Fire Door Assembly 1 : A door assembly for which a fire protection rating is determined and that is intended for installation in door openings in fire-resistive walls
NFPA 252 Standard Methods of Fire Tests of Door Assemblies, 2003 ed. http://www.nfpa.org/codes-and-standards/document-i nformation-pages?mode=code&code=252, (Std: Meth of Fr Tst of Door Assly - Amer) {271 NFC}