Fire Treated Lumber

Fire retardant treated wood shall show no evidence of significant progressive combustion when the test is extended for an additional 20 minute period. In addition, the flame front shall not progress more than 10½ feet beyond the centerline of the burners at any time during the test.

Fire retardant treated lumber and plywood shall be manufactured under the independent third party inspection of Underwriters Laboratories Inc. (UL) Follow-Up Service and each piece shall bear the UL classified mark indicating the extended ASTM E 84 test.

Each piece shall be labeled kiln dried after treatment (KDAT). Timber Products Inspection, Inc. (TP) shall monitor the process and the TP mark shall appear on the label.

FIRE RETARDANT TREATMENT

Interior fire retardant treated lumber and plywood shall have equilibrium moisture content of not over 28% when tested in accordance with ASTM D 3201 at 92% relative humidity.

Interior fire retardant treated wood shall be kiln dried after treatment to a maximum moisture content of 19% for lumber and 15% for plywood.

The fire retardant formulation shall be free of halogens, sulfates, chlorides, ammonium phosphate, formaldehyde and urea formaldehyde.

Provide lumber of the appropriate grade and species as specified by the design criteria of the intended application after consideration of design value adjustments.

Provide plywood of the appropriate size, grade and species as specified by the design criteria of the intended application after consideration of span rating adjustments