Where buildings, or portions thereof, are divided into fire areas so as not to exceed the limits established for requiring a fire protection system in accordance with this chapter, such fire areas shall be separated by fire barriers constructed in accordance with Section 707 of the California Building Code or horizontal assemblies constructed in accordance with Section 711 of the California Building Code, or both, having a fire-resistance rating of not less than that determined in accordance with Section 707.3.10 of the California Building Code.