那是那是，版主說的對。我過去都是瞎說，人家都有，簡單明了

https://bbs.wenxuecity.com/fdcj/1811108.html

 

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.25

https://www.osha.gov/laws-regs/regulations/standardnumber/1917/1917.120#:~:text=Riser%20height%20shall%20be%20from,shall%20be%20straight%20leading%20edges.&text=Stair%20landings%20shall%20be%20at,(50.8%20cm)%20in%20depth.