Is your facility's electrical system compliant with National Fire Protection Association (NFPA) and OSHA codes? Whether your facility was built in the 1940s or just a few years ago, the probability is high that your electrical system does not meet current codes and guidelines and your electrical system documentation is not up to date. If that is the case, you're not alone.
Over the years, as manufacturing operations have felt the financial pressures of competition and cyclic market demand, reductions in facility support staffing levels were often the first "cost reductions" implemented. It was not unusual for the responsibility of a plant's electrical power system to fall on electrical contractors or consultants, who frequently have limited knowledge of the plant's overall system design and no responsibility to maintain the system documentation as changes are made. Even recently constructed facilities have been shown to have inaccurate electrical system documentation as pressure on capital project budgets often eliminates the production of "as built" drawings.
Short-circuit studies, protection coordination and arc flash assessments are becoming an increasing priority in today's industries. NFPA-70E requires all facilities to have up-to-date electrical system documentation and properly labeled equipment, with assessments reviewed every five years (or when significant system changes or renovations are made) and to train personnel to the requirements and procedures necessary to maintain electrical systems in facilities.
The concepts of "limits of approach" and "arc flash" were first introduced in the mid-90s as part of the 5th edition of NFPA- 70E. As interest grows, arc flash assessments are being conducted using both internal and external resources, generally with commercially available software such as EasyPower®, SKM® or ETAP®, but often by individuals with limited power systems expertise. Although these are powerful tools for the analysis of electrical power systems, the quality and accuracy of the results they provide are directly linked to the quality and accuracy of the input variables, as is the experience and knowledge of the engineer performing the assessment.
Collecting the data necessary to accurately model an electrical power system, especially for an arc flash assessment, is typically the most difficult, time consuming and costly aspect of the assessment. However, without an accurate one-line diagram, transformer data, cable data, fuse types and sizes, breaker ratings, trip settings, etc., an effective power system(s) assessment cannot be performed. It is essential the system model be completely up to date, if the goal is to provide a safer workplace. The old saying "garbage in, garbage out" is magnified in the case of software-performed analyses.
Too often, compromises or assumptions are made for the sake of schedules or budgets, simply because data is not readily available. Although previous arc flash studies can serve as a starting point, it should not be assumed the system models they are based on are accurate. The time spent to collect and model system data accurately is essential, and failure to do so can lead to a false sense of security by the operator, who depends on the accuracy of the information provided on the equipment arc flash labels. Proper data collection for an arc flash analysis should always provide the client with an updated one-line diagram for their site, not simply abstract labels without supporting documentation.
When was your facility's electrical system documentation last reviewed? Was the assessment done properly and with the necessary level of detail and thoroughness to provide your employee or contractors with a safe workplace? Or was it done hastily for the purpose of generating equipment labels?
For more information, contact Rick Tyner and Adam Gause of Plant Engineering Services at rick.tyner@ fluor.com, adam.gause@fluor.com or (864) 281-5079, or David Hicks of Stork, A Fluor Company at david.hicks@stork. com or (832) 331-6316.