[Code of Federal Regulations]
[Title 29, Volume 5]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.24]
[Page 120-121]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS--Table of Contents
Subpart D_Walking-Working Surfaces
Sec. 1910.24 Fixed industrial stairs.
(a) Application of requirements. This section contains
specifications for the safe design and construction of fixed general
industrial stairs. This classification includes interior and exterior
stairs around machinery, tanks, and other equipment, and stairs leading
to or from floors, platforms, or pits. This section does not apply to
stairs used for fire exit purposes, to construction operations to
private residences, or to articulated stairs, such as may be installed
on floating roof tanks or on dock facilities, the angle of which changes
with the rise and fall of the base support.
(b) Where fixed stairs are required. Fixed stairs shall be provided
for access from one structure level to another where operations
necessitate regular travel between levels, and for access to operating
platforms at any equipment which requires attention routinely during
operations. Fixed stairs shall also be provided where access to
elevations is daily or at each shift for such purposes as gauging,
inspection, regular maintenance, etc., where such work may expose
employees to acids, caustics, gases, or other
[[Page 121]]
harmful substances, or for which purposes the carrying of tools or
equipment by hand is normally required. (It is not the intent of this
section to preclude the use of fixed ladders for access to elevated
tanks, towers, and similar structures, overhead traveling cranes, etc.,
where the use of fixed ladders is common practice.) Spiral stairways
shall not be permitted except for special limited usage and secondary
access situations where it is not practical to provide a conventional
stairway. Winding stairways may be installed on tanks and similar round
structures where the diameter of the structure is not less than five (5)
feet.
(c) Stair strength. Fixed stairways shall be designed and
constructed to carry a load of five times the normal live load
anticipated but never of less strength than to carry safely a moving
concentrated load of 1,000 pounds.
(d) Stair width. Fixed stairways shall have a minimum width of 22
inches.
(e) Angle of stairway rise. Fixed stairs shall be installed at
angles to the horizontal of between 30[deg] and 50[deg]. Any uniform
combination of rise/tread dimensions may be used that will result in a
stairway at an angle to the horizontal within the permissible range.
Table D-1 gives rise/tread dimensions which will produce a stairway
within the permissible range, stating the angle to the horizontal
produced by each combination. However, the rise/tread combinations are
not limited to those given in Table D-1.
Table D-1
------------------------------------------------------------------------
Tread
Angle to horizontal Rise (in run (in
inches) inches)
------------------------------------------------------------------------
30[deg]35[min]...................................... 6\1/2\ 11
32[deg]08[min]...................................... 6\3/4\ 10\3/4\
33[deg]41[min]...................................... 7 10\1/2\
35[deg]16[min]...................................... 7\1/4\ 10\1/4\
36[deg]52[min]...................................... 7\1/2\ 10
38[deg]29[min]...................................... 7\3/4\ 9\3/4\
40[deg]08[min]...................................... 8 9\1/2\
41[deg]44[min]...................................... 8\1/4\ 9\1/4\
43[deg]22[min]...................................... 8\1/2\ 9
45[deg]00[min]...................................... 8\3/4\ 8\3/4\
46[deg]38[min]...................................... 9 8\1/2\
48[deg]16[min]...................................... 9\1/4\ 8\1/4\
49[deg]54[min]...................................... 9\1/2\ 8
------------------------------------------------------------------------
(f) Stair treads. All treads shall be reasonably slip-resistant and
the nosings shall be of nonslip finish. Welded bar grating treads
without nosings are acceptable providing the leading edge can be readily
identified by personnel descending the stairway and provided the tread
is serrated or is of definite nonslip design. Rise height and tread
width shall be uniform throughout any flight of stairs including any
foundation structure used as one or more treads of the stairs.
(g) Stairway platforms. Stairway platforms shall be no less than the
width of a stairway and a minimum of 30 inches in length measured in the
direction of travel.
(h) Railings and handrails. Standard railings shall be provided on
the open sides of all exposed stairways and stair platforms. Handrails
shall be provided on at least one side of closed stairways preferably on
the right side descending. Stair railings and handrails shall be
installed in accordance with the provisions of Sec. 1910.23.
(i) Vertical clearance. Vertical clearance above any stair tread to
an overhead obstruction shall be at least 7 feet measured from the
leading edge of the tread.
[39 FR 23502, June 27, 1974, as amended at 43 FR 49744, Oct. 24, 1978;
49 FR 5321, Feb. 10, 1984]
