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FMS PublicationsIndex
Assessment and Mitigation of Magnetic Fields in a Commercial Building Adjacent to Transmission LinesThis paper was presented at the 2001 Facilities America Conference in Las Vegas, Nevada. During final construction of a five-story commercial office building in St. Louis, Missouri, the developer's leasing agent expressed concern that magnetic fields from high voltage transmission lines close to the building, could cause interference problems with office equipment and make portions of the building difficult to rent. Field Management Services (FMS) was retained by the building's developer to assess magnetic field conditions in the new building. FMS documented magnetic field conditions in portions of the building sited adjacent (within 75 feet) to a double circuit 345 kV high voltage transmission line. Using the magnetic field measurement data, FMS developed and implemented mitigation recommendations. Click here to see the full article. Power Quality, ELF Magnetic Fields and Real Estate LeasesThis paper was to be presented at the 2001 PowerSystems World Conference in Chicago, Illinois. A new tenant, with sensitive display equipment, requires both clean power and an environment free of magnetic field interference. A valuable real estate lease deal, in mid-town Manhattan, turns on the power quality of the building and the ability to reduce environmental fields from the building electrical distribution system. Solutions to the existing problems will require coordination between the building electrical department, power quality consultants and the local utility. Click here to see the full article. Power Quality Compatibility & ComplianceThis paper was presented as a platform presentation at the 2000 PowerSystems World Conference in Boston, Massachusetts. An elevated EMF and magnetic field interference problem illustrates the interrelationship between Power Quality issues and unusual levels of EMF. Additionally, this case study illuminates the positive customer service changes taking place inside a major power utility in a deregulated environment. Elevated EMF levels in a ground-floor space rendered the space unusable by computers. The building management contacted the Power Quality Group from ConEd to verify field levels, then hired a Los Angeles EMF specialist, Field Management Services (FMS) to support the Power Quality Group as it sorted out the problems and to shield the magnetic fields. As each step of the work progressed, it revealed previously hidden critical and dangerous installation errors in the system. Click here to see the full article. RMS-Induced Current - A Broadband Magnetic Field Exposure Assessment MetricThis paper was presented as a platform presentation at the 2000 Bioelectromagnetics Society (BEMS) Conference in Munich, Germany. The RMS Induced Current metric, proposed by the authors, provides investigators with a powerful and simple method to compare magnetic fields; even if those magnetic fields differ significantly in frequency and waveform. Furthermore, the metric represents known effects, including induced current, induced voltage, power, and heat. The metric RMS Current Induction (mG-Hz), is independent and requires no specific knowledge of the conductive body placed within the field. Instrumentation capable of digitizing and recording magnetic field waveforms over a broad frequency spectrum is readily available for this application. And finally, the approach recognizes and accounts for the substantially greater ability of higher frequency fields to induce voltages and currents into conductive bodies. Click here to see the full article. Pre-emptive Field Mitigation of ELF Magnetic Fields During a Commercial Building Power UpgradeThis paper was presented as a poster session at the 1999 Bioelectromagnetics Society (BEMS) Conference in Long Beach, California. In this case study, the management of a commercial office building in Los Angeles, California planned to substantially increase capacity of its power facilities, both to support increasing demands from tenants' new technology equipment and to provide for future growth. Space and access restrictions in the basement forced a decision to locate a new utility transformer and distribution equipment in an existing street level retail space, with tenant spaces on all sides and above. Computer models confirmed that elevated power frequency magnetic field levels were likely to exist in the adjacent tenant spaces after installation of the new utility transformer facility. Magnetic field reduction measures were incorporated into the power upgrade design. Utilizing computer projections and in collaboration with the local utility, components in the transformer vault were positioned to decrease EMF levels. Click here to see full article. Mitigation of Wiring Interference on Computer SystemsThis paper was presented at the 1999 American Power Conference 61st Annual Meeting in Chicago, Illinois. During a building remodel and electric service upgrade, wiring errors occurred that created elevated magnetic fields and certain unsafe electrical conditions. Detailed investigation identified the net-current conditions and finally the wiring errors that were creating the net-current conditions. Once the wiring errors were corrected, the elevated fields disappeared, except in the area directly adjacent to the power panel, which was later shielded. Click here to see full article. Reduction of ELF Magnetic Fields Emanating From Circuits with Net-Current Conditions by Cancellation TechniquesThis paper was presented as a poster session at the 1998 Annual Review of Bioeffects Research September 13-17, 1998, Tucson, Arizona. Elevated levels of power frequency magnetic fields in commercial buildings are often caused by net-current conditions present on conduits, bus ducts and other distribution circuits. Wiring errors such as multi-point ground connections and shared neutral conductors, typically create net-currents by providing an alternative path for neutral currents. Magnetic fields caused by net-currents are very difficult to shield using traditional shielding materials and methods, thus best reduced by correction of wiring errors to eliminate alternative neutral paths. However in some instances, corrections to wiring systems are not practical. This study tests the effectiveness and viability of using active and passive (induced current) field cancellation techniques to reduce net-current fields in typical commercial building distribution conduits, bus ducts and cable ducts. Click here to see the full article. ELF Magnetic Field Interference with Computer Monitors: Characteristics, Choices and Costs of RemediationThis paper was presented as a poster session at the 1997 Annual Review of Bioeffects Research November 9-13, 1997, San Diego, California. Work on threshold values of ELF magnetic fields which cause computer monitor interference have been studied with conflicting results. There are, generally, four solutions to the problem of computer monitor interference: (1) increase the monitor-source distance, (2) shield the monitor, (3) shield the source, and (4) modify the vertical scan frequency of the monitor. This study investigates at what range of ELF magnetic field levels monitor distortion is apparent on modern computer monitors. It also characterizes the ELF magnetic field strengths and dominant field direction which cause interference and gauges the effectiveness and relative costs of available monitor shields. Click here to see the full article. Power Frequency Magnetic Field Management Using a Combination of Active and Passive Shielding TechnologyA paper recommended and approved by the IEEE Transmission and Distribution Committee of the IEEE Power Engineering Society for presentation at the 1995 IEEE/PES Summer Meeting, July 23-27, 1995, Portland, Oregon. Power frequency magnetic fields are difficult and expensive to shield, particularly when the fields originate from sources with complicated field patterns. A method is discussed and test data presented which suggest that carefully combining active and passive shielding techniques can produce results which are importantly superior to either technique when used alone. The results are generally consistent with an analysis which considers sources as a superposition of elementary source fields with different order terms. Click here to see the full article. Optimum Reduction of Power Frequency Magnetic Fields From Transformer VaultsA poster presented at the Eighteenth Annual Meeting of the Bioelectromagnetics Society at Victoria, B.C., Canada, June 1996. Increasing sensitivity of computer monitors and other electronic equipment to ELF magnetic fields at low levels (5 to 7 mG) has created interest in reducing magnetic fields from sources such as building transformer vaults to significantly lower values than is typical with conventional field mitigation schemes. The objective of this study was to characterize magnetic fields produced by single- and three-phase transformers and their phase conductors, and to develop, test and implement the effectiveness of various techniques to reduce field strengths into the 3 to 5 mG range. Test results demonstrated that field reductions of fifty percent or more can be achieved by the reconfiguration and/or relocation of the transformers, transformer leads and bus bars, but in most cases, reduction of maximum fields to the range of 3 to 5 mG or less requires shielding, either alone or in addition to reconfiguration options. Click here to see the full article. Management of Power Frequency Magnetic Fields From Electrical ConduitsA poster presented at the U.S. Department of Energy 1995 Annual Review of Research on Biological Effects of Electric and Magnetic Fields from the Generation, Delivery & Use of Electricity Conference at Palm Springs, California, November 1995. Power frequency magnetic fields are, typically, extremely difficult and expensive to shield to values of less than 10 mG, particularly when the fields originate from electrical conduit sources which are inaccessible or have net current conditions. This study evaluates methods substantiated with extensive laboratory test data, which suggests that carefully combining active and passive shielding techniques can produce results which are superior and more cost effective than either technique when used alone, and can achieve levels in the range of 2 to 3 mG. Click here to see the full article. Application of Laboratory-Developed ELF Magnetic Field Shielding Schemes to Commercial Power PanelsA poster presented at the U.S. Department of Energy 1994 Annual Review of Research on Biological Effects of Electric and Magnetic Fields from the Generation, Delivery & Use of Electricity Conference at Albuquerque, New Mexico, November 1994. Industrial three-phase service entrance panels produce high magnetic fields in the 10's or 100's of mG due to load unbalance and the separation of internal bus bars. Such fields are extremely complex, since the bus bars travel asymmetrically in all three axis. The objective of this study was to develop a variety of ELF magnetic field management schemes utilizing passive ferromagnetic and/or conductive shielding materials, active cancellation techniques and combinations of each, to reduce fields from a typical three-phase service panel to an average magnetic field level of 2 to 3 mG. The test data suggests that it is possible to reduce ELF magnetic field levels from commercial service entrance panels to values approaching 2 to 3 mG with the use of sufficiently large planes of multiple layer ferromagnetic and conductive shielding materials. Click here to see the full article. |
SEARCHSearch the entire FMS web site to find exactly the information you want to know:Industry ExperienceHaving performed hundreds of major shielding installations and more than a thousand field surveys, FMS delivers innovation tempered with experience. Just take a look at our list of satisfied clients.Commitment to ExcellenceFMS has been eliminating electromagnetic interference issues in commercial & industrial buildings, medical facilities, and research laboratories for over ten years. Using the latest technology, backed by independent research and development, FMS delivers customized, innovative solutions for the most complex interference problems, worldwide. | |||||
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