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Keep the list of Western treaters that make and supply fire retardant treated lumber and plywood handy by downloading the Sources - Fire Retardant Treated Wood.

Interior Fire Retardants

Interior FR

Much of the fire retardant-treated wood in construction today is used in interior applications. In these uses, the wood is protected from the weather and from moisture. It can be found in wall framing, ceiling joists, roof trusses and other structural elements of a building.

The chief reason to use fire retardant wood in interiors is to increase safety reducing or slowing the spread of flames and smoke to give people time to safely exit the structure during a fire. Interior fire retardant wood also can reduce the destruction and damage to a structure, giving fire services more time to extinguish the blaze.

Wood pressure treated with interior fire retardants are typically sold under the brand name of the retardant. The four retardants available today include:


D-Blaze, manufactured by Viance LLC, is regularly used in multifamily and commercial structures, helping reduce construction and insurance costs.

Dricon FS

Produced by Arxada, Dricon was introduced in 1981 and for decades has been used successfully in a variety of structures and projects.


FlamePro from Koppers Performance Chemicals is a proven successful formulation based on the American Wood Protection Association P50 Standard for Fire Retardants. Koppers also manufactures a similar formulation under FirePro.

SaferWood Thermex-FR

Part of the SaferWood line of products, Thermex-FR is a safe and environmentally friendly formulate that renders wood safe from fire. Wood treated with Thermex-FR have passed strict fire and weathering tests and comply with all model building codes.


Other interior fire retardants used by Western treaters include FlameTech and Pyro-Guard, which are designed for use in a wide variety of enclosed structural applications and many other interior applications.


Each interior fire retardant has passed the code-required testing and is approved for use under the building codes per an ICC-ES Evaluation Report for each formulation.

Lumber and plywood that has been treated for interior can be identified by the required quality mark, which will list the name of the fire retardant, the flame spread or smoke developed value and the ICC-ES report number confirming its conformance.

Use the links above to download specification guides and other important information on each fire retardant.