Chapter 12 of the International Building Code addresses the interior environment of buildings. Interior finishes for walls, floors, and ceilings in corridors and other spaces must meet flame-spread ratings established in ASTM E84 standard. Class A finishes (flame spread 0-25) are required in corridors and exits. Class B (flame spread 26-75) is permitted in other areas. Class C (flame spread 76-200) is permitted in certain occupancies and areas. Foam plastic materials require special approval and must meet specific degradation requirements. Carpet in buildings must pass Department of Commerce FF 1-70 flammability standard. Furniture finishes must meet California Technical Bulletin 117 standards in certain jurisdictions. Lighting must provide minimum illumination levels in occupied spaces. Office areas require 30-50 foot-candles, with higher lighting in detailed work areas. Circulation paths require 5-10 foot-candles for safe navigation. Emergency lighting must provide minimum 5-foot candles for 90 minutes during power loss. Ventilation requirements depend on occupancy type. Office buildings require 15 cubic feet per minute per person of outside air, typically 20 percent of total ventilation. Restaurants and kitchens require higher ventilation rates. Moisture control is critical to prevent mold growth and material degradation. Vapor barriers are installed in walls in cold climates to prevent interstitial condensation. Building materials must be protected from moisture during construction.