Chapter 8 - Stairs Flashcards
What is a stair?
Change in elevation consisting of one or more risers
A _______ is the vertical component that connects two ________.
Riser, treads
A stairway is one or more ______________.
Flights of stairs
Stairways serving an occupant load of _____ or more must be at least _______in wide (or as wide as determined by multiplying the occupant load by 0.3 or 0.2)
50, 44 inches
Stairways serving an occupant load of ____ or less must not be less than _____in wide.
49, 36 inches
Handrails may project into the required width _____in on each side.
4 1/2”
The risers on a stair cannot be less than ___” or more than ____” and the tread must not be less than ____”
4”, 7”, 11”
Risers for barrier free stairs cannot exceed ___” and treads must have an acceptable nosing design.
7”
For good design, determine either the required riser or tread and then use the stair formula: ____________.
2R + T = 25”
For residential occupancies and private stairways, serving an occupant load less than 10, the maximum riser may be _____” and the minimum tread may be ____”.
7 3/4”, 10”
Winding, curved, and spiral stairways may be used as exits in ________ ___-__ occupancies and in private stairways of Group R-1 occupancies, only if they meet certain design conditions as specified in the code.
Group R-3,
___________ must be provided at the top and bottom of every exit stairway. The minimum dimension in the direction of travel must not be _____________________________________ but need not be more than ____” if the stair is a straight run.
Landings, less than the width of the stair, 48”
An _________ _______ __________ (as well as an interior exit ramp) is an exit component that serves to meet one or more means-of-egress requirements. An ______ _______ __________ is an interior stairway that is not a required exit stairway such as a monumental stair serving two floors of a retail store.
interior exit stairway, exit access stairway
Interior exit stairways must be completely enclosed because ________________________________________.
vertical shafts provide the most direct path for fire and smoke spreading from floor to floor.
In buildings ______ or more stories high, interior exit stairways must be enclosed with 2-hour-rated walls. In buildings less than _____ stories high, 1-hour rated construction is required.
four, four
Do stories include basements? Do stories include mezzanines?
Yes, no
What are two most common exceptions in which stairways are not required to be enclosed?
- Exit access stairways that serve only two stories (exceptions are Group I-2 and I-3 occupancies).
- Exit access stairways for a single residential dwelling unit of sleeping unit in Group R-1, R-2, or R-3.
List two more common exceptions in which stairways are not required to be enclosed.
- In Group B or M occupancies (with automatic sprinklers), the area of the floor opening between stories is not more than twice the horizontal projected area of the stairway, and the opening is protected by a draft curtain and closely spaced sprinklers in accordance with NFPA 13.
- In occupancies other than Group B and M, if the occupancy complies with all items in previous exception AND the floor opening does not connect more than four stories.
