IBC Means of Egress Overview
Means of egress is one of the most heavily tested topics across the PPD and PDD divisions of the ARE. The International Building Code (IBC) Chapter 10 defines the means of egress as a continuous and unobstructed path of vertical and horizontal egress travel from any occupied portion of a building to a public way. It consists of three distinct components: exit access, exit, and exit discharge.
Exit Access
Exit access is the portion of the egress system that leads from any occupied point to an exit. It includes corridors, aisles, ramps, and intervening rooms. Key requirements include:
- Common path of egress travel: The distance an occupant must travel before two separate paths to two exits become available, limited by occupancy type (typically 75 feet, or 100 feet with sprinklers in some occupancies).
- Dead-end corridors: Limited to 20 feet in unsprinklered buildings and 50 feet in sprinklered buildings for most occupancies.
- Travel distance: Maximum distance from the most remote point to an exit, varying by occupancy and sprinkler status (e.g., 200 feet unsprinklered, 250 feet sprinklered for most occupancies).
- Corridor width: Minimum 44 inches for corridors serving an occupant load of 50 or more; 36 inches for fewer.
Exits
An exit is the protected portion of the egress system that provides a path between the exit access and the exit discharge. Exits include exterior exit doors at grade, exit stairways and ramps enclosed in fire-rated construction, exit passageways, and horizontal exits. Exits must maintain their fire-resistance rating and cannot be interrupted by intervening rooms or spaces.
Exit Discharge
Exit discharge is the path from the exit to a public way. Up to 50% of exits may discharge through the level of exit discharge (typically the ground floor) if the path is protected by sprinklers, clearly marked, and provides a direct line of sight to the exterior exit door.
Occupant Load Calculations
Occupant load is calculated by dividing the floor area by the occupant load factor (OLF) from IBC Table 1004.5. Some common factors include:
| Use | OLF (sq ft/person) |
|---|---|
| Assembly - standing space | 5 net |
| Assembly - unconcentrated (chairs, tables) | 15 net |
| Business | 150 gross |
| Educational classrooms | 20 net |
| Mercantile (ground floor) | 30 gross |
| Storage | 300 gross |
Net area excludes accessory spaces (corridors, restrooms, mechanical rooms), while gross area includes the entire floor area within exterior walls.
Number of Exits and Exit Width
The number of exits required depends on occupant load: one exit for occupant loads up to 49 (with limitations), two exits for 50–500, three exits for 501–1,000, and four exits for more than 1,000 occupants. Exits must be separated by a distance not less than one-half the maximum overall diagonal dimension of the building or area served (one-third in sprinklered buildings).
Exit width is calculated at 0.2 inches per occupant for stairways and 0.15 inches per occupant for other egress components (level components and ramps), with minimum widths of 44 inches for stairways serving occupant loads over 50.
Accessibility and Egress
Accessible means of egress must be provided in accordance with ADA accessibility requirements, including areas of refuge or exterior areas for assisted rescue in buildings without sprinkler systems. See also Fire Protection for how egress requirements interact with fire-resistance-rated construction.
Review these concepts with the Egress Cheat Sheet and test your knowledge with PPD mini exams. For related code topics, see Code Compliance. Sign up free to access all egress practice questions and flashcards.