Section 502

structure shall comply with the requirements of the Califor- nia Building Code or California Residential Code, as appli- cable, for new construction. Alterations to the existing building or structure shall be made to ensure that the existing building or structure together with the addition are not less complying with the provisions of the California Build- ing Code than the existing building or structure was prior to the addition. An existing building together with its additions shall comply with the height and area provisions of Chapter 5 of the California Building Code, or the height provisions of Chapter 3 of the California Residential Code, as applica- ble.

Exception: [BSC] For state-owned buildings, including those owned by the University of California and the Cali- fornia State University and the Judicial Council, the

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100735044

PRESCRIPTIVE COMPLIANCE METHOD

requirements of Sections 502.4 and 502.5 are replaced by the requirements of Sections 317 through 322.

[BS] 502.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.

[BS] 502.3 Flood hazard areas. For buildings and structures in flood hazard areas established in Section 1612.3 of the California Building Code, or Section R322 of the California Residential Code, as applicable, any addition that constitutes substantial improvement of the existing structure shall comply with the flood design requirements for new construction, and all aspects of the existing structure shall be brought into compliance with the requirements for new construction for flood design.

For buildings and structures in flood hazard areas established in Section 1612.3 of the California Building Code, or Section R322 of the California Residential Code, as applicable, any additions that do not constitute substantial improvement of the existing structure are not required to comply with the flood design requirements for new construction.

[BS] 502.4 Existing structural elements carrying gravity load. Any existing gravity load-carrying structural element for which an addition and its related alterations cause an increase in design dead, live or snow load, including snow drift effects, of more than 5 percent shall be replaced or altered as needed to carry the gravity loads required by the California Building Code for new structures. Any existing gravity load-carrying structural element whose vertical loadcarrying capacity is decreased as part of the addition and its related alterations shall be considered to be an altered element subject to the requirements of Section 503.3. Any existing element that will form part of the lateral load path for any part of the addition shall be considered to be an existing lateral load-carrying structural element subject to the requirements of Section 502.5.

Exception: Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes where the existing building and the addition together comply with the conventional lightframe construction methods of the California Building Code or the provisions of the California Residential Code .

[BS] 502.5 Existing structural elements carrying lateral load. Where the addition is structurally independent of the existing structure, existing lateral load-carrying structural elements shall be permitted to remain unaltered. Where the addition is not structurally independent of the existing structure, the existing structure and its addition acting together as a single structure shall be shown to meet the requirements of Sections 1609 and 1613 of the California Building Code using full seismic forces .

Exceptions:

1. Any existing lateral load-carrying structural element whose demand-capacity ratio with the addition con

sidered is not more than 10 percent greater than its demand-capacity ratio with the addition ignored shall be permitted to remain unaltered. For purposes of calculating demand-capacity ratios, the demand shall consider applicable load combinations with design lateral loads or forces in accordance with Sections 1609 and 1613 of the California Building Code . For purposes of this exception, comparisons of demand-capacity ratios and calculation of design lateral loads, forces and capacities shall account for the cumulative effects of additions and alterations since original construction.

2. Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes where the existing building and the addition together comply with the conventional light-frame construction methods of the California Building Code or the provisions of the California Residential Code .

Where an addition is made to a building or structure of a Group R occupancy, the existing building shall be provided with smoke alarms in accordance with Section 1103.8 of the California Fire Code .

building. [HCD 1] Pursuant to Health and Safety Code Sec- tion 17926, carbon monoxide detection shall be provided in all existing Group R buildings, as required in Section 915 of the California Building Code or Section R315 of the Califor- nia Residential Code, as applicable.

502.7.1 Carbon monoxide detection in existing Group E occupancy buildings. Where the new addition includes any of the conditions identified in the California Fire Code Sections 915.1.2 through 915.1.6, carbon monoxide detection shall be installed in accordance with Section 915 of the California Fire Code.

No person shall install, market, distribute, offer for sale, or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Mar- shal.

Group E occupancies, storm shelters shall be provided in accordance with Section 1106.1.