Heat Trace with Plastic Pipes
Heat cable can be used on plastic pipes but the plastic’s durability and thermal properties must be considered. Plastic has approximately 125 times the thermal resistance than steel but is also more susceptible to damage from direct high temperatures. The key to heating plastic pipes is to use a lower temperature and distribute it as evenly as possible.
It is always a good idea to use a heat trace system with an automatic thermostat and control, but especially so when using heat trace on plastic pipe. An automatic heat trace control can monitor and maintain the system’s temperature, alarm for problems, and shut off the heat cable to prevent damage.
There is heat cable designed specifically for plastic pipes that is self-regulating and has limited wattage. Self-regulating heat cables have a conductive core between two bus wires that becomes more conductive when cold. This system increases the power to the cold spots and decreases it to the warmer areas, which provides a more even heat source.
The manufacture of the plastic pipe should be able to provide information as to the maximum temperature and how close heat cable can be spaced or wrapped on the pipe to avoid damage. Some applications may require heat cable to be applied to opposite sides of the pipe at a lower temperature to distribute the heat more evenly, avoiding one direct area of concentrates heat which may damage the pipe.
It is recommended to install a foil material between the pipe and the heat cable to avoid direct contact and help provide a more even heating. If doing this place the heat trace control thermostat directly onto the pipe with no foil over it or between it and the pipe to ensure a more accurate reading.
You can use heat cable on plastic pipes as long as you follow precautions, such as determining your pipe’s thermal capacities, selecting a self-regulating, low wattage heat cable and using an automatic heat trace control with safety functions. Following these guidelines will help prevent damage and increase the life of your heat trace system.