The provisions of Section 503 of IEBC are adopted by reference with the following modifications:
1. Revise exception 3 to Section 503.1 to read:
"3. Where provided in below-grade transportation stations, existing and new escalators shall be allowed to have a clear width of less than 32 inches (815 mm)."
2. Delete Section 503.2.
3. Revise exception 1 to Section 503.3 to read:
"1. Buildings of Group R-5 occupancy where the altered building complies with the conventional light-frame construction methods of the Chicago Building Code."
4. Delete Section 503.5.
5. Revise Sections 503.6 through 503.11 to read:
"503.6 Bracing for unreinforced masonry parapets on reroofing.
Where the intended alteration requires a permit for reroofing and involves removal of roofing materials from more than 25 percent of the roof area of a building assigned to Seismic Design Category D that has parapets constructed of unreinforced masonry, the work shall include installation of parapet bracing to resist out-of-plane seismic forces, unless an evaluation demonstrates compliance of such items. Reduced seismic forces shall be allowed.
503.7 Anchorage for concrete and reinforced masonry walls.
Where the work area exceeds 50 percent of the building area, the building is assigned to Seismic Design Category C or D and the building’s structural system includes concrete or reinforced masonry walls with a flexible roof diaphragm, the alteration work shall include installation of wall anchors at the roof line, unless an evaluation demonstrates compliance of existing wall anchorage. Use of reduced seismic forces shall be allowed.
503.8 Anchorage for unreinforced masonry walls in major alterations.
Where the work area exceeds 50 percent of the building area, the building is assigned to Seismic Design Category C or D and the building’s structural system includes unreinforced masonry bearing walls, the alteration work shall include installation of wall anchors at the floor and roof lines, unless an evaluation demonstrates compliance of existing wall anchorage. Reduced seismic forces shall be allowed.
503.9 Bracing for unreinforced masonry parapets in major alterations.
Where the work area exceeds 50 percent of the building area, and where the building is assigned to Seismic Design Category C or D parapets constructed of unreinforced masonry shall have bracing installed as needed to resist out-of-plane seismic forces, unless an evaluation demonstrates compliance of such items. Reduced seismic forces shall be allowed.
503.10 Anchorage of unreinforced masonry partitions in major alterations.
Where the work area exceeds 50 percent of the building area, and where the building is assigned to Seismic Design Category C or D unreinforced masonry partitions and nonstructural walls within the work area and adjacent to egress paths from the work area shall be anchored, removed or altered to resist out-of-plane seismic forces, unless an evaluation demonstrates compliance of such items. Use of reduced seismic forces shall be allowed.
503.11 Substantial structural alteration.
Where the work area exceeds 50 percent of the building area and where work involves a substantial structural alteration, the lateral load-resisting system of the altered building shall satisfy the requirements of Sections 1609 and 1613 of the Chicago Building Code. Reduced seismic forces shall be allowed.
Exceptions:
1. Buildings of Group R-5 occupancy that are altered based on the conventional light-frame construction methods of the Chicago Building Code.
2. Where the intended alteration involves only the lowest story above grade plane of a building, only the lateral load-resisting components in and below that story need comply with this section."
6. Delete Section 503.12.
7. Revise Section 503.14 to read:
"503.14 Smoke alarms.
Individual sleeping units and individual dwelling units in Group R and I-1 occupancies shall be provided with smoke alarms in accordance with Section 504.8 of the Chicago Minimum Requirements for Existing Buildings."
8. Revise Section 503.15 to read:
"503.15 Carbon monoxide alarms.
Carbon monoxide alarms shall be provided to protect sleeping units and dwelling units in Group I-1, I-2, I-4 and R occupancies and classrooms in Group E and I-4 occupancies in accordance with Section 504.9 of the Chicago Minimum Requirements for Existing Buildings.
Exceptions:
1. Work involving the exterior surfaces of buildings, such as the replacement of roofing or siding, the replacement of windows or doors, or the replacement of porches or decks.
2. Installation, alteration or repairs of plumbing or mechanical systems, other than fuel-burning appliances."
(Amend Coun. J. 2-19-20, p. 14473, Art. IV, § 10)