Planning and Dimensional
Information

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

Stock Number: USS70-20-HT
Stair Diameter: 7" - 0' (213.36cm)
Minimum Opening: 44" x 86" (109.22cm x 218.44cm)
Outside Radius: 42" (106.68cm)
Inside Radius: 10" (25.4cm) - Opt. 6" (15.24cm) or 12" (30.48cm)
Stringer Width, Outer 10 -1/2"  (26.67cm)
Stringer Width, Inner: 5 - 3/4" (14.61cm)
Stringer Thickness: 1 - 1/2" (38. 1mm)
Tread Width at Outer Stringer: 13"  (33.02cm)
Tread Width at Inner Stringer: 5" (12.7cm)
Tread Thickness: 1 -1/2" (38.1mm)
Tread Passageway: 29" (73.66cm) - Opt. 27" (68.58cm) or 33" (83.82cm)
Handrail Width:  3 -1/2" (8.89cm) - Opt. 4 -1/2" (11.43) or 5 -1/2" (13.97cm)
Handrail Thickness: 1 -1/2" (38.1mm)
Baluster Spacing: Approx 6" (15.24cm), - Opt. 4" (10.16cm), or alternating 2", 3", 2"
Turn 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 228.28cm) 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.
745 / 338 Stair Capacity
lbs. / kgs.
@ 114" Ht.
2884 / 1309

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