Cool Down Testing

 

What is Cool Down Testing?

Cool Down Testing is an alternative to on-line Acoustic Emission (AE) testing for hot reactors, towers, columns and associated hot circuit piping systems. Cool down tests always generate high loading in the longitudinal direction of a pipe or vessel. This presents an ideal scenario for detecting hoop-oriented defects. Loading in the hoop direction can be achieved if there is a sufficient thermal gradient through the wall thickness of the vessel or pipe. Thin-walled vessels cannot maintain a thermal gradient through the wall thickness. They should not be considered as candidates for the Cool Down test if longitudinally-oriented defects are suspected. In this case, an on-line overpressure test is recommended.

 

Maximized Cool Down Tests

A 10% over pressurization or MONPAC test can also be conducted just before the Cool Down test is performed. Different types of flaws that would be inactive during a Cool Down now become evident. The over pressurization is done while the hot vessel is on-line.