This work was commissioned by Bilfinger Industrial Services Finland Oy which is a part of the Bilfinger SE Group.

The objective of this thesis was to take a look at the calibration of measurement devices and to produce instructions about calibrations for educational use at Bilfinger.

The theory part of this thesis includes the principles of calibrations and measurement devices. It also deals with the instrumentation on an explosive hazardous environment, the HART-protocol and the equipment that is used in calibrations.