(A) Reserved.
(B) Definitions.
(1) "Bearer" means a horizontal member of a scaffold
upon which the platform rests and which may be supported by
ledgers.
(2) "Boatswain's chair" means a seat supported
by slings attached to a suspended rope, designed to accommodate one employee in
a sitting position.
(3) "Brace" means a tie that holds one scaffold
member in a fixed position with respect to another member.
(4) "Bricklayer's square scaffold" means a
scaffold the platform of which is supported on built-up squares secured to each
other by full and continuous diagonal bracing.
(5) "Carpenter's bracket scaffold" means a
scaffold the platform of which is supported on triangular braced brackets
fastened to the side of the structure.
(6) "Chimney, stack, or tank bracket scaffold" means
a scaffold composed of a platform supported by wood or steel brackets, hooked
over a steel wire rope which surrounds the circumference of the chimney, stack,
or tank.
(7) "Coupler" means a device for locking together the
component parts of a tubular metal scaffold.
(8) "Double pole or independent pole scaffold" means
a scaffold supported from the base by a double row of uprights, independent of
support from the walls and constructed of uprights, ledgers, horizontal
platform bearers, and diagonal bracing.
(9) "Elevating assembly" means a mechanical,
hydraulic, or other type of mechanism used to elevate and lower a work
platform.
(10) "Float or ship
scaffold" means a scaffold hung from overhead supports by means of ropes
and consisting of a platform having diagonal bracing underneath, resting upon
and fastened to two parallel plank bearers at right angles to the
span.
(11) "Foot scaffold"
means a scaffold used to give additional height, the platform of which does not
exceed eighteen inches above the supporting surface.
(12) "Heavy duty
scaffold" means a scaffold designed and constructed to carry a working
load in excess of fifty pounds but no more than seventy-five pounds per square
foot.
(13) "Horizontal wire
rope supported scaffold" means a scaffold the platform of which is
supported at two or more points by horizontal wire ropes.
(14) "Horse
scaffold" means a scaffold or light or medium duty, composed of saw
horses supporting a work platform.
(15) "Interior hung
scaffold" means a scaffold suspended from the ceiling or roof
structure.
(16) "Ladder jack
scaffold" means a light duty scaffold supported by brackets attached to
ladders.
(17) "Lean to, or shore,
scaffold", use prohibited (see paragraph (C)(16) of this rule), means
scaffold the platform of which is supported on members consisting of a putlog
or bearer, knee braced to two diverging inclined legs that are in a plane
substantially transverse to the putlog and that support the outer end of the
putlog or bearer, while the inner end of the bearer or putlog rests on or
against the structure or on a bearing block attached to the
structure.
(18) "Ledgers" or
"stringers" means a horizontal scaffold member which extends from
post to post at right angles to the putlogs or bearers, supports the putlogs or
bearers, and forms a tie between the posts and becomes a part of the scaffold
bracing.
(19) "Light duty
scaffold" means a scaffold designed and constructed to carry a working
load of no more than twenty-five pounds per square foot.
(20) "Manually propelled
mobile scaffold" means a portable rolling scaffold equipped with
casters.
(21) "Mason's
adjustable multiple-point suspension scaffold" means a scaffold having a
continuous platform supported by bearers suspended by wire rope from overhead
supports, so arranged and operated as to permit the raising or lowering of the
platform to desired working positions.
(22) "Maximum rated
load" means the total of all loads including the working load, the weight
of the scaffold, and such other loads as may be reasonably
anticipated.
(23) "Medium duty
scaffold" means a scaffold designed and constructed to carry a working
load in excess of twenty-five pounds but no more than fifty pounds per square
foot.
(24) "Needle beam
scaffold" means a cantilevered light duty scaffold consisting of two
parallel horizontal beam called needle beams supporting a
platform.
(25) "Outrigger
scaffold" means a scaffold supported by outriggers or thrustouts
projecting beyond the wall or face of the building or structure, the inboard
ends of which are secured inside the wall or face of such building or
structure.
(26) "Pick, or kick,
plank" means a platform, similar in construction to a narrow ladder with
light decking strung upon and attached to the rungs, which rests upon
horizontal and parallel stringers, or other bearers, and is movable along the
course of the stringer.
(27) "Platform"
means the temporary flat working surface used to support employees, material,
and equipment.
(28) "Putlog" means
a scaffold member upon which the platform rests (also see
"bearer").
(29) "Runner" means
the lengthwise horizontal bracing or bearing members, or both.
(30) "Scaffold"
means any temporary elevated platform and its supporting structure used for
supporting employees, materials, or equipment.
(31) "Single-point
adjustable suspension scaffold" means a manually or power operated unit
designed for light duty use, supported by a single wire rope from an overhead
support so arranged and operated as to permit the raising or lowering of
platform to desired working positions.
(32) "Single-pole
scaffold" means platforms resting on putlogs or cross beams, the outside
ends of which are supported on ledgers secured to a single row of posts or
uprights, and the inner ends of which are supported on or in a
wall.
(33) "Stack bracket
scaffold" - see "chimney bracket scaffold".
(34) "Suspended
scaffold" means a scaffold supported from above, the platform of which is
supported at more than two points from overhead outriggers which are fastened
to the framework of the structure.
(35) "Tank bracket
scaffold" - see "chimney bracket scaffold".
(36) "Tube and coupler
scaffold" means an assembly consisting of tubing which serves as posts,
bearers, braces, ties, and runner, a base supporting the posts, and special
couplers which serve to connect the uprights and to join the various
members.
(37) "Tubular welded
frame scaffold" means a sectional panel or frame metal scaffold built up
of prefabricated welded sections which consists of posts and horizontal bearers
with intermediate members.
(38) "Two-point
suspension scaffold" or "swinging scaffold" means a scaffold the
platform of which is supported by stirrups or hangers at two points to permit
raising or lowering, suspended from overhead supports.
(39) "Window jack
scaffold" means a scaffold the platform of which is supported by a jack or
thrustout which projects through a window opening.
(40) "Working load"
means the load on the scaffold imposed by employees, material, and
equipment.
(C) General requirements for all scaffolds.
See appendix to this rule for examples of various
scaffolds mentioned throughout this rule.
(1) The footing or
anchorage for scaffolds shall be sound, rigid, and capable of supporting the
load without settling or displacement. Unstable or loose objects shall not be
used to support scaffolds.
(2) Scaffolds and their components shall be capable of
supporting without failure no less than four times the maximum rated
load.
(3) Any scaffold including accessories, such as braces,
brackets, trusses, screw legs, ladders, etc., damaged or weakened from any
cause shall be immediately repaired or replaced.
(4) Guardrails and toeboards.
Standard guardrails and toeboards shall be
installed on all open sides and ends of platforms more than ten feet above the
ground or floor, except on needle beam scaffolds and floats.
(5) Where employees are required to work or
pass under the scaffold, each employee shall be provided with additional
protection from falling hand tools, debris, and other small objects through the
installation of toeboards, screens, or guardrail systems, or through the
erection of debris nets, catch platforms, or canopy structures that contain or
deflect the falling objects. When the objects are too large, heavy or massive
to be contained or deflected by any of the above-listed measures, the employer
shall place such potential falling objects away from the edge of the surface
from which they could fall and shall secure those materials as necessary to
prevent their falling.
(6) Nails provided for the construction of scaffolds shall be
no less than eight-penny common.
(7) All planking shall be "Scaffold Grade," or
equivalent, as recognized by approved grading rules for the species of wood
used.
(8) All planking of platforms shall be overlapped a minimum of
twelve inches or secured from movement.
(9) An access ladder or equivalent safe access shall be
provided for all scaffolds.
(10) Scaffold planks shall
extend over end supports no less than six inches and no more than twelve
inches.
(11) The poles, legs, or
uprights of scaffolds shall be plumb and securely and rigidly braced to prevent
swaying and displacement.
(12) Overhead protection shall
be provided for employees on a scaffold exposed to hazards from
overhead.
(13) Reasonable care shall be
taken to maintain all scaffold surfaces free of debris and slippery
substances.
(14) No welding, burning,
riveting, or open flame work shall be performed on any scaffolding suspended by
means of fiber or synthetic rope. Only fiber or synthetic ropes, properly
treated or protected, shall be used for or near any work involving the use of
corrosive substances or chemicals.
(15) Wire, synthetic, or fiber
rope used for scaffold suspension shall be capable of supporting no less than
six times the maximum rated load.
(16) The use of shore or
lean-to scaffolds is prohibited.
(17) When there is danger of
material being hoisted striking against the scaffold, a tag line shall be
provided.
(18) The free ends of fall
lines from scaffolds shall be guarded.
(D) Wood pole scaffolds.
See appendix to this rule for examples of wood
pole scaffolds.
(1) Scaffold poles
shall bear on a foundation of sufficient size and strength to spread the load
from the pole over a sufficient area to prevent settlement. All poles shall be
set plumb.
(2) Where 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 no less than two adjacent sides and shall be no less than
four feet in length, overlapping the abutted ends equally, and have the same
width and no less than the cross-sectional area of the pole. Splice plates or
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 twenty-five feet, the
scaffold shall be secured at intervals no greater than twenty-five feet
vertically and horizontally.
(5) Putlogs or bearers shall be set with the greater dimension
vertical, long enough to project over the ledgers of the inner and outer rows
of poles no less than three inches for proper support.
(6) Every wooden putlog on single pole scaffolds shall be
reinforced with a three-sixteenths - by two-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 fastened 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, and 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 only at the poles. The inner row of
poles on medium and heavy duty scaffolds shall be braced in similar
manner.
(11) Platform planks shall be
laid with their edges butted together so the platform shall 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 support no less than twelve 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 secured to prevent their
dislodgment.
(13) When a scaffold
materially changes its direction, 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 an angle 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) All wood pole scaffolds
sixty feet or less in height shall be constructed and erected in accordance
with "Tables 10-1 to 10-6." If they are over sixty feet in height,
they shall be designed by a professional engineer competent in this field, and
shall be constructed and erected in accordance with such design.
Table 10-1. Minimum nominal size and maximum
spacing of members of single-pole scaffolds - light duty.
| Maximum height ofscaffold |
| 20 ft. | 60 ft. |
Uniformly distributed load | Not to exceed 25 p.s.f. | |
Poles oruprights | 2 x 4in. | 4 x 4in. |
Pole spacing (longitudinal) | 6 ft. 0 in. | 10 ft. 0 in. |
Maximum width ofscaffold | 5 ft.0 in. | 5 ft. 0in. |
Bearers or putlogs to 3 ft. 0 in. width | 2 x 4 in. | 2 x 4 in. |
Bearers or putlogs to 5 ft.0 in. width | 2x 6 in. or 3 x 4 in. | 2 x 6 in. or 3 x 4 in. (rough). |
Ledgers | 1 x 4 in. | 1 1/4 x 9 in. |
Planking | 1 1/4 x 9 in. (rough) | 2 x 10 in. |
Vertical spacing ofhorizontal members | 7 ft. 0 in. | 9 ft. 0 in. |
Bracing, horizontal anddiagonal | 1 x 4in. | 1 x 4in. |
Tie-ins | 1 x 4 in. | 1 x 4 in. |
Toeboards | 4 in. high (minimum) | 4 in. high(minimum). |
Guardrails | 2 x 4 in. | 2 x 4 in. |
All members except planking shall be used on
edge.
Table 10-2. Minimum nominal size and maximum
spacing of members of single-pole scaffolds - medium duty.
Uniformly distributed load. | Not to exceed 50p.s.f. |
Maximum height of scaffolds. | 60 ft. |
Poles oruprights | 4 x 4in. |
Pole spacing (longitudinal). | 8 ft. 0 in. |
Maximum width ofscaffold. | 5ft. 0 in. |
Bearers or putlogs | 2 x 10 in. or 3 x 4in. |
Spacing of bearers or putlogs. | 8 ft. 0 in. |
Ledgers | 2 x 10 in. |
Vertical spacing ofhorizontal members. | 7 ft. 0 in. |
Bracing, horizontal | 1 x 6 in. or 1 1/4 x 4in. |
Bracing, diagonal | 1 x 4 in. |
Tie-ins | 1 x 4 in. |
Planking | 2 x 10in. |
Toeboards | 4 in. high (minimum). |
Guardrails | 2 x 4in. |
All members except planking shall be used on
edge.
Table 10-3. Minimum nominal size and maximum
spacing of members of single-pole scaffolds - heavy duty.
Uniformly distributedload. | Not toexceed 75 p.s.f. |
Maximum height of scaffold. | 60 ft. |
Poles oruprights | 4 x 6in. |
Pole spacing (longitudinal). | 6 ft. 0 in. |
Maximum width ofscaffold. | 5ft. 0 in. |
Bearers or putlogs | 2 x 10 in. or 3 x 5in. |
Spacing of bearers or putlogs. | 6 ft. 0 in. |
Ledgers | 2 x 10 in. |
Vertical spacing ofhorizontal members. | 6 ft. 6 in. |
Bracing, horizontal and diagonal. | 2 x 4in. |
Tie-ins | 1 x 4 in. |
Planking | 2 x 10 in. |
Toeboards | 4 in. high (minimum). |
Guardrails | 2 x 4in. |
All members except planking shall be used on
edge.
Table 10-4. Minimum nominal size and maximum
spacing of members of independent pole scaffold - light duty.
| Maximum height ofscaffold |
| 20ft. | 60ft. |
Uniformly distributed load | Not to exceed 25 p.s.f. | |
Poles oruprights | 2 x 4in. | 4 x 4in. |
Pole spacing (longitudinal) | 6 ft. 0 in. | 10 ft. 0 in. |
Pole spacing(transverse) | 6ft. 0 in. | 10ft. 0 in. |
Ledgers | 1 1/4 x 4 in. | 1 1/4 x 9 in. |
Bearers to 3 ft. 0 in. span | 2 x 4 in. | 2 x 4in. |
Bearers to 10 ft. 0 in. span | 2 x 6 in. or 3 x 4 in. | 2 x 10 (rough) or 3 x 8in. |
Planking | 1 1/4 x 9 in. | 2 x 10 in. |
Vertical spacing of horizontal members | 7 ft. 0 in. | 7 ft. 0in. |
Bracing, horizontal and diagonal | 1 x 4 in. | 1 x 4in. |
Tie-ins | 1 x 4 in. | 1 x 4 in. |
Toeboards | 4 in. high | 4 in. high(minimum) |
Guardrails | 2 x 4 in. | 2 x 4 in. |
All members except planking shall be used on
edge.
Table 10-5. Minimum nominal size and maximum
spacing of members of independent pole scaffolds - medium duty.
Uniformly distributedload. | Not toexceed 50 p.s.f. |
Maximum height of scaffold. | 60 ft. |
Poles oruprights | 4 x 4in. |
Pole spacing (longitudinal). | 8 ft. 0 in. |
Pole spacing(transverse). | 8 ft. 0 in. |
Ledgers | 2 x 10 in. |
Vertical spacing of horizontal members. | 6 ft. 0in. |
Spacing of bearers | 8 ft. 0 in. |
Bearers | 2 x 10 in. |
Bracing,horizontal | 1 x6 in. or 1 1/4 x 4 in. |
Bracing, diagonal | 1 x 4 in. |
Tie-ins | 1 x 4 in. |
Planking | 2 x 10 in. |
Toeboards | 4 in. high (minimum). |
Guardrails | 2 x 4in. |
All members except planking shall be used on
edge.
Table 10-6. Minimum nominal size and maximum
spacing of members of independent pole scaffold - heavy duty.
Uniformly distributedload. | Not toexceed 75 p.s.f. |
Maximum height of scaffold. | 60 ft. |
Poles oruprights | 4 x 4in. |
Pole spacing (longitudinal). | 6 ft. 0 in. |
Pole spacing(transverse). | 8 ft. 0 in. |
Ledgers | 2 x 10 in. |
Vertical spacing of horizontal members. | 6 ft. 0in. |
Bearers | 2 x 10 in. (rough). |
Bracing, horizontal anddiagonal. | 2 x4 in. |
Tie-ins | 1 x 4 in. |
Planking | 2 x 10 in. |
Toeboards | 4 in. high (minimum). |
Guardrails | 2 x 4in. |
All members except planking shall be used on
edge.
(E) Tube and coupler scaffolds.
(1) The material
used for couplers shall be of a structural type, such as drop-forged steel,
malleable iron, or structural grade aluminum.
(2) A light duty tube and coupler scaffold shall have all
posts, bearers, runners, and bracing of nominal two-inch outside-diameter
(O.D.) steel tubing. The posts shall be spaced no more than six feet apart in
width and ten feet apart in length. Other structural metals when used must be
designed to carry an equivalent load. No dissimilar metals shall be used
together.
(3) A medium duty tube and coupler scaffold shall consist of no
less than nominal two-inch O.D. steel tubing in all posts, runners, and
bracing. Where the posts are spaced no farther apart than five feet by eight
feet, the bearers shall also be no less than nominal two-inch O.D. steel
tubing. Where the posts are spaced at greater distances apart than five feet by
eight feet, the bearers shall be of not less than nominal two and one-half inch
O.D. steel tubing but, in no event, may the posts of a medium duty tube and
coupler scaffold be spaced farther apart than six feet by eight feet. Other
structural metals, when used, must be capable of carrying a load equivalent to
the load supportable by the prescribed tube and coupler scaffold. No dissimilar
metals shall be used together.
(4) A heavy duty tube and coupler scaffold shall have all
posts, runners, and bracing of nominal two-inch O.D. steel tubing, with the
posts spaced no more than six feet by six feet six inches. Other structural
metals, when used, must be designed to carry an equivalent load. No dissimilar
metals shall be used together.
(5) Tube and coupler scaffolds shall be limited in heights and
working levels to those permitted in Tables 10-7 to 10-9. Drawings and
specifications of all tube and coupler scaffolds above the limitations in
Tables 10-7 to 10-9 shall be designed by a qualified engineer competent in this
field.
(6) Posts shall be accurately spaced, erected on suitable
bases, and maintained plumb.
(7) Runners shall be erected along the length of the scaffold,
located on both the inside and the outside posts at even heights. Runners shall
be interlocked to the inside and the outside posts at even heights. 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 no more than six feet six inches on centers.
(8) 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.
(9) Bearers shall extend past the post and
runners.
(10) Cross bracing shall be
installed across the width of the scaffold no less than 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.
(11) Longitudinal diagonal
bracing on the inner and outer rows of poles shall be installed at
approximately a forty-five 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.
(12) The entire scaffold shall
be tied to and securely braced against the building at intervals not to exceed
thirty feet horizontally and twenty-six feet vertically.
Uniformlydistributed load | Not to exceed 25p.s.f. |
Post spacing(longitudinal) | 10 ft. 0in. |
Post spacing(transverse) | |
Workinglevels | Additional plankedlevels | Maximumheight |
1 | 8 | 125ft. |
2 | 4 | 125ft. |
3 | 0 | 91ft. 0 in. |
Uniformlydistributed load | Not to exceed 50p.s.f |
Post spacing(longitudinal) | 8 ft. 6in. |
Post spacing(transverse) | 6 ft. 0in |
Workinglevels | Additional plankedlevels | Maximumheight |
1 | 6 | 125ft |
2 | 0 | 78 ft. 0 in. |
Uniformlydistributed load | Not to exceed 75p.s.f. |
Post spacing(longitudinal) | 6 ft. 6in. |
Post spacing(transverse) | 6 ft. 0in. |
Workinglevels | Additional plankedlevels | Maximumheight |
1 | 6 | 125ft. |
(F) Tubular welded frame scaffolds.
(1) Scaffolds shall
be properly braced by diagonal braces for securing vertical members together
laterally, and the cross braces shall be of such length as will automatically
square and align vertical members so that the erected scaffold is always plumb,
square, and rigid. All brace connections shall be made secure.
(2) Scaffold legs shall be set on adjustable bases or plain
bases placed on mud sills or other adequate foundations.
(3) The frames shall be placed one on top of the other with
coupling or stacking pins to provide proper vertical alignment of the
legs.
(4) Where uplift may occur, panels shall be locked together
vertically by pins or other equivalent suitable means.
(5) Supported scaffolds with a height to base width (including
outrigger supports if used) ratio of more than four to one shall be secured to
the building or structure at intervals not to exceed thirty feet horizontally
and twenty-six feet vertically.
(6) Maximum permissible spans or planking shall be in
conformity with paragraph (C)(7) of this rule.
(G) Manually propelled mobile scaffolds.
(1) When
free-standing mobile scaffold towers are used, the height of the work platform
shall not exceed four times the minimum base dimension.
(2) Casters shall be properly designed for strength and
dimensions to support four times the maximum rated load. All casters shall be
provided with a locking device to hold the scaffold in position.
(3) Scaffolds shall be properly braced by cross bracing and
horizontal bracing conforming with paragraph (F)(1) of this rule.
(4) Platforms shall be tightly planked for the full width of
the scaffold except for necessary entrance opening. Platforms shall be secured
in place.
(5) A ladder or stairway shall be provided for proper access
and exit and shall be affixed or built into the scaffold and so located that
when in use it will not have a tendency to tip the scaffold. A landing platform
must be provided at intervals not to exceed thirty-five feet.
(6) Provision shall be made to stabilize the tower during
movement from one location to another.
(7) The employer shall not require employees to ride on
manually propelled scaffolds unless the following conditions
exist:
(a) The floor or surface is within three degrees of level and
free from pits, holes, or obstructions;
(b) When ready for rolling the height of the
work platform shall not exceed two times the narrowest dimension of the base;
when outriggers are used they shall be included in the base dimension and shall
be installed on both sides of the staging;
(c) The wheels are equipped with rubber or
similar resilient tires;
(d) All tools and materials are secured or
removed from the platform before the mobile scaffold is moved.
(H) Elevated work platforms and self-propelled elevated work
platforms.
(1) The minimum
rated work load of a platform shall be no less than two hundred fifty pounds.
The work platform and all structural components shall have a factor of safety
of no less than four.
(2) Any work platform when raised to its maximum working height
shall be capable of sustaining without reaching instability, a horizontal force
of fifty pounds applied to any point on the platform while the platform is
carrying the working load.
(3) The base shall not be used or placed on an inclined surface
unless leveled by a device that is part of the unit.
(4) Work platform elevating assemblies.
(a) Factors of safety of elevating assembly.
(i) Where the platform is supporting its
working load by a system of wire ropes or lift chains, or both, the factor of
safety of the wire or chain shall be no less than six.
(ii) All critical components of a hydraulic or pneumatic system
used in a work platform shall have a bursting strength that exceeds the
pressure attained when the system is subjected to the equivalent of four times
the maximum rated load. Critical components are those in which a failure would
result in a free fall. All noncritical hydraulic components shall have a
bursting factor of safety of no less than two.
(b) Systems protection.
(i) Where the elevation of the platform is
accomplished by an electromechanical assembly, or a hydraulic or pneumatic
cylinder assembly, the system shall be so equipped as to prevent free fall in
the event of a power failure.
(ii) Where the elevation of the platform is accomplished by a
hydraulic or pneumatic cylinder assembly, the system shall be so equipped as to
prevent free fall in the event of a hydraulic or pneumatic line
failure.
(iii) Where the elevation of the platform is accomplished by a
single hoist cable, the system shall be protected by a broken-cable safety
device.
(iv) Where the elevation of the platform is accomplished by
manual-mechanical or manual-hydraulic assembly, the assembly shall be equipped
to prevent free fall in case of failure.
(c) Controls.
(i) Any powered work platform shall have
both upper and lower control devices. Controls shall be plainly marked as to
their function and guarded to prevent accidental operation. The upper control
device shall be in or beside the platform, within easy reach of the operator.
The lower control device shall have the capability to lower the platform where
the operator's safety is in jeopardy.
(ii) Each elevated work platform shall be equipped with a clear
visible instruction plate stating:
(a) Rated capacity;
(b) Maximum platform height;
(c) Special warning or restrictions necessary
for safe operation.
(iii) Protection to personnel.
(a) Pinch points and shear points shall be guarded with a barrier
to prevent accidental or inadvertent entrapment of personnel while the work
platform is being operated.
(b) All rotating shafts, gearing, and other
moving parts shall be guarded.
(I) Outrigger scaffolds.
See appendix to this rule for examples of
outrigger scaffolds.
(1) Outrigger beams
shall extend no more than six feet beyond the face of the building. The inboard
end of the outrigger beams, measured from the fulcrum point to anchorage point,
shall be no 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 no
less than six inches in each horizontal dimension. The beam shall be secured in
place against movement and shall be securely braced at the fulcrum point
against movement and shall be securely braced at the fulcrum point against
tipping.
(2) The inboard ends of outrigger beams shall be securely
anchored 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 professional
engineer competent in this field, they shall be constructed and erected in
accordance with "Table 10-10." Outrigger scaffolds, designed by a
professional engineer, shall provide equivalent or greater safeguards than
those required herein.
(4) Planking shall be laid tight and shall extend to within
three inches of the building wall. Planking shall be secured to the
beams.
Table 10-10. Minimum nominal size and maximum
spacing of members of outrigger scaffolds.
| Light duty | Medium duty |
Maximum scaffoldload. | 25p.s.f. | 50p.s.f. |
Outrigger size | 2 x 10 in. | 3 x 10 in. |
Maximum outrigger spacing. | 10 ft. 0 in. | 6 ft. 0 in. |
Planking | 2 x 10 in. | 2 x 10in. |
Guardrail | 2 x 4 in. | 2 x 4 in. |
Guardrail uprights | 2 x 4 in. | 2 x 4 in. |
Toeboards | 4 in.(minimum). | 4in. (minimum). |
(J) Masons' adjustable multiple-point suspension
scaffolds.
See appendix to this rule for examples of
masons' adjustable multiple-point suspension scaffolds.
(1) The scaffold
shall be capable of sustaining a working load of fifty 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
an approved
testing laboratory.
(3) The platform shall be supported by wire ropes, capable of
supporting no less than six times the intended load, suspend 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) Where an outrigger beam does not project more than six feet
six inches beyond the bearing point, it shall be equivalent in the strength to
no less than a standard seven-inch, fifteen and three-tenths-pound steel I-beam
no less than fifteen feet long.
(6) Where the overhang exceeds six feet six inches, outrigger
beams shall be composed of stronger beams or multiple beams, providing
proportionally greater strength than that required in paragraph (J)(5) of this
rule.
(7) All outrigger beams shall be set and maintained with their
webs in a vertical position.
(8) A stop bolt shall be placed at each end of every outrigger
beam.
(9) The outrigger beam shall rest on suitable wood bearing
blocks.
(10) The free end of the
suspension wire ropes shall be equipped with proper size thimbles and secured
by splicing or other equivalent means. The running ends shall be securely
attached to the hoisting drum and no less than four turns of wire rope shall at
all times remain on the drum. The use of fiber rope is prohibited.
(11) 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
drum.
(12) The scaffold platform
shall be equivalent in strength to no less than two-inch planking.
(13) When employees are at
work on the scaffold and a hazard exists from overhead, overhead protection
shall be provided on the scaffold, no more than nine feet above the platform,
consisting of two-inch planking, or material of equivalent strength, laid
tight, and extending no less than the width of the scaffold.
(K) Two-point suspension scaffolds (swinging
scaffolds).
See appendix to this rule for examples of
swinging scaffolds.
(1) Two-point
suspension scaffold platforms shall be no more than thirty-six 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 mild steel, or other equivalent materials, having a cross-sectional area
capable of sustaining four times the maximum rated load, and shall be
constructed to accommodate a 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
an approved
testing laboratory.
(4) Employees shall not be required to use a bridge between, or
to move directly from, one swinging scaffold and another unless the platforms
are at the same height, are abutting, and walk through stirrups specifically
designed for this purpose are used.
(5) The roof irons or hooks shall be of mild steel, or other
equivalent material, of proper size and design, securely installed and
anchored. Tiebacks of three-quarter-inch manila rope, or the equivalent, shall
serve as an additional 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.
(6) Two-point suspension scaffolds shall be suspended by wire,
synthetic, or fiber ropes capable of supporting no less than six times the
maximum rated load. All other components shall be capable of supporting no less
than four times the maximum rated load.
(7) The sheaves of all blocks shall fit the size and type of
rope used.
(8) No more than two employees shall be required to be on a
two-point suspension scaffold designed for a working load of five hundred
pounds at any time. No more than three employees shall be required to be on a
two-point suspension scaffold designed for a working load of seven hundred
pounds, at any time. Each employee shall be protected by an approved safety
belt or harness 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 employee in case of a fall.
(9) Two-point suspension scaffolds shall be securely lashed to
the building or structure to prevent from swaying. Window cleaners'
anchors shall not be used for this purpose.
(10) The platform of every
two-point suspension scaffold shall be one of the following types:
(a) Ladder-type platforms.
Ladder-type platforms shall be capable of
sustaining four times the maximum rated load and shall be constructed in
accordance with "Table 10-11."
(b) Plank-type platforms.
Plank-type platforms shall be composed of no
less than "Scaffold Grade" two-inch by ten-inch unspliced planks,
properly cleated together on the underside, starting six inches from each end;
intervals in between shall not exceed four feet. The plank-type platform shall
not extend beyond the hangers more than twelve 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 eight feet.
(c) Beam-type platforms.
Beam-type platforms shall have side stringers
of lumber no less than two inches by six inches set on edge. The span between
hangers shall not exceed twelve feet when beam platforms are used. The flooring
shall be supported on two-inch by six-inch cross beams, laid flat and set into
the upper edge of the stringers with a snug fit, at intervals of no more than
four feet, securely nailed in place. The flooring shall be of one-inch by
six-inch material, or equivalent, properly nailed. Floor boards shall be spaced
no more than one-half-inch apart.
(d) Light metal-type platforms.
Approved light metal-type platforms shall
meet the requirements of paragraph (C)(2) of this rule.
Table 10-11. Schedule for ladder-type
platforms.
(L) Single-point adjustable suspension scaffolds.
(1) The
scaffolding, including power units or manually operated winches, shall be of an
approved type and meet the requirements of paragraph (C)(2) of this
rule.
(2) All power-operated gears and brakes shall be
enclosed.
(3) In addition to the normal operating brake, all power-driven
units shall have an emergency brake which engages automatically when the normal
speed of descent is exceeded.
(4) The units may be combined to form a two-point suspension
scaffold. Such scaffold shall then comply with paragraph (K) of this
rule.
(5) The supporting cable shall be vertical for its entire
length.
(6) Suspension methods shall conform to applicable provisions
of paragraphs (J) and (K) of this rule.
(7) The employee shall be protected by a safety harness and lifeline in accordance with paragraph (J) of
rule 4123:1-3-03 of the Administrative Code. The attachment point of the
lifeline to the structure shall be appropriately changed as the work
progresses.
(M) Boatswains' chairs.
(1) When
constructed of wood the chair seat shall be no less than twelve inches by
twenty-four inches by one-inch thickness, reinforced by cleats on the underside
to prevent splitting. A chair of the same size may be constructed of material
of equal strength.
(2) Seat slings shall be of no less than five-eighths-inch
diameter, "First Grade" manila rope, or its equivalent, which shall
be reeved through the four seat holes so as to cross each other on the
underside of the seat.
(3) Seat slings shall be of no less than three-eighths-inch
wire rope when an employee is conducting a heat-producing process, such as gas
or arc welding.
(4) The employee shall be protected by a safety belt or harness
and lifeline in accordance with paragraph (J) of rule 4123:1-3-03 of the
Administrative Code. The attachment point of the lifeline to the structure
shall be appropriately changed as the work progresses.
(5) The tackle shall consist of correct size ball bearing or
bushed blocks and properly spliced five-eighths-inch diameter, "First
Grade" manila rope, or equivalent.
(6) The roofirons, hooks, or the object to which the tackle is
anchored, shall be securely installed. Tiebacks shall be installed at right
angles to the face of the building and securely fastened when using wall
hooks.
(N) Carpenters' bracket scaffolds.
(1) The brackets
shall consist of a triangular wood frame no less than two inches by three
inches in cross section, or of metal of equivalent strength. Each member shall
be properly fitted and securely joined.
(2) Each bracket shall be secured to the structure by a means
which shall provide a factor of safety of no less than four.
(3) The brackets shall be spaced no more than eight feet
apart.
(4) The platform shall consist of no less than two two-inch by
ten-inch "Scaffold Grade" planks extending no more than twelve inches
or less than six inches beyond each and support.
(O) Bricklayers' square scaffolds.
(1) Bricklayers' square scaffolds shall conform to
"Table 10-12" and the square shall not exceed five feet in width and
five feet in height.
(2) The squares shall be reinforced on both sides of each
corner with one-inch by six-inch gusset pieces. They shall also have diagonal
braces one inch by eight inches on both sides running from center to center of
each member, or other means to secure equivalent strength and
rigidity.
(3) The squares shall be set no more than five feet apart for
medium duty scaffolds, and no more than eight feet apart for light duty
scaffolds. Bracing, one inch by eight 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.
(4) Platform planks shall be no less than two-inch by ten-inch
"Scaffold Grade." The ends of the planks shall overlap the bearers of
the squares and each plank shall be supported by no less than three
squares.
(5) Bricklayers' square scaffold 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.
(6) Scaffolds shall be level and plumb and set upon a firm
foundation.
Table 10-12. Minimum dimensions for
bricklayers' square scaffold members.
Members | Dimensions |
Bearers or horizontal members | 2 x 6 in. |
Legs | 2 x 6in. |
Braces at corners | 1 x 6 in. |
Braces diagonally from centerframe | 1 x 8in. |
(P) Foot scaffolds.
(1) Foot scaffolds
shall not exceed eighteen inches in height, measured from the level upon which
the supports are placed.
(2) Foot scaffolds imposed on other scaffolds when supported on
brick or tile, shall be limited to eighteen inches in height and have a bearing
surface of no less than ninety-six square inches. Supports shall be no more
than seven feet cent to center.
(Q) Horse scaffolds.
(1) Horse scaffolds
shall not be constructed or arranged more than two tiers in
height.
(2) The members of the horses shall be no less than those
specified in "Table 10-13."
(3) Horses shall be spaced no more than five feet for medium
duty and no more than eight feet for light duty.
(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 or otherwise secured to the planks to prevent displacement or
thrust and each tier shall be substantially cross braced.
(6) Defective or damaged horses or parts shall not be
used.
Table 10-13. Minimum dimensions for horse
scaffold members.
Members | Dimensions |
Horizontal members orbearers | 3 x 4in. |
Legs | 1-1/4 x 4-1/2 in. |
Longitudinal brace betweenlegs | 1 x 6in. |
Gusset brace at top of legs | 1 x 8 in. |
Half diagonalbraces | 1-1/4 x4-1/2 in. |
(R) Chimney, stack, or tank bracket scaffolds.
(1) Minimum
width.
The minimum width of platform shall be no less
than eighteen inches.
(2) Spacer blocks.
Spacer blocks, large enough to hold the
suspending cable away form the structure, shall be provided.
(3) Ascending and descending.
For ascending to and descending from a chimney,
stack or tank bracket scaffold, a scaling ladder or boatswain's chair
shall be provided.
(4) Platforms on masonry chimneys or stacks.
Platforms supported on the rim of masonry
chimneys or stacks are prohibited.
(5) Inside scaffolds.
In construction of chimneys or stacks where an
inside scaffold is being used, the working platform shall be no less than
eighteen inches below the top of the wall.
(6) Guardrails.
Chimney, stack, or tank bracket scaffolds shall
be provided with standard guardrails, but no guardrail is required when safety
belts or harness with lifelines are provided.
(S) Needle beam scaffolds.
(1) Wood needle
beams shall be no less than four inches by six inches in size, with the greater
dimensions placed in a vertical direction. Metal beams or the equivalent,
conforming to paragraph (C)(2) of this rule may be used and shall not be
altered or moved horizontally while they are in use.
(2) Ropes or hangers shall be provided for supports. The span
between supports on the needle beam shall not exceed ten feet for four-inch by
six-inch timbers. Rope supports shall be equivalent in strength to one-inch
diameter "First Grade" manila rope.
(3) The scaffold shall be rigged so as to prevent the needle
beam from rolling or becoming otherwise displaced.
(4) The platform span between the need beams shall not exceed
eight feet when using two-inch "Scaffold Grade" planks. For spans
greater than eight feet, platforms shall be constructed based on design
requirements for the special span. The overhang of each end of the platform
planks shall be no less than six inches and no more than twelve inches. Planks
shall be secured against displacement.
(5) All unattached tools, bolts, and nuts used on needle beam
scaffolds shall be kept in suitable containers, properly secured.
(6) One end of a needle beam scaffold may be supported by a
permanent structural member conforming to paragraph (C)(2) of this
rule.
(7) Each employee working on a needle beam scaffold shall be
protected by a safety harness and lifeline in
accordance with paragraph (J) of rule 4123:1-3-03 of the Administrative
Code.
(T) Interior hung scaffolds.
(1) An interior
hung scaffold shall be hung or suspended from a structure capable of providing
a factor of safety of no less than four.
(2) The suspending wire or fiber rope shall be capable of
supporting no less than six times the maximum rated load.
(3) The scaffold shall be designed to sustain a working load
with a factor of safety of no less than four.
(4) For wood scaffolds, the following minimum "Scaffold
Grade" material shall be used:
(a) Supporting bearers, two inches by ten inches on
edge;
(b) Planking, two inches by ten inches, with
maximum span of seven feet for heavy duty and ten feet for light duty or medium
duty.
(5) Steel tube and coupler members may be used for such type
scaffolds.
(U) Ladder jack scaffolds.
(1) All ladder jack
scaffolds shall be limited to light duty and shall not exceed a height of
twenty feet above the floor or ground.
(2) All ladders used in connection with ladder jack scaffolds
shall be heavy duty ladders. Cleated ladder shall not be used for this
purpose.
(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 no less than ten inches on each
rung.
(4) Ladder used in conjunction with ladder jacks shall be so
placed, fastened, held, or equipped with devices so as to prevent
slipping.
(5) The platform shall be "Scaffold Grade," two-inch
by ten-inch plank, or material of equal strength. Planks shall overlap the
bearing surface no less than twelve inches. The span between supports shall not
exceed eight feet. Platform width shall be no less than eighteen inches and
provide a factor of safety of no less than four.
(V) Window jack scaffolds.
(1) Window jack
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 spaced
between one window jack and another or for other elements of
scaffolding.
(3) Window jack scaffolds shall be provided with standard
guardrails unless safety belts or harnesses with lifelines are attached and
provided for the employee.
(4) No more than one employee shall be required to occupy a
window jack scaffold.
(W) Float or ship scaffolds.
See appendix to this rule for examples of float
or ship scaffolds.
(1) No more than
three employees shall be required to occupy a float or ship
scaffold.
(2) The platform shall be no less than three feet wide and six
feet long, made of three-quarter-inch plywood, equal to "American Plywood
Association Grade B-B, Group I, Exterior," or other equivalent
material.
(3) Under the platform, there shall be two supporting bearers
made from two-inch by four-inch, or one-inch by ten-inch, rough, select lumber
or better. Bearers shall be free of knots or other flaws and project six inches
beyond the platform on both sides. The ends of the platform shall extend six
inches beyond the outer edges of the bearers. Each bearer shall be securely
fastened to the platform.
(4) An edging of wood no less than three-fourths by one and
one-half inches shall be placed around all sides of the platform to prevent
tools from rolling off.
(5) Supporting ropes shall be one-inch diameter manila rope, or
equivalent, providing a factor of safety of no less than six. Rope connections
shall be such that the platform cannot shift or slip. Two ropes shall be used
with each float, arranged so as to provide four ends which are to be securely
fastened to an overhead support. Each of the two supporting ropes shall be
securely fastened around one end of the bearer and pass under the platform to
the other end of the bearer where it shall be securely fastened again, leaving
sufficient rope at each end for the supporting ties.
(X) Form scaffolds.
See appendix to this rule for examples of various
types of form scaffolds covered under this rule.
(1) General
requirements for all form scaffolds.
(a) All form scaffolds and their components shall be capable of
supporting without failure no less than four times the maximum rated
load.
(b) Maximum permissible spans shall not exceed
eight feet on centers for two-inch by ten-inch "Scaffold Grade"
planking. Scaffold planks shall be securely fastened to the ledgers or of such
length that they overlap the ledgers no less than six inches. Unsupported
projecting ends of scaffolding planks of all form scaffolds shall be limited to
a maximum overhang of twelve inches.
(2) Figure-four form scaffolds.
Figure-four form scaffolds are intended for
light duty and shall not be used to support loads exceeding twenty-five pounds
per square foot unless specifically designed for heavier loading. Frames shall
be spaced no more than eight feet on centers. (For minimum design criteria, see
"Table 10-14").
Table 10-14. Minimum design criteria for
figure-four form scaffolds.
Members | Dimensions |
Uprights | 2 x 4 in. or 2 x 6 in. |
Outrigger ledgers(two) | 1 x 6in. |
Braces | 1 x 6 in. |
Guardrails | 2 x 4 in. |
Guardrail height | Approximately 42in. |
Intermediate guardrails | 1 x 6 in. |
Toeboards | 4 in. (minimum) |
Maximum length ofledgers | 3 ft.6 in. (unsupported) |
Planking | 2 x 10 in. |
Uprightspacing | 8 ft.0 in. (on centers) |
(3) Metal bracket form scaffolds.
(a) Metal brackets or scaffold jacks which are an integral part
of the form shall be securely bolted or welded to the form. Folding type
brackets shall be either bolted or secured with a locking type pin when
extended for use.
(b) "Clip-on" or
"hook-over" brackets may be used, provided the form walers are bolted
to the form or secured by snap ties or shea-bolt extending through the form and
securely anchored.
(c) Metal brackets shall be spaced no more than
eight feet on centers.
(d) Scaffold planks shall be either bolted to
the metal brackets or of such length that they overlap the brackets at each end
by no less than six inches. Unsupported projecting ends of scaffolding planks
shall be limited to a maximum overhang of twelve inches.
(e) Metal bracket form scaffolds shall be
equipped with standard guardrails and toeboards, meeting the minimum dimensions
shown in "Table 10-15."
Table 10-15. Minimum design criteria for
metal bracket form scaffolds.
Members | Dimensions |
Uprights | 2 x 4 in. |
Guardrails | 2 x 4 in. |
Guardrailheight | Approximately 42 in. |
Intermediate guardrails | 1 x 6in. |
Toeboards | 4 in. (minimum) |
Planking | 2 x 9 in. |
(4) Wooden bracket form scaffolds.
Wooden bracket form scaffolds shall be an
integral part of the form panel. The minimum design criteria set forth herein
and in "Table 10-16" cover scaffolding intended for light duty and
shall not be used to support loads exceeding twenty-five pounds per square
foot, unless specifically designed for heavier loading.
Table 10-16. Minimum design criteria for wooden
bracket form scaffolds.
Members | Dimensions |
Uprights | 2 x 4 in. or2 x 6 in. |
Supportledgers | 2 x 6in. |
Maximum scaffoldwidth | 3 ft. 6in. |
Braces | 1 x 6 in. |
Guardrails | 2 x 4in. |
Guardrailheight | Approximately 42in. |
Intermediateguardrails | 1 x 6in. |
Toeboards | 4 in.(minimum) |
Uprightspacing | 8 ft. 0 in. (oncenters) |
(Y) Pump jack scaffolds.
(1) Pump jack
scaffolds shall:
(a) Not carry a working load exceeding five hundred pounds;
and
(b) Be capable of supporting no less than four
times the maximum rated load.
(c) The manufactured components shall not be
loaded in excess of the manufacturer's recommended limits.
(2) Each pump jack bracket shall have two gripping mechanisms
to prevent any failure or slippage.
(3) The platform bracket shall be fully decked and the planking
secured. Planking, or equivalent, shall conform with paragraph (C)(7) of this
rule.
(4) Poles and bracing.
(a) When wood scaffold planks are used as platforms, poles for
pump jacks shall be spaced no more than ten feet center to center. When
fabricated platforms are used that fully comply with all other provisions of
this section, pole spacing may exceed ten feet center to center.
(b) Poles shall not exceed thirty feet in
height.
(c) Poles shall be secured to the work surface
by rigid triangular bracing, or equivalent, at the bottom, top and other points
as necessary, to provide a maximum vertical spacing of no more than ten feet
between braces. Each brace shall be capable of supporting a minimum of two
hundred twenty-five pounds tension and compression.
(d) For the pump jack bracket to pass bracing
already installed, an extra brace shall be used approximately four feet above
the one to be passed until the original brace is reinstalled.
(e) All poles shall bear on mud sills or other
firm foundations.
(f) Pole lumber shall be two-by-fours, of
Douglas fir, or equivalent, straight-grained, clear, free of cross-grain,
shakes, large knots, and other defects which might impair
strength.
(g) When poles are constructed of two
continuous lengths, they shall be two-by-fours, spiked together with the seam
parallel to the bracket, and with ten-penny common nails, no more than twelve
inches center to center, staggered uniformly from opposite outside
edges.
(h) If two-by-fours are spliced to make up the
pole, the splices shall be so constructed as to develop the full strength of
the member.
(5) A ladder shall be provided for access to the platform
during use.
(6) No more than two employees shall be required at any time to
be on a pump jack scaffold between any two supports.
(7) Pump jack scaffolds shall be provided with standard
guardrails, but no guardrail is required when safety harnesses with lifelines are provided for employees.
(8) When a work bench is used at an approximate height of
forty-two inches, the top guardrail may be omitted in the space occupied by the
work bench, if the work bench is fully decked, the decking is secure, and is
capable of withstanding two hundred pounds pressure in any
direction.
(9) Employees shall not be required to use a work bench as a
scaffold platform.
(Z) Stilts.
Stilts shall be equipped with "feet"
of skid resistant material. Means shall be provided to securely fasten the
stilts to employee's feet and legs. The floor in the work area shall be
maintained free of debris and other possible hazards.