What to remember about electromagnetic waves.
Electromagnetic fields can, beyond certain thresholds, have effects on human health.
It is therefore important to remember a few concepts in order to assess the risks associated with exposure to electromagnetic fields.
Although not perceptible, electromagnetic fields are present everywhere in the environment.
Any electrical installation creates an electromagnetic field in its vicinity, made up of an electric field and a magnetic field.
Some useful reminders
An electromagnetic field appears whenever electrical charges are in motion. This field results from the combination of 2 waves (one electric, the other magnetic) which propagate at the speed of light.
Any energized conductor produces an electric field in its vicinity and its intensity is measured in volts per meter (V/m). Magnetic fields only appear when an electric current passes through a conductor.
Their intensity is measured in amperes per meter (A/m), but we also speak of magnetic induction which is measured in microteslas (µT).
Some materials, such as those used to make magnets, emit magnetic induction in their environment without the presence of a current.
Example: Presence of the electric field and the magnetic field generated by a lamp (Source INRS)
- Lamp off connected to the power outlet: presence of an electric field alone
- Lamp on: presence of an electric field and a magnetic field
Static magnetic fields are linked to the presence of permanent magnets, electromagnets supplied with direct current
or more generally
direct current sources.
Electric, magnetic and electromagnetic fields are part of the so-called non-ionizing radiation.
They are not energetic enough to eject an electron from an atom or molecule (as opposed to ionizing radiation).
Electromagnetic spectrum and emissions from some electrical equipment (source INRS)
Electromagnetic fields can have health consequences.
Their short-term effects can be:
• direct: heating of biological tissues, stimulation of the nervous system, etc.
• indirect: fire or explosion due to a spark or an electric arc, malfunction electronic devices including active medical devices such as pacemakers, projection of metallic objects…
Sensory effects (such as dizziness, nausea, visual disturbances) can be felt at very low frequencies. These effects can have more or less significant consequences depending on each person.
To date, there is no scientific consensus concerning medium or long-term effects due to low but regular exposure to waves. electromagnetic.
Prevention of risks of exposure to electromagnetic fields
At the professional level, the reduction of risks related to exposure to electromagnetic fields is based,
as for any other risk, on the general principles of prevention provided for by the Article L. 4121-2 of the Labor Code.
In addition to these general principles, the Labor Code provides for a system of limitation of exposure levels .
The principle of risk assessment is to compare the exposure of employees to the Exposure Limit Values (ELV)
and to the Action Values (AL) defined by these regulations.
If one of them is likely to be exceeded, prevention measures should be determined and put in place
(reduction to source, collective protection, reduction of exposure by distance, individual protection).
Information, training and individual monitoring of the state of health of employees complete these measures. See regulation tab (source INRS)