Low voltage leak detection is NOW available at National
Often referred to as the “dry test”. This method of flat roof electronic leak detection is ideal for use on any flat or low pitched roof to identify defects in exposed membrane systems allowing for a quicker testing schedule identifying defects such as pinholes and punctures. The Holiday test can also be used for retaining wall waterproofing membranes.
**This test can only be performed in dry conditions**
The detector delivers, via a phosphor-bronze brush, a stabilised D.C. output voltage across the non-conductive waterproofing membrane under test. Detection of defects is by an audible tone and a visual spark from the search electrode (brush)
(Corrosionpedia explains Holiday Testing)
Holiday testing is a non-destructive test carried out on a coating, such as rubberized waterproofing coating on concrete, where holes through the coating are detected by the formation of an electrical circuit in areas where there is insufficient coating to resist the electrical charge. If an electrical flow is detected, then the test area is termed as conductive, indicating the presence of discontinuities such as pinholes and voids. This test is commonly used in the offshore industries where piping and structures are coated with non-conductive coatings.
A holiday detector is an electrical device used to determine the location of a gap or void in the anticorrosion coating of a metal surface. There are various techniques and equipment available for holiday detection. It can be performed by applying low voltage or high voltage across the chosen path. Coatings applied to concrete substrates can also be tested for discontinuities using either low-voltage or high-voltage holiday detectors, depending on the coating thickness.
Low-voltage holiday testing is used when the coating system is less than 500 microns (20 mils) thick. High-voltage holiday testing is used when the coating system is thicker. High-voltage holiday testing requires special care not to damage the coating or cause injury to the operator.