HEAT TRACING SYSTEMS

The term heat-tracing refers to the continuous or intermittent application of heat on the piping, equipment, and instrumentation where fluid (water or other product) in fact can be exposed to low temperature/freezing conditions. Whenever the contents of a pipe or vessel are maintained at temperatures exceeding the ambient temperature, therefore will be a flow of heat from the product to the external air. Therefore, Insulation will slow the heat loss but will not prevent it. Heat tracing is a method to provide the supplemental heat just enough to compensate for the heat loss due to lower ambient temperature.
The general intent of heat tracing is either tracing for winterization and/or tracing for process maintenance. Winterization tracing is designed to protect the product from freezing and is typically designed to operate when the ambient temperature falls below a certain level; commonly 40°F to 50°F. Heat tracing for process maintenance is commonly used where higher temperatures must be maintained for the purpose of reducing product viscosity and/or preventing wax or hydrates from forming in the product. The design is more complex compared to freeze protection in a way that additional heater circuits and more specialized controls may be needed.
Sometimes, heat tracing is used for raising the temperature of a product following short shutdown periods, but this is not the primary objective.