What are the Clearance Requirements for Emergency Exits?

Emergency exits, or egress routes as many may know them by, have set clearance requirements to ensure building occupants have enough space to safely exit the building. These emergency exit clearance requirements, outlined by organizations like OSHA and NFPA, include:

Egress Capacity: These should be based on the width of the component and the type of occupancy. According to the NFPA, the most common capacity feet factor for stairs is 0.3 inches per person and all other modes of egress such as ramps and level areas are 0.2 inchers per person.

Minimum Width of Exit Route and Door: Emergency exit access must be at least 28 inches wide at all points, and the exit door itself should be at least 32 inches wide to allow for proper passage. However, that number can be reduced to 28 if the room is less than 70 square feet. The maximum width of an emergency evacuation door is 48 inches.

Corridors: At a minimum, corridors should be 36 inches wide for new buildings and 28 inches for already existing buildings. The ceiling should be at least 7.5 feet tall.

Egress Routes: Routes such as stairs must have a pathway of at least 44 inches to allow for two people to descend side by side comfortably. The NFPA mentions a minimum 11-inch tread and a maximum of 78-inch risers for new stairs. Landings are needed every 12 feet of height and the dimensions of tread and risers should not exceed 3/16^th of an inch and 3/8ths of an inch respectively. Any stairs that are more than 30 inches from the floor must provide handrails that are no more than 37 inches and no less than 30 inches from the stair treads. Guards must be at least 42 inches tall and prevent a 4-inch sphere from passing through the rails.

As for ramps, the NFPA code allows for a 1-in-12 slope for a 6-inch or greater rise. Steeper yet shorter ramps are allowed but the single rise for a ramp is restricted to 30 inches. These are also in need of guards and handrails with the same specifications as stairways.

Minimum Height of Exit Routes: Ceilings in the emergency exit routes must be at least 7.5 feet high. This applies to the entire path of the exit route, including any corridors or hallways leading to the exit.

Obstructions: Emergency exit routes must be free of any obstructions that could impede safe evacuation. This includes materials, equipment, locked doors, and dead-end corridors.

Exit Doors: Exit doors must be readily openable without the use of keys, tools, or special knowledge, unless specifically permitted by OSHA standards. They should swing outward in the direction of egress and should not reduce the required width of the exit route by more than half when fully open.

Exit Discharge Area: Emergency exit discharges must lead to a street, walkway, refuge area, public way, or open space that provides safe access to the outside. The outdoor exit discharge must be at least as wide as the indoor emergency exit clearance.

The above clearance requirements for emergency exits specify minimum widths and capacities for exit routes and components. In addition to these clearance requirements, exit routes should be well-lit and clearly marked with visible exit signs to ensure safe evacuation in emergencies.