Lipoatrophia Semicircularis: risk assessment and solutions

The increasing occurrence of the condition known as Lipoatrophia Semicircularis, generally but not exclusively in office workers, has highlighted the need to reduce exposures to electromagnetic fields in workplaces.

Contact Radiansa Consulting for a professional risk assessment in your workplace, or investigation and remedy of electric field anomalies that have given rise to existing cases of Lipoatrophia Semicircular (L.S.).

A study of electric field levels in workposts in your office easily reveals whether your staff are at risk or contracting the condition. Once the problem has been diagnosed, it is very often a simple and inexpensive matter to remedy the situation.

The cause of Lipoatrophia Semicircularis

While the biological mechanisms responsible for the appearance of the lesions associated with L.S. are still not clearly understood, the environmental factors that cause the condition are known to be multifactorial, and involve the interaction of electrostatic charges generated on the worker's body through normal actions and movements, with low frequency electric fields generated in the office furniture, generally the desk, due to inductive coupling with with voltage sources such as power cables, unearthed equipment, etc.

Every case of L.S. is associated with an anomalously high electric field in the work post, generally at the edge of the desk. Modern desk surfaces are made with a synthetic resin, and have a small but measurable surface conductivity which acts to reduce the accumulation of static charges on the desk surface. However, this small surface conductivity is sufficient for the desktop to generate an maintain a weak electric field due to coupling with nearby voltage sources. In many cases, the potential is generated in the metallic support structure of the table, due to coupling with nearby power cables, which in turn generates an electric potential in the synthetic desktop. In other cases, a potential may be induced directly in the desktop due to an unearthed electric device, such as PC, positioned on the desk surface.

This latter case is illustrated in the graphic below; an unearthed PC operated at 230V will have a 115V AC potential on the metal case. This potential generates a weak and otherwise harmless electric field on the surface of the desk, but the electric field strength on an object increases with its radius of curvature, and thus relatively large fields (hundreds of volts per meter) can be generated at the edge of the desk, as illustrated in the graphic.

Computer simulation of electric field anomaly at the edge of the desk, in this case caused by an ungrounded PC placed on top of the desk (finite element analysis software provided by Field Precision.)

In many workplaces, the action that generates the largest static potential on the body is the action of raising oneself from the chair. This simple action can generate static charges in the chair and body in the region of 20,000V in quite unexceptional circumstances; such a static potential can be considered as quite normal. In workplaces with low relative humidity and with high resistivity flooring, this potential can reach even higher values. The charges thus produced interact with the AC electric field induced in the desktop, creating an extremely high localized electric field at the point of closest approach to the desk - generally at a high of 72 cm (standard desk height) on the thighs.

Note that the generation of static charges is a normal process, and while it may be desirable to reduce the generation of static electricity for other reasons such as comfort, by far the most effective way to eliminate the cause of L.S. is to reduce electric field anomaly, which is generally a simply and inexpensive process. Of course, it is generally desirable to reduce excessive amounts of static charge generation in workposts for a variety of reason, and especially in the work posts of recovering L.S. cases.

Please feel free to contact us with your inquiry.

Related information: Electromagnetic risk assessment

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