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Beyond Aesthetics: The Crucial Role of Intumescent Finishes in Wood Preservation

| March 21, 2024 | By

Constant innovations in industrial coatings mean today’s finish options look as good as they perform. Naturally, we want our projects and structures to be adequately protected from day-to-day exposure—but what about those that need protection from more extreme conditions?

The reliable but antiquated process of charring has been replaced by advanced coating solutions that can protect against virtually any threat, including fire and high heat. In fact, “char levels” are still used to measure heat resistance and fire protection standards, paying homage to the classic technique.

Below, we explore the crucial role of intumescent solutions for wood preservation (among other common applications) by answering general questions about its use in construction and manufacturing.


What is intumescent coating?

The definition of “intumescent” according to Oxford Languages is a substance that swells when exposed to heat. An intumescent coating creates a foamy barrier between the heat source and the surface underneath, effectively sealing the gap in the event of a fire. Some intumescent options can expand to over 100 times their initial thickness, buying plenty of valuable time.


What type of structures and projects is it used for?

As a rather aesthetic fireproofing product, intumescent applications are virtually limitless. These solutions are especially popular in industrial, commercial, and large-scale public projects because they improve the structure’s overall safety. You’ll also see intumescent coating frequently employed in the following industries:

  • Marine and Naval Engineering
  • Transportation and Infrastructure
  • Oil and Gas Production
  • Commercial Construction

Intumescent protection is especially important for some of the above sectors because the products they deal in often have a high sensitivity to heat or fire. Take fuel storage for example; businesses that store and transport diesel fuel or gasoline must ensure these substances are adequately protected in case of a fire. That means whatever they’re stored in must be optimized for high heat protection.


What’s the difference between fire retardant and intumescent?

Intumescent paint and coatings don’t react the same way as fire retardant finishes. Although the terms appear synonymous, their reactions to heat are actually quite different.

As previously mentioned, “intumescent” suggests that the surface coating will swell when exposed to heat. Conversely, fire retardant coatings are designed to slow the burn rate to reduce damage. The latter doesn’t insulate the surface completely, while the former creates a barrier that buys time before burning. Intumescent coatings protect the underlying material by expanding the space between the substrate and the flame, making them effectively fire-resistant.

Why do we need intumescent paint standards?

No one wants to find out that their product failed to perform as expected—but it’s especially important that intumescent products reliably perform in an emergency. Every stakeholder needs the peace of mind that comes with knowing their structure can stand up to heat and keep occupants safe in the event of a fire.

This is why, like many industrial finishes, intumescent coatings must follow a set of compliance standards to ensure performance in case of a fire-related emergency (particularly in commercial settings.) U.S.-based architects and firms must understand these regulations and meet the fire protection and penetration firestopping criteria set by the International Building Codes (IBC) and the Life Safety Code (NFPA 101). For reference, fire retardant solutions typically have an ASTM E-84 rating, and intumescent coatings usually have an ASTM E-119 rating.


Does an intumescent finish require a special application method?

As an experienced maker, you know that all finishes are not created equal. Every solution should be applied according to the manufacturer’s instructions for best results. That being said, there is a safe and ideal way to apply every type of coating, including the aforementioned fire protection products.

Generally speaking, ensure that the substrate or base for the coating is suitable for the finish being applied. Preserving wood structures, for example, will require a slightly different fireproofing solution than protecting stainless steel. Compatibility between the substrate and the finish is essential for optimal performance.

Follow application instructions as they vary. Specify the necessary factors, including number of coats, base layers, mid-coats, topcoats, and drying times. Also, take into account exposure to elements and the humidity levels of the surrounding environment. Finally, consider subsequent finishes or mixed materials. Managing director of Wilkinson Construction Consultants Geoff Wilkinson advises in Architects’ Journal,

“Check whether any subsequent finish will affect the performance of the intumescent coating ... Be wary of junctions and mixed materials between, for example, a boarded fire-protected column and a beam protected by an intumescent coating. Testing of assemblies that incorporate different manufacturers’ products is rare, and a common practice is to overlap the protection systems; this requires careful detailing to ensure that every solution performs its intended function successfully.”


Where can I purchase intumescent finishes?

Architects and builders certainly aim to design projects that look good. Still, performance is the priority—especially when it comes to safety. To guarantee premium protection and superior aesthetics, only the highest quality finishing products from industry-leading professional brands will cut it.

Thankfully, FinishWorks has a sister company, Nullifire, who is a market leader in fire protective coatings. This newly established partnership further expands FinishWorks' dynamic network of top-notch product lines to ensure every project is finished with finesse. 

Browse our expansive list of leading brands and find out why consumers and businesses alike trust RPM brands like FinishWorks to provide only the best selection of industrial coating products.