NCARB 3.1 Stair Vignette

Ramp, Stair, & Roof Vignettes and Multiple Choice

NCARB 3.1 Stair Vignette

Postby kajmera » Wed Apr 04, 2018 8:50 pm

Trying the 3.1 Stair vignette. The stair is 4'8" wide and has 11" treads through out, but the riser height changes between the first flight and the 2 flights connecting to second floor. One question - the prompt says:
"The area of refuge shall be sized to accommodate one wheel-chair space of 30 inches by 48 inches for each 200 occupants, or portion thereof, based on the stairway occupant load".

I thought that would mean we have to provide 3 wheelchair spaces (30" x 48" each) since the occupant load for second floor is 440. However, I only provided one because that's what other solutions here have. Can someone explain the logic to me please? Is it always just one 30"x48" space regardless of the occupant load?

Thank you in advance for any other feedback! :)
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Re: NCARB 3.1 Stair Vignette

Postby Coach » Wed Apr 04, 2018 11:57 pm

kajmera wrote:I thought that would mean we have to provide 3 wheelchair spaces (30" x 48" each) since the occupant load for second floor is 440. However, I only provided one because that's what other solutions here have. Can someone explain the logic to me please? Is it always just one 30"x48" space regardless of the occupant load?

2nd floor load is 220. Stair load is 110.

AOR appears to reduce required egress width.
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Re: NCARB 3.1 Stair Vignette

Postby kajmera » Fri Apr 06, 2018 4:03 pm

Oh, I see it now. I guess I should've extended the landing
Coach wrote:
kajmera wrote:I thought that would mean we have to provide 3 wheelchair spaces (30" x 48" each) since the occupant load for second floor is 440. However, I only provided one because that's what other solutions here have. Can someone explain the logic to me please? Is it always just one 30"x48" space regardless of the occupant load?

2nd floor load is 220. Stair load is 110. Oh I see because there are 2 exits on 2nd floor (220/2). So, I could possibly need more than one AOR space if the stair load is more than 200.

AOR appears to reduce required egress width. Ok, I will make a note of that. I guess I should have extended the landing west and placed AOR above the stair.
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