Safety, Efficiency, and Outage Prevention: A Case Study in Power Plant Thermography

For conscientious and proactive power station project managers across the country, and even the world, the responsibility to manage the resources and facilities entrusted to their care requires a continual evolution of the tools used. One such project manager, managing a natural gas-fired power station generating over 500 megawatts and commissioned in the early 2000s, is a real-world example of the shape this evolution may take.

Why Visual Assessments Are Often Inconclusive

What initial indicators might first draw attention to the need for a new approach? Perhaps a project manager notices a significant uptick in requests for insulation blankets in specific areas of the plant. Or one of the foremen might describe multiple expansion joints and various repairs that may not be performing to standard.

Another possibility is that the careful observation of the combined-cycle turbines, heat recovery steam generators, and steam turbines during a facility walkthrough may lead an experienced eye to find reasons for further investigation. The project manager may see some signs of wear to certain expansion joints and flanges, for example. Still, it can be difficult to be absolutely certain of their significance when looking from the ground, 15, 40, or even 85 feet away.

For less discerning managers, addressing these concerns might lead to poorly prioritized, unnecessary, and costly repairs. For others, the lack of obvious damage might lead to a hand wave and a comment about “not fixing what ain’t broken.” But those who are determined to use their resources wisely to keep their plant functioning at its best will consistently use the best tools for evaluating needed repairs. What is the most prudent approach in these circumstances?

This scenario was faced by the US power station project manager in our example in 2024. The question of how to best prioritize repairs, retrofits, and other modifications rose to the surface as the facility began to display some possible—but initially inconclusive—signs of weakness, metal fatigue, insulation evacuation, direct metal conductivity, and even improper repair and installation work.

In this instance, the project manager did their homework and found that one of the most effective ways to identify and initiate potential repairs was by engaging professional thermography services.

Using Thermography to Gain an Edge

Among the many benefits of thermography is that testing is completely nondestructive and noninvasive. A certified thermographer can accurately scan a structure, such as a functioning power plant, with little-to-no disruption to operations  and locate hot spots that indicate potential failure points.

In our example, the client learned infrared scanning could pinpoint the temperature of any part of the scanned structure to within a two percent accuracy, conforming to the strictest industry standards. Given that the steel structures in question are in peril of increasing performance degradation and even failure when operated at extremely high temperatures, SVI Dynamics was able to make recommendations for appropriate operational temperatures. Using the principles of the Stefan-Boltzmann relationship, wherein the measurable radiant temperature can be used to extrapolate the actual temperature of the material in question, our thermography experts were able to highlight excessive temperatures that indicated everything from inefficient operation to dangerous potential failure points.

our thermography experts were able to highlight excessive temperatures that indicated everything from inefficient operation to dangerous potential failure points.

Steel gives way to lower tensile and shear strength when exposed to temperatures well above design specifications. As such, the project manager in this example was advised that

• Apparent temperatures above 500ºF required immediate attention from a skilled structural engineering representative.
• Apparent temperatures between 300ºF and 500ºF needed regular monitoring and could eventually require further action.
• Apparent temperatures below 300ºF were within operational specifications and did not require further action at the time of scanning.

These guidelines allowed the project manager to accurately judge the immediacy of the repairs needed.

How the Thermography Process Works

The thermography process was done over two days. It began with an evaluation of exhaust duct surface emissivity and reflectivity.  The procedure, then, involved taking accurate distance measurements, defining the areas to be scanned, and accounting for ambient outdoor temperatures, wind conditions, and humidity. A trained and experienced thermographer then carefully photographed all the relevant areas with a FLIR E85, an advanced thermal imaging system. After all the relevant areas were scanned, the service included careful post-processing to accurately show distinct hot spots and record the temperatures of these areas. (Note: Images are never manipulated except to make temperature contrasts evident and to place markers to highlight specific areas of concern.)

Finally, the project manager was provided with a complete report of findings including reference and thermal images sorted by area and risk level. Each turbine, heat recovery steam generator, and associated area was shown separately, first with areas with temperature readings over 500ºF and then with those between 300ºF and 500ºF. Accompanying the thermal and reference images were notations corresponding to markers that showed particularly significant findings. The project manager was now equipped with thorough, accurate information about where to focus effort on maintenance and repairs.

The project manager was now equipped with thorough, accurate information about where to focus effort on maintenance and repairs.

Making Better Decisions with Thermographic Data

In each of the turbines at the facility, the diffuser duct expansion joints and flanges were of significant and immediate concern as they appeared to be experiencing corrosion that resulted in thermal readings well over 500ºF, risking increasing damage to adjacent parts of the system and creating safety risks for personnel who work in these areas.

Additionally, the temperatures of these parts helped indicate which one needed to be repaired first. While both turbines were in need of repair, one had temperature readings 150º higher and radiating further from the expansion joint; it was readily apparent that this unit needed more immediate attention. Moreover, structures that had unusually high temperature readings located near catwalks and ladders used by personnel posed particular areas of danger; this was another easily prioritized repair.

How Thermography Can Help Your Power Plant

This example is not an outlier; it is the reality for power plants around the world. How can your team operate your station in a way that is responsible, efficient, safe, and reliable for the communities they serve? You must be armed with the information to properly judge what maintenance and repairs need to take precedence while keeping as much of the station online as possible.

Thermography is an unparalleled tool in its ability to provide that information to power station managers. If you are in need of advanced thermal imaging to proactively identify and address structural degradation before it becomes an issue, don’t delay—reach out to us today.