A holiday, also known as jeep, in the context of pipe defects can be defined as an area on the pipe surface that hasn't received adequate anti-corrosive coating compared to the remaining part of the pipe. It could be an insufficient amount of film thickness, a crack or pinhole in the coating or improper bonding of the coating with the pipe material. Anti-corrosive coating is provided on pipes subject to corrosive environment in order to prevent them from corroding.
The holiday can become the start of corrosive damage that if not detected can cause pipe failure.
Trenchlesspedia Explains Holiday
A holiday can be caused by human error and also during application of the anti-corrosive coating. Flaws in the finished coating is a cause of premature corrosion. Holiday detectors can be used to detect flaws that are sometimes invisible to the naked eye. Holiday test is a non-destructive testing (NDT) method that can detect pinholes, voids and discontinuities. The test requires creating an electric circuit and checking if the current flows to complete the circuit. There are different types of holiday tests namely, high voltage holiday detection, continuous DC holiday detection and pulsed DC holiday detection.