I defaulted to 6” vs. 7” in determining the correct number of risers required. From my experience 6” is more suitable for a public building. 7” is more suitable for private residential. What code are we required to rely upon? For me 7” would typically not cut it with the Building Department.
Let me ping one of our experts and see if she can answer this question @heatherrivera
For context, this is in reference to this question from our most recent ARE Live
The 3 story office building you are designing has 9’-0” ceiling heights throughout. In trying to formalize the building sections and the egress stair layout, you review with the structural engineer and the MEP engineer and receive the following information: Structural wide flange beams and girders are 21” max, the corrugated steel deck with the concrete fill is 5” max, the largest duct is likely to be 40”x24”, and the clear area above the dropped ceiling for light fixtures and the sprinkler layout is expected to be 10”. How many stair risers are there between the 2nd floor and 3rd floor?
Thank you. Upon thinking about it Further. In the past, We used to max out at 6.75” to allow room for tolerance in case the contractor exceeds the 7” requirement. So in fact 7” is correct.
I hear you with wanting to give yourself tolerance with the GC, but the ARE is pretty Utopian (and not always practical in terms of the real world and human error). You’ll want to use the 2015 IBC as your baseline for this exam. 1011.5.2 will go over the riser height and tread depth: 7-11 is the magic ratio. For comparison, single family residential (IRC) lets you have it a bit steeper: 7.75-10 (R311.5.3).
Thank you for clarifying. Very helpful to know what our go to source should be!
Heather, great point about the ARE being pretty utopian… that’s a good way to think about it… & good question Pierre thanks for asking!
Candidate: All of these options are correct?
NCARB: But which is THE MOST correct??
No problem Marc. My pleasure.
For the sake of the community here. I have been working in the profession for about 18 years. I have not once used a true 7” riser on a public project application in the US. Overseas is a different story. Construction tolerance is the name of the game and in fact it would be unwise not to use them even though 7” is a perfectly allowable answer in the case of this specific question.
Unlearning almost two decades of real world applications has by far been my biggest challenge irrelevant of any one of the 6 divisions. Finding the BEST answer on these questions seems contradictory to the Standard Of Care we are measured to in the real world.
I appreciate the transparency here with all of the replies. Very beneficial and much appreciated.
Thank you all! The example of NCARB’s Utopian world is spot on and I hope to be able to adapt to it for the benefit of passing these exams.
In reference to the number of risers between the 2nd and 3rd floors of the 3 story Bldg. the real answer is 24- using 7" risers- is this correct? right Heather
Can you please send me the link to access the last ARE live of Project Development & Documentation Mock Exam aired on 1/30/20, I had to work and had to miss it.
Can you please send me a link to the the study set of the AIA and IBC . I am particularly in need of the A, B and General conditions
When you say “study set”, can you be more specific?
I know that there is student/study set of the General Conditions A101, A201, B101, B201 that the AIA has specifically available for us taking the ARE a copy with large letters written diagonally saying (think) SAMPLE, and I believe (not sure) that there is a similar copy of the IBC specifically for us students, check with heather or Mr. Newman.
Oh yes! the study set is available for free, can you help me with the link