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IR Imaging for Checking Tank Levels
Tip written by: Infraspection Institute

For many facilities, obtaining accurate product level information for tanks and silos is critical for effective inventory management and safety. Under the right conditions, a thermal imager can quickly indicate product levels and serve as a cross reference for calibrating level indicators.

When product is stored in a vessel, the density of the product is usually greater than the head space of air or gas above the stored product. For stored products that generate heat, levels may be observed by imaging the vessel’s exterior and noting the temperature gradient between head space and product.

For stored products that do not generate heat, it is possible to rely on solar loading to create a temperature differential. Under solar loading conditions, vessels will usually exhibit cooler temperatures above the product level during the early to mid-morning hours. As the day progresses, the head space will exceed product temperature and show as a warm area above the product. This thermal pattern may remain for up to several hours after sunset and reverses once the head space cools to below stored product temperature.

In general, this application works best for un-insulated, single-wall vessels having a high emittance. For vessels with a low emittance, it may be possible to modify the surface with a stripe of high emittance paint. This application also works best on storage vessels where product level is not subject to rapid changes.

Thermal imaging of storage tanks and silos is one of the many applications covered in the Level I Certified Infrared Thermographer® training course. For more information on open enrollment classes or our convenient, web-based Distance Learning program, call 609-239-4788 or visit us online at: www.infraspection.com.