Fire exits & egress paths, in plain English.

How to use this

Egress is a handful of thresholds.

Cross one and the rules change. These are the model-code numbers (IBC / NFPA 101) that come up on real projects, in the order you actually hit them. A local jurisdiction can be stricter, and a few are — but most adopt the model code as written, so treat these as the baseline and confirm local amendments with the authority having jurisdiction (AHJ) — the local building or fire official who reviews and signs off on the plans.

Step 1

First, count the people.

Every threshold below turns on occupant load. Get this number first.

• Office / business areas: about 1 person per 150 sq ft (gross).
• Conference or assembly with tables & chairs: about 1 per 15 sq ft (net) — a room fills fast.
• Standing or concentrated seating: denser still (as low as 5–7 sq ft).

In practice: Occupant load is area ÷ a code factor, not a headcount. A 900 sq ft training room at 15 sq ft/person is 60 people — which changes the exit rules before a single chair arrives.

The big line

The 50-person line — the room and the floor.

Here’s the part nobody explains: this rule is checked at two scales at once — the individual room, and the whole floor (your suite). Both have to pass, independently.

• The room: any single room needs a second door out once it holds about 50 people — or once the walk to a choice of exits passes 75 ft. A big conference room, training room, or open work area earns its own second exit.
• The floor: counted on its own — add up everyone on the floor, and that total sets how many exits the floor needs: 2 at 50+, 3 at 500+, 4 above 1,000. A floor of small rooms can each be under 50 and the floor still needs two exits.
• It’s counted by area, not heads: an office is figured at roughly 1 person per 150 sq ft, so the plan’s calculated load can be higher than the people actually there — “but we only have 40” doesn’t always help.

What this means for your plan: the number and placement of the doors and exit stairs you see on a drawing isn’t anyone’s taste — it’s driven by these two headcounts. It’s also why “let’s just add a few desks” or “let’s turn that lounge into workstations” can quietly push a room or a floor past a threshold — and suddenly the space legally needs another exit, a wider corridor, or a door that swings the other way. That’s a permit and construction, not a furniture move. We check these lines before you commit to a layout, so a rearrangement later doesn’t turn into a renovation.

The 75-foot rule & its cousin

Two rulers: “when do I get a choice?” and “how far to the door?”

This is where it gets confusing, and fairly so — the code measures the escape route two different ways, and they get mixed up constantly. Both are measured along the real walking path (down the aisles, around the furniture), never a straight line.

• Common path of egress travel — the “when do I get a choice?” ruler. From the most remote seat, how far you walk before the route offers a real choice of two directions: 75 ft, or 100 ft if the building is sprinklered. Pass it and you need a second way out sooner — even under 50 people.
• Exit access travel distance — the “how far to the door?” ruler. From that same seat, the total walk to actually reach an exit (an exit stair, or a door to the outside): 200 ft, or 300 ft if sprinklered.
• If you’ve only ever heard “75 feet,” that’s the common path in a building without sprinklers — the number most people quote, and the strictest of the four.

In practice: the common path is the short ruler that usually governs a suite or a big room — it’s what forces a second door in. Travel distance is the long backstop for the whole floor. Sprinklers buy the extra distance on both because they slow a fire down — that’s the trade the code makes.

Placement

Two exits, far apart.

• Separate required exits by at least half the longest diagonal of the space — one-third if sprinklered.
• One blocked route can’t be allowed to trap everyone.

In practice: Two doors side by side technically count and practically fail. Remoteness is the whole point.

Corridors & doors

Clear, wide, and openable.

• Egress corridor width: 44″ minimum (36″ where it serves fewer than 50).
• Dead-end corridor: 20 ft max (50 ft where sprinklered, business).
• Exit doors: 32″ clear, open from inside without a key or special knowledge, landings clear.

In practice: The required width stays clear floor-to-ceiling. A credenza or rolling whiteboard that pinches a 44″ corridor is the single most common furniture violation we catch.

Aisle widths

Five feet, or less? Where each width applies.

“Make the aisles five feet” is good advice — but it’s mostly best practice, not a fire-code mandate. Here’s what’s actually required, and where the 5-foot number really comes from.

• Workstation aisles: 36″ is the code floor (fire — and ADA’s baseline accessible-route width), but a bare 36″ makes a poor everyday aisle. Our working standard is 42″. We drop to 36″ in only two deliberate spots: the short pinch between wing panels at the entrance to a cluster of stations — where the aisle then opens back to 42″ for the rest of its run — or an aisle serving a run of no more than three people.
• Corridor serving 50+ people: 44″ minimum (fire); below 50, 36″ is allowed. A heavy occupant load can push it wider by the capacity math.
• ADA route: 36″, with a brief pinch to 32″ allowed at a point like a doorway. Where a route runs under 60″ wide, add a 60″ passing / turning space at least every 200 ft.
• The 5-foot (60″) main aisle is where two people — or two wheelchairs — pass and where you can turn, so a 60″ spine doubles as your accessible route without separate alcoves. It’s an accessibility + two-way-traffic best practice, not a fire minimum.

In practice: when someone says “the aisles have to be five feet,” the honest answer is that the code floors are 36″ and 44″ — the 5-foot spine is the smart, accessible way to plan the main circulation, not a number the fire marshal will cite. Our own rule of thumb: a 5-foot primary aisle, 42″ secondary aisles between station runs, and 36″ held for just two spots — the wing-panel throat at a cluster entrance (then back to 42″), or a short run of three people or fewer. Every aisle ends up comfortable and inclusive, not merely legal.

Don’t forget

Signs, light & accessible egress.

• Exit signs and emergency lighting on every egress path.
• Accessible routes of egress, plus areas of refuge in multi-story buildings.

In practice: Getting everyone out includes the people who can’t take the stairs — where egress and ADA meet.

National vs local

The model code is the floor.

The IBC and NFPA 101 figures above are the baseline. A jurisdiction can adopt tighter rules, and a handful do — but most adopt the model code as written. Assume these numbers, then confirm the local amendments with the AHJ. It’s rarely looser; occasionally stricter.

Where we come in

Furniture is where egress goes wrong.

The architect sets the exits — then someone fills the plan with product, and a clear 44″ corridor quietly becomes 38″, or a 60-person room ends up with one door. Bring us in while the furniture plan is being drawn and the exits stay legal without a redraw. Companion primer: ADA in Practice →  ·  How ADA & fire safety work together →