Planning and Dimensional
Information

16 Ft. - 11 In. Diameter, Quarter Turn Series, Spiral Stair

Stock Number: USS1611-117-QT
Stair Diameter: 16'- 11" (5.16mm)
Minimum Opening: 104' x 111" (264.16cm x 281.94cm)
Outside Radius: 101 - 1/2" (257.81cm)
Inside Radius: 58 - 1/2" (148.59cm)
Stringer Width, Outer: 11 - 1/4" (28.58cm)
Stringer Width, Inner: 10" (25.4cm)
Stringer Thickness: 2" (50.8mm) - Opt. 2 - 1/2" (63.5mm) or 3" (76.2mm)
Tread Width at Outer Stringer: 13 - 3/4" (34.93cm)
Tread Width at Inner Stringer: 9" (22.86cm)
Tread Thickness: 1 - 1/2" (38.1 mm)
Tread Passageway: 39" (99.06cm) - Opt. 37" (93.98cm) or 38" (96.52cm)
Handrail Width: 4 - 1/2" (11.43cm) - Opt. 5 - 1/2" (13.97cm) or 6 - 1/2" (16.51cm)
Handrail Thickness: 2" (50.8mm) - Opt. 2 - 1/2" (63.5mm) or 3" (76.2mm)
Baluster Spacing: Approx. 6" (15.24cm), - Opt. 4" (10.16cm), or alternating 2", 3", 2"
Turn per Inch of Rise: 0.8824 Degrees
Rise per Degree of Turn: 1.133" (28.78mm)

Floor to Floor

Risers Degrees of Turn
74" to 82" (187.96cm to 208.28cm) 10 59 to 65 Degrees
>82" to 90" (208.28cm to 228.60cm) 11 65 to 72 Degrees
>90" to 98" (228.60cm to 248-92cm) 12 72 to 79 Degrees
>98" to 106" (248.92cm to 269.24cm) 13 79 to 86 Degrees
>106" to 114" (269.24cm to 289.56cm) 14 86 to 93 Degrees
>114" to 122" (289.56cm to 309.88cm) 15 93 to 100 Degrees
Tread Capacity
lbs. / kgs.
1260 / 572 Stair Capacity
lbs. / kgs.
@ 114" Ht.
10,544 / 4786

Specifications for heights up to 190" (4.83m) are available upon request.