2012 TAS Chapter 3
Chapter 3 of the 2012 Texas Accessibility Standards is titled "Building Blocks" for a reason. It does not talk about doors, ramps, or bathrooms by name. It sets out the small, repeated pieces those elements are built from: what a walkable surface has to be, how much room a wheelchair user needs to approach something, how far a person can reach, and how hard an object can be to operate. Once GCHS staff know these building blocks, later lessons on routes, doors, and toilet rooms are mostly a matter of applying them to a specific room.
Section 302.1 requires floor and ground surfaces to be stable, firm, and slip resistant. That is a performance standard, not a single number, and it is why a GCHS inspector presses on a surface rather than just measuring it: loose gravel, spongy turf, or a rug that shifts underfoot can all fail 302.1 even though nothing about them is out of tolerance on a tape measure. Section 302.2 allows carpet, but caps pile height at 1/2 inch maximum, and requires exposed edges to be fastened down and trimmed. Section 302.3 covers openings in a floor or ground surface, such as the gaps in a grate or the joints in a wood deck: openings cannot allow passage of a sphere more than 1/2 inch in diameter, and where the openings are elongated, such as a slotted drain, they have to run perpendicular to the dominant direction of travel so a cane tip or a narrow wheel does not catch in them lengthwise.
Section 303 sets the limits for small vertical bumps in a walking surface, the kind left by a doorway threshold, a settled sidewalk joint, or a floor transition strip. Section 303.2 permits a change in level up to 1/4 inch high to be a plain vertical face, no bevel needed. Section 303.3 covers the next step up: a change in level between 1/4 inch and 1/2 inch high has to be beveled, with the bevel no steeper than a 1:2 slope. Above 1/2 inch, Section 303.4 says the change in level is no longer a "change in level" at all under this section, it has to be built and treated as a ramp under Section 405 or a curb ramp under Section 406. A GCHS evaluator who finds a 3/4-inch threshold lip is not looking at a borderline change in level, they are looking at an unramped rise that fails outright.
302.3 opening limit: 1/2 inch sphere, elongated openings perpendicular to travel. 303.2 vertical, no bevel required: 1/4 inch maximum. 303.3 beveled: over 1/4 inch up to 1/2 inch maximum, bevel not steeper than 1:2. 303.4 above 1/2 inch: must comply with ramp requirements, Section 405 or 406.
Section 304.3 requires a turning space, room for a wheelchair user to reverse direction, sized either as a 60-inch diameter circle minimum or as a T-shaped space inside a 60-inch square with arms and base 36 inches wide minimum. Section 304.2 requires the floor of a turning space to have no changes in level, other than a slope no steeper than 1:48. Lesson 3 covers turning space in full, including where TAS requires it, such as inside toilet rooms (603.2.1); this lesson only needs the dimensions as a building block other sections build on.
A clear floor or ground space is the minimum footprint a wheelchair needs to sit still in front of an element, such as a sink, a switch, or a counter, in order to use it. Section 305.3 sets that footprint at 30 inches by 48 inches minimum. Section 305.5 requires that space to be positioned for either a forward approach, the wheelchair user facing the element head-on, or a parallel approach, the wheelchair user facing along the element's face, and Section 305.6 requires one full unobstructed side of that 30 by 48 space to adjoin an accessible route or another clear floor space, so a wheelchair user is not required to enter the space diagonally or through an obstruction.
Section 305.7 addresses what happens when that clear floor space sits inside a recess, an alcove where the element is set back from the main wall. Under 305.7.1, an alcove approached head-on (forward approach) has to be 36 inches wide minimum once its depth exceeds 24 inches; a shallower recess does not trigger the wider requirement. Under 305.7.2, an alcove approached from the side (parallel approach) has to be 60 inches wide minimum once its depth exceeds 15 inches. A narrow, deep alcove, a drinking fountain tucked into a masonry recess is the classic example, fails 305.7 even when the fountain itself and its 30 by 48 clear space are otherwise fine, because the recess is too narrow for its depth.
305.3 clear floor or ground space: 30 in. by 48 in. minimum. 305.7.1 forward-approach alcove: 36 in. wide minimum where depth exceeds 24 in. 305.7.2 parallel-approach alcove: 60 in. wide minimum where depth exceeds 15 in.
Knee and toe clearance is the open space under an element, a sink apron or a counter overhang, that lets a wheelchair user's legs and footrests slide underneath so the 30 by 48 clear floor space can overlap the space below the element instead of stopping short of it. Section 306.2 defines toe clearance as the zone from the floor up to 9 inches above the floor: under 306.2.2 it can extend 25 inches maximum under the element, under 306.2.3 at least 17 inches of that depth counts toward a required clear floor space, and under 306.2.5 it has to be 30 inches wide minimum.
Section 306.3 defines knee clearance as the zone from 9 inches above the floor up to 27 inches above the floor. Under 306.3.2 it can extend 25 inches maximum under the element at the 9-inch height, and under 306.3.3 at least 11 inches of depth is required at 9 inches above the floor, reducing to at least 8 inches of depth at 27 inches above the floor. Section 306.3.4 allows that depth to taper between those two points, at a rate of 1 inch less depth for every 6 inches of additional height. Knee clearance also has to be 30 inches wide minimum under 306.3.5. In practice, GCHS checks knee and toe clearance together at any sink, counter, or lavatory: a beautiful 30 by 48 clear floor space in front of a sink is worthless if the cabinet apron underneath only leaves 6 inches of knee room.
Toe clearance (306.2): zone 0-9 in. above floor; 25 in. maximum depth; 17 in. minimum required depth; 30 in. wide minimum. Knee clearance (306.3): zone 9-27 in. above floor; 25 in. maximum depth at 9 in. height; 11 in. minimum depth at 9 in., tapering to 8 in. minimum depth at 27 in.; 30 in. wide minimum.
Section 307 protects the usable width of a circulation path from objects that stick out into it above the floor but below head height, things a cane cannot detect by sweeping the ground. Section 307.2 sets the danger zone as any leading edge more than 27 inches and not more than 80 inches above the floor: an object in that zone can protrude no more than 4 inches into the path (handrails get a narrow exception, up to 4 1/2 inches, under the same section). A wall-mounted fire extinguisher cabinet with its bottom edge at 40 inches and its face sticking out 6 inches into a 44-inch corridor is a textbook 307.2 violation.
Section 307.3 covers freestanding, post-mounted or pylon-mounted objects, such as a sign on a single pole: when the object's underside sits between 27 inches and 80 inches above the floor, it can overhang the circulation path by no more than 12 inches, a larger allowance than the 4-inch wall-mounted limit. Section 307.4 requires 80 inches of vertical clearance throughout a circulation path; where headroom is less than that, a guardrail or barrier has to be added with its own leading edge at 27 inches maximum so the obstruction is cane-detectable, and door closers and stops get a narrow exception down to 78 inches. GCHS runs into 307.4 most often under stairs, where the underside of a stair stringer drops below 80 inches at some point along an adjacent walkway.
Section 308 sets how high and how low an operable part can sit and still be reachable from a wheelchair. Section 308.2.1 covers an unobstructed forward reach, reaching straight ahead over nothing: the high forward reach is 48 inches maximum and the low forward reach is 15 inches minimum above the floor. Section 308.2.2 covers a forward reach over an obstruction, such as a counter a wheelchair user's knees fit under: where the reach depth over the obstruction is 20 inches maximum, the high reach stays at 48 inches maximum; where the depth runs deeper, up to 25 inches maximum, the high reach drops to 44 inches maximum, because a deeper obstruction makes the same 48-inch height harder to reach.
Section 308.3.1 covers an unobstructed side reach, reaching sideways along an element the wheelchair is parallel to: the high side reach is 48 inches maximum and the low side reach is 15 inches minimum, with an exception permitting an obstruction up to 10 inches deep without changing those numbers. Section 308.3.2 covers a side reach over a taller obstruction, up to 34 inches high and 24 inches deep: at 10 inches of depth or less the high reach stays at 48 inches maximum, and at depths beyond that, up to 24 inches maximum, the high reach drops to 46 inches maximum. These stepped-down numbers matter to GCHS because they show up directly at kitchen counters and vanities, covered in Lesson 8, where a deep countertop can turn an otherwise-compliant 48-inch-high switch into a noncompliant reach.
Forward, unobstructed (308.2.1): 15 in. minimum to 48 in. maximum. Forward, obstructed (308.2.2): 48 in. max at 20 in. max depth; 44 in. max at depths over 20 in. up to 25 in. max. Side, unobstructed (308.3.1): 15 in. minimum to 48 in. maximum. Side, obstructed (308.3.2), obstruction up to 34 in. high and 24 in. deep: 48 in. max at 10 in. max depth; 46 in. max at depths over 10 in. up to 24 in. max.
Section 309 covers anything a person has to operate to use a space: light switches, thermostats, door hardware, faucet handles, appliance controls. Section 309.2 requires a clear floor space complying with Section 305 in front of the operable part. Section 309.3 requires the part itself to be mounted within one of the reach ranges set out in Section 308, so a switch sitting 15 to 48 inches above the floor, measured by the correct forward or side reach rule for its location, satisfies this requirement. Section 309.4 covers how the part has to work once someone can reach it: operable with one hand, without tight grasping, pinching, or twisting of the wrist, so a round doorknob or a twist-type faucet handle fails even if it is mounted at the perfect height. Section 309.4 also caps the force needed to operate the part at 5 pounds maximum, with gas pump nozzles the one listed exception.
Why this matters for GCHS
Every one of these numbers is a field measurement GCHS makes constantly. An evaluator scoping a bathroom remodel for an elderly homeowner checks knee clearance under the vanity, checks that the new light switch lands inside reach range, and checks that the replacement door lever does not require a grip the homeowner can no longer manage. None of that requires memorizing Chapter 3 by section number in the field, but knowing that "knee clearance" and "reach range" and "operable parts" are separate, each with their own numbers, keeps an evaluator from assuming that fixing one automatically fixes the others.
1. What three qualities must a floor or ground surface have under Section 302.1?
2. What is the maximum sphere diameter that an opening in a floor or ground surface may allow to pass, under Section 302.3?
3. A GCHS evaluator measures a threshold that is 3/8 inch high. Under Section 303, what treatment does that change in level require?
4. Above what height does a change in level stop being covered by Section 303 and instead require a ramp under Section 405 or a curb ramp under Section 406?
5. What is the minimum size of a clear floor or ground space under Section 305.3?
6. A drinking fountain sits in a recessed alcove 30 inches deep, approached head-on (forward approach). Under Section 305.7.1, how wide must that alcove be?
7. Under Section 305.7.2, when must a parallel-approach alcove be 60 inches wide minimum?
8. Under Section 306.3.3, what is the minimum knee clearance depth required at 9 inches above the floor, and how does it change by 27 inches above the floor?
9. What is the required minimum width of both toe clearance (306.2.5) and knee clearance (306.3.5)?
10. A GCHS inspector finds a wall-mounted cabinet with its leading edge at 42 inches above the floor, projecting 6 inches into a corridor. Does this comply with Section 307.2?
11. Under Section 307.4, what is the minimum vertical clearance required along a circulation path, and what must be added where headroom is less?
12. Under Section 308.2.1, what is the unobstructed forward reach range?
13. A wheelchair user reaches forward over a counter with a 24-inch obstruction depth. Under Section 308.2.2, what is the maximum high forward reach in that case?
14. Under Section 309.4, what two requirements govern how an operable part must work, beyond its mounting height?