BSRIA undertakes electro magnetic field (EMF) surveys to investigate the levels of magnetic fields due to 50 Hz mains supply within buildings and compare the results with international standards for human exposure. Once the location and strength of the field is known, any necessary remedial measures can be advised.
The generation, transmission, and use of electric energy is associated with the production of weak EMF which oscillate 50 times per second (mains frequency). These fields are a fact of daily life: they are emitted by power lines, transformers, service cables, and electrical panels as well as by office equipment and home appliances. Electricity has been used for 100 years with no adverse effect (other than occasional thermal injury and electrocution)! However, in recent years we have become more aware of magnetic fields, principally through their effects on “Cathode Ray Tube” computer monitors. With the advent of Flat Screens, this is no longer the case, but the magnetic fields still remain.
Limits are set to protect our health. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) sets standards to limit overexposure to electromagnetic field levels in our environment. This non-governmental organization, formally recognized by WHO, evaluates scientific results from all over the world. Based on an in-depth review of the literature, ICNIRP produces guidelines recommending limits on exposure. These guidelines are reviewed periodically and updated if necessary.
The table to the right is from ICNIRP, EMF guidelines 1998. These guidelines were revised in 2010 but the EU Recommendation still uses the numbers from 1998.
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