Physikalisch-Technische Bundesanstalt

In the field of electrical explosion protection devices and systems for measuring, control and automation, which need only small electrical values, can be protected by "Intrinsic Safety". This means that with sufficient safety a spark occurring in the normal operation or in the event of faults is limited in its energy in such a way that it cannot become an ignition source. For the experimental ignition testing of intrinsically safe electrical circuits as well as for basic research studies a spark test apparatus developed in Germany under co-operation of the PTB (see above) is used, which found world-wide acknowledgement and was later adopteded in IEC and European standards.

Also thermal ignition sources (e.g. hot surfaces) are to be considered in normal operation as well as under fault conditions.