The Structural Steel Fissure Detection Paint is a coating for structural materials that contains a built-in, self-activating, crack-indicating or warning capability. This method of fissure detection includes applying to the structure surface a coating of a first color that has microcapsules containing a second color that are designed to break upon detection of a fissure. The dye and the coating are mutually insoluble so as not to degrade the capsule wall from either the inside or outside. The coating releases the dye which becomes visible at the surface shortly after the substrate material fractures, and is observable to the unaided eye at a distance of up to thirty feet. Test data indicates successful detection of cracks as small as 3 mm. in length.

Most structural parts, e.g., steel bridges, whether new or reconstructed, are painted. The paint layer applied to the steel structure serves as a protective coating against agents that cause corrosion, which weakens the structure. This technology provides a means for simultaneously implementing crack detection along with application of the protective paint coating.

Two formulations of the technology have been developed:

• A formulation based on a nitrocellulose lacquer designed to be used in a lab setting with its main advantage being that testing can be done on a coated material soon after application of the paint;
• Epoxy-based formula as a crack indicating tool and a protective coating for structural steel exposed to the elements, as well as for other materials requiring crack detection.