Here is a waste water treatment stairway that reaches four levels. This stair was fabricated in one section, spliced into four sections for shipping, and welded back together at the job site. At each level there is an access landing to the floor.
The stair is 60" in diameter, approximately 75 feet tall, and with one hundred twelve (112), 30 degree treads and four (4) 90 degree landings. The handrail is a # 200 (1 1/2") round tubing, balusters are # 302 (1") square tubing, two per tread, treads are a # 110 (12 gauge) checker plate steel, and the landings are made with # 420, 90 degree, square checker plate steel.
The center column is a heavy duty 3 1/2" ID schedule 40 round pipe. The finish is a standard red oxide primer with finish paint applied at the job site by others.