[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: 29CFR1910.27]
[Page 125-130]
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. 1910.27 Fixed ladders.
(a) Design requirements--(1) Design considerations. All ladders,
appurtenances, and fastenings shall be designed to meet the following
load requirements:
(i) The minimum design live load shall be a single concentrated load
of 200 pounds.
(ii) The number and position of additional concentrated live-load
units of 200 pounds each as determined from anticipated usage of the
ladder shall be considered in the design.
(iii) The live loads imposed by persons occupying the ladder shall
be considered to be concentrated at such points as will cause the
maximum stress in the structural member being considered.
(iv) The weight of the ladder and attached appurtenances together
with the live load shall be considered in the design of rails and
fastenings.
(2) Design stresses. Design stresses for wood components of ladders
shall not exceed those specified in Sec. 1910.25. All wood parts of
fixed ladders shall meet the requirements of Sec. 1910.25(b).
For fixed ladders consisting of wood side rails and wood rungs or
cleats, used at a pitch in the range 75 degrees to 90 degrees, and
intended for use by no more than one person per section, single ladders
as described in Sec. 1910.25(c)(3)(ii) are acceptable.
(b) Specific features--(1) Rungs and cleats. (i) All rungs shall
have a minimum diameter of three-fourths inch for metal ladders, except
as covered in paragraph (b)(7)(i) of this section and a minimum diameter
of 1\1/8\ inches for wood ladders.
(ii) The distance between rungs, cleats, and steps shall not exceed
12 inches and shall be uniform throughout the length of the ladder.
(iii) The minimum clear length of rungs or cleats shall be 16
inches.
(iv) Rungs, cleats, and steps shall be free of splinters, sharp
edges, burrs, or projections which may be a hazard.
(v) The rungs of an individual-rung ladder shall be so designed that
the foot cannot slide off the end. A suggested design is shown in figure
D-1.
[GRAPHIC] [TIFF OMITTED] TC27OC91.001
Figure D-1--Suggested Design for Rungs on Individual-rung Ladders.
(2) Side rails. Side rails which might be used as a climbing aid
shall be of such cross sections as to afford adequate gripping surface
without sharp edges, splinters, or burrs.
(3) Fastenings. Fastenings shall be an integral part of fixed ladder
design.
(4) Splices. All splices made by whatever means shall meet design
requirements as noted in paragraph (a) of this section. All splices and
connections shall have smooth transition with original members and with
no sharp or extensive projections.
(5) Electrolytic action. Adequate means shall be employed to protect
dissimilar metals from electrolytic action when such metals are joined.
(6) Welding. All welding shall be in accordance with the ``Code for
Welding in Building Construction'' (AWSD1.0-1966).
(7) Protection from deterioration. (i) Metal ladders and
appurtenances shall be painted or otherwise treated to resist corrosion
and rusting when location demands. Ladders formed by individual metal
rungs imbedded in concrete, which serve as access to pits and to other
areas under floors, are frequently located in an atmosphere that causes
corrosion and rusting. To increase rung life in such atmosphere,
individual metal rungs shall have a minimum diameter of 1 inch or shall
be
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painted or otherwise treated to resist corrosion and rusting.
(ii) Wood ladders, when used under conditions where decay may occur,
shall be treated with a nonirritating preservative, and the details
shall be such as to prevent or minimize the accumulation of water on
wood parts.
(iii) When different types of materials are used in the construction
of a ladder, the materials used shall be so treated as to have no
deleterious effect one upon the other.
[GRAPHIC] [TIFF OMITTED] TC27OC91.002
Figure D-2--Rail Ladder With Bar Steel Rails and Round Steel Rungs
(c) Clearance--(1) Climbing side. On fixed ladders, the
perpendicular distance from the centerline of the rungs to the nearest
permanent object on the climbing side of the ladder shall be 36 inches
for a pitch of 76 degrees, and 30 inches for a pitch of 90 degrees (fig.
D-2 of this section), with minimum clearances for intermediate pitches
varying between these two limits in proportion to the slope, except as
provided in subparagraphs (3) and (5) of this paragraph.
(2) Ladders without cages or wells. A clear width of at least 15
inches shall be provided each way from the centerline of the ladder in
the climbing space, except when cages or wells are necessary.
(3) Ladders with cages or baskets. Ladders equipped with cage or
basket are excepted from the provisions of subparagraphs (1) and (2) of
this paragraph, but shall conform to the provisions of paragraph
(d)(1)(v) of this section. Fixed ladders in smooth-walled wells are
excepted from the provisions of subparagraph (1) of this paragraph, but
shall conform to the provisions of paragraph (d)(1)(vi) of this section.
(4) Clearance in back of ladder. The distance from the centerline of
rungs, cleats, or steps to the nearest permanent object in back of the
ladder shall be not less than 7 inches, except that when unavoidable
obstructions are encountered, minimum clearances as shown in figure D-3
shall be provided.
Minimum Ladder Clearances
[GRAPHIC] [TIFF OMITTED] TC27OC91.003
Figure D-3--Clearance for Unavoidable Obstruction at Rear of Fixed
Ladder
(5) Clearance in back of grab bar. The distance from the centerline
of the grab bar to the nearest permanent object in back of the grab bars
shall be not less than 4 inches. Grab bars shall not protrude on the
climbing side beyond the rungs of the ladder which they serve.
(6) Step-across distance. The step-across distance from the nearest
edge of ladder to the nearest edge of equipment or structure shall be
not more
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than 12 inches, or less than 2\1/2\ inches (fig. D-4).
[GRAPHIC] [TIFF OMITTED] TC27OC91.004
Figure D-4--Ladder Far from Wall
(7) Hatch cover. Counterweighted hatch covers shall open a minimum
of 60 degrees from the horizontal. The distance from the centerline of
rungs or cleats to the edge of the hatch opening on the climbing side
shall be not less than 24 inches for offset wells or 30 inches for
straight wells. There shall be not protruding potential hazards within
24 inches of the centerline of rungs or cleats; any such hazards within
30 inches of the centerline of the rungs or cleats shall be fitted with
deflector plates placed at an angle of 60 degrees from the horizontal as
indicated in figure D-5. The relationship of a fixed ladder to an
acceptable counterweighted hatch cover is illustrated in figure D-6.
(d) Special requirements--(1) Cages or wells. (i) Cages or wells
(except on chimney ladders) shall be built, as shown on the applicable
drawings, covered in detail in figures D-7, D-8, and D-9, or of
equivalent construction.
(ii) Cages or wells (except as provided in subparagraph (5) of this
paragraph) conforming to the dimensions shown in figures D-7, D-8, and
D-9 shall be provided on ladders of more than 20 feet to a maximum
unbroken length of 30 feet.
[GRAPHIC] [TIFF OMITTED] TC27OC91.005
Figure D-5--Deflector Plates for Head Hazards
[GRAPHIC] [TIFF OMITTED] TC27OC91.006
Figure D-6--Relationship of Fixed Ladder to a Safe Access Hatch
(iii) Cages shall extend a minimum of 42 inches above the top of
landing, unless other acceptable protection is provided.
(iv) Cages shall extend down the ladder to a point not less than 7
feet nor more than 8 feet above the base of the ladder, with bottom
flared not less than 4 inches, or portion of cage opposite ladder shall
be carried to the base.
(v) Cages shall not extend less than 27 nor more than 28 inches from
the centerline of the rungs of the ladder. Cage shall not be less than
27 inches in width. The inside shall be clear of projections. Vertical
bars shall be located at a maximum spacing of 40 degrees around the
circumference of the cage; this will give a maximum spacing of
approximately 9\1/2\ inches, center to center.
(vi) Ladder wells shall have a clear width of at least 15 inches
measured each way from the centerline of the ladder. Smooth-walled wells
shall be a
[[Page 128]]
minimum of 27 inches from the centerline of rungs to the well wall on
the climbing side of the ladder. Where other obstructions on the
climbing side of the ladder exist, there shall be a minimum of 30 inches
from the centerline of the rungs.
[GRAPHIC] [TIFF OMITTED] TC27OC91.007
Figure D-7--Cages for Ladders More Than 20 Feet High
[GRAPHIC] [TIFF OMITTED] TC27OC91.008
Figure D-8--Clearance Diagram for Fixed Ladder in Well
[[Page 129]]
[GRAPHIC] [TIFF OMITTED] TC27OC91.009
Figure D-9--Cages--Special applications.
(2) Landing platforms. When ladders are used to ascend to heights
exceeding 20 feet (except on chimneys), landing platforms shall be
provided for each 30 feet of height or fraction thereof, except that,
where no cage, well, or ladder safety device is provided, landing
platforms shall be provided for each 20 feet of height or fraction
thereof. Each ladder section shall be offset from adjacent sections.
Where installation conditions (even for a short, unbroken length)
require that adjacent sections be offset, landing platforms shall be
provided at each offset.
(i) Where a man has to step a distance greater than 12 inches from
the centerline of the rung of a ladder to the nearest edge of structure
or equipment, a landing platform shall be provided. The minimum step-
across distance shall be 2\1/2\ inches.
(ii) All landing platforms shall be equipped with standard railings
and toeboards, so arranged as to give safe access to the ladder.
Platforms shall be not less than 24 inches in width and 30 inches in
length.
(iii) One rung of any section of ladder shall be located at the
level of the landing laterally served by the ladder. Where access to the
landing is through the ladder, the same rung spacing as used on the
ladder shall be used from the landing platform to the first rung below
the landing.
(3) Ladder extensions. The side rails of through or side-step ladder
extensions shall extend 3\1/2\ feet above parapets and landings. For
through ladder extensions, the rungs shall be omitted from the extension
and shall have not less than 18 nor more than 24 inches clearance
between rails. For side-step or offset fixed ladder sections, at
landings, the side rails and rungs shall be carried to the next regular
rung beyond or above the 3\1/2\ feet minimum (fig. D-10).
[GRAPHIC] [TIFF OMITTED] TC27OC91.010
Figure D-10--Offset Fixed Ladder Sections
(4) Grab bars. Grab bars shall be spaced by a continuation of the
rung spacing when they are located in the horizontal position. Vertical
grab bars shall have the same spacing as the ladder side rails. Grab-bar
diameters shall be the equivalent of the round-rung diameters.
(5) Ladder safety devices. Ladder safety devices may be used on
tower, water tank, and chimney ladders over 20 feet in unbroken length
in lieu of cage protection. No landing platform is required in these
cases. All ladder safety devices such as those that incorporate
[[Page 130]]
lifebelts, friction brakes, and sliding attachments shall meet the
design requirements of the ladders which they serve.
(e) Pitch--(1) Preferred pitch. The preferred pitch of fixed ladders
shall be considered to come in the range of 75 degrees and 90 degrees
with the horizontal (fig. D-11).
[GRAPHIC] [TIFF OMITTED] TC27OC91.011
Figure D-11--Pitch of Fixed Ladders
(2) Substandard pitch. Fixed ladders shall be considered as
substandard if they are installed within the substandard pitch range of
60 and 75 degrees with the horizontal. Substandard fixed ladders are
permitted only where it is found necessary to meet conditions of
installation. This substandard pitch range shall be considered as a
critical range to be avoided, if possible.
(3) Scope of coverage in this section. This section covers only
fixed ladders within the pitch range of 60 degrees and 90 degrees with
the horizontal.
(4) Pitch greater than 90 degrees. Ladders having a pitch in excess
of 90 degrees with the horizontal are prohibited.
(f) Maintenance. All ladders shall be maintained in a safe
condition. All ladders shall be inspected regularly, with the intervals
between inspections being determined by use and exposure.
