Measuring electric and magnetic fields

Structural Survey

ISSN: 0263-080X

Article publication date: 4 April 2008


Jayne, M. (2008), "Measuring electric and magnetic fields", Structural Survey, Vol. 26 No. 1.



Emerald Group Publishing Limited

Copyright © 2008, Emerald Group Publishing Limited

Measuring electric and magnetic fields

Article Type: Editorial From: Structural Survey, Volume 26, Issue 1.

Measuring electric and magnetic fields

Knowing how to understand and react to risk is a problem increasingly faced by our modern society. In our personal lives the risks may arise from obesity, alcohol consumption or the latest high-risk activity reported on some news bulletin. In our work we may be more concerned with keeping up with the latest legislation, changes in building regulations or health and safety issues such as the use of Wi-Fi in the home. While these risks may initially present us with the problem of knowing how to react, they may also offer opportunities for the building professional to add value to their services.

SAGE (Stakeholder Advisory Group on Extremely Low Frequency Electric Magnetic Fields) is a working group funded equally by the Department of Health, the electricity industry and Children with Leukaemia. It has been working for the last few years with the remit “to bring together the range of stakeholders to identify and explore the implications for a precautionary approach to ELF EMF and make practical recommendations for precautionary measures … ” There are several definitions of the precautionary principle. The one adopted was from principle 15 of the 1992 Rio Declaration. “In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”

It could be considered that the SAGE assessment dealt more with understanding the scientific uncertainties rather than the certainties of exposure. This is, perhaps, another way of defining lack of scientific certainty. The allegations of health risks relate primarily to the radiation fields. These radiation fields take two forms; electric fields and magnetic fields. Although the primary public concerns have been expressed over high voltage pylons and transmission cables, both fields, magnetic in particular, will also be encountered when using electrical equipment and from internal wiring. Domestic exposure can occur from internal property wiring and electrical appliances; televisions, lighting, electric kettles and so on. This is irrespective of any high voltage cables, which might be in the vicinity. While the SAGE assessment does not review the science it does provide a valuable source of information. It reports that there is an acceptance of a link between childhood exposure to magnetic fields of 0.4 microteslas and above with a doubling in the incidence of childhood leukaemia. Currently there is no accepted causal process, only a statistical link. Some members within the group believe that other adverse health affects may also be associated with exposure and this apparent schism is reported in the two part interim assessment. The first part relates to SAGE deliberations and conclusions; the second comprises a collection of the supporting papers. These, alone, warrant the little time taken to download, but why should building professionals bother? While public concerns relate primarily to high voltage pylons and overhead transmission lines, one of the conclusions of the SAGE assessment is that the electric and magnetic fields existing within some buildings may substantially exceed 0.4 microteslas or fields arising from nearby high voltage apparatus. This could be a result of local electrical equipment, internal wiring or nearby problems with the mains distribution system. As a result, they suggest that measurement of electric and magnetic fields might form part of future residential property surveys. Similar conclusions were also reached by the recent Cross-Party Inquiry chaired by Dr Howard Stoate MP.

And if fields higher than 0.4 microteslas are encountered, what cost effective measure should be advised and, if they are advised, should the advice be part of the residential survey or should that advice be confined to merely reporting the measured field levels? If indeed it is feasible and right for measurement of these fields to be part of a residential survey, then what about non-residential surveys? If it is accepted as good practice, are there other measurements which might be made to better inform purchasing decisions where there is currently lack of full scientific certainty - micro wave activity maybe?. There are those who would say this should not be part of the survey process and they may be right. Conversely it could be argued that this represents an area of opportunity, which if not exploited by the building professional, will be taken up by others. If the building professional does take up this area of work there will almost certainly be a consequent requirement for additional CPD, if only to satisfy professional indemnity insurers. The author is undertaking research in this area and readers' views are welcomed.

The SAGE report can be downloaded at:

Michael JayneNottingham Trent University, Nottingham, UK and member of the Stakeholder Advisory Group on Extremely Low Frequency Electric Magnetic Fields (