Rmax Design Thermasheath wall (NFPA 285)

1-Hour Fire Rated Exterior Wall (NFPA 285) — COMPLYING NFPA 285 configuration from the Rmax Thermasheath NFPA 285 A

COMPLYING NFPA 285 configuration from the Rmax Thermasheath NFPA 285 Assembly Guide, based on testing plus a Fire Analysis Summary (engineering extension) by Priest & Associates. Base wall of 3-5/8 in, 20-gauge minimum steel studs at 24 in o.c. max with minimum 1/2 in Type X gypsum wallboard interior, minimum 1/2 in exterior gypsum sheathing, approved WRB, Thermasheath polyiso continuous insulation at 4.5 in maximum, and standard 4 in clay brick with maximum 2 in air gap. Note: NFPA 285 compliance is pass/fail for exterior fire propagation, not an hourly rating — the guide states no hourly rating for the base wall, so 1 hour is a placeholder only. (Details per the cited source; confirm before specifying.)