IBC Chapter 10: Means of Egress
Exit requirements, occupant loads, and egress design criteria for safe evacuation
Overview
IBC Chapter 10 provides comprehensive requirements for the design, construction, and arrangement of means of egress components required to provide safe evacuation from all structures and portions thereof. The 2024 edition includes updates for accessible means of egress, coordination with NFPA 101, and clarifications for exit discharge requirements.
The means of egress system consists of three parts: the exit access (path to an exit), the exit (protected path to exit discharge), and the exit discharge (path from exit to public way). Each component has specific requirements to ensure occupants can safely evacuate during emergencies.
Occupant Load Calculations
Occupant load determines the required number and capacity of exits:
| Occupancy Type | Load Factor (sq ft/person) | Examples |
|---|---|---|
| Assembly - Standing | 5 | Concert venues, bars |
| Assembly - Unconcentrated | 15 | Dining areas, lounges |
| Assembly - Concentrated | 7 | Auditoriums, churches |
| Business | 150 | Offices, banks |
| Educational - Classroom | 20 | Schools, training rooms |
| Mercantile - Ground Floor | 60 | Retail stores |
| Mercantile - Upper Floors | 60 | Department stores |
| Storage | 300 | Warehouses, stockrooms |
Calculation Method
- Divide floor area by occupant load factor from Table 1004.5
- For mixed occupancies, calculate each area separately
- Include all occupiable spaces in calculations
- Actual number of occupants if greater than calculated
- Posted occupant load required for assembly spaces over 50
Number of Exits Required
| Occupant Load | Minimum Exits Required | Notes |
|---|---|---|
| 1-49 | 1 (with restrictions) | See single exit exceptions |
| 50-500 | 2 | Standard requirement |
| 501-1,000 | 3 | Additional capacity needed |
| Over 1,000 | 4 | Large assembly spaces |
Single Exit Exceptions (Table 1006.3.4)
- Business (B): 30 occupants max, 75 ft travel distance
- Mercantile (M): 30 occupants max, 75 ft travel distance
- Storage (S): 30 occupants max, 100 ft travel distance
- Residential (R-2): 4 dwelling units per floor, 2 stories max
- Buildings with automatic sprinkler systems may have increased limits
Exit Separation & Width
Exit Separation Requirements
- Two Exit Rule: Separated by 1/2 the maximum diagonal dimension of the area served
- Three or More Exits: Arranged a reasonable distance apart
- Sprinklered Buildings: Separation reduced to 1/3 the diagonal
- Measurement: In straight line between exit centerlines
- Interlocking Exits: Prohibited in high-rise buildings
Exit Width Calculations
- Stairways: 0.3 inches per occupant (0.2" if sprinklered)
- Other Egress: 0.2 inches per occupant (0.15" if sprinklered)
- Minimum Door Width: 32 inches clear (36 inches nominal)
- Minimum Corridor Width: 44 inches (36 inches with exceptions)
- Minimum Stair Width: 44 inches (36 inches for occupant load < 50)
Door & Hardware Requirements
Door Swing Direction
- In Direction of Egress: Required for occupant loads over 50
- High Hazard: Always swing in direction of egress
- Exception: Individual dwelling units may swing either direction
- Encroachment: Cannot reduce required width by more than 7 inches when open 90°
Door Hardware & Locks
- Panic Hardware: Required for assembly and educational over 50 occupants
- Single Motion: One operation to release latch
- Operating Force: Maximum 15 pounds to release
- Height: 34-48 inches above floor
- Delayed Egress: 15-second maximum with sprinkler system
- Controlled Egress: Permitted in healthcare and detention
Special Locking Arrangements
- Electromagnetically locked egress doors (Section 1010.2.13)
- Sensor release of electrically locked doors (Section 1010.2.14)
- Stairway doors may be locked from stairway side (Section 1010.2.5)
Corridors & Stairways
Exit Access Corridors
- Fire-Resistance Rating: 1-hour for non-sprinklered, 0-hour for sprinklered (with exceptions)
- Width: 44 inches minimum (36 inches for occupant load < 50)
- Height: 7 feet 6 inches minimum
- Dead Ends: 20 feet maximum (50 feet if sprinklered)
- Projections: Maximum 1.5 inches decorative, 4 inches handrails
Interior Exit Stairways
- Enclosure: 2-hour for 4+ stories, 1-hour for less
- Width: 44 inches minimum (36 inches for occupant load < 50)
- Riser Height: 7 inches maximum, 4 inches minimum
- Tread Depth: 11 inches minimum
- Handrails: Both sides, 34-38 inches high
- Landings: Required every 12 feet vertical rise
Accessible Means of Egress
All accessible spaces must have accessible means of egress equal to the number of exits required:
Components of Accessible Routes
- Accessible Routes: Connect accessible spaces to exits
- Areas of Refuge: Required in non-sprinklered buildings
- Exterior Areas for Assisted Rescue: Alternative to areas of refuge
- Elevators: Permitted as part of accessible means of egress
- Platform Lifts: Permitted with restrictions
Area of Refuge Requirements
- Size: 30" x 48" clear space per wheelchair
- Separation: 1-hour fire-resistance rating minimum
- Communication: Two-way communication system to fire command
- Identification: Signs at doors to areas of refuge
- Instructions: Posted instructions for use
2024 IBC Updates
Key changes in the 2024 edition of Chapter 10:
- Exit Discharge: Clarified requirements for termination at public way
- Door Operations: Updated requirements for sensor-activated automatic doors
- Photoluminescent Markings: Expanded requirements for high-rise buildings
- Guards: Updated height requirements for certain occupancies
- Handrails: New provisions for alternating tread devices
- Emergency Escape: Clarified requirements for residential emergency escape openings
- Coordination: Better alignment with NFPA 101 Life Safety Code
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