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CBC 11B-505.2.1 Orientation

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formdb

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Mar 29, 2018
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34
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California
Had a question regarding a specific code section in the California Building Code. The model code states:

11B-505.2 Where required. Handrails shall be provided on both sides of stairs and ramps.

The CBC adds in an italicized section:

11B-505.2.1 Orientation. The orientation of at least one handrail shall be in the direction of the stair run, perpendicular to the direction of the stair nosing, and shall not reduce the minimum required width of the stair.

So let's say I have an exit access stair, and the minimum required width is 44". 1014.8 tells me I can project into the required width of my stairway up to 4-1/2" at or below the handrail. This section seems to suggest that I am not able to project into the required width for one of the two handrails. Am I reading this wrong?
 
formdb said:
Had a question regarding a specific code section in the California Building Code. The model code states:

11B-505.2 Where required. Handrails shall be provided on both sides of stairs and ramps.

The CBC adds in an italicized section:

11B-505.2.1 Orientation. The orientation of at least one handrail shall be in the direction of the stair run, perpendicular to the direction of the stair nosing, and shall not reduce the minimum required width of the stair.

So let's say I have an exit access stair, and the minimum required width is 44". 1014.8 tells me I can project into the required width of my stairway up to 4-1/2" at or below the handrail. This section seems to suggest that I am not able to project into the required width for one of the two handrails. Am I reading this wrong?
Click to expand...

I can't pull down that section of code from the web, Cali has that page blanked out on the ICC free view, but i would love to see the interpretation they have for it, based on the reading I would venture a guess they added it to stop architects from curving handrails on straight flights of stairs with requiring the handrails at the intersection point of each stair tread for the handrail above to be 90 degrees to the edge. Not sure why they see a need to add this with 505.10 already specifying "in the direction of travel for the extensions. But they did, but the italic is a specific modification by Cali and I would ask for a clarification from their state level code technical department and how it works with the other sections like 1014.8 and 11B-505.10.

There seems to be two contradictions in the standard code language, because they need to define if the stair flights width needs to be between one handrail and the opposite side of the stair flight or above the handrails and the projections are allowed on both sides.

And the second is saying that one handrail is allowed to change direction and not follow the requirements of 505.10 with the handrails following the direction of the stair flight travel for the handrail extensions. Wish I had more information on this, but without being able to read everything else around it and a clarification from the state technical staff, I would be guessing just like you. Good luck and post a result, once you get the final answer... Regards Tom
 
Have you viewed the DSA Access interpretive manual with comments? It is under DSA publications on their website.
 
I hadn't looked at that prior to you mentioning it, but there's nothing there addressing this issue directly.

However, I was able to get on the phone with the senior architect with DSA, and she confirmed what I was beginning to suspect. 11B-505.2.1 is addressing stairs that do not have parallel sides. For instance, a wedge-shaped flight that is wider at the bottom than it is at the top. You can imagine that the side that is not perpendicular to the tread nosings would be more difficult to navigate. This section essentially requires one of the two sides to be perpendicular to the nosings.

The last line of the section about the width is stating that the handrail perpendicular to the nosings (the one that would be installed along the straight wall) would not be allowed to reduce the required stair width. So your stair width would be from the outside edge of that handrail to the face of the angled wall, rather than from wall to wall. Hopefully that makes sense.

This is an interesting condition to think about, because at that angled wall, your handrail extensions would want to continue "in the direction of travel" at the landings... if you have an angled side, would they follow that angle, or turn at the landing and follow the 'direction of travel' (perpendicular to the stair nosings)? If it needs to follow the angle, the extensions could really pinch your landing widths and force you to have a wider stair than required. Which would in turn force your landing width in the direction of travel to increase... quite a complicated little code section to consider.

To put a fine point on it though, stair flights with parallel sides are not subject to 11B-505.2.1. It would be nice if that section was prefaced with, "At stairs without parallel sides..."
 
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