[Code of Federal Regulations]
[Title 29, Volume 8]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1926.452]
[Page 287-293]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1926_SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION--Table of Contents
Subpart L_Scaffolds
Sec. 1926.452 Additional requirements applicable to specific types of
scaffolds.
In addition to the applicable requirements of Sec. 1926.451, the
following requirements apply to the specific types of scaffolds
indicated. Scaffolds not specifically addressed by Sec. 1926.452, such
as but not limited to systems scaffolds, must meet the requirements of
Sec. 1926.451.
(a) Pole scaffolds. (1) When platforms are being moved to the next
level, the existing platform shall be left undisturbed until the new
bearers have been set in place and braced, prior to receiving the new
platforms.
(2) Crossbracing shall be installed between the inner and outer sets
of poles on double pole scaffolds.
(3) Diagonal bracing in both directions shall be installed across
the entire inside face of double-pole scaffolds used to support loads
equivalent to a uniformly distributed load of 50 pounds (222 kg) or more
per square foot (929 square cm).
(4) Diagonal bracing in both directions shall be installed across
the entire outside face of all double- and single-pole scaffolds.
(5) Runners and bearers shall be installed on edge.
(6) Bearers shall extend a minimum of 3 inches (7.6 cm) over the
outside edges of runners.
(7) Runners shall extend over a minimum of two poles, and shall be
supported by bearing blocks securely attached to the poles.
(8) Braces, bearers, and runners shall not be spliced between poles.
(9) Where wooden poles are spliced, the ends shall be squared and
the upper section shall rest squarely on the lower section. Wood splice
plates shall be provided on at least two adjacent sides, and shall
extend at least 2 feet (0.6 m) on either side of the splice, overlap the
abutted ends equally, and have at least the same cross-sectional areas
as the pole. Splice plates of other materials of equivalent strength may
be used.
(10) Pole scaffolds over 60 feet in height shall be designed by a
registered professional engineer, and shall be constructed and loaded in
accordance with that design. Non-mandatory Appendix A to this subpart
contains examples of
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criteria that will enable an employer to comply with design and loading
requirements for pole scaffolds under 60 feet in height.
(b) Tube and coupler scaffolds. (1) When platforms are being moved
to the next level, the existing platform shall be left undisturbed until
the new bearers have been set in place and braced prior to receiving the
new platforms.
(2) Transverse bracing forming an ``X'' across the width of the
scaffold shall be installed at the scaffold ends and at least at every
third set of posts horizontally (measured from only one end) and every
fourth runner vertically. Bracing shall extend diagonally from the inner
or outer posts or runners upward to the next outer or inner posts or
runners. Building ties shall be installed at the bearer levels between
the transverse bracing and shall conform to the requirements of Sec.
1926.451(c)(1).
(3) On straight run scaffolds, longitudinal bracing across the inner
and outer rows of posts shall be installed diagonally in both
directions, and shall extend from the base of the end posts upward to
the top of the scaffold at approximately a 45 degree angle. On scaffolds
whose length is greater than their height, such bracing shall be
repeated beginning at least at every fifth post. On scaffolds whose
length is less than their height, such bracing shall be installed from
the base of the end posts upward to the opposite end posts, and then in
alternating directions until reaching the top of the scaffold. Bracing
shall be installed as close as possible to the intersection of the
bearer and post or runner and post.
(4) Where conditions preclude the attachment of bracing to posts,
bracing shall be attached to the runners as close to the post as
possible.
(5) Bearers shall be installed transversely between posts, and when
coupled to the posts, shall have the inboard coupler bear directly on
the runner coupler. When the bearers are coupled to the runners, the
couplers shall be as close to the posts as possible.
(6) Bearers shall extend beyond the posts and runners, and shall
provide full contact with the coupler.
(7) Runners shall be installed along the length of the scaffold,
located on both the inside and outside posts at level heights (when tube
and coupler guardrails and midrails are used on outside posts, they may
be used in lieu of outside runners).
(8) Runners shall be interlocked on straight runs to form continuous
lengths, and shall be coupled to each post. The bottom runners and
bearers shall be located as close to the base as possible.
(9) Couplers shall be of a structural metal, such as drop-forged
steel, malleable iron, or structural grade aluminum. The use of gray
cast iron is prohibited.
(10) Tube and coupler scaffolds over 125 feet in height shall be
designed by a registered professional engineer, and shall be constructed
and loaded in accordance with such design. Non-mandatory Appendix A to
this subpart contains examples of criteria that will enable an employer
to comply with design and loading requirements for tube and coupler
scaffolds under 125 feet in height.
(c) Fabricated frame scaffolds (tubular welded frame scaffolds). (1)
When moving platforms to the next level, the existing platform shall be
left undisturbed until the new end frames have been set in place and
braced prior to receiving the new platforms.
(2) Frames and panels shall be braced by cross, horizontal, or
diagonal braces, or combination thereof, which secure vertical members
together laterally. The cross braces shall be of such length as will
automatically square and align vertical members so that the erected
scaffold is always plumb, level, and square. All brace connections shall
be secured.
(3) Frames and panels shall be joined together vertically by
coupling or stacking pins or equivalent means.
(4) Where uplift can occur which would displace scaffold end frames
or panels, the frames or panels shall be locked together vertically by
pins or equivalent means.
(5) Brackets used to support cantilevered loads shall:
(i) Be seated with side-brackets parallel to the frames and end-
brackets at 90 degrees to the frames;
(ii) Not be bent or twisted from these positions; and
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(iii) Be used only to support personnel, unless the scaffold has
been designed for other loads by a qualified engineer and built to
withstand the tipping forces caused by those other loads being placed on
the bracket-supported section of the scaffold.
(6) Scaffolds over 125 feet (38.0 m) in height above their base
plates shall be designed by a registered professional engineer, and
shall be constructed and loaded in accordance with such design.
(d) Plasterers', decorators', and large area scaffolds. Scaffolds
shall be constructed in accordance with paragraphs (a), (b), or (c) of
this section, as appropriate.
(e) Bricklayers' square scaffolds (squares). (1) Scaffolds made of
wood shall be reinforced with gussets on both sides of each corner.
(2) Diagonal braces shall be installed on all sides of each square.
(3) Diagonal braces shall be installed between squares on the rear
and front sides of the scaffold, and shall extend from the bottom of
each square to the top of the next square.
(4) Scaffolds shall not exceed three tiers in height, and shall be
so constructed and arranged that one square rests directly above the
other. The upper tiers shall stand on a continuous row of planks laid
across the next lower tier, and shall be nailed down or otherwise
secured to prevent displacement.
(f) Horse scaffolds. (1) Scaffolds shall not be constructed or
arranged more than two tiers or 10 feet (3.0 m) in height, whichever is
less.
(2) When horses are arranged in tiers, each horse shall be placed
directly over the horse in the tier below.
(3) When horses are arranged in tiers, the legs of each horse shall
be nailed down or otherwise secured to prevent displacement.
(4) When horses are arranged in tiers, each tier shall be
crossbraced.
(g) Form scaffolds and carpenters' bracket scaffolds. (1) Each
bracket, except those for wooden bracket-form scaffolds, shall be
attached to the supporting formwork or structure by means of one or more
of the following: nails; a metal stud attachment device; welding;
hooking over a secured structural supporting member, with the form wales
either bolted to the form or secured by snap ties or tie bolts extending
through the form and securely anchored; or, for carpenters' bracket
scaffolds only, by a bolt extending through to the opposite side of the
structure's wall.
(2) Wooden bracket-form scaffolds shall be an integral part of the
form panel.
(3) Folding type metal brackets, when extended for use, shall be
either bolted or secured with a locking-type pin.
(h) Roof bracket scaffolds. (1) Scaffold brackets shall be
constructed to fit the pitch of the roof and shall provide a level
support for the platform.
(2) Brackets (including those provided with pointed metal
projections) shall be anchored in place by nails unless it is
impractical to use nails. When nails are not used, brackets shall be
secured in place with first-grade manila rope of at least three-fourth
inch (1.9 cm) diameter, or equivalent.
(i) Outrigger scaffolds. (1) The inboard end of outrigger beams,
measured from the fulcrum point to the extreme point of anchorage, shall
be not less than one and one-half times the outboard end in length.
(2) Outrigger beams fabricated in the shape of an I-beam or channel
shall be placed so that the web section is vertical.
(3) The fulcrum point of outrigger beams shall rest on secure
bearings at least 6 inches (15.2 cm) in each horizontal dimension.
(4) Outrigger beams shall be secured in place against movement, and
shall be securely braced at the fulcrum point against tipping.
(5) The inboard ends of outrigger beams shall be securely anchored
either by means of braced struts bearing against sills in contact with
the overhead beams or ceiling, or by means of tension members secured to
the floor joists underfoot, or by both.
(6) The entire supporting structure shall be securely braced to
prevent any horizontal movement.
(7) To prevent their displacement, platform units shall be nailed,
bolted, or otherwise secured to outriggers.
[[Page 290]]
(8) Scaffolds and scaffold components shall be designed by a
registered professional engineer and shall be constructed and loaded in
accordance with such design.
(j) Pump jack scaffolds. (1) Pump jack brackets, braces, and
accessories shall be fabricated from metal plates and angles. Each pump
jack bracket shall have two positive gripping mechanisms to prevent any
failure or slippage.
(2) Poles shall be secured to the structure by rigid triangular
bracing or equivalent at the bottom, top, and other points as necessary.
When the pump jack has to pass bracing already installed, an additional
brace shall be installed approximately 4 feet (1.2 m) above the brace to
be passed, and shall be left in place until the pump jack has been moved
and the original brace reinstalled.
(3) When guardrails are used for fall protection, a workbench may be
used as the toprail only if it meets all the requirements in paragraphs
(g)(4) (ii), (vii), (viii), and (xiii) of Sec. 1926.451.
(4) Work benches shall not be used as scaffold platforms.
(5) When poles are made of wood, the pole lumber shall be straight-
grained, free of shakes, large loose or dead knots, and other defects
which might impair strength.
(6) When wood poles are constructed of two continuous lengths, they
shall be joined together with the seam parallel to the bracket.
(7) When two by fours are spliced to make a pole, mending plates
shall be installed at all splices to develop the full strength of the
member.
(k) Ladder jack scaffolds. (1) Platforms shall not exceed a height
of 20 feet (6.1 m).
(2) All ladders used to support ladder jack scaffolds shall meet the
requirements of subpart X of this part--Stairways and Ladders, except
that job-made ladders shall not be used to support ladder jack
scaffolds.
(3) The ladder jack shall be so designed and constructed that it
will bear on the side rails and ladder rungs or on the ladder rungs
alone. If bearing on rungs only, the bearing area shall include a length
of at least 10 inches (25.4 cm) on each rung.
(4) Ladders used to support ladder jacks shall be placed, fastened,
or equipped with devices to prevent slipping.
(5) Scaffold platforms shall not be bridged one to another.
(l) Window jack scaffolds. (1) Scaffolds shall be securely attached
to the window opening.
(2) Scaffolds shall be used only for the purpose of working at the
window opening through which the jack is placed.
(3) Window jacks shall not be used to support planks placed between
one window jack and another, or for other elements of scaffolding.
(m) Crawling boards (chicken ladders). (1) Crawling boards shall
extend from the roof peak to the eaves when used in connection with roof
construction, repair, or maintenance.
(2) Crawling boards shall be secured to the roof by ridge hooks or
by means that meet equivalent criteria (e.g., strength and durability).
(n) Step, platform, and trestle ladder scaffolds. (1) Scaffold
platforms shall not be placed any higher than the second highest rung or
step of the ladder supporting the platform.
(2) All ladders used in conjunction with step, platform and trestle
ladder scaffolds shall meet the pertinent requirements of subpart X of
this part--Stairways and Ladders, except that job-made ladders shall not
be used to support such scaffolds.
(3) Ladders used to support step, platform, and trestle ladder
scaffolds shall be placed, fastened, or equipped with devices to prevent
slipping.
(4) Scaffolds shall not be bridged one to another.
(o) Single-point adjustable suspension scaffolds. (1) When two
single-point adjustable suspension scaffolds are combined to form a two-
point adjustable suspension scaffold, the resulting two-point scaffold
shall comply with the requirements for two-point adjustable suspension
scaffolds in paragraph (p) of this section.
(2) The supporting rope between the scaffold and the suspension
device shall be kept vertical unless all of the following conditions are
met:
(i) The rigging has been designed by a qualified person, and
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(ii) The scaffold is accessible to rescuers, and
(iii) The supporting rope is protected to ensure that it will not
chafe at any point where a change in direction occurs, and
(iv) The scaffold is positioned so that swinging cannot bring the
scaffold into contact with another surface.
(3) Boatswains' chair tackle shall consist of correct size ball
bearings or bushed blocks containing safety hooks and properly ``eye-
spliced'' minimum five-eighth (\5/8\) inch (1.6 cm) diameter first-grade
manila rope, or other rope which will satisfy the criteria (e.g.,
strength and durability) of manila rope.
(4) Boatswains' chair seat slings shall be reeved through four
corner holes in the seat; shall cross each other on the underside of the
seat; and shall be rigged so as to prevent slippage which could cause an
out-of-level condition.
(5) Boatswains' chair seat slings shall be a minimum of five-eight
(\5/8\) inch (1.6 cm) diameter fiber, synthetic, or other rope which
will satisfy the criteria (e.g., strength, slip resistance, durability,
etc.) of first grade manila rope.
(6) When a heat-producing process such as gas or arc welding is
being conducted, boatswains' chair seat slings shall be a minimum of
three-eight (\3/8\) inch (1.0 cm) wire rope.
(7) Non-cross-laminated wood boatswains' chairs shall be reinforced
on their underside by cleats securely fastened to prevent the board from
splitting.
(p) Two-point adjustable suspension scaffolds (swing stages). The
following requirements do not apply to two-point adjustable suspension
scaffolds used as masons' or stonesetters' scaffolds. Such scaffolds are
covered by paragraph (q) of this section.
(1) Platforms shall not be more than 36 inches (0.9 m) wide unless
designed by a qualified person to prevent unstable conditions.
(2) The platform shall be securely fastened to hangers (stirrups) by
U-bolts or by other means which satisfy the requirements of Sec.
1926.451(a).
(3) The blocks for fiber or synthetic ropes shall consist of at
least one double and one single block. The sheaves of all blocks shall
fit the size of the rope used.
(4) Platforms shall be of the ladder-type, plank-type, beam-type, or
light-metal type. Light metal-type platforms having a rated capacity of
750 pounds or less and platforms 40 feet (12.2 m) or less in length
shall be tested and listed by a nationally recognized testing
laboratory.
(5) Two-point scaffolds shall not be bridged or otherwise connected
one to another during raising and lowering operations unless the bridge
connections are articulated (attached), and the hoists properly sized.
(6) Passage may be made from one platform to another only when the
platforms are at the same height, are abutting, and walk-through
stirrups specifically designed for this purpose are used.
(q) Multi-point adjustable suspension scaffolds, stonesetters'
multi-point adjustable suspension scaffolds, and masons' multi-point
adjustable suspension scaffolds. (1) When two or more scaffolds are used
they shall not be bridged one to another unless they are designed to be
bridged, the bridge connections are articulated, and the hoists are
properly sized.
(2) If bridges are not used, passage may be made from one platform
to another only when the platforms are at the same height and are
abutting.
(3) Scaffolds shall be suspended from metal outriggers, brackets,
wire rope slings, hooks, or means that meet equivalent criteria (e.g.,
strength, durability).
(r) Catenary scaffolds. (1) No more than one platform shall be
placed between consecutive vertical pickups, and no more than two
platforms shall be used on a catenary scaffold.
(2) Platforms supported by wire ropes shall have hook-shaped stops
on each end of the platforms to prevent them from slipping off the wire
ropes. These hooks shall be so placed that they will prevent the
platform from falling if one of the horizontal wire ropes breaks.
(3) Wire ropes shall not be tightened to the extent that the
application of a scaffold load will overstress them.
(4) Wire ropes shall be continuous and without splices between
anchors.
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(s) Float (ship) scaffolds. (1) The platform shall be supported by a
minimum of two bearers, each of which shall project a minimum of 6
inches (15.2 cm) beyond the platform on both sides. Each bearer shall be
securely fastened to the platform.
(2) Rope connections shall be such that the platform cannot shift or
slip.
(3) When only two ropes are used with each float:
(i) They shall be arranged so as to provide four ends which are
securely fastened to overhead supports.
(ii) Each supporting rope shall be hitched around one end of the
bearer and pass under the platform to the other end of the bearer where
it is hitched again, leaving sufficient rope at each end for the
supporting ties.
(t) Interior hung scaffolds. (1) Scaffolds shall be suspended only
from the roof structure or other structural member such as ceiling
beams.
(2) Overhead supporting members (roof structure, ceiling beams, or
other structural members) shall be inspected and checked for strength
before the scaffold is erected.
(3) Suspension ropes and cables shall be connected to the overhead
supporting members by shackles, clips, thimbles, or other means that
meet equivalent criteria (e.g., strength, durability).
(u) Needle beam scaffolds. (1) Scaffold support beams shall be
installed on edge.
(2) Ropes or hangers shall be used for supports, except that one end
of a needle beam scaffold may be supported by a permanent structural
member.
(3) The ropes shall be securely attached to the needle beams.
(4) The support connection shall be arranged so as to prevent the
needle beam from rolling or becoming displaced.
(5) Platform units shall be securely attached to the needle beams by
bolts or equivalent means. Cleats and overhang are not considered to be
adequate means of attachment.
(v) Multi-level suspended scaffolds. (1) Scaffolds shall be equipped
with additional independent support lines, equal in number to the number
of points supported, and of equivalent strength to the suspension ropes,
and rigged to support the scaffold in the event the suspension rope(s)
fail.
(2) Independent support lines and suspension ropes shall not be
attached to the same points of anchorage.
(3) Supports for platforms shall be attached directly to the support
stirrup and not to any other platform.
(w) Mobile scaffolds. (1) Scaffolds shall be braced by cross,
horizontal, or diagonal braces, or combination thereof, to prevent
racking or collapse of the scaffold and to secure vertical members
together laterally so as to automatically square and align the vertical
members. Scaffolds shall be plumb, level, and squared. All brace
connections shall be secured.
(i) Scaffolds constructed of tube and coupler components shall also
comply with the requirements of paragraph (b) of this section;
(ii) Scaffolds constructed of fabricated frame components shall also
comply with the requirements of paragraph (c) of this section.
(2) Scaffold casters and wheels shall be locked with positive wheel
and/or wheel and swivel locks, or equivalent means, to prevent movement
of the scaffold while the scaffold is used in a stationary manner.
(3) Manual force used to move the scaffold shall be applied as close
to the base as practicable, but not more than 5 feet (1.5 m) above the
supporting surface.
(4) Power systems used to propel mobile scaffolds shall be designed
for such use. Forklifts, trucks, similar motor vehicles or add-on motors
shall not be used to propel scaffolds unless the scaffold is designed
for such propulsion systems.
(5) Scaffolds shall be stabilized to prevent tipping during
movement.
(6) Employees shall not be allowed to ride on scaffolds unless the
following conditions exist:
(i) The surface on which the scaffold is being moved is within 3
degrees of level, and free of pits, holes, and obstructions;
(ii) The height to base width ratio of the scaffold during movement
is two to one or less, unless the scaffold is designed and constructed
to meet or exceed nationally recognized stability test requirements such
as those listed
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in paragraph (x) of Appendix A to this subpart (ANSI/SIA A92.5 and
A92.6);
(iii) Outrigger frames, when used, are installed on both sides of
the scaffold;
(iv) When power systems are used, the propelling force is applied
directly to the wheels, and does not produce a speed in excess of 1 foot
per second (.3 mps); and
(v) No employee is on any part of the scaffold which extends outward
beyond the wheels, casters, or other supports.
(7) Platforms shall not extend outward beyond the base supports of
the scaffold unless outrigger frames or equivalent devices are used to
ensure stability.
(8) Where leveling of the scaffold is necessary, screw jacks or
equivalent means shall be used.
(9) Caster stems and wheel stems shall be pinned or otherwise
secured in scaffold legs or adjustment screws.
(10) Before a scaffold is moved, each employee on the scaffold shall
be made aware of the move.
(x) Repair bracket scaffolds. (1) Brackets shall be secured in place
by at least one wire rope at least \1/2\ inch (1.27 cm) in diameter.
(2) Each bracket shall be attached to the securing wire rope (or
ropes) by a positive locking device capable of preventing the
unintentional detachment of the bracket from the rope, or by equivalent
means.
(3) Each bracket, at the contact point between the supporting
structure and the bottom of the bracket, shall be provided with a shoe
(heel block or foot) capable of preventing the lateral movement of the
bracket.
(4) Platforms shall be secured to the brackets in a manner that will
prevent the separation of the platforms from the brackets and the
movement of the platforms or the brackets on a completed scaffold.
(5) When a wire rope is placed around the structure in order to
provide a safe anchorage for personal fall arrest systems used by
employees erecting or dismantling scaffolds, the wire rope shall meet
the requirements of subpart M of this part, but shall be at least \5/16\
inch (0.8 cm) in diameter.
(6) Each wire rope used for securing brackets in place or as an
anchorage for personal fall arrest systems shall be protected from
damage due to contact with edges, corners, protrusions, or other
discontinuities of the supporting structure or scaffold components.
(7) Tensioning of each wire rope used for securing brackets in place
or as an anchorage for personal fall arrest systems shall be by means of
a turnbuckle at least 1 inch (2.54 cm) in diameter, or by equivalent
means.
(8) Each turnbuckle shall be connected to the other end of its rope
by use of an eyesplice thimble of a size appropriate to the turnbuckle
to which it is attached.
(9) U-bolt wire rope clips shall not be used on any wire rope used
to secure brackets or to serve as an anchor for personal fall arrest
systems.
(10) The employer shall ensure that materials shall not be dropped
to the outside of the supporting structure.
(11) Scaffold erection shall progress in only one direction around
any structure.
(y) Stilts. Stilts, when used, shall be used in accordance with the
following requirements:
(1) An employee may wear stilts on a scaffold only if it is a large
area scaffold.
(2) When an employee is using stilts on a large area scaffold where
a guardrail system is used to provide fall protection, the guardrail
system shall be increased in height by an amount equal to the height of
the stilts being used by the employee.
(3) Surfaces on which stilts are used shall be flat and free of
pits, holes and obstructions, such as debris, as well as other tripping
and falling hazards.
(4) Stilts shall be properly maintained. Any alteration of the
original equipment shall be approved by the manufacturer.
