Under OSHA’s workplace safety rules, a building must have at least two exit routes so employees can evacuate promptly during an emergency, and the two must be placed far enough apart that a single fire or smoke plume is unlikely to block both. More exits are required as the occupant count climbs, and a single exit is allowed only in very small, low-hazard workplaces where everyone can clearly get out through one path. How many exit routes a building must have depends on the number of employees, the building’s size and occupancy type, and its layout.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes
The Two-Exit Baseline
OSHA’s default rule is two. At least two exit routes must be available in a workplace so employees can evacuate promptly during an emergency.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes Each route runs as a continuous, unobstructed path from any occupied point in the building to a public way such as a street, sidewalk, or open space safely away from the structure.
Two exits alone are not enough if they sit next to each other. OSHA requires exit routes to be located as far away from each other as practical, so that one blocked path does not take out the other at the same time.2Occupational Safety and Health Administration. Emergency Exit Routes FactSheet Many building codes apply a “half-diagonal” rule for this, requiring the distance between two exits to be at least half the length of the longest diagonal of the floor. Even where no specific measurement is spelled out, inspectors look for meaningful separation rather than doors clustered in one corner.
When a Single Exit Is Enough
OSHA allows one exit route only when the number of employees, the size and occupancy of the building, and the arrangement of the workplace are such that everyone can evacuate safely through that single path during an emergency.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes In practice this covers very small workplaces: few occupants, low hazard levels, and a short walk to the door. A two-person office with the front door ten steps away is the kind of setup that qualifies.
The employer carries the burden of showing that one exit truly allows safe evacuation. When there is any doubt, the second route is the safer answer.
When Three or Four Exits Are Required
OSHA requires more than two exit routes whenever the employee count, building size, occupancy type, or layout means two routes would not get everyone out safely.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes The regulation itself does not name exact occupant thresholds. For those, most jurisdictions rely on the International Building Code, which sets clear per-story minimums:
- 1 to 500 occupants: at least 2 exits
- 501 to 1,000 occupants: at least 3 exits
- More than 1,000 occupants: at least 4 exits
These figures come from IBC Table 1006.3.3 and apply per story, not to the building as a whole.3ICC. IBC 2021 Chapter 10 Means of Egress A five-story office with 400 people on every floor still satisfies the two-exit minimum on each story. A single-story convention hall holding 800 people needs at least three. Local codes can modify these thresholds, so check the version adopted in your jurisdiction.
Travel Distance and Layout
Even the right number of exits can fail the layout test if the farthest occupied point on a floor sits too far from any of them. Maximum travel distances vary with occupancy type and whether the building has automatic sprinklers, but the underlying principle is consistent: no one should have to cover an unreasonable distance to reach safety. Where travel distances run long, the answer is usually additional exits or relocated ones rather than wider corridors.
What Each Exit Route Has to Meet
Counting exits is only the first step. Each route also has to function as an exit route under OSHA’s design rules.
Width and Height
OSHA sets a minimum width of 28 inches at all points along the exit access, and where only one exit access leads to an exit or exit discharge, the exit and discharge must be at least as wide as the access.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes Ceiling height must be at least seven feet six inches, with no projection lower than six feet eight inches from the floor. Building codes generally require wider corridors: the IBC default minimum is 44 inches, dropping to 36 inches only for corridors serving fewer than 50 occupants.3ICC. IBC 2021 Chapter 10 Means of Egress The 28-inch OSHA figure is a floor, not a design target.
Exit routes must stay clear of obstructions at all times. Stored boxes, parked carts, vending machines, and propped-open fire doors are among the most common violations inspectors find.
Doors That Open From the Inside
Employees must be able to open any exit route door from the inside at all times, without keys, tools, or special knowledge. Electronic locks and mag-locks are permitted only if they default to unlocked during a power failure or alarm. The narrow exception covers mental health facilities, prisons, and correctional institutions where supervisory staff are continuously on duty and the employer has a plan to evacuate occupants during an emergency.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes
Signs and Lighting
Every exit route must be lit well enough for a person with normal vision to see the entire path. Exit signs must be posted at each exit and anywhere the direction to the nearest exit is not obvious. The word “Exit” must be at least six inches tall with letter strokes at least three-quarters of an inch wide, and the sign must be illuminated to at least five foot-candles.4GovInfo. 29 CFR 1910.37 – Maintenance, Safeguards, and Operational Features for Exit Routes Emergency lighting that activates during a power failure is a standard requirement in most jurisdictions.
Fire-Resistant Construction
The exit itself, meaning the protected segment between the exit access and the exit discharge, must be separated from the rest of the building with fire-resistant construction. OSHA requires a one-hour fire-resistance rating when the exit connects three or fewer stories and a two-hour rating when it connects four or more.1Occupational Safety and Health Administration. Occupational Safety and Health Standards 1910.36 – Design and Construction Requirements for Exit Routes Fire doors within the enclosure must carry a matching rating and close automatically.
What Non-Compliance Costs
OSHA treats exit route violations as safety violations, not paperwork. A blocked exit, a missing sign, or an insufficient number of exit routes can each be cited separately. As of 2025, a serious violation carries a maximum penalty of $16,550 per violation, and a willful or repeated violation can reach $165,514 per violation.5Occupational Safety and Health Administration. OSHA Penalties Those amounts are adjusted annually for inflation. A single inspection of a building with multiple egress deficiencies can generate stacked penalties into five or six figures, on top of any wrongful-death or personal-injury exposure if inadequate exits contribute to injuries during an emergency.