What the Scale Checker measures
High-temperature boiler operation, especially above 1000 degrees F or 500 degrees C, forms brittle iron oxide, or magnetite, on the inner surfaces of tubing. That layer reduces heat transfer, raises the tube-wall operating temperature, and shortens the creep life of the tube.
The Scale Checker is a radioisotope system built around a Cs-137 source that measures scale, sludge, and fouling inside live tubes and pipelines without removing insulation or stopping flow. Early and accurate measurement of the internal oxide scale guides descaling decisions, supports remaining-life estimation on the tubes, and helps recover the heat-transfer efficiency that scale erodes.