|
|
|
Electromagnetic Fields > Static / Low Frequency Fields
|
|
Static / Low Frequency Fields
|
| |
|
Basic Principles
|
|
|
In industry, traffic, research and medicine as well as in every household we find electrical machines and appliances. Most of them use electric energy with a voltage of 230 or 400 Volt (V) and a frequency of 50 Hz. The power frequency falls within the low frequency range of the electromagnetic spectrum. The wires where the electric current circulates are always surrounded by low frequency electric and magnetic fields.
more...
|
|
|
|
Occurrence in Everyday Life
|
|
In everyday life we are exposed to static as well as to low frequency electric and magnetic fields in various forms. Sources of static fields are e.g. direct current systems, electrified traffic systems operated with direct current (e.g. tramway) as well as devices for daily use as, e.g., loudspeakers and electric blankets. The terrestrial magnetic field is a natural magnetic field with a magnetic flux density of approximately 40 microtesla (µT). The range of low frequency fields comprises time varying electric and magnetic fields with frequencies between 1 Hz and 100 kHz. Exposure of the population in everyday life mainly results from electric and magnetic fields of the electrical power supply at 50 Hz and of electrified traffic systems as e.g. the railway at 16,7 Hz. Home appliances and electric installation also generate low frequency electric and magnetic fields.
more...
|
|
|
Other Applications
|
|
|
Apart from the obvious sources of electric and magnetic fields in everyday life, there are some other very special applications available, which cause static or low frequency fields in their environments, e.g., electronic article surveillance systems (EAS) or medical applications. The effects of “magnetic remedies” sold without a prescription are scientifically dubious. Wearing small permanent magnets, such as magnetic name tags is, as a rule, not harmful to the health.
more...
|
|
|
|
|
Limit Values and Precautionary Measures
|
|
|
The German Electromagnetic Field Ordinance which is based on the Federal Pollution Control Act (26th BImSchV) entered into force in 1997. This ordinance was enacted to protect the population against possible health effects from electric, magnetic, and electromagnetic fields originating from low frequency and high frequency installations. The standards are based on guidelines by the German Commission on Radiological Protection (SSK) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The recommendations are based on scientifically established adverse health effects caused by exposure to electric, magnetic or electromagnetic fields.
more...
|
|
|
|
Occupational Safety
|
|
|
Contrary to the relatively low acceptable exposure levels of the general public to static and low frequency, electric and magnetic fields rather high levels can occur at certain workplaces. At such workplaces field intensity can even exceed the internationally recommended limits for exposure of the general public. Among others, provisions issued by the Employer´s Liability Insurance Association are applied for the protection of workers against possible health impairment.
more...
|
|
|
WHO Updates Risk Assessment of Low Frequency Fields
|
|
|
In 2002 the International Agency for Research on Cancer (IARC) which is associated with WHO classified low frequency fields as class 2B “possibly carcinogenic”. The crucial factor for this decision were the epidemiological observations of a statistical association of childhood leukaemia and an exposure of the children to magnetic fields in the range of >0.3 – 0.4 µT, averaged over time. Based on an up-to-date risk assessment, WHO issued a Fact Sheet entitled “Electromagnetic fields and public health – exposure to extremely low frequency fields”. Among others, this paper provides recommendations on how to proceed further.
more...
|
|
|
|
|
|
|
