| Pathway Type | Description | Common Use Cases | Example Capacity Rule | | :--- | :--- | :--- | :--- | | | Piping (metallic or nonmetallic) that encloses and protects cables | Running cables vertically between floors or through walls and floors to provide high levels of protection | Initial fill should be 25% , with a maximum fill of 50% to allow for future growth. | | Cable Trays | Ladder-like racks or wire mesh baskets that support and organize cables, often used in ceiling spaces | Managing large numbers of horizontal cables above hallways or in equipment rooms | A maximum fill ratio of 25% is recommended to allow for future additions and proper airflow. | | Underfloor Pathways | Systems using cellular floors, underfloor ducts, and access floors to route cables beneath the raised floor | Data centers and other environments where flexibility and frequent changes are required | General fill recommendations of 25-50% apply to the pathway's internal volume. | | Perimeter Pathways | Baseboard raceways, surface-mounted raceways, or other systems that run along the edges of rooms | Retrofitting buildings where overhead or underfloor access is difficult | Fill capacity is determined by the cross-sectional area of the raceway. | | Ceiling Pathways | Cables routed above a suspended ceiling, often using J-hooks or trapeze hangers | A common method for horizontal distribution in commercial office spaces | J-hooks must be spaced no more than 5 ft (1.5 m) apart to prevent cable sag. |

: Clear height must be 2.4 m (8 ft.) without obstructions, with a minimum of 3 m (10 ft.) between finished floor and lowest ceiling point.