What is your take on circular stair cases. I am well aware that they are a dangerous means of emergency egress. Could they be the only means to access an area? Do 4" and 6" sphere measurements apply? Tread sizing matter?
The same (almost) requirements exist for circular as for other stairs.
The minimum requirements have changes in recent years but none the less many of standard stair requirements exist for circular stairs.
IRC Stair Building Code
R318.104.22.168 Spiral stairways. Spiral stairways are permitted, provided the minimum clear width at and below the handrail shall be 26 inches (660 mm) with each tread having a 71/2-inch(190 mm) minimum tread depth at 12 inches (914 mm) from the narrower edge. All treads shall be identical. and the rise shall be no more than 91/2inches (241mm). A minimum headroom of 6 feet 6 inches (1982mm) shall be provided (See above diagram).
Minimum clear walking path of 26 inches. A 5-foot diameter or larger stair will provide this width.
Each tread will have a minimum of 7 1/2 inch tread depth at 12 inches from the narrow edge.
All treads will be identical.
The tread rise shall not be more than 9 1/2 inches high.
Minimum headroom of 6 foot 6 inches shall be provided, measuring plumb from the edge of the platform down to the tread below.
Landing width shall not be less than the required width of the stairway. Minimum spiral stair tread width is 26 inches. (Salter’s code platforms start at 31 inches wide.)
Stair balusters shall be spaced so a 4-inch object cannot pass between. The IRC Code permits a 4 3/8 inch space.
Balcony/Well Enclosure guardrail balusters shall be spaced so a 4-inch object cannot pass.
Balcony/Well Enclosure guardrail height shall not be less than 36 inches. (If your state or municipality requires 42-inch tall guardrails, the sales order must reflect this detail.)
The stairway shall be equipped with one handrail on the wide edge of the tread.
Handrail height, measured vertically from the tread nosing, shall be not less than 34 inches and not more than 38 inches.
Handrail grip size.
Type I-Handrails with a circular cross section shall have an outside diameter of at least 1 1/4 inches and not greater than 2 inches. (Salter’s standard circular handrail is 1 1/2 inch diameter. This will address the UBC minimum cross section of 1 1/2 inch diameter.) If the handrail is not circular, it shall have a perimeter dimension not greater than 6 1/4 inches.
Type II-Handrails, with a perimeter greater than 6 1/4 inches, shall provide a graspable finger recess area on both sides of the profile. For further information on our Type II options, please contact our sales department.
(Verify what handrail size and shape your inspector will require. Handrail size and shape are a very controversial area within the building code. We recommend that you use our standard 1 1/2″ round handrails or our 1 3/4″ x 1 3/4″ solid wood handrail to comply with the proper circumference.)
A 300 lb. concentrated load is required.
Just because they put it in doesn’t make it safe - call it out as unsafe and let them figure it out. If you don’t call it out and somebody falls down the spiral stair it will be on you, so just make them aware of the safety issues and don’t get caught up on the codes.
Really? What’s safe is subjective. I like to kayak but they aren’t very safe.
How can an inspector say something isn’t safe if it meets the minimum code? If someone falls down the stairs it isn’t the home inspectors fault.
We see these in Chicago quite a bit.
I am 6’4" tall and 235 lbs. These stairs are brutal to ascend and descend, let alone get furniture up there. Thank god for a balcony to the rear yard.
I appreciate all the input! The stairs were spot on in the specs. But I did call it as a hazard in an emergency egress situation, for small children and the elderly. I recommended that they consider adding another means of exiting the guest bedroom suite being installed in the future.