What Is Holiday Testing in Coatings — and When Is It Required?

A ‘holiday’ in coating terminology is a pinhole, void, or discontinuity in a cured coating film — a spot where the coating has failed to cover the substrate completely. The word comes from the idea of a gap or break, like a holiday from coverage. Holiday testing (also called discontinuity testing or pinhole testing) is […]

What Is DFT in Coating — and Why Does It Matter More Than Most People Think?

DFT stands for dry film thickness. It’s the thickness of a coating layer after the solvents have evaporated and the film has fully cured — measured in micrometres (µm) or sometimes mils (thousandths of an inch, used mainly in North American specifications). That’s the short answer. But if DFT were just a measurement, it wouldn’t […]

How to Calculate Intumescent Coating Thickness for Structural Steel

Here’s a question we get from engineers and project managers fairly often: how thick does the intumescent coating actually need to be? It sounds like it should have a simple answer. It doesn’t — at least not without knowing a few things about the steel section you’re protecting. The required dry film thickness (DFT) varies […]