1/2 x 4 x 8 Fire Retardant Plywood Sheathing at Menards®Class A/Class 1 fire retardant (ASTM E-84); This plywood slows the spread of flames and reduces smoke; Wood species is Fir; UL listed; Rated sheathing Exterior Fire-X - Exterior Fire Retardant Treated WoodExterior Fire-X is pressure-impregnated fire-retardant lumber and plywood that provides tested fire protection for applications directly exposed to the weather or 3/4 in. x 4 ft. x 8 ft. Fire-Rated KDAT Douglas Fir PressureFire retardant treated (FRT) plywood reduces the effects of fire with innovative materials that Kiln dried for added stability; Versatile for interior and exterior useFRX® Fire Retardant Treated Wood for Exterior ApplicationsEffective for lumber, plywood, logs, siding, LVL. Common Applications. FRX® fire retardant treated wood may be used in exterior applications permitted byExterior Fire-X™ Treated Products - Curtis Lumber andExterior Fire-X™ (XFX) products are fire-retardant treated, giving it the durability of wood with the fire-safety benefits of non-combustible materials