Planning and Dimensional
Information

8 Ft. - 0 In. Diameter, Half Turn Series, Spiral Stair

Stock Number: USS80-24-HT
Stair Diameter: 8' - 0" (243.84cm)
Minimum Opening: 50" x 98" (27cm x 248.92cm)
Outside Radius: 48" (121.92cm)
Inside Radius: 12" (30-48cm) - Opt. 10" (25.4cm)
Stringer Width, Outer: 11" (27.94cm)
Stringer Width, Inner: 5 - 3/4" (14.61cm)
Stringer Thickness: 1 - 1/2" (38.1mm) - Opt. 2" (50.8mm)
Tread Width at Outer Stringer: 14" (35.56cm)
Tread Width at Inner Stringer: 5" (12.7cm)
Tread Thickness: 1 - 1/2" (38.1mm)
Tread Passageway: 33" (83.82cm) - Opt. 32" (81.28cm), 34" (86.36cm), 35" (88.9cm)
Handrail Width: 3 - 1/2" (8-89cm) - Opt. 4 - 1/2" (11.43) or 5-1/2" (13.97cm)
Handrail Thickness: 1 - 1/2" (38.1 mm) - Opt. 2" (50.8mm)
Baluster Spacing: Approx. 6" (15.24cm), - Opt. 4" (10.16cm), or alternating 2", 3", 2"
Tum per Inch of Rise: 1.816 Degrees
Rise per Degree of Turn: 0.55"  (13.97mm)
Floor to Floor Riser Degrees of Turn
74" to 82" (187.96cm to 208.28cm) 9 119 to 132 Degrees
>82" to 90" (208.28cm to 228,60cm) 10 132 to 147 Degrees
>90" to 98" (228.60cm to 248.92cm) 11 147 to 161 Degrees
>98" to 106" (248.92cm to 269.24cm) 12 161 to 176 Degrees
>106" to 114" (269.24cm to 289.56cm) 13 176 to 191 Degrees
>114" to 122" (289.56cm to 309.88cm) 14 191 to 206 Degrees
>122" to 130" (309.88cm to 330.20cm) 15 206 to 220 Degrees
Tread Capacity
lbs. / kgs.
790 / 358 Stair Capacity
lbs. / kgs.
@ 114" Ht.
2666 / 1210

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