Holiday / Spark Testing
A test that passes an electrical charge over a coated surface to locate pinholes, voids and discontinuities — 'holidays' — that are invisible to the eye.
On an actual building
On tank and containment linings a single pinhole defeats the lining. This is the only practical way to find them before the structure goes into service.
What we most often have to correct
That a visual inspection is enough. Pinholes from entrapped air or a missed spot are routinely invisible and routinely found by spark testing.
Terms that come up alongside this one
- Dry Film Thickness (DFT)
The thickness of a coating after it has cured, measured with a gauge across a grid of points..
- Adhesion Pull-Off Test
A test in which a dolly is bonded to the coating and pulled off under measured force, recording both the load and where the failure occurred..
- FRP Lining
Fibre-reinforced plastic lining, built up from glass fibre reinforcement saturated with resin and cured into a hard, seamless, chemically resistant shell..
Holiday / Spark Testing — questions we get asked
What does holiday / spark testing mean in waterproofing?
A test that passes an electrical charge over a coated surface to locate pinholes, voids and discontinuities — 'holidays' — that are invisible to the eye.
Why does holiday / spark testing matter on a real project?
On tank and containment linings a single pinhole defeats the lining. This is the only practical way to find them before the structure goes into service.
What do people commonly get wrong about holiday / spark testing?
That a visual inspection is enough. Pinholes from entrapped air or a missed spot are routinely invisible and routinely found by spark testing.
Have a building showing this?
If a term on this page describes something you are looking at, a site inspection will tell you how far it has gone and what it needs. It costs nothing.
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