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This article explains the accuracy of and calibration methods for a variety of low-cost EMF measuring instruments used for performing electromagnetic field (EMF) or electro-magnetic radiation EMR and radio frequency (RF) field strength measurements to measure RF EMF exposure levels in gauss or milligauss or at other appropriate yardsticks of field strength. We discusses sources of RF and EMF fields, and RF/EMF measurement error and variation in electromagnetic field strength measurements and we review and make suggestions for using several low-cost RF or EMF measurement devices to determine the instantaneous electromagnetic field or radio frequency field strength exposure. Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman. Evaluation of and Advice for Using Some Low-Cost Electromagnetic Field Measurement (EMF) Instruments for Consumer Use Because RF and EMF measurement tools need to be properly chosen to measure the particular type and frequency of RF or EMF signal that is of interest, be sure to also see EMF RF FIELD & FREQUENCY DEFINITIONS for a simple explanation of different types of radio frequency (RF) and electromagnetic frequency (EMF) types and where they are found. Specific ELF measurement tools (power lines, electrical wiring, appliances) are described and their sources listed at Electromagnetic Field EMF Measurement Instruments. Specific RF measurement tools (radio, TV, cell tower, microwaves) are described and their sources listed at Radio Frequency RF Detection Meters. See ENVIRO-SCARE, EMF & Property Values if you don't know what EMF, ELF, or electromagnetic fields are or if you want a summary of the possible health effects of EMF exposure and the more likely effect on the property value of homes located very close to power transmission lines. Readers who intend to make their own EMF measurements should be sure to also see EMF MEASUREMENT WORKSHEET and also WORKSHEET for EMF MEASUREMENTS - Example. Also see Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues which discusses the impact of EMF and other environmental concerns on property values. And see EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE which discusses EMF exposure in the workplace. Small absolute health risk from EMF: Most researchers indicate that where a risk is present, the absolute risk level from EMF is likely to be small, and less than other less obscure hazards. (Automobile accidents, trip and fall, fire, and shock hazards, smoking and other health risks.) Consumers should not let focus on a specific emotionally-charged hazard distract them from these other more mundane but more dangerous concerns. For added confidence in our measurement results, we use two independent measurement instruments - a Safeco™ analog meter and a Walker Scientific™ digital meter. Both instruments measure magnetic fields which may be generated from power lines, transformers, household wiring, computers, TV's, and other electric devices. Measurements made by these devices should be considered as a general screening procedure designed to discover the possible presence of magnetic fields in and around the building or site. Such measurements are not exhaustive. Before making decisions involving any significant expense we recommend that additional instrumentation and expertise be considered. The Walker™ digital meter provides a direct readout of field strengths in gauss or milligauss. The Safeco™ analog meter permits visual observation of field orientation and strength, but requires mathematical computations to develop a final field strength number. Our staff are not experts in electromagnetic fields. As the first and currently the only home inspection professional firm to offer this service in our area we have relied on the quality of instrumentation, information and consulting provided by the manufacturer, and field experience at a range of buildings and environments. Specific ELF measurement tools (power lines, electrical wiring, appliances) are described and their sources listed at Electromagnetic Field EMF Measurement Instruments. Specific RF measurement tools (radio, TV, cell tower, microwaves) are described and their sources listed at Radio Frequency RF Detection Meters.Accuracy and Calibration of Electromagnetic Field Measurement InstrumentsQuite a few electromagnetic field strength metering devices are available to the public, and they're not costly. A typical price for a decent EMF measuring device is less than $200. with some instruments selling at twice that price. Because some people offering to perform EMF measurement services are not careful about procedure, do not offer sound scientific advice, and may not themselves understand how to examine a property effectively, some consumers may be better off buying their own EMF meter or gaussmeter and using the procedures we describe here. See Definitions of Gauss vs Milligauss for details about gauss and milligauss and definitions of these terms Please do not contact us with a request buy EMF or RF measuring equipment. We do not sell anything. To do so would be a conflict of interest for this website. These devices are readily available from many electrical equipment and home inspection equipment suppliers. Field Calibration of EMF Electromagnetic Field Strength Measurement InstrumentsOur standard measurement procedure includes confirming normal instrument operation by measuring a known common field source - the electric meter at each property as well as at a baseline meter. We measure at 1' and 2' distances from the electric meter, typically finding a field strength between 2 and 7 milligauss in those areas. Calibration of EMF Measurement Instruments With Electric Power Company Instruments for Measuring Electromagnetic Field Strengthwe have compared our test measurements of specific sites with those obtained by local electric utility company representatives and have found our measurements and theirs to be in close agreement. [Measurements made at the same electric meter at the same distances produced results within 7% of one another. Most power utility companies use equipment which is more sophisticated (and costly) than our own and their personnel may have additional training. See AHS Report #I9189105] Instead of contacting us with a request to perform EMF Electromagnetic or RF Radio Frequency Field Strength measurements, in most cases it is more economical and convenient for a property owner to purchase their own instrument, making measurements under varying conditions. In this series of articles we describe how to make measurements using a consistent approach and using good documentation. See Recommended EMF Measurement Procedure for details of how to collect EMF measurement data. Following good procedure and using instruments properly are two steps towards making accurate, repeatable EMF measurements. But because the signal transmission for RF sources such as radio, TV, or cell towers, the load on a power transmission line is not under control of an individual property owner, and because the EMF strength varies as the power transmission line load varies, it is important to have an idea of that condition as well when attempting to characterize EMF exposure at a specific location. In contrast, EMF measurements are quite accurate and repeatable at other EMF sources such as close to electrical appliances and service entry cables. Please do not contact us with a request buy EMF or RF measuring equipment. We do not sell anything. To do so would be a conflict of interest for this website. These devices are readily available from many electrical equipment and home inspection equipment suppliers. See Evaluation of Low-Cost EMF Instruments This article describes several low-cost and reasonably accurate EMF measurement devices that are readily available. See Radio Frequency RF Detection Meters This article describes several low-cost and accurate radio frequency or RF detection and measurement devices suitable for radio, TV, cellphone, microwave, and similar signals. Frequently Asked Questions (FAQs)... Ask a Question or Search InspectApediaUse the search box below to ask a question or to search the InspectApedia.com website. Ask a Question or Enter Search Terms in the InspectApedia search box just below. Technical Reviewers & ReferencesRelated Topics, found near the top of this page suggest articles closely related to this one.
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