Means of Egress and Life Safety
The three-part path
NFPA 101 Chapter 7 splits egress into exit access, exit, and exit discharge. Every check you perform falls into one of these. Occupant load comes first, because capacity, number of exits, and travel distance all flow from it - occupant load factors are gross or net square feet per occupant depending on use (business is 100 gross; assembly unconcentrated is 15 net; standing space is 5 net).
The sequence a reviewer follows
- Compute occupant load room by room, then for the floor and building.
- Determine required number of exits and their arrangement (remote from each other, no common path of travel exceeding the limit, no dead-end corridor beyond the limit).
- Check capacity using the egress width factor for the component - level surfaces and stairs carry different factors, and the controlling number is usually the narrowest point, such as a door leaf or a stair width between handrails.
- Check travel distance, door swing direction and hardware, corridor width, stair geometry, handrails, and re-entry.
- Check the supporting systems: exit signage, means-of-egress illumination, and emergency lighting duration.
Traps
- Mixing capacity factors from a model building code with those in NFPA 101. They are not interchangeable.
- Using net area where the table specifies gross, or forgetting to deduct fixed seating.
- Assuming two exits always satisfy arrangement - they must also be remote and independent.
- Forgetting that a door serving a high-occupancy space must swing in the direction of travel and carry panic hardware.
- Treating an exit discharge into a fenced courtyard as compliant.
Rule of thumb
Capacity is governed by the tightest single point, not the average width. Worked example: a 4,000 sq ft business occupancy at 100 gross sq ft per occupant is 40 occupants. That load is small enough that one exit may be permitted where travel distance and common path limits are met - but the reviewer must confirm the limits, not just the count.