The Code Chase: K225 Stair Safety (Part 2)
Stairway Requirements
Welcome back to The Code Chase! In this issue, we’re diving into the second half of K225, which focuses entirely on stairs—specifically the technical requirements found in NFPA 101 Section 7.2.2. These stairway rules are critical for safe evacuation and emergency access in healthcare and other occupancies.
Not all stair requirements apply to every building. Some apply only to new construction, so always confirm whether a rule is for new or existing stairs.
Stair Basics: Where the Rules Start
General
All exit stairs must meet both the general rules in 7.1 and the specific rules in 7.2.2.
Step Dimensions Matter
Dimensional Criteria
New vs. Existing
New stairs follow stricter measurements.
Existing stairs can remain if they meet older rules (Table 7.2.2.2.1.1(b)).
Minimum Width
If the stair serves under 50 people:
Minimum 36 inches wide (clear space).If the stair serves over 50 people:
Use Table 7.2.2.2.1.2(B) and related formulas for correct width.
Curved and Spiral Stairs
Allowed in specific cases and must meet depth, radius, and handrail requirements.
Spiral stairs have strict riser height, tread depth, and handrail rules.
Small occupant loads (3 or fewer) have more lenient spiral stair options.
Construction and Surfaces
Stair Details
Permanent and Fire-Resistant
Must be permanent and fixed—no portable stairs.
In buildings with Type I or II construction, stairs must be noncombustible (excluding handrails and certain existing stairs).
Landings
Landings are required at doors unless the door serves <50 people and doesn’t swing over the stair.
In new buildings, the landing depth must be at least the width of the stair, but not more than 48 inches if it’s a straight run.
Tread & Landing Surface
Must be solid with no holes or lips that could trip someone.
Sloped risers (under the tread) allowed if slope is <30° and nosing doesn’t stick out more than 1½ inches.
Exceptions for grated steps exist only in assembly, detention, industrial, and storage occupancies.
Uniformity is Key
Riser Height & Tread Depth
Measured from nosing to nosing.
No step beveling over ½ inch horizontally or sloping more than 20°.
Variations
Maximum variation between adjacent treads or risers: 3⁄16 inch.
Largest-to-smallest variation in one stair flight: ⅜ inch.
If top/bottom risers meet sloped ground, a 1-inch variance per foot of stair width is allowed.
Marking Required:
If a riser’s height is inconsistent, the nosing must be marked in yellow.
Handrails and Guards
Required Safety Features
Handrails
Required on both sides of stairs.
New stairs: Handrails must be within 30 inches of the egress width.
Existing stairs: 44 inches is acceptable.
Exceptions:
Dwelling unit stairs can have one side only.
Handrail Height and Size
New stairs: 34–38 inches high.
Existing stairs: 30–38 inches high.
Must be continuously graspable and return to the wall or terminate at a post.
Minimum 2¼ inches from the wall.
Allowed shapes:
Circular (1¼ to 2 inches in diameter)
Non-circular shapes with grip-friendly profiles
Guards for Safety
Guardrails
Guards must be 42 inches high, except:
In dwelling units: 36 inches
Some existing guards: 30 inches
Openings in guards must be small enough that a 4-inch ball cannot pass through (some exceptions for industrial/storage use).
The triangular space under handrails (by the treads) must prevent a 6-inch ball from falling through.
Stair Enclosures & Protection
Enclosure and Protection
Enclosure Requirements
Interior exit stairs must be enclosed by fire-rated construction per 7.1.3.2.
In existing two-story stairs, one level of enclosure may be enough if 50% of exits are independent.
No Storage in Stairs
No storage allowed inside stairwells.
You may build a room under stairs only if:
It’s separated by the same fire rating.
You enter from outside the stair enclosure.
Stair Signage & Identification
Clear and Helpful Signs
Required For:
New enclosed stairs with 3+ stories
Existing enclosed stairs with 5+ stories
Must Include:
Floor level
Top and bottom of stairway
Direction to exit discharge
“NO ROOF ACCESS” if it doesn’t reach the roof
Tactile and large-print identifiers
Directional arrows required when exit is upward.
Exit Path Markings
Where required by occupancy type, exit stair paths need:
Tread Markings
Contrast stripe at the leading edge of each step (1–2 inches wide)
No tape—must be permanent or integral to material
Landing & Handrail Markings
Landings need the same contrasting stripe as steps
Handrails must have a contrasting stripe across their top surface
Perimeter Lines
Solid or striped lines around the landing edge or wall
Must be continuous and uniform
No adhesive tape allowed
Final Thoughts
NFPA 101 Section 7.2.2 includes a lot of detail, but it all comes down to one thing: safe and consistent egress.
Not every rule applies to every stair, especially when it comes to new vs. existing construction. When unsure, check the wording in the Code or consult with a Life Safety professional, your AHJ, or architect.
How I Can Help
Staying ahead of Life Safety Compliance doesn’t have to be overwhelming. At Dustin Phillips Consulting, I make it easier for your team to understand what’s required, prepare for surveys, and improve safety across your facility.
Whether it’s mock surveys, staff training, or reviewing your documentation and fire plans, I bring real-world experience with practical solutions. My job isn’t just to point out issues—it’s to help you fix them before they become citations.
If you're looking for clear guidance and a partner who makes life safety surveys easier, let’s connect. A quick conversation today could save you a major headache tomorrow.
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