As autumn approaches, we know that winter’s cold weather is not far behind. Soon, pipelines and industrial processes will once again be the target of freezing temperatures.
Tip 1: Be Vigilant
Because heat tracing systems typically lie dormant in the summer months, any damage to or issues with heat tracing that occur during that time usually are not discovered until a line freezes in cold weather. This can cause downtime in your plant -- and downtime costs money, which no business can afford, especially in today’s economic conditions. Therefore, effective maintenance of an electric heat tracing system is crucial.
Tip 2: Consider the Whole System
A complete electrical heat tracing system is much more than just the heating cable. It starts with an electrical transformer and power distribution panels; includes electronic control and monitoring systems for proper temperature maintenance; and ends on the pipe with power connections, heating cable, end terminations and thermal insulation. Checking all of these areas is essential to ensure heat is being applied to the pipelines, keeping them from freezing during cold weather.
Tip 3: Take Advantage of Autumn
Late summer and early fall are ideal times to check electric heat tracing systems. The days are mild and long, and any work required on the system is unhampered by freezing temperatures, darkness and urgency. By following a few simple steps now, you can ensure that your electric heat tracing system is fully operational and ready to heat pipes when the winter season hits.
Tip 4: Keep Good Records
Preventive maintenance starts with maintaining detailed system installation drawings, especially of the upstream power supply and maintenance records. This allows you to easily locate the breakers supplying the heat trace and verify completed system tests, original electrical values, operating parameters, etc. This information can be valuable in identifying significant operational performance changes and in determining if the system is operating properly over time.
Tip 5: Inspect Insulation
Because insulation plays a critical role in the overall heat tracing system, check your thermal insulation at least annually. Missing or wet insulation reduces retention of the heat transferred from the heating cable to the pipe and can render electric heat tracing completely ineffective. Visually inspect all lines for missing, damaged or wet insulation, especially at valves or pumps where other maintenance is common. If weatherproof cladding is being used to protect the insulation from the environment, it also must be checked for cracks, splits or open seals. Electric heat trace labels should be installed on any repaired and reinsulated lines or valves.
Tip 6: Look at Components and Connections
Check your heat tracing components. Damaged or loose components can result in water ingress, corrosion or the loosening of electrical connections. Check the components against installation documentation to confirm that installation is correct. Ensure all component locations are marked with the electrical connection labels supplied with the kit.
Tip 7: Test Insulation Resistance
Perform an insulation resistance test on all heat tracing circuits. An insulation resistance (IR) test allows you to verify the integrity of the heating cable and components. Perform the test on each heat tracing circuit as detailed in the product installation and maintenance manuals. Confirm that the values are consistent with product specifications.
Tip 8: Inspect the Distribution System
Inspect the conduit distribution system for openings in the conduit and damaged or missing components and low-point drains. Energize each circuit via a centralized control system or by increasing the thermostat setpoint to make sure the electric heat trace system does not trip any ground fault breakers or control devices. Test all ground-fault breakers or controllers according to the manufacturer’s instructions.
Tip 9: Don't Forget the Thermostat or Control System
Once all your circuits are checked and in order, check your thermostat or control system. They allow you to optimize your energy usage while keeping your process running at temperature. Some manufacturers’ systems allow a “power-cycle” feature to be programmed so that the heat tracing system is periodically energized and tested. If a fault is present, an alarm is indicated. Using this feature is one effective way to automatically test your heat tracing system. Also review settings and alarms to ensure that they are set properly, and perform all basic maintenance procedures as found in the product operation and maintenance manuals.
Tip 10: Stock Spare Components
Don’t wait until you get the call at midnight in the middle of December to find out that your pipes are frozen. Now is the time to check your heat tracing for the winter, help protect your product and guard against freeze-ups. However, if after completing all your checks, you should still have a failure of your electric heat tracing system, stocking spare components and cable will allow for timely repairs or replacements. All installation and maintenance manuals can direct you in the repair or replacement of heat tracing system components.
This article originally was published with the title "10 Tips: Get Ready for Winter" in the September 2009 issue of Process Heating.