To upgrade a portion of the existing 1-hr. rated corridor to 2 hr. construction to serve as the extension of the stair enclosure to an exterior exit. Location on the 1st floor as noted on the approved set of plans. Work to include removing penetrating items from walls, repairing, infilling or constructing two hour walls assemblies; removing ductwork from 2-hour corridor enclosure portion; smoke/fire dampers at 1-hour corridor portion & floor penetration; installation of 2-hour floor/ceiling assembly, Design No. J201; & install complying door assemblies. All per approved plans, to include notes & attachments thereto. NOTE: This building is fully fire sprinklered. (P.C.#677-98)/drs