The Code distinguishes four principal types of stair treads:
- rectangular treads, which are found in straight flights;
- tapered treads are found in curved flights;
- winders are described in Appendix Note A-9.8.4.6.; and
- spiral stairs are described in Appendix Note A-9.8.4.7. See Figure A-9.8.4.-A.
Types of Treads
Articles 9.8.4.1. to 9.8.4.8. specify various dimensional limits for steps. Figure A-9.8.4.-B illustrates the elements of a step and how these are to be measured.
