High-temperature corrosion protection coatings are developed to meet the harsh environmental conditions common to pipelines and the demanding requirements of corrosion engineers. High-performance coatings offer protection for steel surfaces in conditions nearing 1,200 degrees Fahrenheit. These coatings are ideal for hot piping, stack exteriors, furnaces, exhaust pipes, mufflers, and other substrates operating at high temperatures.
Various high-temperature pipeline-coating technologies include, but are not limited to, fusion-bonded epoxies, liquid epoxies, and field-applied tapes. This article will define the important characteristics of high temp coatings and their applications.
We have a companion blog to this piece discussing the steps and preparation required to ensure that high temp coatings are up to the very demanding task set before them. You can subscribe to our mailing list to ensure you're notified of its release.
High-Temperature Coating Applications
High-temperature coatings are used in both above-ground and below-ground applications and on irregular surfaces. Types of pipeline applications include:
- Power plant Steam line
- High-pressure natural gas lines
- Shipbuilding
- Oil refineries
- Industrial manufacturing facilities
- High-pressure airlines
- Steel mills
Different application types come with different requirements. To these requirements, not all high-temperature coatings are made equal. There are different strengths and weaknesses to each that may impact your decision on which type of coating to use.
Related Article: Pipe Color Coding Standards
The Different Types of High-Temperature Coatings
High-temperature epoxies are typically two-part, 100% solids coatings intended to provide corrosion protection to pipelines with service temperatures up to, and in some cases exceeding, 300 degrees Fahrenheit. Many of these products are used as standalone coatings in above or below applications or as primers beneath high-temperature tape coating systems.
When epoxies are applied in above-grade applications, oxidation in the form of chalking may occur. However, long-term corrosion protection is expected when the epoxy coating is applied at the manufacturer's recommended mil thickness.
High-temperature tapes are generally comprised of butyl adhesives or petrolatum wax-based coating systems. Like epoxies, high-temperature tapes are intended to provide corrosion protection to pipelines with service temperatures up to 300 degrees Fahrenheit. These tapes perform well in above and below-grade applications and in various soil conditions. The incorporation of mesh backings on high-temperature tapes allows the coating to conform well to pipe surfaces but does not stretch or elongate as some of the other backings; this aspect is advantageous in environments where exceptional strength against soil stress is needed.
A minimum of 50% overlap is required to achieve the desired long-term performance on high-temperature pipelines. These tapes require the use of a primer before application.
For example, Tapecoat Omniprime is required in service conditions up to 180° F when working on a straight-line pipe application. Apply Tapecoat TC 7000 Epoxy as a primer when temperatures exceed 180°F. For irregular surfaces, consider using a petrolatum tape such as Tapecoat Envirotape and Enviroprime in conditions with service temperatures up to 250°F.
Related Article: How Tape Failure Impacts Pipeline Service Life
Certain conditions require coatings that can withstand extreme heat. We just published a case study about a pipeline repair and a tape recoat in Saudi Arabia that required the tape to withstand average temperatures of 176 °F. Most brands of corrosion-protecting tape fail at these temperatures. That's why it's essential to pick a product designed to target a project's conditions, but this is no easy task. That's where we come in! The next time you need a protective coating--high temperature or otherwise--reach out! Our specialists are happy to assist in finding a proven product that'll yield the greatest results for your unique needs. Contact us anytime to get started!
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