Field & trade terms
Holiday test
Also called: holiday detection, spark test, pinhole test
A holiday test is a way of finding the tiny defects in a continuous protective coating or waterproofing membrane that a visual check cannot see — the pinholes, skips and thin spots the trade calls holidays. An electrical charge is run across the coating; wherever the film is intact it insulates, and wherever there is a gap to the conductive substrate the tester registers it, flagging the exact spot to repair. It turns coating continuity from a judgment call into a located, repairable finding.
Why it matters
A protective coating only works if it is continuous — a single pinhole down to the substrate is where corrosion or water intrusion starts, and it will spread from that point. On a below-grade membrane or a tank lining, that one unseen gap can defeat the whole system, and it is invisible until it leaks.
The test is worth the most before the coating is buried or covered. Finding and patching a holiday while the surface is still accessible is a minor touch-up; finding the same leak after backfill or topping is an excavation.
How it shows up on site
A holiday survey run over the finished coating or membrane before it is covered, each flagged location marked, repaired and re-tested, and the survey documented so the continuity of the concealed layer is on the record.
Standards it's verified against
Checklists that put holiday test to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- DelaminationA separation between layers that were supposed to bond — a coating from its substrate, a topping from a slab, plies of a membrane — leaving a hollow, loose plane.
- Pull testA field load test that applies a specified tension to an installed anchor or fastener to confirm it holds without failing or pulling out.
- WaterstopA strip embedded across a concrete joint that blocks water from passing through the joint — the built-in seal at construction and expansion joints below grade.
- Acceptance criteriaThe stated, measurable conditions installed work has to meet before it can pass — the yardstick an inspection judges against.
- MEP (mechanical, electrical, plumbing)The mechanical, electrical and plumbing trades — the systems run through a building's structure that get inspected at rough-in and again at final.
- FirestoppingSealing openings where pipe, conduit or cable pass through a fire-rated wall or floor so the assembly's rating is restored.
Knowing the term is step one. Proving it is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.