Upgrading an existing qualified historical building or property to one-hour fire-resistive construction and one-hour fire-resistive corridors shall not be required regardless of construction or occupancy when one of the following is provided:
New non-historical interior wall and ceiling finishes shall conform to the provisions of the regular code. Existing non-conforming materials used in interior walls and finishes may be surfaced with an approved fire-retardant to increase the rating of the natural finish to within reasonable proximity of the required rating. For wood lath and plaster walls, see Section 8-404.
Exception: When an automatic sprinkler system is provided throughout the building, existing finishes shall be approved.
Existing or original roofing materials may be repaired or reconstructed subject to the following requirements:
- The original or historical roofing system shall be detailed or modified as necessary in order to be capable of providing shelter while preserving the historical materials and appearance of the roof.
- Wooden roof materials may be utilized where fire resistance is required, provided they are treated with fire-retardant treatments to achieve a Class "B" roof covering rating. Wood roofing in state designated Urban Wildland and High Fire Zones shall be permitted when installed in class "A" assemblies.
- Jurisdictions that prohibit wood roofing materials for application as roof coverings and roof assemblies shall submit documentation for the adoption. Express Terms, statement of reasons and minutes of the action by the adopting authority Health and Safety Code, Section 18959(f).
When required by the CHBC, an automatic sprinkler system is defined by the following standards as adopted by the State Fire Marshal (for nonhazardous occupancies).
- Buildings of four stories or less: NFPA 13R.
- For floors above the fourth, NFPA 13.
- Buildings with floors above 75 feet, NFPA 13.
- When the building is free standing or with property line separation, two floors and 1500 sf per floor or less, NFPA 13D.
- For exterior wall and opening protection. As required by this chapter.
Exception: When the automatic sprinkler systems are used to reach compliance using this code, in three or more occasions, NFPA 13D standard shall be increased to NFPA 13R standard, or NFPA 13R standard shall be increased to a NFPA 13 standard.