All pipes and vessels experience heat loss and when subjected to low ambient temperatures this heat loss can cause the contents to crystallise and freeze. This can cause the pipe or vessel to burst. To minimise the effects of heat loss trace heating is used in conjunction with thermal insulation to supply a heat source to replace this heat loss and therefore maintain the pipe temperature. Typically, an air sensing thermostat is used to sense the ambient air temperature and energise the trace heating between 3 to 5°C.