What is a Heat Tracing? Why and how it is used?

 What is a heat tracing system?

A heat tracing system is system used to increase or maintain the temperature of pipe/flowline or vessel in a process industry. The system primarily comprises  an electrical setup employed to uphold or elevate the temperature of pipes and vessels. Electric heating is accomplished by deploying a resistive element positioned adjacent to the piping or vessel. Modern heat trace technology employs a self-regulating polymer to govern the element's wattage. As ambient temperature decreases, the polymer forms conductive pathways, facilitating the flow of current and generating heat. Conversely, with rising ambient temperatures, the conductive pathways start to disengage, reducing the passage of current.

Components of a Heat Tracing System

1. Heat Thermostat / Temperature Regulator
2. Heat Tracing Cable
3. End Terminator

Types of Heat Tracing Cable

There are three types of heat tracing cables available: 

1. Constant Power Cable
2. Constant Wattage Cable 
3. Self-regulating Cable

Each type of trace heating cable works differently, and the choice of cable is influenced by the intended application.

Installation Precautions

Suitability Check: 

Check for the suitability of the heat tracing system. Make sure the heat tracing system is applicable for hazardous area applications in case of its installation in a hazardous area. For non-hazardous applications it is okay. 

PPE Check: 

The person responsible for installation must be suitably qualified and well-equipped with relevant tools and gadgets. Job performer must have proper PPE personal protective equipment and duly calibrated gadgets (the digital multimeter for example). 

Visual Inspection Check: 

Carry out a visual inspection of the insulating cable for any damage. This damage can be incurred during transportation or placement in the warehouse. Replace the cable if necessary. 

Conduct meggering of the cable as per the OEM manual to qualify the health of the cable. Select the time duration and voltage level for the DC meggering test of the cable as prescribed in the manual. For example, it can be 500VDC for 10 seconds. Record the cable test result in the cable test report. 

Manufacturer 

Please note that I am only mentioning the manufacturer with whom I have working experience. I have seen the heat tracing on process pipings in upstream oil and gas processing facilities on various service lines. The instrument team was responsible for ensuring the functionality of these heat tracing units which included periodic inspection on quarterly frequency per year. Inspection of cladding/heat tracing insulation was generally carried out during this preventive maintenance. However, the corrective maintenance work orders were also raised by the production process team based on process condition parameters. 

The renowned brand is Thermon electric heat tracing system.