HOW CAN ELECTROMAGNETIC FIELDS FROM VDUS BE MEASURED?
Exposure to VDU fields can be reduced by either shielding the source of the fields or reorganising the workplace to reduce avoidable exposures. Shielding Most VDUs are shielded by the manufacturer to reduce electromagnetic emissions that may affect electronic components. A magnetic field is more difficult to shield. The special metals needed are expensive and must be thick enough to be effective. Therefore, magnetic fields are seldom shielded. Electrostatic and VLF electric fields at the front of the VDU screen can be reduced by transparent conductive mesh filter placed over the screen but these are not necessary since the electric field at the operator’s position is very low. Reducing or avoiding exposure High levels of electric field may occur at the side of a VDU near the fly-back transformer, though the field is negligible at the operator’s position. Furthermore, the field strength decreases rapidly with distance from the terminal. It is advisable, therefore, to organise VDU equipm
