Some general requirements for means of egress include that they should be unobstructed, clearly visible, and identifiable. The emergency lights and exit signs should be illuminated at all times when the building is occupied. However, there is more to the proper design and maintenance of means of egress as defined by NFPA and IBC. Let’s go through each of them one by one:

NFPA Requirements For Egress Capacity

When it comes to core requirements for egress capacity, it is more than technical criteria. They also include how many exits are needed based on the occupancy load, how wide those exits must be, and how far apart the exits should be from each other. 

The minimum number of exits directly depends on the occupancy load, which in turn depends on the type of occupancy. For example, assembly occupancy like theatres, stadiums, etc., or high-hazard areas such as chemical plants may require a larger number of exits based on the complexity of the layout and specific risks. Our blog on calculating occupancy load factor for any building type has provided a detailed table for these special cases. 

The main goal of this entire concept is to make sure that the maximum number of people are able to evacuate as quickly as possible, even if one of the exits is inaccessible or blocked by debris, smoke, or fire.

Here is the general rule for most occupancy:

Another important factor to consider is the width of the exits. They should be wide enough to accommodate the flow of evacuating occupants without crowding. As outlined in the regulations, the width of any exit, corridor, stair, or door should be calculated based on the occupant load multiplied by the width factor, which is measured in inches per person.

The following table outlines the width factor based on a specific condition of the building:

Let’s take an example:

Suppose a building has a sprinkler system, and a certain floor of this building has 600 occupants. So the required width will be 600 *0.2 inches per person = 120 inches. This width will now be divided among the available exits. So, if there are two stairwells, then each of them must be at least 60 inches wide. However, the occupancy type may vary based on the local regulations and consequently, the width factor.

Apart from the minimum number and width of exits, another important factor to consider is how far apart the exits are. The standard requirement outlined by IBC and NFPA 101 is that the distance between exits must be at least ½ the length of the maximum overall diagonal dimension of the building or area. So, if a large open floor is 200 feet diagonally, then the minimum separation between two exits should be at least 100 feet measured in a straight line. 

Additionally, if the building has an automatic sprinkler system installed throughout, then some codes allow a reduction to ⅓ of the length of the diagonal distance. 

NFPA Requirements For The Exit Access

Exit access primarily consists of doors, corridors, and aisles. These components need to be designed in such a way that the path to safety is immediately usable and safe. Here are the requirements outlined by NFPA on the design and operation of these components:

Exit Access Doors

The first and foremost factor to consider is the direction of the door swing. The door must swing in the direction of the egress, i.e, outwards the exit path, if the occupant load served by that single door is more than 50 people; otherwise, it might trap people due to crowding. The door must open easily with no tight grasping or twisting of the wrist and must leave a minimum 32-inch clear opening after it is opened to a 90-degree angle. Another factor to keep in mind is that the doors in the fire barriers must be self-closing and positive latching. 

Dead End Corridors and Aisles

The minimum width of corridors and aisles must be 44 inches. However, if the occupancy load is less than 50 people, 36 inches can be acceptable. The dead-end corridors must be a maximum of 20 ft long, but if the building has a maximum coverage of sprinklers, then the dead-end corridors can be 50 ft long under specific conditions. The travel distance to an exit directly depends on the occupancy type. Generally, the maximum travel distance to an exit in a building without a sprinkler system is typically 200 feet, and 250 feet for a building with a sprinkler system. 

Additionally, the corridors and aisles must not be blocked by furniture, displays, equipment, or any temporary barriers. 

NFPA Requirements For The Exit

For multi-story buildings, exit stairways must be enclosed in a protected shaft. This prevents the fire or smoke from travelling vertically and trapping the occupants. According to the NFPA requirements, the shaft rating should be a 1-hour fire-rated enclosure for buildings with 3 to 4 floors, and for buildings with four or more stories, the shaft rating should be a 2-hour fire-rated enclosure. Handrails of the exit stairs should be installed on both sides at a vertical height of 34-38 inches from the stair nosing. The diameter of the handrails should be 1.5 to 2 inches. According to the IBC, the tread height should be greater than 11 inches, and the riser height should be less than 7 inches for any commercial buildings. 

Apart from this, there are horizontal exits that provide refuge on the same floor by moving the occupants through a fire-rated wall into a separate fire compartment. There must be a 2-hour fire-rated barrier between the spaces and sufficient refuge space on the protected side of the horizontal exit. 

NFPA Requirements For The Exit Discharge

The traditional requirement for any exit discharge is that it must directly lead the occupants to a public way, like a street, alley, sidewalk, etc., or to an open space that is far enough from the building. With the 2024 update in NFPA 101, buildings are required to have an automatic sprinkler system installed throughout that complies with NFPA 13. Furthermore, the earlier code allowed only 50% of the egress capacity to pass through interior paths. The 2024 edition allows 75% of the occupant load to take the interior paths if all the protection, such as sprinklers and 1-hour fire-rated construction, is present. The remaining 25% need to take the exit discharge that leads directly to the outside.

NFPA Emergency Exit Door Requirements For Marking

There must be proper exit signs to direct the occupants towards the exit doors. The letters should be a minimum of 6 inches in height and at least ¾ inches in width. They must be continuously illuminated during normal conditions and even during power failures. 

NFPA Requirements For Special Egress

There are special means of egress, such as access-controlled egress doors and delayed egress locks. 

Access-controlled egress doors are permitted by NFPA and IBC if and only if there is a motion detector installed on the egress side and a clearly marked push-to-exit button is present within 5 feet of the door. Furthermore, if a fire alarm system is triggered, the door must automatically unlock even if no one is near the door. With delayed egress locks, the door must open after 15 seconds of delay. However, with special permission from the Authority Having Jurisdiction (AHJ), a 30-second delay can be permitted. 

An additional requirement was included in the 2024 edition, where it is mandatory for buildings to develop Emergency Action Plans (EAP) if they are using access control, delayed egress, and lockdown systems. Additionally, the design of this special egress should consider scenarios like allowing the emergency responders to access locked-down areas immediately and the quick escape of occupants from the secured zone.