Thermal Growth
Machines may experience positional change from the time it is off-line to when it is running under normal operating conditions. Some of these changes are due to process forces( fluid pressures, airflow, etc.) and some may be cause by a change in the temperature of a machine. This is called thermal growth. These changes differ depending on the material used. The change can be minute or significant, depending on the temperature, size and make-up of the machine.