BCAB #931 - Stair Winders, Article 188.8.131.52.
August 20, 1987
Re: Stair Winders, Article 184.108.40.206.
With reference to your letter of June 9, 1987, regarding winders and curved stairs within a dwelling unit.
You have included six diagrams, of which Nos. 2 to 6 seem generally to be acceptable, subject to compliance with other provisions. Design No. 1 is impossible to assess, as the information is inadequate. Part of your problem is dealt with under Appeal No. 853, a copy of which is attached. This included uniformity of run, not addressed in your diagrams.
With respect to winders there may be some misunderstanding of terms. Winders are basically treads negotiating a curve in direction. They may, or may not, converge to a point, but if they do then Article 220.127.116.11. applies. If they do not, they would be regarded as curved stairs falling under the provisions of Article 18.104.22.168. Every curved tread can be projected to a point, but this does not bring them under the control of Article 22.214.171.124.
J.C. Currie, Chair