machtafstand

machtafstand is a term used in Dutch occupational safety and engineering that refers to the maximum permissible distance between a machine or other source of hazardous energy and a person or other asset that must be protected. It is most often applied to high voltage electrical equipment, rotating machinery, and sources of ionising radiation.

The concept is analogous to the “maximum safe operating distance” found in international standards such as ISO 12100 for machine safety and IEC 60204 for electrical equipment. An engineer will calculate a machtafstand by analysing the energy level of the hazard, the mode of release and the environment in which the equipment operates. For electrical equipment the value is influenced by the voltage, current, fault level and the type of insulation. For mechanical hazards, the calculation takes into account the speed and mass of moving parts and the likelihood of contact. Radiation sources use dose rate relationships to determine the safe distance at which the natural background exposure is not exceeded.

In practice, a machtafstand is used to design safe barriers, to select protective gear, and to write safety procedures. It helps to fulfil legal obligations under Dutch law and the European Union’s Machinery Directive, providing a clear numeric boundary within which operation or maintenance can be considered safe. Because the value depends on many variables, it is normally documented together with the hazard assessment for each specific installation.