Door Butt Hinge vs. Stair Building Code Dimensions
Comparing 2 standards across 14 specifications. 14 key differences identified.
Standard door butt hinges under ANSI/BHMA A156.1 standardize hinge leaf dimensions, corner radius mortises, leaf thickness, and screw hole template patterns. Sized in 3.5×3.5" for 1-3/8" residential interior doors, 4.0×4.0" for 1-3/4" solid doors, and 4.5×4.5" for commercial ball-bearing fire doors, hinges maintain standardized spacing along door edges.
Residential stair construction is strictly regulated under the International Residential Code (IRC Section R311.7) and OSHA into mandatory geometric limits: maximum 7-3/4 inch (197 mm) riser height, minimum 10 inch (254 mm) tread run depth, 36 inch minimum width, 6'8" headroom, and 34–38 inch handrail height.
Specification Comparison Table
14 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
ANSI/BHMA A156.1 / SDI-100 / NFPA 80 | IRC Section R311.7 (Residential) / IBC Section 1011 (Commercial) / OSHA 1910.25 |
|
3.5" Residential Hinge
|
3.5 × 3.5" (89 × 89 mm) | Leaf: 0.085" (2.2 mm) | 1-3/8" hollow-core doors | — |
|
4.0" Heavy Residential Hinge
|
4.0 × 4.0" (102 × 102 mm) | Leaf: 0.097" (2.5 mm) | 1-3/4" solid-core entry doors | — |
|
4.5" Commercial Hinge
|
4.5 × 4.5" (114 × 114 mm) | Leaf: 0.134"–0.180" | Ball-bearing fire doors | — |
|
Corner Radius Types
|
Square corner | 1/4" radius (dime size) | 5/8" radius (quarter size) | — |
|
Top Hinge Standard Spacing
|
5.0 inches (127 mm) down from top edge of door to top of hinge | — |
|
Bottom Hinge Standard Spacing
|
10.0 inches (254 mm) up from finished floor to bottom of hinge | — |
|
Maximum Riser Height
|
— | 7-3/4 inches (197 mm) IRC Residential | 7.0 inches (178 mm) IBC Commercial |
|
Minimum Riser Height
|
— | 4.0 inches (102 mm) | Prevents tripping from unexpectedly shallow steps |
|
Minimum Tread Run Depth
|
— | 10.0 inches (254 mm) IRC with nosing | 11.0 inches (279 mm) IBC Commercial |
|
Maximum Riser / Tread Tolerance
|
— | Maximum 3/8 inch (9.5 mm) variance between the tallest and shortest riser in a single flight |
|
Minimum Stairway Clear Width
|
— | 36 inches (914 mm) clear width above handrail height (IRC R311.7.1) |
|
Minimum Vertical Headroom
|
— | 6 feet 8 inches (2032 mm / 80 in) measured vertically from the sloped tread nosing line |
|
Handrail Height Standard
|
— | 34 to 38 inches (864 to 965 mm) measured vertically from the leading edge of stair treads |