The International Building Code requires that each piece of fire retardant lumber and plywood be properly labeled to identify that it has been properly treated for the intended use and meets required industry standards.
The code details specific information that must appear on the label, which is typically applied as a stamp on the wood. The label requirements are listed in the International Building Code in Chapter 23 - Wood, in Section 2303.2.4.
The appearance and order of the required information as it appears on the stamp will vary, depending on the manufacturer and fire retardant formulation used. However, all the required elements should be shown.
Interior
- FR brand/product name or logo
- Identification of treating manufacturer
- Species of wood treated
- Method of drying after treatment
- Identification mark or name of approved inspection agency
- Flame spread or smoked develop index value
- Conformance to appropriate standard or ESR number
Exterior
- FR brand/product name or logo
- Identification of treating manufacturer
- Species of wood treated
- Method of drying after treatment
- Identification mark or name of approved inspection agency
- Flame spread or smoked develop index value
- Conformance to appropriate standard or ESR number
- Required statement for products exposed to weather, damp or wet conditions
Building codes require stamps on fire retardant-treated wood products for both interior use and exterior use to have the same seven elements, as listed above. Exterior use products must have one additional element referencing the specific standard for fire retardant lumber and plywood exposed to weather.
The presence of one of these stamps on the wood assure that it has been infused with fire retardants to provide long-lasting protection against fire. Beware of wood products that may be promoted as fire retardant treated but do not have the code-required stamp.