ANSI Accessibility Guide
A practical, searchable overview of ICC A117.1 accessibility requirements—what they do, why they matter, and the measurements designers reach for most.
Before you draw: “ANSI” generally refers to ICC A117.1 in building design. It is a model standard, while the ADA is federal civil-rights law. Your locally adopted code determines which ANSI edition applies and where accessibility is required. Verify the project’s jurisdiction and use the most restrictive applicable requirement.
Four numbers to remember
These reflect common ICC A117.1-2017 criteria. They are starting points—not a substitute for the adopted code.
The space a mobility device needs to stop, approach an element, turn, and travel safely.
| Requirement | Typical ANSI measurement | What it does | Why it matters |
|---|---|---|---|
| Clear floor space | 30″ × 52″ | Creates a wheelchair approach area. | Allows positioning at fixtures, appliances and controls. |
| Turning circle | 67″ diameter | Allows a wheelchair to reverse direction. | Prevents users from backing through a room. |
| Walking surface | 1:20 max slope | Maintains a usable walking route. | Steeper surfaces are treated as ramps. |
| Cross slope | 1:48 maximum | Keeps a route level side-to-side. | Reduces drifting, tipping and balance issues. |
| Level change | ¼″ max untreated | Controls abrupt transitions. | Reduces tripping and wheel obstruction. |
| Headroom | 80″ minimum | Maintains overhead clearance. | Protects users, including people with low vision. |
ANSI 2017 ADA commonly uses a 30″ × 48″ clear floor space and a 60″ turning circle. Do not mix standards without confirming which requirements govern.
A continuous, unobstructed path connecting required entrances, rooms, fixtures, amenities, parking and site features.
| Requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Route width | 36″ minimum | Creates a continuous travel path. | Accommodates wheelchairs and mobility devices. |
| Brief narrowing | 32″ minimum | Allows limited pinch points. | Useful at doorways and isolated obstructions. |
| Passing space | 60″ × 60″ | Allows mobility devices to pass. | Prevents long routes from becoming one-way. |
| Protruding objects | Generally 4″ max | Limits wall-mounted projections between 27″ and 80″ AFF. | Cane users may not detect objects above the floor. |
Door size alone is not enough. Clear opening, approach, latch-side space, threshold and hardware must work together.
| Requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Clear opening | 32″ minimum | Provides usable passage. | A 36″ door may not yield 32″ clear—measure to the face of the open door. |
| Clear height | 80″ minimum | Provides safe headroom. | Prevents overhead hazards. |
| Threshold | ½″ max; beveled as required | Limits the bump at an opening. | Helps wheels cross and reduces trips. |
| Hardware | 34″–48″ AFF | Keeps handles within reach. | Must operate without tight grasping, pinching or wrist twisting. |
| Maneuvering clearance | Varies by approach | Provides room at latch and door swing. | Users need space to reach the handle and move clear. |
Ramps form part of an accessible route; stairs do not. A compliant ramp, lift or elevator may be required where levels change.
| Ramp requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Running slope | 1:12 maximum | Limits steepness. | Each inch of rise needs at least 12 inches of run. |
| Clear width | 36″ minimum | Creates usable travel width. | Accommodates mobility devices. |
| Rise per run | 30″ maximum | Limits uninterrupted climbing. | Reduces fatigue and loss of control. |
| Landings | Generally 60″ long | Provides level rest and maneuvering space. | Required at top, bottom and changes in direction. |
| Handrail height | 34″–38″ | Provides continuous support. | Assists users with balance or strength limitations. |
Stairs Specify uniform risers and treads, compliant handrails and extensions, limited openings, and visual contrast or detectable warnings where required.
Controls should be reachable from seated and standing positions and usable with limited strength or dexterity.
| Requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Forward reach | 15″–48″ AFF | Defines unobstructed usable heights. | Keeps controls reachable from a wheelchair. |
| Side reach | 15″–48″ AFF | Allows parallel approach. | Common for switches and dispensers. |
| Operating force | 5 lb max for many parts | Limits required strength. | Helps users with arthritis or limited grip. |
| Operation | No tight grasping, pinching or twisting | Makes controls broadly usable. | Lever, push, touch and sensor controls are easier. |
The room must allow entry, door operation, turning, fixture use, transfer and exit—not simply contain “accessible” fixtures.
| Element | Typical requirement | What it does | Why |
|---|---|---|---|
| Toilet centerline | Commonly 16″–18″ | Positions the fixture from the side wall. | Supports side transfer. |
| Seat height | 17″–19″ AFF | Aligns with common wheelchair seat height. | Makes transfer easier. |
| Side grab bar | Generally 42″ min | Supports side transfer. | Assists balance and repositioning. |
| Rear grab bar | Generally 36″ min | Provides rear and lateral support. | Assists transfer and stability. |
| Grab-bar height | Generally 33″–36″ AFF | Places the gripping surface within reach. | Provides leverage while seated or standing. |
| Lavatory | 34″ max AFF | Lowers the rim or counter. | Supports seated use. |
| Knee clearance | 27″ min high at required portion | Allows forward approach. | Open space must remain clear of cabinetry and plumbing. |
| Mirror | Commonly 40″ max AFF to reflective surface | Lowers the usable reflection. | Makes the mirror useful while seated. |
Protect exposed pipes and locate faucets, flush controls, dispensers and accessories within the applicable reach range. Verify door-swing overlap rules for the specific room configuration.
Compartment type determines its width, depth, door position, transfer clearance and grab-bar configuration.
| Type | Typical measurement | What it does | Why |
|---|---|---|---|
| Wheelchair accessible | Confirm adopted standard | Provides wheelchair transfer and maneuvering space. | Requires coordinated toilet, door, clearance and grab bars. |
| Ambulatory | 35″–37″ wide; 60″ min deep | Supports walking users who need assistance. | Grab bars are typically placed on both sides. |
| Compartment door | Configuration-specific | Maintains the required minimum area. | Generally self-closing with compliant pulls and swing. |
The enclosure, seat, controls, spray, grab bars and approach clearance must function as one transfer system.
| Element | Typical requirement | What it does | Why |
|---|---|---|---|
| Transfer shower | Approximately 36″ × 36″ | Supports transfer to a shower seat. | Keeps controls and bars within reach. |
| Roll-in shower | Commonly 30″ × 60″ min under ADA | Allows wheelchair entry. | ANSI edition and shower type must be verified. |
| Threshold | Limited or prohibited by type | Controls the wheel barrier. | Supports safe entry and transfer. |
| Hand shower | Usually 59″ min hose | Allows seated bathing. | Must be reachable from the seat. |
| Tub or shower seat | Configuration-specific | Creates a stable bathing position. | Enclosures cannot obstruct transfer or controls. |
Clearances depend on whether the space is public, accessible residential, Type A or Type B. One layout does not fit every classification.
| Requirement | Typical criterion | What it does | Why |
|---|---|---|---|
| Work surface | Portion generally 34″ max AFF | Provides a seated work area. | Supports food preparation from a wheelchair. |
| Turning space | Per applicable layout | Allows maneuvering within the kitchen. | Especially important in enclosed and U-shaped plans. |
| Sink access | Knee/toe clearance where required | Allows forward approach. | Pipes must be protected from contact. |
| Appliance approach | Clear floor space required | Provides access to operable parts. | Controls should not require reaching across burners. |
| Storage | Required portion within reach | Makes shelves and cabinets usable. | Deep or high storage may be inaccessible. |
Where required, fountains must serve wheelchair users and standing users while avoiding protrusion hazards.
| Element | What it does | Why |
|---|---|---|
| Wheelchair fountain | Provides knee space, clear floor space and reachable controls. | Allows a forward approach. |
| Standing fountain | Places a second spout at standing height. | Serves users who have difficulty bending. |
| Cane detection | Controls projecting profiles. | Reduces collision risk for people with low vision. |
Accessible communication must work without relying exclusively on sight, hearing or decorative typography.
| Element | What it does | Why |
|---|---|---|
| Raised characters + Braille | Provides tactile permanent-room identification. | Assists users who are blind. |
| Contrast + non-glare finish | Improves visual readability. | Assists users with low vision. |
| Consistent mounting | Makes tactile signs predictable to find. | Users should not have to search a wall. |
| Audible alarm | Warns occupants through sound. | Provides an acoustic notification. |
| Visible strobe | Warns occupants through light. | Serves people who are deaf or hard of hearing. |
Parking only works when the stall, aisle, surface, signage, vertical clearance and route to the entrance all comply.
| Requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Car stall | 96″ min wide | Provides accessible parking. | Pairs with an adjacent access aisle. |
| Van stall | 132″ stall + 60″ aisle, or permitted equivalent | Accommodates vehicle ramps and lifts. | Provides additional transfer width. |
| Access aisle | 60″ minimum | Creates transfer and travel space. | Must connect to the accessible route. |
| Vertical clearance | 98″ minimum | Accommodates raised vans. | Applies along the applicable vehicular route. |
| Surface slope | 1:48 maximum | Creates a stable transfer surface. | Prevents wheelchairs from rolling during transfer. |
Accessible surfaces require both a usable height and an approach that remains clear.
| Requirement | Typical measurement | What it does | Why |
|---|---|---|---|
| Knee clearance | 27″ min high | Allows forward approach. | Supports seated dining, writing and work. |
| Clear width | 30″ minimum | Accommodates a wheelchair. | Keeps the usable position open. |
| Accessible surface | Commonly 28″–34″ AFF | Creates usable table height. | Supports both seated and standing users. |
| Service counter | Accessible portion generally 36″ max AFF | Lowers the transaction surface. | Supports communication and payment. |
Unit classifications are not interchangeable. Each carries different requirements for routes, doors, kitchens, bathrooms, controls and adaptability.
| Classification | What it does | Why it is used |
|---|---|---|
| Accessible unit | Provides the highest level of built-in accessibility. | Designed for immediate use by occupants with disabilities. |
| Type A unit | Provides accessible features and adaptable elements. | Often required for a percentage of units under building code. |
| Type B unit | Provides a baseline of accessibility and adaptability. | Commonly associated with Fair Housing requirements. |
| Type C / visitable unit | Provides limited visitability where adopted. | Allows a visitor with mobility limitations to use essential spaces. |
ICC A117.1 extends well beyond bathrooms and doors.
Elevators + liftsAssembly seatingDressing roomsSaunas + steam roomsStorageLaundryMailboxesHotelsMedical carePools + spasPlay areasExercise spacesOperable windowsTwo-way communication
The core test remains the same: can a person reach it, operate it and use it safely and independently?
The standards overlap but are not identical. ADA is federal law; ICC A117.1 becomes enforceable through adoption by a building code or jurisdiction.
| Topic | ICC A117.1-2017 | 2010 ADA Standards | Designer action |
|---|---|---|---|
| Clear floor space | Generally 30″ × 52″ | Generally 30″ × 48″ | Confirm all applicable standards and use the governing dimension. |
| Turning circle | Generally 67″ | Generally 60″ | Do not reuse an ADA-only room template on an ANSI 2017 project. |
| Enforcement | Through adopted building code | Federal civil-rights enforcement | Plan review approval does not necessarily settle ADA liability. |
Before finalizing documents, identify the governing regulations and verify every clearance after finishes, fixtures, casework and door swings are drawn.
This guide is educational and is not a substitute for the complete standard, construction documents, an architect, an accessibility specialist or the authority having jurisdiction.
No matching requirements
Try a broader term such as “door,” “toilet,” “route” or “counter.”