25 Stairs

U.S. ADA Access Board, Stairways
https://www.access-board.gov/guidelines-and-standards/buildings-and-sites/about-the-ada-standards/guide-to-the-ada-standards/chapter-5-stairways

Single Family Dwelling Stairways, Guards Handrails
https://www.escondido.org/Data/Sites/1/media/pdfs/Building/InfoGuideline19.pdf

Lecture Summary
https://openlab.citytech.cuny.edu/bt2-2023f/files/2019/05/25_Stairs_PDF.pdf