Section 3411A Additions, Alterations, Repairs and Seismic Retrofit to Existing Buildings or Structures Designed in Accordance With Pre-1973 Building Code
Incidental and minor structural additions shall be permitted provided the additions meet this code for new construction using importance factor, Ie, equal to or greater than 1.0. Alterations or repairs to the existing affected lateral force-resisting systems shall be made to conform to the requirements of Sections 3404A or 3405A respectively using importance factor, Ie, equal to or greater than 1.0.
Component importance factor, Ip, shall be permitted to be 1.0.
Exception: Components required for life-safety purposes after an earthquake, including emergency and standby power systems, mechanical smoke removal systems, fire protection sprinkler systems, fire alarm control panels, and egress stairways shall have a component importance factor (Ip) of 1.5.