that the electrical engineer conducting this study have background in power distribution and also be involved with other aspects of arc flash safety such as data collection, safety consulting and training.
Once the data collection is completed, we recommend that one line diagrams are generated for use by the facilities’ maintenance and engineering staff. The SKM software generates a one-line, but it is not especially useful on a day to day basis. Our group actually utilized AutoCAD to create separate, detailed one-lines and include them as a project deliverable.
From these results, it should be expected that the engineer/consultant return to the facility and install the appropriate arc flash labeling. Although it might be inviting to simply return the labeling and reports to the client’s maintenance staff to save a site visit by the consultant, many find the reports confusing, which has led to the mislabeling of electrical enclosures. The problem is that if enclosures are incorrectly labeled, electrical personnel could be put into situations where the PPE that they are wearing is inadequate for the level of arc flash exposure.
Once the hazard assessment and labeling is complete, your consultant should provide direction as to the best clothing and PPE options which are based on the results of your study, the frequency that your maintenance personnel work in energized enclosures and other plant considerations. A competent consultant can lay out these options for you and make recommendations as to the best choices for your facility.
A key service that an arc flash consultant should provide is the ability and willingness to answer application questions as they arise. Regardless of how much time is spent in the data collection, analysis, consulting and training stages, there are ALWAYS other questions that arise. Your consultant should readily be at your service.
NPFA 70E-2009 mandates that you update your assessment at least every five years. However, it is much easier, once the initial work has been performed, to conduct on-going documentation management. This means that periodically, monthly, semi-annually or annually, you review, document and update your one-lines and arc flash study. The cost of making minor changes to both the one-lines and SKM model on a regular basis is miniscule when compared to a major re-evaluation every five years.
Training should also be conducted periodically and we recommend that it be completed on the same intervals as your lock-out tag-out training. For the vast majority of our clients, this is conducted annually.
QUESTIONS & INFORMATION
Contact us for more information about our Arc Flash safety services and a free consultation. For more information on electrical safety requirements take a look at this article published in Facility Care magazine, "Electrical Safety in the Workplace" written by our VP and expert in the field, Robert J. St. Pierre.