What is Intumescent Coating and How Does it Protect?

July 25, 2012

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Intumescent coating is a substance that serves as a protection against fire damage. If exposed to high temperatures, the coating expands to form a sort of foam, known as char, which protects steel in buildings and businesses from the heat. This char doesn’t conduct heat very well, so it keeps the structure beneath it cooler for a longer period of time.

Steel can only remain stable below 550° C, so a steel framed building without this coating could lose its structural integrity extremely quickly. The coating doesn’t protect the structure permanently, but different types of coating can add anywhere from 30 minutes to 3 1/2 hours to the amount of time available for people to exit the building and for rescue crews to get in and out safely.

The composition of this coating varies, but it always consists of a carbon, an acid, and an expanding agent, mixed into a binding agent. When the coating reaches around 250° C, the binder melts and releases the expanding agent. This begins to harden and forms a protective barrier between the heat and the structure.

Intumescents have an obvious practical use, but because they are available in paint, they can also serve an aesthetic purpose for exposed steel. For indoor supports, this paint can be the perfect way to make your space both beautiful and safe. There are also forms of epoxy intumescent that can protect structures against wider threats, such as explosions and higher temperatures. This is good for especially hazardous settings and exteriors.

An epoxy intumescent will also last longer than its prettier counterpart. This special substance gets harder and thicker, so it is much more difficult for it to corrode. Furthermore, it is made without water, so it will not be subject to damage from freezing and thawing. Special epoxies also exist for pipes. When pipes are exposed to fire, they melt and burst. This can be extremely dangerous depending on what is inside those pipes. Intumescents have been created that expand with enough force to close the pipe when it expands to prevent leakage.

Intumescent coatings are not just beneficial for steel. They can also be applied to sheet rock, wood, foams, sheet metal, fiberglass, and carbon graphite. The uses range from offices, restaurants, marine applications, military applications, hotels, churches, schools, electricity and telephone poles, indoor stairways, and much more. Different coatings have higher or lower fire ratings, so it is important to research available products and the needs of your structure.

Correct application is crucial because poorly applied intumescents cannot perform at maximum efficiency. Many intumescent products are non-toxic, required to be safe for the environment, and designed to keep smoke levels down. This amazing substance has transformed architecture by making it possible to use steel beams in places where special fire-retardant boards were necessary before.

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