2.2 Turning Space and Clear Floor Space: New Versus Existing Buildings
Key Takeaways
In new buildings a circular turning space is 67 inches in diameter; in existing buildings it is 60 inches (A117.1-2017 304.3.1).
New-building T-shaped turning spaces have three permitted configurations (68 x 60 with chamfers, 64 x 60 with 38/42-inch legs, or 64 x 60 with 40-inch legs); existing buildings use a T within a 60-inch square with 36-inch legs.
Clear floor space is 30 x 52 inches in new buildings and 30 x 48 inches in existing buildings, with slopes not steeper than 1:48 and no changes in level.
Knee and toe clearance may overlap a new 67-inch circle only 10 inches deep, no deeper than the clearance provided, and only within the permitted area.
Alcoves: a parallel approach needs a 60-inch-wide alcove where it is more than 15 inches deep (305.7.1); a forward approach needs 36 inches where it is more than 24 inches deep (305.7.2).
2.2 Turning Space and Clear Floor Space: New Versus Existing Buildings
Wheelchair Turning Spaces (3%) and Clearances (2%) are separate subtopics in the Building Blocks domain, and both changed significantly in ICC A117.1-2017. The 2017 edition is based on anthropometric research on wheeled mobility devices that found many current wheelchairs and scooters need more room than the 2009 dimensions. Larger "new buildings and facilities" dimensions were added, and the 2009 dimensions were kept for "existing buildings and facilities." Using the old numbers for new construction is the most common error on this topic.
General Rules (Sections 301 to 305)
- 301.2 Overlap: Unless specifically stated otherwise, clear floor spaces, clearances at fixtures, maneuvering clearances at doors and turning spaces may overlap.
- 304.2 and 305.2 Floor surfaces: Comply with Section 302. Changes in level are not permitted; slopes not steeper than 1:48 are allowed.
- 304.4 Door swing: Unless otherwise specified, doors may swing into turning spaces.
- 305.4: Unless otherwise specified, clear floor space may include knee and toe clearance complying with Section 306.
Turning Space (Section 304)
Circular Turning Space (304.3.1)
| Condition | Diameter | Knee and toe overlap |
|---|---|---|
| New buildings and facilities (304.3.1.1) | 67 in. (1700 mm) minimum | Permitted only if the overlap is 10 in. maximum deep, no deeper than the knee and toe clearance provided, and only within the area shown in the figure (304.3.1.1.1) |
| Existing buildings and facilities (304.3.1.2) | 60 in. (1525 mm) minimum | Knee and toe clearance complying with 306 permitted (304.3.1.2.1) |
T-Shaped Turning Space (304.3.2)
New buildings (304.3.2.1) may use any one of three configurations:
| New-building option | Envelope | Arm and base widths | Arm and base extension |
|---|---|---|---|
| 1 | 68 in. wide x 60 in. deep | Arms and base 36 in. minimum | Each arm 16 in. from each side of the base; base 24 in. from the arms; interior corners chamfered 8 in. along both the arm and the base |
| 2 | 64 in. wide x 60 in. deep | Arms 38 in.; base 42 in. | Each arm 11 in. from each side of the base; base 22 in. from each arm |
| 3 | 64 in. wide x 60 in. deep | Arms and base 40 in. | Each arm 12 in.; base 20 in. |
In new T-shaped spaces, knee and toe clearance may be included in the base or one arm (for the first configuration, only the portion beyond the chamfer).
Existing buildings (304.3.2.2) use the familiar T: a T-shaped space within a 60-inch square with arms and base 36 in. wide, each arm clear for 12 in. in each direction and the base clear for 24 in. Knee and toe clearance is permitted only at the end of either the base or one arm.
Clear Floor Space (Section 305)
| Condition | Size |
|---|---|
| New buildings and facilities (305.3.1) | 30 in. wide x 52 in. long minimum |
| Existing buildings and facilities (305.3.2) | 30 in. wide x 48 in. long minimum |
Section 305.5 positions the space for a forward or parallel approach, unless an element specifies one. Section 305.6 requires one full unobstructed side of the clear floor space to adjoin or overlap an accessible route or adjoin another clear floor space.
Alcoves (305.7)
When a clear floor space is in an alcove or otherwise confined on all or part of three sides, extra maneuvering width is required. Note the section numbers: in A117.1-2017 the parallel approach is 305.7.1 and the forward approach is 305.7.2.
| Approach | Trigger depth | Required alcove width |
|---|---|---|
| Parallel (305.7.1) | Depth more than 15 in. | 60 in. minimum |
| Forward (305.7.2) | Depth more than 24 in. | 36 in. minimum |
Applying the Rules
Worked Example 1: New Toilet Room
A new single-user toilet room must contain a turning space (Section 603.2.1). The designer shows a 60-inch circle. Because the building is new, the circle must be 67 inches, or the designer must show one of the three new-building T configurations. A 60-inch circle would be acceptable only in an existing building.
Worked Example 2: Using Knee Space in a New Circle
A lavatory provides knee and toe clearance 17 inches deep. In a new building, the 67-inch turning circle may overlap that clearance by no more than 10 inches, so at least 57 inches of the circle's 67-inch diameter must lie outside the area beneath the lavatory. In an existing building with a 60-inch circle, the standard simply permits knee and toe clearance complying with Section 306 to be included.
Worked Example 3: Vending Machine Alcove
A vending machine sits in an alcove 20 inches deep and 48 inches wide, approached in parallel. Because the depth exceeds 15 inches, Section 305.7.1 requires the alcove to be 60 inches wide. The design fails; either widen the alcove or reduce its depth to 15 inches or less.
Exam Traps
| Trap | Correct rule |
|---|---|
| "Turning space is a 60-inch circle" | Only in existing buildings; new is 67 in. |
| "Clear floor space is 30 x 48" | Only in existing buildings; new is 30 x 52 |
| Swapped alcove numbers | 305.7.1 parallel (15 in./60 in.); 305.7.2 forward (24 in./36 in.) |
| Unlimited knee space in a new circle | 10 in. maximum overlap depth |
| Doors may never swing into turning spaces | 304.4 permits it unless a specific section says otherwise (for example, toilet room door swing into fixture clear floor spaces, Section 603.2.2) |
A new medical office building is designed with circular turning spaces in its toilet rooms. Under ICC A117.1-2017, what minimum diameter is required?
60 inches
64 inches
67 inches
72 inches
A clear floor space for a forward approach to a drinking fountain in a new building sits in an alcove 26 inches deep. What is the minimum alcove width and the minimum clear floor space length?
30 inches wide; 48 inches long
36 inches wide; 52 inches long
60 inches wide; 52 inches long
36 inches wide; 48 inches long
In a new building, how much knee and toe clearance under a counter may be counted as part of a 67-inch circular turning space?
The full 25-inch maximum knee clearance depth
Up to 17 inches, matching the minimum toe clearance
None; knee space may never overlap a turning space in new construction
Up to 10 inches, and no deeper than the knee and toe clearance actually provided
Sections you finish are checked off in the contents.