Interior partition walls divide interior spaces and typically do not support structural loads (are non-load-bearing). These walls are constructed similarly to exterior walls but may be lighter and simpler. Typical framing uses 2x4 studs spaced 16 inches on center. Studs are attached to top and bottom plates with nails or screws. Plates are nailed or bolted to the floor and ceiling structure. Interior walls do not require exterior sheathing but may be sheathed with drywall or other materials on one or both sides. Sound isolation between spaces can be improved with resilient channels, extra drywall layers, and insulation. Sound transmission class (STC) ratings indicate sound reduction; ratings of 60 or higher provide adequate privacy for most applications. Fire rating of partition walls may be required between certain occupancy types. Fire-rated walls extend from floor slab to underside of the slab or roof above, preventing fire from traveling through the plenum (space above drop ceilings). Electrical outlets and switches are installed within the partition. Wiring must be protected from nails and screws; protection plates or wire shields prevent accidental contact. Plumbing may be routed through interior walls if sized adequately. HVAC ducts are commonly run in or above partition walls. After framing, drywall is installed and finished. Corner reinforcement and proper finishing creates a professional appearance. Partition layout is planned during design; modification of partition locations after framing requires approval and structural assessment.