Does using spark testing after the anti-corrosion treatment is completed cause any damage to the anti-corrosion coating?
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This post was last edited by cuicunzhi on 2009-9-21 at 14:08. After the construction party carries out anti-corrosion treatment, and once the coating meets the required standards, the construction party conducts an internal inspection, followed by a re-inspection by the supervisor. If it does not meet the standards, further testing is required. Is repeated use of spark testing likely to cause damage to the anti-corrosion coating? This applies especially to coatings such as epoxy resin-based coatings
There is some damage. It is prone to breakdown, which is caused by problems reoccurring with the anti-corrosion layer. There are specified requirements for inspections; they are not conducted indefinitely, and the voltage used for testing must not be higher than the specified level.
The principle of spark detection relies on the insulating properties of the coating; the positive and negative electrodes are connected to the brush head and the object to be tested respectively. When there are defects in the coating such as pinholes or insufficient thickness (coating materials generally have a certain insulating capacity, and a certain coating thickness allows them to withstand a certain voltage), a discharge alarm is triggered, thereby enabling the assessment of the coating quality. When the coating quality is poor and has pinhole defects, the spark detector gives an alarm. When the coating thickness is insufficient, an alarm will also be triggered due to high voltage breakdown, but this breakdown is not an actual one that results in the formation of holes ； It means that at that voltage, the coating is conductive, but its thickness has not reached the desired level.
Proper spark testing does not cause any damage to the anti-corrosion coating. It is carried out using a voltage level that corresponds to the thickness the coating is designed to withstand; when there are defects in the coating such as pinholes or insufficient thickness, the testing device emits an alarm signal, thereby allowing the quality of the coating to be assessed. Any defective areas can then be addressed and repaired, so only quality issues are detected, without any harm being done to the coating’s quality.
Thank you to the two friends upstairs for their detailed answers
It should be tested at the specified voltage; this has little impact on the anti-corrosion coating! It is the only method for checking whether there is any penetration in the anti-corrosion coating!
That’s a good question; currently, many people in the anti-corruption teams have misconceptions. I would like to add another question: how is the detection voltage chosen in practice?
Do all pipes need to undergo spark testing as long as they are coated with anti-corrosion paint? I’m sorry, I’m a beginner; please help me out
There are settings on the spark machine – just adjust the voltage to the appropriate level. Depending on the thickness of the coating, a coating of xx thickness should be able to withstand a voltage of xx; under normal circumstances it won’t be penetrated, but if it is, then some action needs to be taken. So there’s no problem. Moreover, leaks and pinholes are the most common issues that occur~
If discharge damages the coating, it means the coating itself is of poor quality and needs to be repaired or reworked; so the original poster is overthinking it
What was said upstairs is right! The coating material itself should be non-conductive; if electric sparks can penetrate it, then there is indeed a problem with the installation process! Additionally, the voltage can be selected based on the material and construction thickness