- The building envelope consists of exterior walls, windows, doors, and roof, which protect and shelter
interior spaces from the exterior environment.
- Interior walls, partitions, and ceilings subdivide and define interior space. Many of these components are nonstructural in nature and carry no loads other than their own weight.
- Mechanical systems provide essential services to a building, such as the heating, ventilation, and airconditioning of interior spaces.
- Plumbing systems supply water suitable for consumption and firefighting and dispose of sanitary
waste. Electrical systems control and safely distribute power for lighting, equipment, security, communication, and vertical transportation.