Intercommunicating stairways are stairways which connect two or more floor
levels of a building. They may be open to one floor level. They are not
required to discharge directly to grade. Intercommunicating stairways shall
comply with subsections (b)-(q) when used as a required means of
stairways shall be Class A or Class B types in accordance with the following
||Class A Stair
||Class B Stair
|Minimum clear width in inches
|Maximum height of riser
|Minimum width of tread
|Maximum angle of stairs in degrees
|Required handrails (Each handrail is allowed to
project 3" without decreasing the minimum clear width)
||One side under 40" in width, both
sides 40" or more in width
|Maximum vertical distances between
(c) The minimum width of landings shall be
the same width as the stairs they serve. Intermediate landings on straight run
stairs shall have a minimum length of 3 feet.
(d) The narrowest width in a stairway or
landing serving a stairway shall determine the units of width for the entire
(e) There shall be no
variation in the width of treads or the height of risers in any flight.
Variation in height of risers in adjacent flights shall not exceed 1/4 inch.
All treads less than 10 inches, as measured horizontally between the face of
risers, shall have an effective projection of approximately 1 inch beyond the
face of the riser below.
material of stair treads and landings is such as to present a danger of
slipping, nonskid material shall be applied.
(g) No arrangement of treads known as winders
shall be permitted in required exit stairways.
(h) All stairways, landings, balconies, open
sided floors, and the like shall have well secured handrails. The clear
distance between handrail and wall or other obstruction shall be not less than
1 1/2 inches. Longitudinal rails or balusters or both shall be provided.
Balusters shall be spaced not more than 6 inches apart. Longitudinal rails
shall not exceed 6 inches measured at right angles to the rails. The lowest
rail shall be measured vertically from the tread nosing.
(i) Handrails on stairs shall be not less
than 30 inches nor more than 34 inches above the upper surface of the tread,
measured vertically to the top of the rail, from a point on the tread 1 inch
back from the leading edge.
Handrails shall be provided on any stair landing, balcony, ramp, aisle, and the
like located along the edge of open sided floors or mezzanines to prevent falls
over the open side. Railings protecting open sides of landings, balconies,
mezzanines, and the like shall be at least 42 inches high.
(k) Storage or obstructions of any kind shall
not be permitted in stairways.
A door opening into a stairway shall at no point in its swing reduce the
required units of width of the stair or landing.
(m) Every door to a stairway shall open onto
a landing at least as wide as the stairs.
(n) Doors and frames used in connection with
stairways shall be of approved label and be of substantial construction,
installed in a workmanlike manner, fitted with reliable hardware of approved
label and shall be of the side hinged, swinging type.
(o) Stairway doors shall swing with the exit
(p) Stairway doors shall be
provided with panic hardware or fire exit hardware. No lock or other device
which prevents egress shall be permitted on such doors during any period of
(q) Stairway doors shall
be a minimum of 32 inches in width. All doors used in connection with stairways
shall be a minimum of 6 feet, 8 inches in height.