29 Cfr 1910.28

§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

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).

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.

§ 1910.28 Safety requirements for scaffolding.
(a) General requirements for all scaffolds. (1) Scaffolds shall be furnished
and erected in accordance with this
standard for persons engaged in work
that cannot be done safely from the
ground or from solid construction, except that ladders used for such work
shall conform to § 1910.25 and § 1910.26.
(2) The footing or anchorage for scaffolds shall be sound, rigid, and capable
of carrying the maximum intended
load without settling or displacement.
Unstable objects such as barrels, boxes,
loose brick, or concrete blocks shall
not be used to support scaffolds or
planks.
(3) [Reserved]
(4) Scaffolds and their components
shall be capable of supporting without
failure at least four times the maximum intended load.
(5) Scaffolds and other devices mentioned or described in this section shall
be maintained in safe condition. Scaffolds shall not be altered or moved
horizontally while they are in use or
occupied.
(6) Any scaffold damaged or weakened from any cause shall be immediately repaired and shall not be used
until repairs have been completed.
(7) Scaffolds shall not be loaded in
excess of the working load for which
they are intended.
(8) All load-carrying timber members
of scaffold framing shall be a minimum
of 1,500 f. (Stress Grade) construction
grade lumber. All dimensions are nominal sizes as provided in the American
Lumber Standards, except that where
rough sizes are noted, only rough or
undressed lumber of the size specified
will satisfy minimum requirements.
(NOTE: Where nominal sizes of lumber
are used in place of rough sizes, the
nominal size lumber shall be such as to
provide equivalent strength to that
specified in tables D–7 through D–12
and D–16.)
(9) All planking shall be Scaffold
Grade as recognized by grading rules
for the species of wood used. The maximum permissible spans for 2- × 9-inch
or wider planks are shown in the following table:

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Occupational Safety and Health Admin., Labor
Material
Nominal
thickness
lumber

Full thickness undressed lumber

Working load
(p.s.f.) ...............
Permissible span
(ft.) ...................

25

50

75

25

50

10

8

6

8

9

The maximum permissible span for
11⁄4×9-inch or wider plank of full thickness is 4 feet with medium loading of 50
p.s.f.
(10) Nails or bolts used in the construction of scaffolds shall be of adequate size and in sufficient numbers at
each connection to develop the designed strength of the scaffold. Nails
shall not be subjected to a straight pull
and shall be driven full length.
(11) All planking or platforms shall
be overlapped (minimum 12 inches) or
secured from movement.
(12) An access ladder or equivalent
safe access shall be provided.
(13) Scaffold planks shall extend over
their end supports not less than 6
inches nor more than 18 inches.
(14) The poles, legs, or uprights of
scaffolds shall be plumb, and securely
and rigidly braced to prevent swaying
and displacement.
(15) Materials being hoisted onto a
scaffold shall have a tag line.
(16) Overhead protection shall be provided for men on a scaffold exposed to
overhead hazards.
(17) Scaffolds shall be provided with a
screen between the toeboard and the
guardrail, extending along the entire
opening, consisting of No. 18 gauge U.S.
Standard Wire one-half-inch mesh or
the equivalent, where persons are required to work or pass under the scaffolds.
(18) Employees shall not work on
scaffolds during storms or high winds.
(19) Employees shall not work on
scaffolds which are covered with ice or
snow, unless all ice or snow is removed
and planking sanded to prevent slipping.
(20) Tools, materials, and debris shall
not be allowed to accumulate in quantities to cause a hazard.
(21) Only treated or protected fiber
rope shall be used for or near any work

§ 1910.28

involving the use of corrosive substances or chemicals.
(22) Wire or fiber rope used for scaffold suspension shall be capable of supporting at least six times the intended
load.
(23) When acid solutions are used for
cleaning buildings over 50 feet in
height, wire rope supported scaffolds
shall be used.
(24) The use of shore scaffolds or
lean-to scaffolds is prohibited.
(25) Lumber sizes, when used in this
section, refer to nominal sizes except
where otherwise stated.
(26) Scaffolds shall be secured to permanent structures, through use of anchor bolts, reveal bolts, or other equivalent means. Window cleaners’ anchor
bolts shall not be used.
(27) Special precautions shall be
taken to protect scaffold members, including any wire or fiber ropes, when
using a heat-producing process.
(b) General requirements for wood pole
scaffolds. (1) Scaffold poles shall bear
on a foundation of sufficient size and
strength to spread the load from the
poles over a sufficient area to prevent
settlement. All poles shall be set
plumb.
(2) Where wood 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 not be less than 4 feet 0
inches in length, overlapping the abutted ends equally, and have the same
width and not less than the cross-sectional area of the pole. Splice plates of
other materials of equivalent strength
may be used.
(3) Independent pole scaffolds shall be
set as near to the wall of the building
as practicable.
(4) All pole scaffolds shall be securely
guyed or tied to the building or structure. Where the height or length exceeds 25 feet, the scaffold shall be secured at intervals not greater than 25
feet vertically and horizontally.
(5) Putlogs or bearers shall be set
with their greater dimensions vertical,
long enough to project over the ledgers
of the inner and outer rows of poles at
least 3 inches for proper support.
(6) Every wooden putlog on single
pole scaffolds shall be reinforced with a

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

3⁄16×2-inch steel strip or equivalent secured to its lower edge throughout its
entire length.
(7) Ledgers shall be long enough to
extend over two pole spaces. Ledgers
shall not be spliced between the poles.
Ledgers shall be reinforced by bearing
blocks securely nailed to the side of
the pole to form a support for the ledger.
(8) Diagonal bracing shall be provided
to prevent the poles from moving in a
direction parallel with the wall of the
building, or from buckling.
(9) Cross bracing shall be provided between the inner and outer sets of poles
in independent pole scaffolds. The free
ends of pole scaffolds shall be cross
braced.
(10) Full diagonal face bracing shall
be erected across the entire face of pole
scaffolds in both directions. The braces
shall be spliced at the poles.
(11) Platform planks shall be laid
with their edges close together so the
platform will be tight with no spaces
through which tools or fragments of
material can fall.
(12) Where planking is lapped, each
plank shall lap its end supports at least
12 inches. Where the ends of planks
abut each other to form a flush floor,
the butt joint shall be at the centerline
of a pole. The abutted ends shall rest
on separate bearers. Intermediate
beams shall be provided where necessary to prevent dislodgment of
planks due to deflection, and the ends
shall be nailed or cleated to prevent
their dislodgment.
(13) When a scaffold turns a corner,
the platform planks shall be laid to

prevent tipping. The planks that meet
the corner putlog at an angle shall be
laid first, extending over the diagonally placed putlog far enough to have
a good safe bearing, but not far enough
to involve any danger from tipping.
The planking running in the opposite
direction at right angles shall be laid
so as to extend over and rest on the
first layer of planking.
(14) When moving platforms to the
next level, the old platform shall be
left undisturbed until the new putlogs
or bearers have been set in place, ready
to receive the platform planks.
(15) Guardrails not less than 2 × 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1 × 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(16) All wood pole scaffolds 60 feet or
less in height shall be constructed and
erected in accordance with tables D–7
through D–12 of this section. If they are
over 60 feet in height they shall be designed by a registered professional engineer and constructed and erected in
accordance with such design. A copy of
the typical drawings and specifications
shall be made available to the employer and for inspection purposes.
(17) Wood-pole scaffolds shall not be
erected beyond the reach of effective
firefighting apparatus.

TABLE D–7—MINIMUM NOMINAL SIZE AND MAXIMUM SPACING OF MEMBERS OF SINGLE POLE
SCAFFOLDS—LIGHT DUTY
Maximum height of scaffold
20 feet
Uniformly distributed load ................................................
Poles or uprights ..............................................................
Pole spacing (longitudinal) ...............................................
Maximum width of scaffold ..............................................
Bearers or putlogs to 3 ft. 0 in. width ..............................
Bearers or putlogs to 5 ft. 0 in. width ..............................
Ledgers ............................................................................
Planking ...........................................................................
Vertical spacing of horizontal members ..........................
Bracing, horizontal and diagonal .....................................
Tie-ins ..............................................................................
Toeboards ........................................................................

Not to exceed 25 pounds per
square foot..
2 by 4 in .......................................
6 ft. 0 in ........................................
5 ft. 0 in ........................................
2 by 4 in .......................................
2 by 6 in. or 3 by 4 in ..................
1 by 4 in .......................................
11⁄4 by 9 in. (rough) ......................
7 ft. 0 in ........................................
1 by 4 in .......................................
1 by 4 in .......................................
4 in. high (minimum) ....................

60 feet

4 by 4 in.
10 ft. 0 in.
5 ft. 0 in.
2 by 4 in.
2 by 6 in. or 3 by 4 in.(rough).
11⁄4 by 9 in.
2 by 9 in.
7 ft. 0 in.
1 by 4 in.
1 by 4 in.
4 in. high (minimum).

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Occupational Safety and Health Admin., Labor

§ 1910.28

TABLE D–7—MINIMUM NOMINAL SIZE AND MAXIMUM SPACING OF MEMBERS OF SINGLE POLE
SCAFFOLDS—LIGHT DUTY—Continued
Maximum height of scaffold
20 feet
Guardrail ..........................................................................

60 feet

2 by 4 in .......................................

2 by 4 in.

All members except planking are used on edge.

TABLE D–8—MINIMUM NOMINAL SIZE AND MAXIMUM SPACING OF MEMBERS OF SINGLE POLE
SCAFFOLDS—MEDIUM DUTY

TABLE D–9—MINIMUM NOMINAL SIZE AND MAXIMUM SPACING OF MEMBERS OF SINGLE POLE
SCAFFOLDS—HEAVY DUTY

Uniformly distributed load .............

Uniformly distributed load .............

Maximum height of scaffold .........
Poles or uprights ..........................
Pole spacing (longitudinal) ...........
Maximum width of scaffold ...........
Bearers or putlogs ........................
Spacing of bearers or putlogs ......
Ledgers .........................................
Vertical spacing of horizontal
members.
Bracing, horizontal ........................
Bracing, diagonal ..........................
Tie-ins ...........................................
Planking ........................................
Toeboards .....................................
Guardrail .......................................

Not to exceed 50 pounds
per square foot.
60 ft.
4 by 4 in.
8 ft. 0 in.
5 ft. 0 in.
2 by 9 in. or 3 by 4 in.
8 ft. 0 in.
2 by 9 in.
9 ft. 0 in.
1
1
1
2
4
2

by
by
by
by
in.
by

6 in. or 11⁄4 by 4 in.
4 in.
4 in.
9 in.
high (minimum).
4 in.

Maximum height of scaffold .........
Poles or uprights ..........................
Pole spacing (longitudinal) ...........
Maximum width of scaffold ...........
Bearers or putlogs ........................
Spacing of bearers or putlogs ......
Ledgers .........................................
Vertical spacing of horizontal
members.
Bracing, horizontal and diagonal ..
Tie-ins ...........................................
Planking ........................................
Toeboards .....................................
Guardrail .......................................

All members except planking are used on edge.

Not to exceed 75 pounds
per square foot.
60 ft.
4 by 4 in.
6 ft. 0 in.
5 ft. 0 in.
2 by 9 in. or 3 by 5 in.
(rough).
6 ft. 0 in.
2 by 9 in.
6 ft. 6 in.
2
1
2
4
2

by
by
by
in.
by

4 in.
4 in.
9 in.
high (minimum).
4 in.

All members except planking are used on edge.

TABLE D–10—MINIMUM NOMINAL SIZE AND MAXIMUM SPACING OF MEMBERS OF INDEPENDENT POLE
SCAFFOLDS—LIGHT DUTY
Maximum height of scaffold
20 feet
Uniformly distributed load ................................................
Poles or uprights ..............................................................
Pole spacing (longitudinal) ...............................................
Pole spacing (transverse) ................................................
Ledgers ............................................................................
Bearers to 3 ft. 0 in. span ................................................
Bearers to 10 ft. 0 in. span ..............................................
Planking ...........................................................................
Vertical spacing of horizontal members ..........................
Bracing, horizontal and diagonal .....................................
Tie-ins ..............................................................................
Toeboards ........................................................................
Guardrail ..........................................................................

Not to exceed 25 pounds per
square foot..
2 by 4 in .......................................
6 ft. 0 in ........................................
6 ft. 0 in ........................................
11⁄4 by 4 in ...................................
2 by 4 in .......................................
2 by 6 in. or 3 by 4 in ..................
11⁄4 by 9 in ...................................
7 ft. 0 in ........................................
1 by 4 in .......................................
1 by 4 in .......................................
4 in. high ......................................
2 by 4 in .......................................

60 feet

4 by 4 in.
10 ft. 0 in.
10 ft. 0 in.
11⁄4 by 9 in.
2 by 4 in.
2 by 9 (rough) or 3 by 8 in.
2 by 9 in.
7 ft. 0 in.
1 by 4 in.
1 by 4 in.
4 in. high (minimum).
2 by 4 in.

All members except planking are used on edge.

TABLE D–11—MINIMUM NOMINAL SIZE AND
MAXIMUM SPACING OF MEMBERS OF INDEPENDENT POLE SCAFFOLDS—MEDIUM DUTY
Uniformly distributed load .............
Maximum height of scaffold .........
Poles or uprights ..........................
Pole spacing (longitudinal) ...........
Pole spacing (transverse) .............
Ledgers .........................................
Vertical spacing of horizontal
members.
Spacing of bearers .......................
Bearers .........................................
Bracing, horizontal ........................

Not to exceed 50 pounds
per square foot.
60 ft.
4 by 4 in.
8 ft. 0 in.
8 ft. 0 in.
2 by 9 in.
6 ft. 0 in.

TABLE D–11—MINIMUM NOMINAL SIZE AND
MAXIMUM SPACING OF MEMBERS OF INDEPENDENT POLE SCAFFOLDS—MEDIUM DUTY—
Continued
Bracing, diagonal ..........................
Tie-ins ...........................................
Planking ........................................
Toeboards .....................................
Guardrail .......................................

1
1
2
4
2

by
by
by
in.
by

4 in.
4 in.
9 in.
high (minimum).
4 in.

All members except planking are used on edge.

8 ft. 0 in.
2 by 9 in. (rough) or 2 by
10 in.
1 by 6 in. or 11⁄4 by 4 in.

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

TABLE D–12—MINIMUM NOMINAL SIZE AND
MAXIMUM SPACING OF MEMBERS OF INDEPENDENT POLE SCAFFOLDS—HEAVY DUTY
Uniformly distributed load .............
Maximum height of scaffold .........
Poles or uprights ..........................
Pole spacing (longitudinal) ...........
Pole spacing (transverse) .............
Ledgers .........................................
Vertical spacing of horizontal
members.
Bearers .........................................
Bracing, horizontal and diagonal ..
Tie-ins ...........................................
Planking ........................................
Toeboards .....................................
Guardrail .......................................

Not to exceed 75 pounds
per square foot.
60 ft.
4 by 4 in.
6 ft. 0 in.
8 ft. 0 in.
2 by 9 in.
4 ft. 6 in.
2
2
1
2
4
2

by
by
by
by
in.
by

9 in. (rough).
4 in.
4 in.
9 in.
high (minimum).
4 in.

All members except planking are used on edge.

TABLE D–13—TUBE AND COUPLER
SCAFFOLDS—LIGHT DUTY
Uniformly distributed load .............
post spacing (longitudinal) ............
Post spacing (transverse) .............

Not to exceed 25 p.s.f.
10 ft. 0 in.
6 ft. 0 in.

Additional planked
levels

Working levels
1
2
3

Maximum height

8
4
0

125 ft.
125 ft.
91 ft. 0 in.

TABLE D–14—TUBE AND COUPLER
SCAFFOLDS—MEDIUM DUTY
Uniformly distributed load .............
Post spacing (longitudinal) ...........
Post spacing (transverse) .............

Not to exceed 50 p.s.f.
8 ft. 0 in.
6 ft. 0 in.

Additional planked
levels

Working levels
1
2

Maximum height

6
0

125 ft.
78 ft. 0 in.

TABLE D–15—TUBE AND COUPLER
SCAFFOLDS—HEAVY DUTY
Uniformly distributed load .............
Post spacing (longitudinal) ...........
Post spacing (transverse) .............

Not to exceed 75 p.s.f.
6 ft. 6 in.
6 ft. 0 in.

Additional planked
levels

Working levels
1

Maximum height

6

125 ft.

(c) Tube and coupler scaffolds. (1) A
light-duty tube and coupler scaffold
shall have all posts, bearers, runners,
and bracing of nominal 2-inch O.D.
steel tubing. The posts shall be spaced
no more than 6 feet apart by 10 feet
along the length of the scaffold. Other
structural metals when used must be
designed to carry an equivalent load.

(2) A medium-duty tube and coupler
scaffold shall have all posts, runners,
and bracing of nominal 2-inch O.D.
steel tubing. Posts spaced not more
than 6 feet apart by 8 feet along the
length of the scaffold shall have bearers of nominal 21⁄2-inch O.D. steel tubing. Posts spaced not more than 5 feet
apart by 8 feet along the length of the
scaffold shall have bearers of nominal
2-inch O.D. steel tubing. Other structural metals when used must be designed to carry an equivalent load.
(3) A heavy-duty tube and coupler
scaffold shall have all posts, runners,
and bracing of nominal 2-inch O.D.
steel tubing, with the posts spaced not
more than 6 feet apart by 6 feet 6
inches along the length of the scaffold.
Other structural metals when used
must be designed to carry an equivalent load.
(4) Tube and coupler scaffolds shall
be limited in heights and working levels to those permitted in tables D–13,
14, and 15, of this section. Drawings and
specifications of all tube and coupler
scaffolds above the limitations in tables D–13, 14, and 15 of this section
shall be designed by a registered professional engineer and copies made
available to the employer and for inspection purposes.
(5) All tube and coupler scaffolds
shall be constructed and erected to
support four times the maximum intended loads as set forth in tables D–13,
14, and 15 of this section, or as set forth
in the specifications by a registered
professional engineer, copies which
shall be made available to the employer and for inspection purposes.
(6) All tube and coupler scaffolds
shall be erected by competent and experienced personnel.
(7) Posts shall be accurately spaced,
erected on suitable bases, and maintained plumb.
(8) Runners shall be erected along the
length of the scaffold located on both
the inside and the outside posts at even
height. Runners shall be interlocked to
form continuous lengths and coupled to
each post. The bottom runners shall be
located as close to the base as possible.
Runners shall be placed not more than
6 feet 6 inches on centers.

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Occupational Safety and Health Admin., Labor
(9) Bearers shall be installed transversely between posts and shall be securely coupled to the posts bearing on
the runner coupler. When coupled directly to the runners, the coupler must
be kept as close to the posts as possible.
(10) Bearers shall be at least 4 inches
but not more than 12 inches longer
than the post spacing or runner spacing. Bearers may be cantilevered for
use as brackets to carry not more than
two planks.
(11) Cross bracing shall be installed
across the width of the scaffold at least
every third set of posts horizontally
and every fourth runner vertically.
Such bracing shall extend diagonally
from the inner and outer runners upward to the next outer and inner runners.
(12) Longitudinal diagonal bracing
shall be installed at approximately a
45-degree angle from near the base of
the first outer post upward to the extreme top of the scaffold. Where the
longitudinal length of the scaffold permits, such bracing shall be duplicated
beginning at every fifth post. In a similar manner, longitudinal diagonal bracing shall also be installed from the last
post extending back and upward toward the first post. Where conditions
preclude the attachment of this bracing to the posts, it may be attached to
the runners.
(13) The entire scaffold shall be tied
to and securely braced against the
building at intervals not to exceed 30
feet horizontally and 26 feet vertically.
(14) Guardrails not less than 2×4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1×4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(d) Tubular welded frame scaffolds. (1)
Metal tubular frame scaffolds, including accessories such as braces, brackets, trusses, screw legs, ladders, etc.,
shall be designed and proved to safely
support four times the maximum intended load.

§ 1910.28

(2) Spacing of panels or frames shall
be consistent with the loads imposed.
(3) Scaffolds shall be properly braced
by cross bracing or diagonal braces, or
both, for securing vertical members together laterally, and the cross braces
shall be of such length as will automatically square and aline vertical
members so that the erected scaffold is
always plumb, square, and rigid. All
brace connections shall be made secure.
(4) Scaffold legs shall be set on adjustable bases or plain bases placed on
mud sills or other foundations adequate to support the maximum intended load.
(5) The frames shall be placed one on
top of the other with coupling or stacking pins to provide proper vertical
alinement of the legs.
(6) Where uplift may occur, panels
shall be locked together vertically by
pins or other equivalent suitable
means.
(7) Guardrails not less than 2 × 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- × 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(8) All tubular metal scaffolds shall
be constructed and erected to support
four times the maximum intended
loads.
(9) To prevent movement, the scaffold shall be secured to the building or
structure at intervals not to exceed 30
feet horizontally and 26 feet vertically.
(10) Maximum permissible spans of
planking shall be in conformity with
paragraph (a)(9) of this section.
(11) Drawings and specifications for
all frame scaffolds over 125 feet in
height above the base plates shall be
designed by a registered professional
engineer and copies made available to
the employer and for inspection purposes.
(12) All tubular welded frame scaffolds shall be erected by competent and
experienced personnel.

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

(13) Frames and accessories for scaffolds shall be maintained in good repair and every defect, unsafe condition,
or noncompliance with this section
shall be immediately corrected before
further use of the scaffold. Any broken,
bent, excessively rusted, altered, or
otherwise structurally damaged frames
or accessories shall not be used.
(14) Periodic inspections shall be
made of all welded frames and accessories, and any maintenance, including
painting, or minor corrections authorized by the manufacturer, shall be
made before further use.
(e) Outrigger scaffolds. (1) Outrigger
beams shall extend not more than 6
feet beyond the face of the building.
The inboard end of outrigger beams,
measured from the fulcrum point to
the extreme point of support, shall be
not less than one and one-half times
the outboard end in length. The beams
shall rest on edge, the sides shall be
plumb, and the edges shall be horizontal. The fulcrum point of the beam
shall rest on a secure bearing at least
6 inches in each horizontal dimension.
The beam shall be secured in place
against movement and shall be securely braced at the fulcrum point
against tipping.
(2) The inboard ends of outrigger
beams shall be securely supported either by means of 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 if necessary. The inboard ends of outrigger
beams shall be secured against tipping
and the entire supporting structure
shall be securely braced in both directions to prevent any horizontal movement.
(3) Unless outrigger scaffolds are designed by a licensed professional engineer, they shall be constructed and
erected in accordance with table D–16.
Outrigger scaffolds designed by a registered professional engineer shall be
constructed and erected in accordance
with such design. A copy of the detailed drawings and specifications
showing the sizes and spacing of members shall be kept on the job.
(4) Planking shall be laid tight and
shall extend to within 3 inches of the

building wall. Planking shall be nailed
or bolted to outriggers.
(5) Where there is danger of material
falling from the scaffold, a wire mesh
or other enclosure shall be provided between the guardrail and the toeboard.
(6) Where additional working levels
are required to be supported by the
outrigger method, the plans and specifications of the outrigger and scaffolding structure shall be designed by a
registered professional engineer.
(f) Masons’ adjustable multiple-point
suspension scaffolds. (1) The scaffold
shall be capable of sustaining a working load of 50 pounds per square foot
and shall not be loaded in excess of
that figure.
(2) The scaffold shall be provided
with hoisting machines that meet the
requirements of a nationally recognized testing laboratory. Refer to
§ 1910.7 for definition of nationally recognized testing laboratory.
TABLE D–16—MINIMUM NOMINAL SIZE AND
MAXIMUM SPACING OF MEMBERS OF OUTRIGGER SCAFFOLDS
Light duty
Maximum scaffold load ...............
Outrigger size .............................
Maximum outrigger spacing .......
Planking ......................................
Guardrail .....................................
Guardrail uprights .......................
Toeboards (minimum) ................

25 p.s.f. .....
2×10 in ......
10 ft 0 in ....
2×9 in ........
2×4 in ........
2×4 in ........
4 in ............

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3×10 in.
6 ft 0 in.
2×9 in.
2×4 in.
2×4 in.
4 in.

(3) The platform shall be supported
by wire ropes in conformity with paragraph (a)(22) of this section, suspended
from overhead outrigger beams.
(4) The scaffold outrigger beams shall
consist of structural metal securely
fastened or anchored to the frame or
floor system of the building or structure.
(5) Each outrigger beam shall be
equivalent in strength to at least a
standard 7-inch, 15.3-pound steel Ibeam, be at least 15 feet long, and shall
not project more than 6 feet 6 inches
beyond the bearing point.
(6) Where the overhang exceeds 6 feet
6 inches, outrigger beams shall be composed of stronger beams or multiple
beams and be installed in accordance
with approved designs and instructions.

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Occupational Safety and Health Admin., Labor
(7) If channel iron outrigger beams
are used in place of I-beams, they shall
be securely fastened together with the
flanges turned out.
(8) All outrigger beams shall be set
and maintained with their webs into
vertical position.
(9) A stop bolt shall be placed at each
end of every outrigger beam.
(10) The outrigger beam shall rest on
suitable wood-bearing blocks.
(11) All parts of the scaffold such as
bolts, nuts, fittings, clamps, wire rope,
and outrigger beams and their fastenings, shall be maintained in sound
and good working condition and shall
be inspected before each installation
and periodically thereafter.
(12) The free end of the suspension
wire ropes shall be equipped with proper size thimbles and be secured by
splicing or other equivalent means.
The running ends shall be securely attached to the hoisting drum and at
least four turns of rope shall at all
times remain on the drum.
(13) Where a single outrigger beam is
used, the steel shackles or clevises
with which the wire ropes are attached
to the outrigger beams shall be placed
directly over the hoisting drums.
(14) The scaffold platform shall be
equivalent in strength to at least 2inch planking. (For maximum planking
spans see paragraph (a)(9) of this section.)
(15) Guardrails not less than 2 × 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1 × 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(16) Overhead protection shall be provided on the scaffold, not more than 9
feet above the platform, consisting of
2-inch planking or material of equivalent strength laid tight, when men are
at work on the scaffold and an overhead hazard exists.
(17) Each scaffold shall be installed
or relocated in accordance with designs
and instructions, of a registered profes-

§ 1910.28

sional engineer, and supervised by a
competent, designated person.
(g) Two-point suspension scaffolds
(swinging scaffolds). (1) Two-point suspension scaffold platforms shall be not
less than 20 inches no more than 36
inches wide overall. The platform shall
be securely fastened to the hangers by
U-bolts or by other equivalent means.
(2) The hangers of two-point suspension scaffolds shall be made of wrought
iron, mild steel, or other equivalent
material having a cross-sectional area
capable of sustaining four times the
maximum intended load, and shall be
designed with a support for guardrail,
intermediate rail, and toeboard.
(3) When hoisting machines are used
on two-point suspension scaffolds, such
machines shall be of a design tested
and approved by a nationally recognized testing laboratory. Refer to
§ 1910.7 for definition of nationally recognized testing laboratory.
(4) The roof irons or hooks shall be of
wrought iron, mild steel, or other
equivalent material of proper size and
design, securely installed and anchored. Tie-backs of three-fourth inch
manila rope or the equivalent shall
serve as a secondary means of anchorage, installed at right angles to the
face of the building whenever possible
and secured to a structurally sound
portion of the building.
(5) Guardrails not less than 2 × 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- × 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(6) Two-point suspension scaffolds
shall be suspended by wire or fiber
ropes. Wire and fiber ropes shall conform to paragraph (a)(22) of this section.
(7) The blocks for fiber ropes shall be
of standard 6-inch size, consisting of at
least one double and one single block.
The sheaves of all blocks shall fit the
size of rope used.

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

(8) All wire ropes, fiber ropes, slings,
hangers, platforms, and other supporting parts shall be inspected before
every installation. Periodic inspections
shall be made while the scaffold is in
use.
(9) On suspension scaffolds designed
for a working load of 500 pounds no
more than two men shall be permitted
to work at one time. On suspension
scaffolds with a working load of 750
pounds, no more than three men shall
be permitted to work at one time. Each
workman shall be protected by a safety
lifebelt attached to a lifeline. The lifeline shall be securely attached to substantial members of the structure (not
scaffold), or to securely rigged lines,
which will safely suspend the workman
in case of a fall.
(10) Where acid solutions are used,
fiber ropes are not permitted unless
acid-proof.
(11) Two-point suspension scaffolds
shall be securely lashed to the building
or structure to prevent them from
swaying. Window cleaners’ anchors
shall not be used for this purpose.
(12) The platform of every two-point
suspension scaffold shall be one of the
following types:
(i) The side stringer of ladder-type
platforms shall be clear straightgrained spruce or materials of equivalent strength and durability. The rungs
shall be of straight-grained oak, ash, or
hickory, at least 11⁄8 inch in diameter,
with seven-eighth inch tenons mortised
into the side stringers at least seven-

eighth inch. The stringers shall be tied
together with the tie rods not less than
one-quarter inch in diameter, passing
through the stringers and riveted up
tight against washers on both ends.
The flooring strips shall be spaced not
more than five-eighth inch apart except at the side rails where the space
may be 1 inch. Ladder-type platforms
shall be constructed in accordance with
table D–17.
(ii) Plank-type platforms shall be
composed of not less than nominal 2×8inch unspliced planks, properly cleated
together on the underside starting 6
inches from each end; intervals in between shall not exceed 4 feet. The
plank-type platform shall not extend
beyond the hangers more than 18
inches. A bar or other effective means
shall be securely fastened to the platform at each end to prevent its slipping
off the hanger. The span between hangers for plank-type platforms shall not
exceed 10 feet.
(iii) Beam platforms shall have side
stringers of lumber not less than 2×6
inches set on edge. The span between
hangers shall not exceed 12 feet when
beam platforms are used. The flooring
shall be supported on 2- and 6-inch
crossbeams, laid flat and set into the
upper edge of the stringers with a snug
fit, at intervals of not more than 4 feet,
securely nailed in place. The flooring
shall be of 1×6inch material properly
nailed. Floorboards shall not be spaced
more than one-half inch apart.

TABLE D–17—SCHEDULE FOR LADDER-TYPE PLATFORMS
Length of platform (feet)

Side stringers, minimum cross section (finished sizes):
At ends (in.) ......................................................................
At middle (in.) ...................................................................
Reinforcing strip (minimum) 1 ...................................................
Rungs 2 .....................................................................................
Tie rods:
Number (minimum) ...........................................................
Diameter (minimum) .........................................................
Flooring, minimum finished size (in.) .......................................

12

14 & 16

18 & 20

22 & 24

28 & 30

13⁄4×23⁄4
13⁄4×33⁄4
..................
..................

13⁄4×23⁄4
13⁄4×33⁄4
..................
..................

13⁄4×3
13⁄4×4
..................
..................

13⁄4×3
13⁄4×41⁄4
..................
..................

13⁄4×31⁄2
13⁄4×5
..................
..................

4
1⁄4 in
⁄ ×23⁄4

14
12 34

3
1⁄4 in
⁄ ×23⁄4

12

4
1⁄4 in
⁄ ×23⁄4

12

12

5
⁄ in
⁄ × ⁄

6
1⁄4 in.
⁄ ×23⁄4

12

1 A 1⁄8x7⁄8-in. steel reinforcing strip or its equivalent shall be attached to the side or underside full length.
2 Rungs shall be 11⁄8-in. minimum, diameter with at least 7⁄8-in. diameter tenons, and the maximum spacing shall be 12 in. center to center.

(h) Stone setters’ adjustable multiplepoint suspension scaffolds. (1) The scaffold shall be capable of sustaining a

working load of 25 pounds per square

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Occupational Safety and Health Admin., Labor
foot and shall not be overloaded. Scaffolds shall not be used for storage of
stone or other heavy materials.
(2) The hoisting machine and its supports shall be of a type tested and listed by a nationally recognized testing
laboratory. Refer to § 1910.399(a)(77) for
definition of listed, and § 1910.7 for nationally recognized testing laboratory.
(3) The platform shall be securely fastened to the hangers by U-bolts or
other equivalent means.
(4) The scaffold unit shall be suspended from metal outriggers, iron
brackets, wire rope slings, or iron
hooks which will safely support the
maximum intended load.
(5) Outriggers when used shall be set
with their webs in a vertical position,
securely anchored to the building or
structure and provided with stop bolts
at each end.
(6) The scaffold shall be supported by
wire rope conforming with paragraph
(a)(22) of this section, suspended from
overhead supports.
(7) The free ends of the suspension
wire ropes shall be equipped with proper size thimbles, secured by splicing or
other equivalent means. The running
ends shall be securely attached to the
hoisting drum and at least four turns
of rope shall remain on the drum at all
times.
(8) Guardrails not less than 2 by 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- by 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(9) When two or more scaffolds are
used on a building or structure they
shall not be bridged one to the other
but shall be maintained at even height
with platforms butting closely.
(10) Each scaffold shall be installed
or relocated in accordance with designs
and instructions of a registered professional engineer, and such installation
or relocation shall be supervised by a
competent designated person.
(i) Single-point adjustable suspension
scaffolds. (1) The scaffolding, including

§ 1910.28

power units or manually operated
winches, shall be a type tested and listed by a nationally recognized testing
laboratory. Refer to § 1910.399(a)(77) for
definition of listed, and § 1910.7 for nationally recognized testing laboratory.
(2) [Reserved]
(3) All power-operated gears and
brakes shall be enclosed.
(4) In addition to the normal operating brake, all-power driven units
must have an emergency brake which
engages automatically when the normal speed of descent is exceeded.
(5) Guards, mid-rails, and toeboards
shall completely enclose the cage or
basket. Guardrails shall be no less than
2 by 4 inches or the equivalent installed no less than 36 inches nor more
than 42 inches above the platform. Midrails shall be 1 by 6 inches or the equivalent, installed equidistant between
the guardrail and the platform.
Toeboards shall be a minimum of 4
inches in height.
(6) The hoisting machines, cables,
and equipment shall be regularly serviced and inspected after each installation and every 30 days thereafter.
(7) The units may be combined to
form a two-point suspension scaffold.
Such scaffold shall comply with paragraph (g) of this section.
(8) The supporting cable shall be
straight for its entire length, and the
operator shall not sway the basket and
fix the cable to any intermediate
points to change his original path of
travel.
(9) Equipment shall be maintained
and used in accordance with the manufacturers’ instructions.
(10) Suspension methods shall conform to applicable provisions of paragraphs (f) and (g) of this section.
(j) Boatswain’s chairs. (1) The chair
seat shall be not less than 12 by 24
inches, and of 1-inch thickness. The
seat shall be reinforced on the underside to prevent the board from splitting.
(2) The two fiber rope seat slings
shall be of 5⁄8-inch diameter, reeved
through the four seat holes so as to
cross each other on the underside of
the seat.

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

(3) Seat slings shall be of at least 3⁄8inch wire rope when a workman is conducting a heat producing process such
as gas or arc welding.
(4) The workman shall be protected
by a safety life belt attached to a lifeline. The lifeline shall be securely attached to substantial members of the
structure (not scaffold), or to securely
rigged lines, which will safely suspend
the worker in case of a fall.
(5) The tackle shall consist of correct
size ball bearing or bushed blocks and
properly spliced 5⁄8-inch diameter firstgrade manila rope.
(6) The roof irons, hooks, or the object to which the tackle is anchored
shall be securely installed. Tiebacks
when used shall be installed at right
angles to the face of the building and
securely fastened to a chimney.
(k) Carpenters’ bracket scaffolds. (1)
The brackets shall consist of a triangular wood frame not less than 2 by
3 inches in cross section, or of metal of
equivalent strength. Each member
shall be properly fitted and securely
joined.
(2) Each bracket shall be attached to
the structure by means of one of the
following:
(i) A bolt no less than five-eighths
inch in diameter which shall extend
through the inside of the building wall.
(ii) A metal stud attachment device.
(iii) Welding to steel tanks.
(iv) Hooking over a well-secured and
adequately strong supporting member.
The brackets shall be spaced no more
than 10 feet apart.
(3) No more than two persons shall
occupy any given 10 feet of a bracket
scaffold at any one time. Tools and materials shall not exceed 75 pounds in addition to the occupancy.
(4) The platform shall consist of not
less than two 2- by 9-inch nominal size
planks extending not more than 18
inches or less than 6 inches beyond
each end support.
(5) Guardrails not less than 2 by 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- by 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in

height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(l) Bricklayers’ square scaffolds. (1) The
squares shall not exceed 5 feet in width
and 5 feet in height.
(2) Members shall be not less than
those specified in Table D–18.
(3) The squares shall be reinforced on
both sides of each corner with 1- by 6inch gusset pieces. They shall also have
braces 1 by 8 inches on both sides running from center to center of each
member, or other means to secure
equivalent strength and rigidity.
(4) The squares shall be set not more
than 5 feet apart for medium duty scaffolds, and not more than 8 feet apart
for light duty scaffolds. Bracing 1×8
inches, extending from the bottom of
each square to the top of the next
square, shall be provided on both front
and rear sides of the scaffold.
TABLE D–18—MINIMUM DIMENSIONS FOR
BRICKLAYERS’ SQUARE SCAFFOLD MEMBERS
Dimensions
(inches)

Members
Bearers or horizontal members .......................
Legs .................................................................
Braces at corners .............................................
Braces diagonally from center frame ...............

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by
by
by

6.
6.
6.
8.

(5) Platform planks shall be at least
2- by 9-inch nominal size. The ends of
the planks shall overlap the bearers of
the squares and each plank shall be
supported by not less than three
squares.
(6) Bricklayers’ square scaffolds shall
not exceed three tiers in height and
shall be so constructed and arranged
that one square shall rest directly
above the other. The upper tiers shall
stand on a continuous row of planks
laid across the next lower tier and be
nailed down or otherwise secured to
prevent displacement.
(7) Scaffolds shall be level and set
upon a firm foundation.
(m) Horse scaffolds. (1) Horse scaffolds
shall not be constructed or arranged
more than two tiers or 10 feet in
height.
(2) The members of the horses shall
be not less than those specified in
Table D–19.
(3) Horses shall be spaced not more
than 5 feet for medium duty and not
more than 8 feet for light duty.

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Occupational Safety and Health Admin., Labor
(4) When arranged in tiers, each horse
shall be placed directly over the horse
in the tier below.
(5) On all scaffolds arranged in tiers,
the legs shall be nailed down to the
planks to prevent displacement or
thrust and each tier shall be substantially cross braced.
TABLE D–19—MINIMUM DIMENSIONS FOR
HORSE SCAFFOLD MEMBERS
Dimensions
(inches)

Members
Horizontal members or bearers .......................
Legs .................................................................
Longitudinal brace between legs .....................
Gusset brace at top of legs .............................
Half diagonal braces ........................................

3 by 4.
11⁄4 by 41⁄2.
1 by 6.
1 by 8.
11⁄4 by 41⁄2.

(6) Horses or parts which have become weak or defective shall not be
used.
(7) Guardrails not less than 2 by 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high with a mid-rail, when required, of
1- by 4-inch lumber or equivalent and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(n) Needle beam scaffold. (1) Wood needle beams shall be in accordance with
paragraph (a) (5) and (9) of this section,
and shall be not less than 4 by 6 inches
in size, with the greater dimension
placed in a vertical direction. Metal
beams or the equivalent conforming to
paragraph (a) (4) and (8) of this section
may be used.
(2) Ropes or hangers shall be provided
for supports. The span between supports on the needle beam shall not exceed 10 feet for 4- by 6-inch timbers.
Rope supports shall be equivalent in
strength to 1-inch diameter first-grade
manila rope.
(3) The ropes shall be attached to the
needle beams by a scaffold hitch or a
properly made eye splice. The loose end
of the rope shall be tied by a bowline
knot or by a round turn and one-half
hitch.
(4) The platform span between the
needle beams shall not exceed 8 feet
when using 2-inch scaffold plank. For
spans greater than 8 feet, platforms

§ 1910.28

shall be designed based on design requirements for the special span. The
overhang of each end of the platform
planks shall be not less than 1 foot and
not more than 18 inches.
(5) When one needle beam is higher
than the other or when the platform is
not level the platform shall be secured
against slipping.
(6) All unattached tools, bolts, and
nuts used on needle beam scaffolds
shall be kept in suitable containers.
(7) One end of a needle beam scaffold
may be supported by a permanent
structural member conforming to paragraphs (a) (4) and (8) of this section.
(8) Each man working on a needle
beam scaffold 20 feet or more above the
ground or floor and working with both
hands, shall be protected by a safety
life belt attached to a lifeline. The lifeline shall be securely attached to substantial members of the structure (not
scaffold), or to securely rigged lines,
which will safely suspend the workman
in case of a fall.
(o) Plasterers’, decorators’, and large
area scaffolds. (1) Plasterers’, decorators’, lathers’, and ceiling workers’ inside scaffolds shall be constructed in
accordance with the general requirements set forth for independent wood
pole scaffolds.
(2) Guardrails not less than 2 by 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- by 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(3) All platform planks shall be laid
with the edges close together.
(4) When independent pole scaffold
platforms are erected in sections, such
sections shall be provided with connecting runways equipped with substantial guardrails.
(p) Interior hung scaffolds.
(1) [Reserved]
(2) The suspended steel wire rope
shall conform to paragraph (a)(22) of
this section. Wire may be used providing the strength requirements of

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§ 1910.28

29 CFR Ch. XVII (7–1–05 Edition)

paragraph (a)(22) of this section are
met.
(3) For hanging wood scaffolds, the
following minimum nominal size material is recommended:
(i) Supporting bearers 2 by 9 inches
on edge.
(ii) Planking 2 by 9 inches or 2 by 10
inches, with maximum span 7 feet for
heavy duty and 10 feet for light duty or
medium duty.
(4) Steel tube and coupler members
may be used for hanging scaffolds with
both types of scaffold designed to sustain a uniform distributed working
load up to heavy duty scaffold loads
with a safety factor of four.
(5) When a hanging scaffold is supported by means of wire rope, such wire
rope shall be wrapped at least twice
around the supporting members and
twice around the bearers of the scaffold, with each end of the wire rope secured by at least three standard wirerope clips.
(6) All overhead supporting members
shall be inspected and checked for
strength before the scaffold is erected.
(7) Guardrails not less than 2 by 4
inches or the equivalent and not less
than 36 inches or more than 42 inches
high, with a mid-rail, when required, of
1- by 4-inch lumber or equivalent, and
toeboards, shall be installed at all open
sides on all scaffolds more than 10 feet
above the ground or floor. Toeboards
shall be a minimum of 4 inches in
height. Wire mesh shall be installed in
accordance with paragraph (a)(17) of
this section.
(q) Ladder-jack scaffolds. (1) All ladder-jack scaffolds shall be limited to
light duty and shall not exceed a
height of 20 feet above the floor or
ground.
(2) All ladders used in connection
with ladder-jack scaffolds shall be
heavy-duty ladders and shall be designed and constructed in accordance
with § 1910.25 and § 1910.26.
(3) The ladder jack shall be so designed and constructed that it will bear
on the side rails in addition to the ladder rungs, or if bearing on rungs only,
the bearing area shall be at least 10
inches on each rung.
(4) Ladders used in conjunction with
ladder jacks shall be so placed, fas-

tened, held, or equipped with devices so
as to prevent slipping.
(5) The wood platform planks shall be
not less than 2 inches nominal in
thickness. Both metal and wood platform planks shall overlap the bearing
surface not less than 12 inches. The
span between supports for wood shall
not exceed 8 feet. Platform width shall
be not less than 18 inches.
(6) Not more than two persons shall
occupy any given 8 feet of any ladderjack scaffold at any one time.
(r) Window-jack scaffolds. (1) Windowjack scaffolds shall be used only for the
purpose of working at the window
opening through which the jack is
placed.
(2) Window jacks shall not be used to
support planks placed between one window jack and another or for other elements of scaffolding.
(3) Window-jack scaffolds shall be
provided with suitable guardrails unless safety belts with lifelines are attached and provided for the workman.
Window-jack scaffolds shall be used by
one man only.
(s) Roofing brackets. (1) Roofing
brackets shall be constructed to fit the
pitch of the roof.
(2) Brackets shall be secured in place
by nailing in addition to the pointed
metal projections. The nails shall be
driven full length into the roof. When
rope supports are used, they shall consist of first-grade manila of at least
three-quarter-inch diameter, or equivalent.
(3) A substantial catch platform shall
be installed below the working area of
roofs more than 20 feet from the
ground to eaves with a slope greater
than 3 inches in 12 inches without a
parapet. In width the platform shall extend 2 feet beyond the projection of the
eaves and shall be provided with a safety rail, mid-rail, and toeboard. This
provision shall not apply where employees engaged in work upon such
roofs are protected by a safety belt attached to a lifeline.
(t) Crawling boards or chicken ladders.
(1) Crawling boards shall be not less
than 10 inches wide and 1 inch thick,
having cleats 1×11⁄2 inches. The cleats
shall be equal in length to the width of
the board and spaced at equal intervals
not to exceed 24 inches. Nails shall be

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Occupational Safety and Health Admin., Labor
driven through and clinched on the underside. The crawling board shall extend from the ridge pole to the eaves
when used in connection with roof construction, repair, or maintenance.
(2) A firmly fastened lifeline of at
least three-quarter-inch rope shall be
strung beside each crawling board for a
handhold.
(3) Crawling boards shall be secured
to the roof by means of adequate ridge
hooks or equivalent effective means.
(u) Float or ship scaffolds. (1) Float or
ship scaffolds shall support not more
than three men and a few light tools,
such as those needed for riveting, bolting, and welding. They shall be constructed in accordance with paragraphs
(u) (2) through (6) of this section, unless substitute designs and materials
provide equivalent strength, stability,
and safety.
(2) The platform shall be not less
than 3 feet wide and 6 feet long, made
of three-quarter-inch plywood, equivalent to American Plywood Association
Grade B-B, Group I, Exterior.
(3) Under the platform, there shall be
two supporting bearers made from 2×4inch, or 1×10-inch rough, selected lumber, or better. They shall be free of
knots or other flaws and project 6
inches beyond the platform on both
sides. The ends of the platform shall
extend about 6 inches beyond the outer
edges of the bearers. Each bearer shall
be securely fastened to the platform.
(4) An edging of wood not less than
3⁄4×11⁄2 inches, or equivalent, shall be
placed around all sides of the platform
to prevent tools from rolling off.
(5) Supporting ropes shall be 1-inch
diameter manila rope or equivalent,
free from deterioration, chemical damage, flaws, or other imperfections.
Rope connections shall be such that
the platform cannot shift or slip. If two
ropes are used with each float, each of
the two supporting ropes shall be
hitched around one end of a bearer and
pass under the platforms to the other
end of the bearer where it is hitched
again, leaving sufficient rope at each
end for the supporting ties.
(6) Each workman shall be protected
by a safety lifebelt attached to a lifeline. The lifeline shall be securely attached to substantial members of the
structure (not scaffold), or to securely

§ 1910.29

rigged lines, which will safely suspend
the workman in case of a fall.
(v) Scope. This section establishes
safety requirements for the construction, operation, maintenance, and use
of scaffolds used in the maintenance of
buildings and structures.
[39 FR 23502, June 27, 1974, as amended at 43
FR 49746, Oct. 24, 1978; 49 FR 5321, Feb. 10,
1984; 53 FR 12121, Apr. 12, 1988]

§ 1910.29 Manually propelled mobile
ladder stands and scaffolds (towers).
(a) General requirements—(1) Application. This section is intended to prescribe rules and requirements for the
design, construction, and use of mobile
work
platforms
(including
ladder
stands but not including aerial ladders)
and rolling (mobile) scaffolds (towers).
This standard is promulgated to aid in
providing for the safety of life, limb,
and property, by establishing minimum
standards for structural design requirements and for the use of mobile work
platforms and towers.
(2) Working loads. (i) Work platforms
and scaffolds shall be capable of carrying the design load under varying
circumstances depending upon the conditions of use. Therefore, all parts and
appurtenances necessary for their safe
and efficient utilization must be integral parts of the design.
(ii) Specific design and construction
requirements are not a part of this section because of the wide variety of materials and design possibilities. However, the design shall be such as to
produce a mobile ladder stand or scaffold that will safely sustain the specified loads. The material selected shall
be of sufficient strength to meet the
test requirements and shall be protected against corrosion or deterioration.
(a) The design working load of ladder
stands shall be calculated on the basis
of one or more 200-pound persons together with 50 pounds of equipment
each.
(b) The design load of all scaffolds
shall be calculated on the basis of:
Light— Designed and constructed to carry a
working load of 25 pounds per square foot.
Medium— Designed and constructed to carry
a working load of 50 pounds per square
foot.

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