1. Fireproofing shall be required on all dwellings that exceeds 6 stories or is at least 75 feet high. No multiple dwelling shall be altered so as to exceed either of such heights without being made fireproof.
2. Multiple dwellings shall have fireproofed walls, floors, roof, stairs and public halls except as provided in subdivision 3 hereof. No beams, lintels and such structural members shall be made of wood. Inflammable materials such as wood shall not be used in any partition, furrings or ceilings. If the dwelling is more than 150 feet above the curb level, no wood shall be used except for interior trim of windows and as provided in the subdivision 3 hereof.
3. The foregoing requirements shall not be construed as prohibiting:
- Elsewhere than within, or in stairs and shafts, in the openings to, the public halls, the use of wood for sleepers, nailing blocks, grounds, under flooring, finish flooring, interior doors with their assemblies and saddles, floor base not more than one foot in height, picture and wall molding, shelving, closet and kitchen fixtures, cupboards, cabinets and wardrobes.
- The use of wood for windows and for interior trim as well as finish backed solidly against, or filled with, incombustible material when the location is not more than 150 feet above the curb level and elsewhere than within, or in the openings to, the public halls, stairs and shafts.
- The use within apartments of wood for decorative wall paneling, wainscoting, mantels or other interior finish, and the use in an entrance hall of wall paneling or wainscoting made of fireproof wood or other material capable of successfully withstanding standard fire tests prescribed in the local building code and in a manner approved by the department.
- Where fireproof doors are required, the use for such doors, with their assemblies and saddles, of material and construction capable of successfully withstanding a one-hour standard fire test prescribed in the local building code and in a manner approved by the department. Should any door required to be fireproof be found to have deteriorated so that it shall after installation fail to conform to the standard fire tests prescribed, such door shall be removed by the owner and replaced by him with a door capable of successfully withstanding such tests.
- All naturally combustible materials which are constructed, processed or protected so that their combustible state will be retarded shall, before being installed in a multiple dwelling for any purpose, must be identified with proper labelling as approved by the department, will note the name of the manufacturer and manufacturing date.
- When required to be fireproof, any outer wall or any wall or partition which carries any load in addition to its own weight shall, unless otherwise in this chapter expressly required, be constructed of materials capable of successfully withstanding a four-hour standard fire test as prescribed in the local building code and in a manner approved by the department. When required to be fireproof, any wall or partition which carries only its own weight, other than an outer wall, shall be constructed of materials capable of successfully withstanding a one-hour standard fire test prescribed in the local building code and in a manner approved by the department.