Pipe Lining Thickness and Thickness Gages

Abstract

Corrosion and incrustation in carbon steel raw water pipes have been problems at many of TVA's fossil and nuclear power plants. Lining existing carbon steel raw water pipes with cement mortar conforming to AWWA C602 requirements is one way to correct these problems. It is possible to measure the thickness of the cement-mortar lining by drilling a small hole through the lining and after measurement is made, the hole can be filled with cement mortar. A better way is to use an eddy-current thickness gage. The thickness measured is a function of the impedance of the probe-pipe system. Each thickness measurement takes only a few seconds and the results are very accurate and stable.