Current through September 21, 2024
(a) Design
requirements and 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.
(b) Specific features-Rungs and cleats.
(i) All rungs shall have a minimum diameter
of three-fourths (3/4) inch for metal ladders, and a minimum diameter of one
and one-eighths (1-1/8) inches for wooden ladders.
(ii) The distance between rungs, cleats, or
steps shall not exceed twelve (12) inches, measured from the top of rung, cleat
or step to the top of the next rung, cleat or step, and shall be uniform
throughout the length of the ladder.
(iii) The minimum clear length of rungs or
cleats shall be sixteen (16) inches.
(iv) Rungs, cleats, and steps shall be free
of splinters, sharp edges, burrs, or projections which may be a
hazard.
(v) Where there is a
walking/working platform or access to a ladder twenty-four (24) inches or more
above the floor or ground level, a step or steps of not more than twelve (12)
inches riser height shall be provided for access.
(vi) 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.
(vii) Fastenings shall be an integral part of
fixed ladder design.
(viii) All
splices and connections shall have smooth transition with original members and
with no sharp or extensive projections.
(ix) Adequate means shall be employed to
protect dissimilar metals from electrolytic action when such metals are
joined.
(x) All welding shall be in
accordance with the "Code for Welding in Building Construction " (A WS
Dl. 0-66).
(xi) Protection
from deterioration. Metal ladders and appurtenances shall be painted or
otherwise treated to resist corrosion and rusting when location demands. 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.
(c) On the
climbing side of fixed ladders, the perpendicular distance from the centerline
of the rungs to the nearest permanent object shall be thirty-six (36) inches
for a pitch of 76°, and thirty (30) inches for a pitch of 90°, with
minimum clearances for intermediate pitches varying between these two limits in
proportion to the slope, except as provided in paragraph (3) of this
subsection.
(i) Ladders without cages or
wells. A clear width of at least fifteen (15) inches shall be provided each way
from the centerline of the ladder in the climbing space, except when cages or
wells are necessary.
(ii) Clearance
in back of ladder. The distance from the center-line of rungs, cleats or steps
to the nearest permanent object in back of the ladder shall be not less than
seven (7) inches. When unavoidable obstructions are encountered, minimum
clearances for the two rungs on either side of the obstruction shall be
measured vertically from the obstruction no less than one and a half (1 V-i)
inches to the upper rung and four and a half (4%) inches to the lower
rung.
(iii) 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 bar shall not be less than four (4)
inches. Grab bars shall not protrude on the climbing side beyond the rungs of
the ladder which they serve.
(iv)
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 than 12 inches,
or less than two and a half (21/2) inches.
(d) Cages or wells shall be provided on
ladders of more than twenty (20) feet to a maximum unbroken length of thirty
(30) feet.
(i) Cages shall extend a minimum
of forty-two (42) inches above the top of landing, unless other acceptable
protection is provided.
(ii) Cages
shall extend down the ladder to a point not less than seven (7) feet nor more
than eight (8) feet above the base of the ladder, with bottom flared not less
than four (4) inches, or portion of cage opposite ladder shall be carried to
the base.
(iii) Cages shall not
extend less than twenty-seven (27) nor more than twenty-eight (28) inches from
the centerline of the rungs of the ladder. Cage shall not be less than
twenty-seven (27) inches in width. The inside shall be clear of projections.
Vertical bars shall be located at a maximum spacing of 40° around the
circumference of the cage; this will give a maximum spacing of approximately
nine and a half (9%) inches, center-to-center.
(iv) Ladder wells shall have a clear width of
at least fifteen (15) inches measured each way from the centerline of the
ladder. Smooth-walled wells shall be a minimum of twenty-seven (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 thirty (30) inches from the centerline of the rungs.
(e) Landing platforms. When
ladders are used to ascend to heights exceeding twenty (20) feet (except on
chimneys), landing platforms shall be provided for each thirty (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 twenty (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 an
employee has to step a distance greater than twelve (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 two and a half (21/2) 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 twenty-four (24) inches in width and
thirty (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.
(f) Ladder extensions. The side rails of
through or side-step ladder extensions shall extend three and a half (31/2)
feet above parapets and landing. For through ladder extensions, the rungs shall
be omitted from the extension and shall have not less than eighteen (18) nor
more than twenty-four (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 three and a half (31/2)
foot minimum.
(g) 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.
(h) Ladder safety
devices may be used on tower, water tank and chimney ladders over twenty (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 lifebelts, full body harnesses, friction brakes, and sliding
attachments as an integral unit shall meet the design requirements of the
ladders they serve.
(i) The
preferred pitch of fixed ladders shall be considered to come in the range of
75° and 90° with the horizontal.
(i)
Fixed ladders shall be considered as substandard if they are installed within
the substandard pitch range of 60° and 75° 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.
(ii) This section covers only fixed ladders
within the pitch range of 60° and 90° with the horizontal.
(iii) Ladders having a pitch in excess of
90° with the horizontal are prohibited.
(j) 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.
(k) Ladder requirements not specifically
referenced in this section shall be in accordance with the State of Wyoming
Occupational Health and Safety 1910 - General Rules and Regulations, Subpart D,
Walking and Working Surfaces.
(l)
All mast ladders on all drilling rigs are exempted from the requirements of
subsections (b)(i), (ii), (iii) and (c) (ii) and (d) of this section, provided
the employer makes available and requires the use of an approved personal fall
arrest system.
