2012 TAS Chapters 4-5
Stairs get built into almost every multi-story property GCHS evaluates, and staff get asked constantly whether a stair or lift setup counts toward accessibility. The short answer is that a stair, no matter how well built, never does. This lesson covers what TAS still requires of stairs and handrails, then turns to the three ways a building gets an accessible connection between floors: elevators, limited-use/limited-application (LULA) elevators, and platform lifts, and the Section 206 scoping that decides which one a building may use.
Section 402.2 says an accessible route consists of walking surfaces with a running slope not steeper than 1:20, doorways, ramps, curb ramps, elevators, and platform lifts. A stair is not on that list. A building with a beautifully built, fully code-compliant stair connecting its first and second floors still has zero accessible connection between those floors unless an elevator, LULA elevator, or platform lift also exists. GCHS evaluators run into this constantly on older two-story houses considered for a program that requires ground-floor accessible living space: a perfect stair changes nothing about whether the home meets that requirement. At the same time, TAS does regulate stairs. Section 210.1 scopes Section 504 to interior and exterior stairs that are part of a means of egress, whether or not they are on an accessible route, because people who are not wheelchair users still rely on stairs being safe and consistent. There are exceptions; for example, in alterations, stairs between levels that are connected by an accessible route do not have to meet 504, though handrails complying with 505 must be provided when those stairs are altered.
Section 504.2 requires riser height and tread depth to be uniform within a flight, with riser height between 4 inches minimum and 7 inches maximum, and tread depth 11 inches minimum. Inconsistent risers, even by a fraction of an inch, are a common trip hazard and a common finding on older houses where a stair was patched over the years. Section 504.3 prohibits open risers entirely: every riser needs a solid backing, not a gap a foot or a cane can slip through. Section 504.4 requires the tread surface to be essentially level, sloped no steeper than 1:48, the same cross-slope limit used elsewhere in TAS.
Section 504.5 governs the leading edge of each tread. The nosing can have a radius of curvature up to 1/2 inch maximum, and can project no more than 1 1/2 inches over the tread below; a nosing that projects beyond the riser needs the underside of its leading edge curved or beveled. Risers are also permitted to slope back under the tread above them, at up to 30 degrees from vertical. A foot coming down should land on a predictable edge, not catch on an oversized lip.
Section 504.6 requires stairs to have handrails complying with Section 505. Section 505.2 requires handrails on both sides of stairs and ramps, not just one, with a narrow exception for aisle ramps in assembly areas. Section 505.3 requires the handrail to be continuous within the full length of each stair flight or ramp run, so a resident climbing the stair has something to hold the entire way, without a gap partway along the flight. On switchback or dogleg stairs, the inside handrail also has to be continuous between flights.
Section 505.4 sets the top of the gripping surface at 34 inches minimum and 38 inches maximum, measured vertically above the walking surface, the stair nosings, or the ramp surface, and at a consistent height along the run. Section 505.5 requires at least 1 1/2 inches of clearance between the gripping surface and any adjacent surface, so a hand is not scraping the wall. Section 505.6 requires the gripping surface to be continuous and unobstructed along its top and sides, so a hand can slide along it without hitting a bracket, and limits obstruction of the bottom to 20 percent of its length. Section 505.7 sets the cross-section: a circular rail needs an outside diameter between 1 1/4 and 2 inches; a non-circular rail needs a perimeter between 4 and 6 1/4 inches and a cross-section dimension of 2 1/4 inches maximum. A rail too fat or too thin to close a hand around defeats the purpose even at the right height.
Section 505.10 requires the gripping surface to extend beyond the top and bottom of the stair flight or ramp run, so a person has something to hold before their feet reach the change in level and after they leave it. Section 505.10.1 covers ramps: the extension runs 12 inches minimum beyond the top and bottom of each run, horizontally above the landing. Section 505.10.2 covers the top of a stair: 12 inches minimum, horizontal, starting directly above the first riser nosing. Section 505.10.3 covers the bottom: the extension continues along the stair's slope, for a horizontal distance at least equal to one tread depth, beyond the last riser nosing. The two are not the same shape: the top one is flat, the bottom one keeps sloping with the stair.
Why this matters for GCHS
A homeowner's existing interior stair is a common complaint during a GCHS evaluation, and it is usually the handrail, not the stair itself, that is the problem: too high, too low, mounted flush against the wall with no room for fingers, or stopping a step short of the landing where a hand is needed most. Checking height, clearance, and extension length on both rails takes a few minutes and catches most of what actually causes a fall.
Section 206.2.3 requires at least one accessible route to connect each story and mezzanine in a multi-story building, subject to seven numbered exceptions. The one that matters most in small projects covers private buildings that are less than three stories or that have less than 3,000 square feet per story, unless the building is a shopping center, a shopping mall, the professional office of a health care provider, a transportation terminal or station, an airport passenger terminal, or another type of facility the U.S. Attorney General determines. Other exceptions cover certain public buildings with a story occupied by five or fewer people, detention and correctional facilities, residential facilities, transient lodging guest rooms, air traffic control towers, and qualified historic buildings. Where no exception applies, the building needs a real vertical connection: an elevator, LULA elevator, or platform lift, chosen under the scoping in Sections 206.6 and 206.7, not a stair no matter how compliant its risers and handrails are.
Section 206.6 requires elevators provided for passengers to comply with Section 407, and requires every elevator to comply where more than one is provided. At a summary level, Section 407 requires call buttons at least 3/4 inch in their smallest dimension, within reach ranges, up above down; hall signals with the visible fixture centered at least 72 inches above the floor and an audible signal at each hoistway entrance; door reopening devices that sense an obstruction at 5 and 29 inches nominal height; and a car sized under Table 407.4.1, for example an 80 by 54 inch interior (side to side, back wall to inside face of door) with a centered 42-inch door, or a 68 by 54 inch interior with a 36-inch off-center door. Car control buttons follow the same 3/4 inch size rule and ascending order, with emergency controls at least 35 inches above the floor.
Section 408 covers limited-use/limited-application, or LULA, elevators, a smaller and less expensive class. A standard LULA car is at least 42 inches wide and 54 inches deep with car doors at the narrow ends and a 32-inch minimum clear door width, though the standard also allows a wider, shallower car (51 by 51 inches, 36-inch door) and, for existing cars, a smaller 36 by 54 inch configuration with at least 15 square feet of platform area. Swinging LULA doors must be power-operated and stay open at least 20 seconds once activated. Section 206.6 limits where a LULA elevator can substitute for a full elevator: only in a building already using a 206.2.3 exception, where a platform lift is permitted under 206.7, or, under a separate exception, in multi-story residential dwelling units. It is not a general substitute wherever an owner prefers the smaller unit.
Section 410 covers platform lifts, which run under ASME A18.1 rather than the elevator code and must provide unassisted entry and exit. In new construction, Section 206.7 permits them only for a list of specific uses, which is narrower than the LULA scoping; TAS also permits a platform lift as a component of an accessible route in an existing building or facility. The listed uses include routes to performance areas and speakers' platforms, wheelchair space dispersion, incidental spaces that are not public use and hold five people maximum, judicial spaces such as jury boxes and witness stands, places where existing exterior site constraints make a ramp or elevator technically infeasible, guest rooms and dwelling units with mobility features, amusement ride load and unload areas, play areas, team or player seating, and recreational boating and fishing facilities. A platform lift needs clear floor space per Section 305, no more than 1 inch of clearance between the platform sill and the runway landing edge, and low-energy power-operated doors or gates that stay open at least 20 seconds, at least 32 inches wide for an end door or 42 for a side door, with an exception for self-closing manual doors on a lift serving no more than two landings and having doors on opposite sides.
1. What riser height range does Section 504.2 allow, and what else does it require of risers within one flight?
2. What is the minimum tread depth under Section 504.2, and are open risers permitted?
3. A GCHS evaluator measures a stair riser at 7 1/4 inches. Is this riser compliant with Section 504.2?
4. Under Section 504.5, what is the maximum nosing projection over the tread below, and what is also permitted for risers?
5. Under Section 505.2, on how many sides of a stair are handrails required?
6. What does Section 505.3 require about handrail continuity along a stair flight?
7. What height range does Section 505.4 set for the top of a handrail's gripping surface?
8. A GCHS evaluator measures a handrail's gripping surface at 40 inches above the tread nosing. Is it compliant with Section 505.4?
9. What clearance does Section 505.5 require between a handrail's gripping surface and an adjacent wall?
10. Under Section 505.7, what outside diameter range applies to a circular handrail?
11. How do the top and bottom handrail extensions required by Section 505.10 differ in shape?
12. A two-story building has only a stair connecting its first and second floors, with fully compliant risers, treads, and handrails throughout. Does this satisfy the accessible-route requirement to connect the two stories?
13. Under Section 206.6, when may a LULA elevator complying with Section 408 be used in place of a full passenger elevator?
14. Which of the following is a use Section 206.7 permits for a platform lift?