[Code of Federal Regulations]
[Title 29, Volume 5]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.66]
[Page 152-186]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS--Table of Contents
Subpart F_Powered Platforms, Manlifts, and Vehicle-Mounted Work
Platforms
Sec. 1910.66 Powered platforms for building maintenance.
Authority: Secs. 4, 6, and 8 of the Occupational Safety and Health
Act of 1970 (29 U.S.C. 653, 655, and 657); Secretary of Labor's Order
No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), or 1-90
(55 FR 9033), as applicable; and 29 CFR part 1911.
Effective Date Note: At 72 FR 7190, Feb. 14, 2007, the authority
citation to Subpart F was revised, effective Aug. 13, 2007. For the
convenience of the user, the revised text is set forth as follows:
Authority: Secs. 4, 6, and 8 of the Occupational Safety and Health
Act of 1970 (29 U.S.C. 653, 655, and 657); Secretary of Labor's Order
No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), 1-90 (55
FR 9033), or 5-2002 (67 FR 65008), as applicable; and 29 CFR part 1911.
(a) Scope. This section covers powered platform installations
permanently dedicated to interior or exterior building maintenance of a
specific structure or group of structures. This section does not apply
to suspended scaffolds (swinging scaffolds) used to service buildings on
a temporary basis and covered under subpart D of this part,
[[Page 153]]
nor to suspended scaffolds used for construction work and covered under
subpart L of 29 CFR part 1926. Building maintenance includes, but is not
limited to, such tasks as window cleaning, caulking, metal polishing and
reglazing.
(b) Application--(1) New installations. This section applies to all
permanent installations completed after July 23, 1990. Major
modifications to existing installations completed after that date are
also considered new installations under this section.
(2) Existing installations. (i) Permanent installations in existence
and/or completed before July 23, 1990 shall comply with paragraphs (g),
(h), (i), (j) and appendix C of this section.
(ii) In addition, permanent installations completed after August 27,
1971, and in existence and/or completed before July 23, 1990, shall
comply with appendix D of this section.
(c) Assurance. (1) Building owners of new installations shall inform
the employer before each use in writing that the installation meets the
requirements of paragraphs (e)(1) and (f)(1) of this section and the
additional design criteria contained in other provisions of paragraphs
(e) and (f) of this section relating to: required load sustaining
capabilities of platforms, building components, hoisting and supporting
equipment; stability factors for carriages, platforms and supporting
equipment; maximum horizontal force for movement of carriages and
davits; design of carriages, hoisting machines, wire rope and
stabilization systems; and design criteria for electrical wiring and
equipment.
(2) Building owners shall base the information required in paragraph
(c)(1) of this section on the results of a field test of the
installation before being placed into service and following any major
alteration to an existing installation, as required in paragraph (g)(1)
of this section. The assurance shall also be based on all other relevant
available information, including, but not limited to, test data,
equipment specifications and verification by a registered professional
engineer.
(3) Building owners of all installations, new and existing, shall
inform the employer in writing that the installation has been inspected,
tested and maintained in compliance with the requirements of paragraphs
(g) and (h) of this section and that all protection anchorages meet the
requirements of paragraph (I)(c)(10) of appendix C.
(4) The employer shall not permit employees to use the installation
prior to receiving assurance from the building owner that the
installation meets the requirements contained in paragraphs (c)(1) and
(c)(3) of this section.
(d) Definitions.
Anemometer means an instrument for measuring wind velocity.
Angulated roping means a suspension method where the upper point of
suspension is inboard from the attachments on the suspended unit, thus
causing the suspended unit to bear against the face of the building.
Building face roller means a rotating cylindrical member designed to
ride on the face of the building wall to prevent the platform from
abrading the face of the building and to assist in stabilizing the
platform.
Building maintenance means operations such as window cleaning,
caulking, metal polishing, reglazing, and general maintenance on
building surfaces.
Cable means a conductor, or group of conductors, enclosed in a
weatherproof sheath, that may be used to supply electrical power and/or
control current for equipment or to provide voice communication
circuits.
Carriage means a wheeled vehicle used for the horizontal movement
and support of other equipment.
Certification means a written, signed and dated statement confirming
the performance of a requirement of this section.
Combination cable means a cable having both steel structural members
capable of supporting the platform, and copper or other electrical
conductors insulated from each other and the structural members by
nonconductive barriers.
Competent person means a person who, because of training and
experience, is capable of identifying hazardous or dangerous conditions
in powered platform installations and of training employees to identify
such conditions.
[[Page 154]]
Continuous pressure means the need for constant manual actuation for
a control to function.
Control means a mechanism used to regulate or guide the operation of
the equipment.
Davit means a device, used singly or in pairs, for suspending a
powered platform from work, storage and rigging locations on the
building being serviced. Unlike outriggers, a davit reacts its operating
load into a single roof socket or carriage attachment.
Equivalent means alternative designs, materials or methods which the
employer can demonstrate will provide an equal or greater degree of
safety for employees than the methods, materials or designs specified in
the standard.
Ground rigging means a method of suspending a working platform
starting from a safe surface to a point of suspension above the safe
surface.
Ground rigged davit means a davit which cannot be used to raise a
suspended working platform above the building face being serviced.
Guide button means a building face anchor designed to engage a guide
track mounted on a platform.
Guide roller means a rotating cylindrical member, operating
separately or as part of a guide assembly, designed to provide
continuous engagement between the platform and the building guides or
guideways.
Guide shoe means a device attached to the platform designed to
provide a sliding contact between the platform and the building guides.
Hoisting machine means a device intended to raise and lower a
suspended or supported unit.
Hoist rated load means the hoist manufacturer's maximum allowable
operating load.
Installation means all the equipment and all affected parts of a
building which are associated with the performance of building
maintenance using powered platforms.
Interlock means a device designed to ensure that operations or
motions occur in proper sequence.
Intermittent stabilization means a method of platform stabilization
in which the angulated suspension wire rope(s) are secured to regularly
spaced building anchors.
Lanyard means a flexible line of rope, wire rope or strap which is
used to secure the body belt or body harness to a deceleration device,
lifeline or anchorage.
Lifeline means a component consisting of a flexible line for
connection to an anchorage at one end to hang vertically (vertical
lifeline), or for connection to anchorages at both ends to stretch
horizontally (horizontal lifeline), and which serves as a means for
connecting other components of a personal fall arrest system to the
anchorage.
Live load means the total static weight of workers, tools, parts,
and supplies that the equipment is designed to support.
Obstruction detector means a control that will stop the suspended or
supported unit in the direction of travel if an obstruction is
encountered, and will allow the unit to move only in a direction away
from the obstruction.
Operating control means a mechanism regulating or guiding the
operation of equipment that ensures a specific operating mode.
Operating device means a device actuated manually to activate a
control.
Outrigger means a device, used singly or in pairs, for suspending a
working platform from work, storage, and rigging locations on the
building being serviced. Unlike davits, an outrigger reacts its
operating moment load as at least two opposing vertical components
acting into two or more distinct roof points and/or attachments.
Platform rated load means the combined weight of workers, tools,
equipment and other material which is permitted to be carried by the
working platform at the installation, as stated on the load rating
plate.
Poured socket means the method of providing wire rope terminations
in which the ends of the rope are held in a tapered socket by means of
poured spelter or resins.
Primary brake means a brake designed to be applied automatically
whenever power to the prime mover is interrupted or discontinued.
Prime mover means the source of mechanical power for a machine.
Rated load means the manufacturer's recommended maximum load.
[[Page 155]]
Rated strength means the strength of wire rope, as designated by its
manufacturer or vendor, based on standard testing procedures or
acceptable engineering design practices.
Rated working load means the combined static weight of men,
materials, and suspended or supported equipment.
Registered professional engineer means a person who has been duly
and currently registered and licensed by an authority within the United
States or its territories to practice the profession of engineering.
Roof powered platform means a working platform where the hoist(s)
used to raise or lower the platform is located on the roof.
Roof rigged davit means a davit used to raise the suspended working
platform above the building face being serviced. This type of davit can
also be used to raise a suspended working platform which has been
ground-rigged.
Rope means the equipment used to suspend a component of an equipment
installation, i.e., wire rope.
Safe surface means a horizontal surface intended to be occupied by
personnel, which is so protected by a fall protection system that it can
be reasonably assured that said occupants will be protected against
falls.
Secondary brake means a brake designed to arrest the descent of the
suspended or supported equipment in the event of an overspeed condition.
Self powered platform means a working platform where the hoist(s)
used to raise or lower the platform is mounted on the platform.
Speed reducer means a positive type speed reducing machine.
Stability factor means the ratio of the stabilizing moment to the
overturning moment.
Stabilizer tie means a flexible line connecting the building anchor
and the suspension wire rope supporting the platform.
Supported equipment means building maintenance equipment that is
held or moved to its working position by means of attachment directly to
the building or extensions of the building being maintained.
Suspended equipment means building maintenance equipment that is
suspended and raised or lowered to its working position by means of
ropes or combination cables attached to some anchorage above the
equipment.
Suspended scaffold (swinging scaffold) means a scaffold supported on
wire or other ropes, used for work on, or for providing access to,
vertical sides of structures on a temporary basis. Such scaffold is not
designed for use on a specific structure or group of structures.
Tail line means the nonsupporting end of the wire rope used to
suspend the platform.
Tie-in guides means the portion of a building that provides
continuous positive engagement between the building and a suspended or
supported unit during its vertical travel on the face of the building.
Traction hoist means a type of hoisting machine that does not
accumulate the suspension wire rope on the hoisting drum or sheave, and
is designed to raise and lower a suspended load by the application of
friction forces between the suspension wire rope and the drum or sheave.
Transportable outriggers means outriggers designed to be moved from
one work location to another.
Trolley carriage means a carriage suspended from an overhead track
structure.
Verified means accepted by design, evaluation, or inspection by a
registered professional engineer.
Weatherproof means so constructed that exposure to adverse weather
conditions will not affect or interfere with the proper use or functions
of the equipment or component.
Winding drum hoist means a type of hoisting machine that accumulates
the suspension wire rope on the hoisting drum.
Working platform means suspended or supported equipment intended to
provide access to the face of a building and manned by persons engaged
in building maintenance.
Wrap means one complete turn of the suspension wire rope around the
surface of a hoist drum.
(e) Powered platform installations--Affected parts of buildings--(1)
General requirements. The following requirements apply to affected parts
of buildings
[[Page 156]]
which utilize working platforms for building maintenance.
(i) Structural supports, tie-downs, tie-in guides, anchoring devices
and any affected parts of the building included in the installation
shall be designed by or under the direction of a registered professional
engineer experienced in such design;
(ii) Exterior installations shall be capable of withstanding
prevailing climatic conditions;
(iii) The building installation shall provide safe access to, and
egress from, the equipment and sufficient space to conduct necessary
maintenance of the equipment;
(iv) The affected parts of the building shall have the capability of
sustaining all the loads imposed by the equipment; and,
(v) The affected parts of the building shall be designed so as to
allow the equipment to be used without exposing employees to a hazardous
condition.
(2) Tie-in guides. (i) The exterior of each building shall be
provided with tie-in guides unless the conditions in paragraph
(e)(2)(ii) or (e)(2)(iii) of this section are met.
Note: See Figure 1 in appendix B of this section for a description
of a typical continuous stabilization system utilizing tie-in guides.
(ii) If angulated roping is employed, tie-in guides required in
paragraph (e)(2)(i) of this section may be eliminated for not more than
75 feet (22.9 m) of the uppermost elevation of the building, if
infeasible due to exterior building design, provided an angulation force
of at least 10 pounds (44.4 n) is maintained under all conditions of
loading.
(iii) Tie-in guides required in paragraph (e)(2)(i) of this section
may be eliminated if one of the guide systems in paragraph
(e)(2)(iii)(A), (e)(2)(iii)(B) or (e)(2)(iii)(C) of this section is
provided, or an equivalent.
(A) Intermittent stabilization system. The system shall keep the
equipment in continuous contact with the building facade, and shall
prevent sudden horizontal movement of the platform. The system may be
used together with continuous positive building guide systems using tie-
in guides on the same building, provided the requirements for each
system are met.
(1) The maximum vertical interval between building anchors shall be
three floors or 50 feet (15.3 m), whichever is less.
(2) Building anchors shall be located vertically so that attachment
of the stabilizer ties will not cause the platform suspension ropes to
angulate the platform horizontally across the face of the building. The
anchors shall be positioned horizontally on the building face so as to
be symmetrical about the platform suspension ropes.
(3) Building anchors shall be easily visible to employees and shall
allow a stabilizer tie attachment for each of the platform suspension
ropes at each vertical interval. If more than two suspension ropes are
used on a platform, only the two building-side suspension ropes at the
platform ends shall require a stabilizer attachment.
(4) Building anchors which extend beyond the face of the building
shall be free of sharp edges or points. Where cables, suspension wire
ropes and lifelines may be in contact with the building face, external
building anchors shall not interfere with their handling or operation.
(5) The intermittent stabilization system building anchors and
components shall be capable of sustaining without failure at least four
times the maximum anticipated load applied or transmitted to the
components and anchors. The minimum design wind load for each anchor
shall be 300 (1334 n) pounds, if two anchors share the wind load.
(6) The building anchors and stabilizer ties shall be capable of
sustaining anticipated horizontal and vertical loads from winds
specified for roof storage design which may act on the platform and wire
ropes if the platform is stranded on a building face. If the building
anchors have different spacing than the suspension wire rope or if the
building requires different suspension spacings on one platform, one
building anchor and stabilizer tie shall be capable of sustaining the
wind loads.
Note: See Figure 2 in appendix B of this section for a description
of a typical intermittent stabilization system.
[[Page 157]]
(B) Button guide stabilization system.
(1) Guide buttons shall be coordinated with platform mounted
equipment of paragraph (f)(5)(vi) of this section.
(2) Guide buttons shall be located horizontally on the building face
so as to allow engagement of each of the guide tracks mounted on the
platform.
(3) Guide buttons shall be located in vertical rows on the building
face for proper engagement of the guide tracks mounted on the platform.
(4) Two guide buttons shall engage each guide track at all times
except for the initial engagement.
(5) Guide buttons which extend beyond the face of the building shall
be free of sharp edges or points. Where cables, ropes and lifelines may
be in contact with the building face, guide buttons shall not interfere
with their handling or operation.
(6) Guide buttons, connections and seals shall be capable of
sustaining without damage at least the weight of the platform, or
provision shall be made in the guide tracks or guide track connectors to
prevent the platform and its attachments from transmitting the weight of
the platform to the guide buttons, connections and seals. In either
case, the minimum design load shall be 300 pounds (1334 n) per building
anchor.
Note: See paragraph (f)(5)(vi) of this section for relevant
equipment provisions.
Note: See Figure 3 in appendix B of this section for a description
of a typical button guide stabilization system.
(C) System utilizing angulated roping and building face rollers. The
system shall keep the equipment in continuous contact with the building
facade, and shall prevent sudden horizontal movement of the platform.
This system is acceptable only where the suspended portion of the
equipment in use does not exceed 130 feet (39.6 m) above a safe surface
or ground level, and where the platform maintains no less than 10 pounds
(44.4 n) angulation force on the building facade.
(iv) Tie-in guides for building interiors (atriums) may be
eliminated when a registered professional engineer determines that an
alternative stabilization system, including systems in paragraphs
(e)(2)(iii) (A), (B) and (C), or a platform tie-off at each work station
will provide equivalent safety.
(3) Roof guarding. (i) Employees working on roofs while performing
building maintenance shall be protected by a perimeter guarding system
which meets the requirements of paragraph (c)(1) of Sec. 1910.23 of
this part.
(ii) The perimeter guard shall not be more than six inches (152 mm)
inboard of the inside face of a barrier, i.e. the parapet wall, or roof
edge curb of the building being serviced; however, the perimeter guard
location shall not exceed an 18 inch (457 mm) setback from the exterior
building face.
(4) Equipment stops. Operational areas for trackless type equipment
shall be provided with structural stops, such as curbs, to prevent
equipment from traveling outside its intended travel areas and to
prevent a crushing or shearing hazard.
(5) Maintenance access. Means shall be provided to traverse all
carriages and their suspended equipment to a safe area for maintenance
and storage.
(6) Elevated track. (i) An elevated track system which is located
four feet (1.2 m) or more above a safe surface, and traversed by
carriage supported equipment, shall be provided with a walkway and
guardrail system; or
(ii) The working platform shall be capable of being lowered, as part
of its normal operation, to the lower safe surface for access and egress
of the personnel and shall be provided with a safe means of access and
egress to the lower safe surface.
(7) Tie-down anchors. Imbedded tie-down anchors, fasteners, and
affected structures shall be resistant to corrosion.
(8) Cable stabilization. (i) Hanging lifelines and all cables not in
tension shall be stabilized at each 200 foot (61 m) interval of vertical
travel of the working platform beyond an initial 200 foot (61 m)
distance.
(ii) Hanging cables, other than suspended wire ropes, which are in
constant tension shall be stabilized when the vertical travel exceeds an
initial 600 foot (183 m) distance, and at further intervals of 600 feet
(183 m) or less.
[[Page 158]]
(9) Emergency planning. A written emergency action plan shall be
developed and implemented for each kind of working platform operation.
This plan shall explain the emergency procedures which are to be
followed in the event of a power failure, equipment failure or other
emergencies which may be encountered. The plan shall also explain that
employees inform themselves about the building emergency escape routes,
procedures and alarm systems before operating a platform. Upon initial
assignment and whenever the plan is changed the employer shall review
with each employee those parts of the plan which the employee must know
to protect himself or herself in the event of an emergency.
(10) Building maintenance. Repairs or major maintenance of those
building portions that provide primary support for the suspended
equipment shall not affect the capability of the building to meet the
requirements of this standard.
(11) Electrical requirements. The following electrical requirements
apply to buildings which utilize working platforms for building
maintenance.
(i) General building electrical installations shall comply with
Sec. Sec. 1910.302 through 1910.308 of this part, unless otherwise
specified in this section;
(ii) Building electrical wiring shall be of such capacity that when
full load is applied to the equipment power circuit not more than a five
percent drop from building service-vault voltage shall occur at any
power circuit outlet used by equipment regulated by this section;
(iii) The equipment power circuit shall be an independent electrical
circuit that shall remain separate from all other equipment within or on
the building, other than power circuits used for hand tools that will be
used in conjunction with the equipment. If the building is provided with
an emergency power system, the equipment power circuit may also be
connected to this system;
(iv) The power circuit shall be provided with a disconnect switch
that can be locked in the ``OFF'' and ``ON'' positions. The switch shall
be conveniently located with respect to the primary operating area of
the equipment to allow the operators of the equipment access to the
switch;
(v) The disconnect switch for the power circuit shall be locked in
the ``ON'' position when the equipment is in use; and
(vi) An effective two-way voice communication system shall be
provided between the equipment operators and persons stationed within
the building being serviced. The communications facility shall be
operable and shall be manned at all times by persons stationed within
the building whenever the platform is being used.
(f) Powered platform installations--Equipment--(1) General
requirements. The following requirements apply to equipment which are
part of a powered platform installation, such as platforms, stabilizing
components, carriages, outriggers, davits, hoisting machines, wire ropes
and electrical components.
(i) Equipment installations shall be designed by or under the
direction of a registered professional engineer experienced in such
design;
(ii) The design shall provide for a minimum live load of 250 pounds
(113.6 kg) for each occupant of a suspended or supported platform;
(iii) Equipment that is exposed to wind when not in service shall be
designed to withstand forces generated by winds of at least 100 miles
per hour (44.7 m/s) at 30 feet (9.2 m) above grade; and
(iv) Equipment that is exposed to wind when in service shall be
designed to withstand forces generated by winds of at least 50 miles per
hour (22.4 m/s) for all elevations.
(2) Construction requirements. Bolted connections shall be self-
locking or shall otherwise be secured to prevent loss of the connections
by vibration.
(3) Suspension methods. Elevated building maintenance equipment
shall be suspended by a carriage, outriggers, davits or an equivalent
method.
(i) Carriages. Carriages used for suspension of elevated building
maintenance equipment shall comply with the following:
[[Page 159]]
(A) The horizontal movement of a carriage shall be controlled so as
to ensure its safe movement and allow accurate positioning of the
platform for vertical travel or storage;
(B) Powered carriages shall not exceed a traversing speed of 50 feet
per minute (0.3 m/s);
(C) The initiation of a traversing movement for a manually propelled
carriage on a smooth level surface shall not require a person to exert a
horizontal force greater than 40 pounds (444.8 n);
(D) Structural stops and curbs shall be provided to prevent the
traversing of the carriage beyond its designed limits of travel;
(E) Traversing controls for a powered carriage shall be of a
continuous pressure weatherproof type. Multiple controls when provided
shall be arranged to permit operation from only one control station at a
time. An emergency stop device shall be provided on each end of a
powered carriage for interrupting power to the carriage drive motors;
(F) The operating controls(s) shall be so connected that in the case
of suspended equipment, traversing of a carriage is not possible until
the suspended portion of the equipment is located at its uppermost
designed position for traversing; and is free of contact with the face
of the building or building guides. In addition, all protective devices
and interlocks are to be in the proper position to allow traversing of
the carriage;
(G) Stability for underfoot supported carriages shall be obtained by
gravity, by an attachment to a structural support, or by a combination
of gravity and a structural support. The use of flowing counterweights
to achieve stability is prohibited.
(1) The stability factor against overturning shall not be less than
two for horizontal traversing of the carriage, including the effects of
impact and wind.
(2) The carriages and their anchorages shall be capable of resisting
accidental over-tensioning of the wire ropes suspending the working
platform, and this calculated value shall include the effect of one and
one-half times the stall capacity of the hoist motor. All parts of the
installation shall be capable of withstanding without damage to any part
of the installation the forces resulting from the stall load of the
hoist and one half the wind load.
(3) Roof carriages which rely on having tie-down devices secured to
the building to develop the required stability against overturning shall
be provided with an interlock which will prevent vertical platform
movement unless the tie-down is engaged;
(H) An automatically applied braking or locking system, or
equivalent, shall be provided that will prevent unintentional traversing
of power traversed or power assisted carriages;
(I) A manual or automatic braking or locking system or equivalent,
shall be provided that will prevent unintentional traversing of manually
propelled carriages;
(J) A means to lock out the power supply for the carriage shall be
provided;
(K) Safe access to and egress from the carriage shall be provided
from a safe surface. If the carriage traverses an elevated area, any
operating area on the carriage shall be protected by a guardrail system
in compliance with the provisions of paragraph (f)(5)(i)(F) of this
section. Any access gate shall be self-closing and self-latching, or
provided with an interlock;
(L) Each carriage work station position shall be identified by
location markings and/or position indicators; and
(M) The motors shall stall if the load on the hoist motors is at any
time in excess of three times that necessary for lifting the working
platform with its rated load.
(ii) Transportable outriggers. (A) Transportable outriggers may be
used as a method of suspension for ground rigged working platforms where
the point of suspension does not exceed 300 feet (91.5 m) above a safe
surface. Tie-in guide system(s) shall be provided which meet the
requirements of paragraph (e)(2) of this section.
(B) Transportable outriggers shall be used only with self-powered,
ground rigged working platforms.
(C) Each transportable outrigger shall be secured with a tie-down to
a
[[Page 160]]
verified anchorage on the building during the entire period of its use.
The anchorage shall be designed to have a stability factor of not less
than four against overturning or upsetting of the outrigger.
(D) Access to and egress from the working platform shall be from and
to a safe surface below the point of suspension.
(E) Each transportable outrigger shall be designed for lateral
stability to prevent roll-over in the event an accidental lateral load
is applied to the outrigger. The accidental lateral load to be
considered in this design shall be not less than 70 percent of the rated
load of the hoist.
(F) Each transportable outrigger shall be designed to support an
ultimate load of not less than four times the rated load of the hoist.
(G) Each transportable outrigger shall be so located that the
suspension wire ropes for two point suspended working platforms are hung
parallel.
(H) A transportable outrigger shall be tied-back to a verified
anchorage on the building with a rope equivalent in strength to the
suspension rope.
(I) The tie-back rope shall be installed parallel to the centerline
of the outrigger.
(iii) Davits. (A) Every davit installation, fixed or transportable,
rotatable or non-rotatable shall be designed and installed to insure
that it has a stability factor against overturning of not less than
four.
(B) The following requirements apply to roof rigged davit systems:
(1) Access to and egress from the working platform shall be from a
safe surface. Access or egress shall not require persons to climb over a
building's parapet or guard railing; and
(2) The working platform shall be provided with wheels, casters or a
carriage for traversing horizontally.
(C) The following requirements apply to ground rigged davit systems:
(1) The point of suspension shall not exceed 300 feet (91.5 m) above
a safe surface. Guide system(s) shall be provided which meet the
requirements of paragraph (e)(2) of this section;
(2) Access and egress to and from the working platform shall only be
from a safe surface below the point of suspension.
(D) A rotating davit shall not require a horizontal force in excess
of 40 pounds (177.9 n) per person to initiate a rotating movement.
(E) The following requirements shall apply to transportable davits:
(1) A davit or part of a davit weighing more than 80 pounds (36 kg)
shall be provided with a means for its transport, which shall keep the
center of gravity of the davit at or below 36 inches (914 mm) above the
safe surface during transport;
(2) A davit shall be provided with a pivoting socket or with a base
that will allow the insertion or removal of a davit at a position of not
more than 35 degrees above the horizontal, with the complete davit
inboard of the building face being serviced; and
(3) Means shall be provided to lock the davit to its socket or base
before it is used to suspend the platform.
(4) Hoisting machines. (i) Raising and lowering of suspended or
supported equipment shall be performed only by a hoisting machine.
(ii) Each hoisting machine shall be capable of arresting any
overspeed descent of the load.
(iii) Each hoisting machine shall be powered only by air, electric
or hydraulic sources.
(iv) Flammable liquids shall not be carried on the working platform.
(v) Each hoisting machine shall be capable of raising or lowering
125 percent of the rated load of the hoist.
(vi) Moving parts of a hoisting machine shall be enclosed or guarded
in compliance with paragraphs (a)(1) and (2) of Sec. 1910.212 of this
part.
(vii) Winding drums, traction drums and sheaves and directional
sheaves used in conjunction with hoisting machines shall be compatible
with, and sized for, the wire rope used.
(viii) Each winding drum shall be provided with a positive means of
attaching the wire rope to the drum. The attachment shall be capable of
developing at least four times the rated load of the hoist.
(ix) Each hoisting machine shall be provided with a primary brake
and at least one independent secondary brake, each capable of stopping
and holding
[[Page 161]]
not less than 125 percent of the lifting capacity of the hoist.
(A) The primary brake shall be directly connected to the drive train
of the hoisting machine, and shall not be connected through belts,
chains, clutches, or set screw type devices. The brake shall
automatically set when power to the prime mover is interrupted.
(B)(1) The secondary brake shall be an automatic emergency type of
brake that, if actuated during each stopping cycle, shall not engage
before the hoist is stopped by the primary brake.
(2) When a secondary brake is actuated, it shall stop and hold the
platform within a vertical distance of 24 inches (609.6 mm).
(x) Any component of a hoisting machine which requires lubrication
for its protection and proper functioning shall be provided with a means
for that lubrication to be applied.
(5) Suspended equipment--(i) General requirements. (A) Each
suspended unit component, except suspension ropes and guardrail systems,
shall be capable of supporting, without failure, at least four times the
maximum intended live load applied or transmitted to that component.
(B) Each suspended unit component shall be constructed of materials
that will withstand anticipated weather conditions.
(C) Each suspended unit shall be provided with a load rating plate,
conspicuously located, stating the unit weight and rated load of the
suspended unit.
(D) When the suspension points on a suspended unit are not at the
unit ends, the unit shall be capable of remaining continuously stable
under all conditions of use and position of the live load, and shall
maintain at least a 1.5 to 1 stability factor against unit upset.
(E) Guide rollers, guide shoes or building face rollers shall be
provided, and shall compensate for variations in building dimensions and
for minor horizontal out-of-level variations of each suspended unit.
(F) Each working platform of a suspended unit shall be secured to
the building facade by one or more of the following methods, or by an
equivalent method:
(1) Continuous engagement to building anchors as provided in
paragraph (e)(2)(i) of this section;
(2) Intermittent engagement to building anchors as provided in
paragraph (e)(2)(iii)(A) of this section;
(3) Button guide engagement as provided in paragraph (e)(2)(iii)(B)
of this section; or
(4) Angulated roping and building face rollers as provided in
paragraph (e)(2)(iii)(C) of this section.
(G) Each working platform of a suspended unit shall be provided with
a guardrail system on all sides which shall meet the following
requirements:
(1) The system shall consist of a top guardrail, midrail, and a
toeboard;
(2) The top guardrail shall not be less than 36 inches (914 mm) high
and shall be able to withstand at least a 100-pound (444 n) force in any
downward or outward direction;
(3) The midrail shall be able to withstand at least a 75-pound (333
n) force in any downward or outward direction; and
(4) The areas between the guardrail and toeboard on the ends and
outboard side, and the area between the midrail and toeboard on the
inboard side, shall be closed with a material that is capable of
withstanding a load of 100 pounds (45.4 KG.) applied horizontally over
any area of one square foot (.09 m\2\). The material shall have all
openings small enough to reject passage of life lines and potential
falling objects which may be hazardous to persons below.
(5) Toeboards shall be capable of withstanding, without failure, a
force of at least 50 pounds (222 n) applied in any downward or
horizontal direction at any point along the toeboard.
(6) Toeboards shall be three and one-half inches (9 cm) minimum in
length from their top edge to the level of the platform floor.
(7) Toeboards shall be securely fastened in place at the outermost
edge of the platform and have no more than one-half inch (1.3 cm)
clearance above the platform floor.
(8) Toeboards shall be solid or with an opening not over one inch
(2.5 cm) in the greatest dimension.
[[Page 162]]
(ii) Two and four-point suspended working platforms. (A) The working
platform shall be not less than 24 inches (610 mm) wide and shall be
provided with a minimum of a 12 inch (305 mm) wide passage at or past
any obstruction on the platform.
(B) The flooring shall be of a slip-resistant type and shall contain
no opening that would allow the passage of life lines, cables and other
potential falling objects. If a larger opening is provided, it shall be
protected by placing a material under the opening which shall prevent
the passage of life lines, cables and potential falling objects.
(C) The working platfrom shall be provided with a means of
suspension that will restrict the platform's inboard to outboard roll
about its longitudinal axis to a maximum of 15 degrees from a horizontal
plane when moving the live load from the inboard to the outboard side of
the platform.
(D) Any cable suspended from above the platform shall be provided
with a means for storage to prevent accumulation of the cable on the
floor of the platform.
(E) All operating controls for the vertical travel of the platform
shall be of the continuous-pressure type, and shall be located on the
platform.
(F) Each operating station of every working platform shall be
provided with a means of interrupting the power supply to all hoist
motors to stop any further powered ascent or descent of the platform.
(G) The maximum rated speed of the platform shall not exceed 50 feet
per minute (0.3 ms) with single speed hoists, nor 75 feet per minute
(0.4 ms) with multi-speed hoists.
(H) Provisions shall be made for securing all tools, water tanks,
and other accessories to prevent their movement or accumulation on the
floor of the platform.
(I) Portable fire extinguishers conforming to the provisions of
Sec. 1910.155 and Sec. 1910.157 of this part shall be provided and
securely attached on all working platforms.
(J) Access to and egress from a working platfrom, except for those
that land directly on a safe surface, shall be provided by stairs,
ladders, platforms and runways conforming to the provisions of subpart D
of this part. Access gates shall be self-closing and self-latching.
(K) Means of access to or egress from a working platform which is 48
inches (1.2 m) or more above a safe surface shall be provided with a
guardrail system or ladder handrails that conform to the provisions of
subpart D of this part.
(L) The platform shall be provided with a secondary wire rope
suspension system if the platform contains overhead structures which
restrict the emergency egress of employees. A horizontal lifeline or a
direct connection anchorage shall be provided, as part of a fall arrest
system which meets the requirements of appendix C, for each employee on
such a platform.
(M) A vertical lifeline shall be provided as part of a fall arrest
system which meets the requirements of appendix C, for each employee on
a working platform suspended by two or more wire ropes, if the failure
of one wire rope or suspension attachment will cause the platform to
upset. If a secondary wire rope suspension is used, vertical lifelines
are not required for the fall arrest system, provided that each employee
is attached to a horizontal lifeline anchored to the platform.
(N) An emergency electric operating device shall be provided on roof
powered platforms near the hoisting machine for use in the event of
failure of the normal operating device located on the working platform,
or failure of the cable connected to the platform. The emergency
electric operating device shall be mounted in a secured compartment, and
the compartment shall be labeled with instructions for use. A means for
opening the compartment shall be mounted in a break-glass receptable
located near the emergency electric operating device or in an equivalent
secure and accessible location.
(iii) Single point suspended working platforms. (A) The requirements
of paragraphs (f)(5)(ii) (A) through (K) of this section shall also
apply to a single point working platform.
(B) Each single point suspended working platform shall be provided
with a secondary wire rope suspension system, which will prevent the
working
[[Page 163]]
platform from falling should there be a failure of the primary means of
support, or if the platform contains overhead structures which restrict
the egress of the employees. A horizontal life line or a direct
connection anchorage shall be provided, as part of a fall arrest system
which meets the requirements of appendix C, for each employee on the
platform.
(iv) Ground-rigged working platforms. (A) Groundrigged working
platforms shall comply with all the requirements of paragraphs
(f)(5)(ii) (A) through (M) of this section.
(B) After each day's use, the power supply within the building shall
be disconnected from a ground-rigged working platform, and the platform
shall be either disengaged from its suspension points or secured and
stored at grade.
(v) Intermittently stabilized platforms. (A) The platform shall
comply with paragraphs (F)(5)(ii) (A) through (M) of this section.
(B) Each stabilizer tie shall be equipped with a ``quick connect-
quick disconnect'' device which cannot be accidently disengaged, for
attachment to the building anchor, and shall be resistant to adverse
environmental conditions.
(C) The platform shall be provided with a stopping device that will
interrupt the hoist power supply in the event the platform contacts a
stabilizer tie during its ascent.
(D) Building face rollers shall not be placed at the anchor setting
if exterior anchors are used on the building face.
(E) Stabilizer ties used on intermittently stabilized platforms
shall allow for the specific attachment length needed to effect the
predetermined angulation of the suspended wire rope. The specific
attachment length shall be maintained at all building anchor locations.
(F) The platform shall be in continuous contact with the face of the
building during ascent and descent.
(G) The attachment and removal of stabilizer ties shall not require
the horizontal movement of the platform.
(H) The platform-mounted equipment and its suspension wire ropes
shall not be physically damaged by the loads from the stabilizer tie or
its building anchor. The platform, platform mounted equipment and wire
ropes shall be able to withstand a load that is at least twice the
ultimate strength of the stabilizer tie.
Note: See Figure II in appendix B of this section for a description
of a typical intermittent stabilization system.
(vi) Button-guide stabilized platforms. (A) The platform shall
comply with paragraphs (f)(5)(ii) (A) through (M) of this section.
(B) Each guide track on the platform shall engage a minimum of two
guide buttons during any vertical travel of the platform following the
initial button engagement.
(C) Each guide track on a platform that is part of a roof rigged
system shall be provided with a storage position on the platform.
(D) Each guide track on the platform shall be sufficiently
maneuverable by platform occupants to permit easy engagement of the
guide buttons, and easy movement into and out of its storage position on
the platform.
(E) Two guide tracks shall be mounted on the platform and shall
provide continuous contact with the building face.
(F) The load carrying components of the button guide stabilization
system which transmit the load into the platform shall be capable of
supporting the weight of the platform, or provision shall be made in the
guide track connectors or platform attachments to prevent the weight of
the platform from being transmitted to the platform attachments.
Note: See Figure III in appendix B of this section for a description
of a typical button guide stabilization system.
(6) Supported equipment. (i) Supported equipment shall maintain a
vertical position in respect to the face of the building by means other
than friction.
(ii) Cog wheels or equivalent means shall be incorporated to provide
climbing traction between the supported equipment and the building
guides. Additional guide wheels or shoes shall be incorporated as may be
necessary to ensure that the drive wheels are continuously held in
positive engagement with the building guides.
(iii) Launch guide mullions indexed to the building guides and
retained in
[[Page 164]]
alignment with the building guides shall be used to align drive wheels
entering the building guides.
(iv) Manned platforms used on supported equipment shall comply with
the requirements of paragraphs (f)(5)(ii)(A), (f)(5)(ii)(B), and
(f)(5)(ii) (D) through (K) of this section covering suspended equipment.
(7) Suspension wire ropes and rope connections. (i) Each specific
installation shall use suspension wire ropes or combination cable and
connections meeting the specification recommended by the manufacturer of
the hoisting machine used. Connections shall be capable of developing at
least 80 percent of the rated breaking strength of the wire rope.
(ii) Each suspension rope shall have a ``Design Factor'' of at least
10. The ``Design Factor'' is the ratio of the rated strength of the
suspension wire rope to the rated working load, and shall be calculated
using the following formula:
[GRAPHIC] [TIFF OMITTED] TR25SE06.005
Where:
F = Design factor
S = Manufacturer's rated strength of one suspension rope
N = Number of suspension ropes under load
W = Rated working load on all ropes at any point of travel
(iii) Suspension wire rope grade shall be at least improved plow
steel or equivalent.
(iv) Suspension wire ropes shall be sized to conform with the
required design factor, but shall not be less than 5/16 inch (7.94 mm)
in diameter.
(v) No more than one reverse bend in six wire rope lays shall be
permitted.
(vi) A corrosion-resistant tag shall be securely attached to one of
the wire rope fastenings when a suspension wire rope is to be used at a
specific location and will remain in that location. This tag shall bear
the following wire rope data:
(A) The diameter (inches and/or mm);
(B) Construction classification;
(C) Whether non-preformed or preformed;
(D) The grade of material;
(E) The manufacturer's rated strength;
(F) The manufacturer's name;
(G) The month and year the ropes were installed; and
(H) The name of the person or company which installed the ropes.
(vii) A new tag shall be installed at each rope renewal.
(viii) The original tag shall be stamped with the date of the
resocketing, or the original tag shall be retained and a supplemental
tag shall be provided when ropes are resocketed. The supplemental tag
shall show the date of resocketing and the name of the person or company
that resocketed the rope.
(ix) Winding drum type hoists shall contain at least three wraps of
the suspension wire rope on the drum when the suspended unit has reached
the lowest possible point of its vertical travel.
(x) Traction drum and sheave type hoists shall be provided with a
wire rope of sufficient length to reach the lowest possible point of
vertical travel of the suspended unit, and an additional length of the
wire rope of at least four feet (1.2 m).
(xi) The lengthening or repairing of suspension wire ropes is
prohibited.
(xii) Babbitted fastenings for suspension wire rope are prohibited.
(8) Control circuits, power circuits and their components. (i)
Electrical wiring and equipment shall comply with subpart S of this
part, except as otherwise required by this section.
(ii) Electrical runway conductor systems shall be of a type designed
for use in exterior locations, and shall be located so that they do not
come into contact with accumulated snow or water.
(iii) Cables shall be protected against damage resulting from
overtensioning or from other causes.
(iv) Devices shall be included in the control system for the
equipment which will provide protection against electrical overloads,
three phase reversal and phase failure. The control system shall have a
separate method, independent of the direction control circuit, for
breaking the power circuit in case of an emergency or malfunction.
[[Page 165]]
(v) Suspended or supported equipment shall have a control system
which will require the operator of the equipment to follow predetermined
procedures.
(vi) The following requirements shall apply to electrical protection
devices:
(A) On installations where the carriage does not have a stability
factor of at least four against overturning, electrical contact(s) shall
be provided and so connected that the operating devices for the
suspended or supported equipment shall be operative only when the
carriage is located and mechanically retained at an established
operating point.
(B) Overload protection shall be provided in the hoisting or
suspension system to protect against the equipment operating in the
``up'' direction with a load in excess of 125 percent of the rated load
of the platform; and
(C) An automatic detector shall be provided for each suspension
point that will interrupt power to all hoisting motors for travel in the
``down'' direction, and apply the primary brakes if any suspension wire
rope becomes slack. A continuous-pressure rigging-bypass switch designed
for use during rigging is permitted. This switch shall only be used
during rigging.
(vii) Upper and lower directional switches designed to prevent the
travel of suspended units beyond safe upward and downward levels shall
be provided.
(viii) Emergency stop switches shall be provided on remote
controlled, roof-powered manned platforms adjacent to each control
station on the platform.
(ix) Cables which are in constant tension shall have overload
devices which will prevent the tension in the cable from interfering
with the load limiting device required in paragraph (f)(8)(vi)(B) of
this section, or with the platform roll limiting device required in
paragraph (f)(5)(ii)(C) of this section. The setting of these devices
shall be coordinated with other overload settings at the time of design
of the system, and shall be clearly indicated on or near the device. The
device shall interrupt the equipment travel in the ``down'' direction.
(g) Inspection and tests--(1) Installations and alterations. All
completed building maintenance equipment installations shall be
inspected and tested in the field before being placed in initial service
to determine that all parts of the installation conform to applicable
requirements of this standard, and that all safety and operating
equipment is functioning as required. A similar inspection and test
shall be made following any major alteration to an existing
installation. No hoist in an installation shall be subjected to a load
in excess of 125 percent of its rated load.
(2) Periodic inspections and tests. (i) Related building supporting
structures shall undergo periodic inspection by a competent person at
intervals not exceeding 12 months.
(ii) All parts of the equipment including control systems shall be
inspected, and, where necessary, tested by a competent person at
intervals specified by the manufacturer/supplier, but not to exceed 12
months, to determine that they are in safe operating condition. Parts
subject to wear, such as wire ropes, bearings, gears, and governors
shall be inspected and/or tested to determine that they have not worn to
such an extent as to affect the safe operation of the installation.
(iii) The building owner shall keep a certification record of each
inspection and test required under paragraphs (g)(2)(i) and (ii) of this
section. The certification record shall include the date of the
inspection, the signature of the person who performed the inspection,
and the number, or other identifier, of the building support structure
and equipment which was inspected. This certification record shall be
kept readily available for review by the Assistant Secretary of Labor or
the Assistant Secretary's representative and by the employer.
(iv) Working platforms and their components shall be inspected by
the employer for visible defects before every use and after each
occurrence which could affect the platform's structural integrity.
(3) Maintenance inspections and tests. (i) A maintenance inspection
and, where necessary, a test shall be made of each platform installation
every 30 days, or where the work cycle is less than 30 days such
inspection and/or test shall be made prior to each work
[[Page 166]]
cycle. This inspection and test shall follow procedures recommended by
the manufacturer, and shall be made by a competent person.
(ii) The building owner shall keep a certification record of each
inspection and test performed under paragraph (g)(3)(i) of this section.
The certification record shall include the date of the inspection and
test, the signature of the person who performed the inspection and/or
test, and an identifier for the platform installation which was
inspected. The certification record shall be kept readily available for
review by the Assistant Secretary of Labor or the Assistant Secretary's
representative and by the employer.
(4) Special inspection of governors and secondary brakes. (i)
Governors and secondary brakes shall be inspected and tested at
intervals specified by the manufacturer/supplier but not to exceed every
12 months.
(ii) The results of the inspection and test shall confirm that the
initiating device for the secondary braking system operates at the
proper overspeed.
(iii) The results of the inspection and test shall confirm that the
secondary brake is functioning properly.
(iv) If any hoisting machine or initiating device for the secondary
brake system is removed from the equipment for testing, all reinstalled
and directly related components shall be reinspected prior to returning
the equipment installation to service.
(v) Inspection of governors and secondary brakes shall be performed
by a competent person.
(vi) The secondary brake governor and actuation device shall be
tested before each day's use. Where testing is not feasible, a visual
inspection of the brake shall be made instead to ensure that it is free
to operate.
(5) Suspension wire rope maintenance, inspection and replacement.
(i) Suspension wire rope shall be maintained and used in accordance with
procedures recommended by the wire rope manufacturer.
(ii) Suspension wire rope shall be inspected by a competent person
for visible defects and gross damage to the rope before every use and
after each occurrence which might affect the wire rope's integrity.
(iii) A thorough inspection of suspension wire ropes in service
shall be made once a month. Suspension wire ropes that have been
inactive for 30 days or longer shall have a thorough inspection before
they are placed into service. These thorough inspections of suspension
wire ropes shall be performed by a competent person.
(iv) The need for replacement of a suspension wire rope shall be
determined by inspection and shall be based on the condition of the wire
rope. Any of the following conditions or combination of conditions will
be cause for removal of the wire rope:
(A) Broken wires exceeding three wires in one strand or six wires in
one rope lay;
(B) Distortion of rope structure such as would result from crushing
or kinking;
(C) Evidence of heat damage;
(D) Evidence of rope deterioration from corrosion;
(E) A broken wire within 18 inches (460.8 mm) of the end
attachments;
(F) Noticeable rusting and pitting;
(G) Evidence of core failure (a lengthening of rope lay, protrusion
of the rope core and a reduction in rope diameter suggests core
failure); or
(H) More than one valley break (broken wire).
(I) Outer wire wear exceeds one-third of the original outer wire
diameter.
(J) Any other condition which the competent person determines has
significantly affected the integrity of the rope.
(v) The building owner shall keep a certification record of each
monthly inspection of a suspension wire rope as required in paragraph
(g)(5)(iii) of this section. The record shall include the date of the
inspection, the signature of the person who performed the inspection,
and a number, or other identifier, of the wire rope which was inspected.
This record of inspection shall be made available for review by the
Assistant Secretary of Labor or the Assistant Secretary's representative
and by the employer.
(6) Hoist inspection. Before lowering personnel below the top
elevation of the building, the hoist shall be tested each day in the
lifting direction with the intended load to make certain it
[[Page 167]]
has sufficient capacity to raise the personnel back to the boarding
level.
(h) Maintenance--(1) General maintenance. All parts of the equipment
affecting safe operation shall be maintained in proper working order so
that they may perform the functions for which they were intended. The
equipment shall be taken out of service when it is not in proper working
order.
(2) Cleaning. (i) Control or power contactors and relays shall be
kept clean.
(ii) All other parts shall be kept clean if their proper functioning
would be affected by the presence of dirt or other contaminants.
(3) Periodic resocketing of wire rope fastenings. (i) Hoisting ropes
utilizing poured socket fastenings shall be resocketed at the non-drum
ends at intervals not exceeding 24 months. In resocketing the ropes, a
sufficient length shall be cut from the end of the rope to remove
damaged or fatigued portions.
(ii) Resocketed ropes shall conform to the requirements of paragraph
(f)(7) of this section.
(iii) Limit switches affected by the resocketed ropes shall be
reset, if necessary.
(4) Periodic reshackling of suspension wire ropes. The hoisting
ropes shall be reshackled at the nondrum ends at intervals not exceeding
24 months. When reshackling the ropes, a sufficient length shall be cut
from the end of the rope to remove damaged or fatigued portions.
(5) Roof systems. Roof track systems, tie-downs, or similar
equipment shall be maintained in proper working order so that they
perform the function for which they were intended.
(6) Building face guiding members. T-rails, indented mullions, or
equivalent guides located in the face of a building shall be maintained
in proper working order so that they perform the functions for which
they were intended. Brackets for cable stabilizers shall similarly be
maintained in proper working order.
(7) Inoperative safety devices. No person shall render a required
safety device or electrical protective device inoperative, except as
necessary for tests, inspections, and maintenance. Immediately upon
completion of such tests, inspections and maintenance, the device shall
be restored to its normal operating condition.
(i) Operations--(1) Training. (i) Working platforms shall be
operated only by persons who are proficient in the operation, safe use
and inspection of the particular working platform to be operated.
(ii) All employees who operate working platforms shall be trained in
the following:
(A) Recognition of, and preventive measures for, the safety hazards
associated with their individual work tasks.
(B) General recognition and prevention of safety hazards associated
with the use of working platforms, including the provisions in the
section relating to the particular working platform to be operated.
(C) Emergency action plan procedures required in paragraph (e)(9) of
this section.
(D) Work procedures required in paragraph (i)(1)(iv) of this
section.
(E) Personal fall arrest system inspection, care, use and system
performance.
(iii) Training of employees in the operation and inspection of
working platforms shall be done by a competent person.
(iv) Written work procedures for the operation, safe use and
inspection of working platforms shall be provided for employee training.
Pictorial methods of instruction, may be used, in lieu of written work
procedures, if employee communication is improved using this method. The
operating manuals supplied by manufacturers for platform system
components can serve as the basis for these procedures.
(v) The employer shall certify that employees have been trained in
operating and inspecting a working platform by preparing a certification
record which includes the identity of the person trained, the signature
of the employer or the person who conducted the training and the date
that training was completed. The certification record shall be prepared
at the completion of the training required in paragraph (i)(1)(ii) of
this section, and shall be maintained in a file for the duration of the
employee's employment. The
[[Page 168]]
certification record shall be kept readily available for review by the
Assistant Secretary of Labor or the Assistant Secretary's
representative.
(2) Use. (i) Working platforms shall not be loaded in excess of the
rated load, as stated on the platform load rating plate.
(ii) Employees shall be prohibited from working on snow, ice, or
other slippery material covering platforms, except for the removal of
such materials.
(iii) Adequate precautions shall be taken to protect the platform,
wire ropes and life lines from damage due to acids or other corrosive
substances, in accordance with the recommendations of the corrosive
substance producer, supplier, platform manufacturer or other equivalent
information sources. Platform members which have been exposed to acids
or other corrosive substances shall be washed down with a neutralizing
solution, at a frequency recommended by the corrosive substance producer
or supplier.
(iv) Platform members, wire ropes and life lines shall be protected
when using a heat producing process. Wire ropes and life lines which
have been contacted by the heat producing process shall be considered to
be permanently damaged and shall not be used.
(v) The platform shall not be operated in winds in excess of 25
miles per hour (40.2 km/hr) except to move it from an operating to a
storage position. Wind speed shall be determined based on the best
available information, which includes on-site anemometer readings and
local weather forecasts which predict wind velocities for the area.
(vi) On exterior installations, an anemometer shall be mounted on
the platform to provide information of on-site wind velocities prior to
and during the use of the platform. The anemometer may be a portable
(hand held) unit which is temporarily mounted during platform use.
(vii) Tools, materials and debris not related to the work in
progress shall not be allowed to accumulate on platforms. Stabilizer
ties shall be located so as to allow unencumbered passage along the full
length of the platform and shall be of such length so as not to become
entangled in rollers, hoists or other machinery.
(j) Personal fall protection. Employees on working platforms shall
be protected by a personal fall arrest system meeting the requirements
of appendix C, section I, of this standard, and as otherwise provided by
this standard.
Appendix A to Sec. 1910.66, Guidelines (Advisory)
1. Use of the Appendix. Appendix A provides examples of equipment
and methods to assist the employer in meeting the requirements of the
indicated provision of the standard. Employers may use other equipment
or procedures which conform to the requirements of the standard. This
appendix neither adds to nor detracts from the mandatory requirements
set forth in Sec. 1910.66.
2. Assurance. Paragraph (c) of the standard requires the building
owner to inform the employer in writing that the powered platform
installation complies with certain requirements of the standard, since
the employer may not have the necessary information to make these
determinations. The employer, however, remains responsible for meeting
these requirements which have not been set off in paragraph (c)(1).
3. Design Requirements. The design requirements for each
installation should be based on the limitations (stresses, deflections,
etc.), established by nationally recognized standards as promulgated by
the following organizations, or to equivalent standards:
AA--The Aluminum Association, 818 Connecticut Avenue, NW., Washington,
DC, 20006
Aluminum Construction Manual
Specifications For Aluminum Structures
Aluminum Standards and Data
AGMA--American Gear Manufacturers Association, 101 North Fort Meyer Dr.,
Suite 1000, Arlington, VA 22209
AISC--American Institute of Steel Construction, 400 North Michigan
Avenue, Chicago, IL 60611
ANSI--American National Standards Institute, Inc., 1430 Broadway, New
York, NY 10018
ASCE--American Society of Civil Engineers, 345 East 47th Street, New
York, NY 10017
ASME--American Society of Mechanical Engineers, 345 East 47th Street,
New York, NY 10017
ASTM--American Society for Testing and Materials, 1916 Race Street,
Philadelphia, PA 19103
AWS--American Welding Society, Inc., Box 351040, 550 NW. LeJeunne Road,
Miami, FL 33126
JIC--Joint Industrial Council, 2139 Wisconsin Avenue NW., Washington, DC
20007
[[Page 169]]
NEMA--National Electric Manufacturers Association, 2101 L Street, NW.,
Washington, DC 20037
4. Tie-in-guides. Indented mullions, T-rails or other equivalent
guides are acceptable as tie-in guides in a building face for a
continuous stabilization system. Internal guides are embedded in other
building members with only the opening exposed (see Figure 1 of appendix
B). External guides, however, are installed external to the other
building members and so are fully exposed. The minimum opening for tie-
in guides is three-quarters of an inch (19 mm), and the minimum inside
dimensions are one-inch (25 mm) deep and two inches (50 mm) wide.
Employers should be aware of the hazards associated with tie-in
guides in a continuous stabilization system which was not designed
properly. For example, joints in these track systems may become extended
or discontinuous due to installation or building settlement. If this
alignment problem is not corrected, the system could jam when a guide
roller or guide shoe strikes a joint and this would cause a hazardous
situation for employees. In another instance, faulty design will result
in guide rollers being mounted in a line so they will jam in the track
at the slightest misalignment.
5. Building anchors (intermittent stabilization system). In the
selection of the vertical distance between building anchors, certain
factors should be given consideration. These factors include building
height and architectural design, platform length and weight, wire rope
angulation, and the wind velocities in the building area. Another factor
to consider is the material of the building face, since this material
may be adversely affected by the building rollers.
External or indented type building anchors are acceptable.
Receptacles in the building facade used for the indented type should be
kept clear of extraneous materials which will hinder their use. During
the inspection of the platform installation, evidence of a failure or
abuse of the anchors should be brought to the attention of the employer.
6. Stabilizer tie length. A stabilizer tie should be long enough to
provide for the planned angulation of the suspension cables. However,
the length of the tie should not be excessive and become a problem by
possibly becoming entangled in the building face rollers or parts of the
platform machinery.
The attachment length may vary due to material elongation and this
should be considered when selecting the material to be used.
Consideration should also be given to the use of ties which are easily
installed by employees, since this will encourage their use.
7. Intermittent stabilization system. Intermittent stabilization
systems may use different equipment, tie-in devices and methods to
restrict the horizontal movement of a powered platform with respect to
the face of the building. One acceptable method employs corrosion-
resistant building anchors secured in the face of the building in
vertical rows every third floor or 50 feet (15.3 m), whichever is less.
The anchors are spaced horizontally to allow a stabilization attachment
(stabilizer tie) for each of the two platform suspension wire ropes. The
stabilizer tie consists of two parts. One part is a quick connect-quick
disconnect device which utilizes a corrosion-resistant yoke and retainer
spring that is designed to fit over the building anchors. The second
part of the stabilizer tie is a lanyard which is used to maintain a
fixed distance between the suspension wire rope and the face of the
building.
In this method, as the suspended powered platform descends past the
elevation of each anchor, the descent is halted and each of the platform
occupants secures a stabilizer tie between a suspension wire rope and a
building anchor. The procedure is repeated as each elevation of a
building anchor is reached during the descent of the powered platform.
As the platform ascends, the procedure is reversed; that is, the
stabilizer ties are removed as each elevation of a building anchor is
reached. The removal of each stabilizer tie is assured since the
platform is provided with stopping devices which will interrupt power to
its hoist(s) in the event either stopping device contacts a stabilizer
during the ascent of the platform.
Figure 2 of appendix B illustrates another type of acceptable
intermittent stabilization system which utilizes retaining pins as the
quick connect-quick disconnect device in the stabilizer tie.
8. Wire Rope Inspection. The inspection of the suspension wire rope
is important since the rope gradually loses strength during its useful
life. The purpose of the inspection is to determine whether the wire
rope has sufficient integrity to support a platform with the required
design factor.
If there is any doubt concerning the condition of a wire rope or its
ability to perform the required work, the rope should be replaced. The
cost of wire rope replacement is quite small if compared to the cost in
terms of human injuries, equipment down time and replacement.
No listing of critical inspection factors, which serve as a basis
for wire rope replacement in the standard, can be a substitute for an
experienced inspector of wire rope. The listing serves as a user's guide
to the accepted standards by which ropes must be judged.
Rope life can be prolonged if preventive maintenance is performed
regularly. Cutting off an appropriate length of rope at the end
termination before the core degrades and valley breaks appear minimizes
degradation at these sections.
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9. General Maintenance. In meeting the general maintenance
requirement in paragraph (h)(1) of the standard, the employer should
undertake the prompt replacement of broken, worn and damaged parts,
switch contacts, brushes, and short flexible conductors of electrical
devices. The components of the electrical service system and traveling
cables should be replaced when damaged or significantly abraded. In
addition, gears, shafts, bearings, brakes and hoisting drums should be
kept in proper alignment.
10. Training. In meeting the training requirement of paragraph
(i)(1) of the standard, employers should use both on the job training
and formal classroom training. The written work procedures used for this
training should be obtained from the manufacturer, if possible, or
prepared as necessary for the employee's information and use.
Employees who will operate powered platforms with intermittent
stabilization systems should receive instruction in the specific ascent
and descent procedures involving the assembly and disassembly of the
stabilizer ties.
An acceptable training program should also include employee
instruction in basic inspection procedures for the purpose of
determining the need for repair and replacement of platform equipment.
In addition, the program should cover the inspection, care and use of
the personal fall protection equipment required in paragraph (j)(1) of
the standard.
In addition, the training program should also include emergency
action plan elements. OSHA brochure <greek-i>1B3088 (Rev.) 1985, ``How
to Prepare for Workplace Emergencies,'' details the basic steps needed
to prepare to handle emergencies in the workplace.
Following the completion of a training program, the employee should
be required to demonstrate competency in operating the equipment safely.
Supplemental training of the employee should be provided by the
employer, as necessary, if the equipment used or other working
conditions should change.
An employee who is required to work with chemical products on a
platform should receive training in proper cleaning procedures, and in
the hazards, care and handling of these products. In addition, the
employee should be supplied with the appropriate personal protective
equipment, such as gloves and eye and face protection.
11. Suspension and Securing of Powered Platforms (Equivalency). One
acceptable method of demonstrating the equivalency of a method of
suspending or securing a powered platform, as required in paragraphs
(e)(2)(iii), (f)(3) and (f)(5)(i)(F), is to provide an engineering
analysis by a registered professional engineer. The analysis should
demonstrate that the proposed method will provide an equal or greater
degree of safety for employees than any one of the methods specified in
the standard.
Appendix B to Sec. 1910.66--Exhibits (Advisory)
The three drawings in appendix B illustrate typical platform
stabilization systems which are addressed in the standard. The drawings
are to be used for reference purposes only, and do not illustrate all
the mandatory requirements for each system.
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Appendix C to Sec. 1910.66--Personal Fall Arrest System (Section I--
Mandatory; Sections II and III--Non-Mandatory)
Use of the Appendix
Section I of appendix C sets out the mandatory criteria for personal
fall arrest systems used by all employees using powered platforms, as
required by paragraph (j)(1) of this standard. Section II sets out
nonmandatory test procedures which may be used to determine compliance
with applicable requirements contained in section I of this appendix.
Section III provides nonmandatory guidelines which are intended to
assist employers in complying with these provisions.
I. Personal fall arrest systems--(a) Scope and application. This
section establishes the application of and performance criteria for
personal fall arrest systems which are required for use by all employees
using powered platforms under paragraph 1910.66(j).
(b) Definitions. Anchorage means a secure point of attachment for
lifelines, lanyards or deceleration devices, and which is independent of
the means of supporting or suspending the employee.
Body belt means a strap with means both for securing it about the
waist and for attaching it to a lanyard, lifeline, or deceleration
device.
Body harness means a design of straps which may be secured about the
employee in a manner to distribute the fall arrest forces over at least
the thighs, pelvis, waist, chest and shoulders with means for attaching
it to other components of a personal fall arrest system.
Buckle means any device for holding the body belt or body harness
closed around the employee's body.
Competent person means a person who is capable of identifying
hazardous or dangerous conditions in the personal fall arrest system or
any component thereof, as well as in their application and use with
related equipment.
Connector means a device which is used to couple (connect) parts of
the system together. It may be an independent component of the system
(such as a carabiner), or an integral component of part of the system
(such as a buckle or dee-ring sewn into a body belt or body harness, or
a snap-hook spliced or sewn to a lanyard or self-retracting lanyard).
Deceleration device means any mechanism, such as a rope grab,
ripstitch lanyard, specially woven lanyard, tearing or deforming
lanyard, or automatic self retracting-lifeline/lanyard, which serves to
dissipate a substantial amount of energy during a fall arrest, or
otherwise limits the energy imposed on an employee during fall arrest.
Deceleration distance means the additional vertical distance a
falling employee travels, excluding lifeline elongation and free fall
distance, before stopping, from the point at which the deceleration
device begins to operate. It is measured as the distance between the
location of an employee's body belt or body harness attachment point at
the moment of activation (at the onset of fall arrest forces) of the
deceleration device during a fall, and the location of that attachment
point after the employee comes to a full stop.
Equivalent means alternative designs, materials or methods which the
employer can demonstrate will provide an equal or greater degree of
safety for employees than the methods, materials or designs specified in
the standard.
Free fall means the act of falling before the personal fall arrest
system begins to apply force to arrest the fall.
Free fall distance means the vertical displacement of the fall
arrest attachment point on the employee's body belt or body harness
between onset of the fall and just before the system begins to apply
force to arrest the fall. This distance excludes deceleration distance,
lifeline and lanyard elongation but includes any deceleration device
slide distance or self-retracting lifeline/lanyard extension before they
operate and fall arrest forces occur.
Lanyard means a flexible line of rope, wire rope, or strap which is
used to secure the body belt or body harness to a deceleration device,
lifeline, or anchorage.
Lifeline means a component consisting of a flexible line for
connection to an anchorage at one end to hang vertically (vertical
lifeline), or for connection to anchorages at both ends to stretch
horizontally (horizontal lifeline), and which serves as a means for
connecting other components of a personal fall arrest system to the
anchorage.
Personal fall arrest system means a system used to arrest an
employee in a fall from a working level. It consists of an anchorage,
connectors, a body belt or body harness and may include a lanyard,
deceleration device, lifeline, or suitable combinations of these.
Qualified person means one with a recognized degree or professional
certificate and extensive knowledge and experience in the subject field
who is capable of design, analysis, evaluation and specifications in the
subject work, project, or product.
Rope grab means a deceleration device which travels on a lifeline
and automatically frictionally engages the lifeline and locks so as to
arrest the fall of an employee. A rope grab usually employs the
principle of inertial locking, cam/lever locking, or both.
Self-retracting lifeline/lanyard means a deceleration device which
contains a drum-wound line which may be slowly extracted from, or
retracted onto, the drum under slight tension during normal employee
movement, and which, after onset of a fall, automatically locks the drum
and arrests the fall.
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Snap-hook means a connector comprised of a hookshaped member with a
normally closed keeper, or similar arrangement, which may be opened to
permit the hook to receive an object and, when released, automatically
closes to retain the object. Snap-hooks are generally one of two types:
1. The locking type with a self-closing, self-locking keeper which
remains closed and locked until unlocked and pressed open for connection
or disconnection, or
2. The non-locking type with a self-closing keeper which remains
closed until pressed open for connection or disconnection.
Tie-off means the act of an employee, wearing personal fall
protection equipment, connecting directly or indirectly to an anchorage.
It also means the condition of an employee being connected to an
anchorage.
(c) Design for system components. (1) Connectors shall be drop
forged, pressed or formed steel, or made of equivalent materials.
(2) Connectors shall have a corrosion-resistant finish, and all
surfaces and edges shall be smooth to prevent damage to interfacing
parts of the system.
(3) Lanyards and vertical lifelines which tie-off one employee shall
have a minimum breaking strength of 5,000 pounds (22.2 kN).
(4) Self-retracting lifelines and lanyards which automatically limit
free fall distance to two feet (0.61 m) or less shall have components
capable of sustaining a minimum static tensile load of 3,000 pounds
(13.3 kN) applied to the device with the lifeline or lanyard in the
fully extended position.
(5) Self-retracting lifelines and lanyards which do not limit free
fall distance to two feet (0.61 m) or less, ripstitch lanyards, and
tearing and deforming lanyards shall be capable of sustaining a minimum
tensile load of 5,000 pounds (22.2 kN) applied to the device with the
lifeline or lanyard in the fully extended position.
(6) Dee-rings and snap-hooks shall be capable of sustaining a
minimum tensile load of 5,000 pounds (22.2 kN).
(7) Dee-rings and snap-hooks shall be 100 percent proof-tested to a
minimum tensile load of 3,600 pounds (16 kN) without cracking, breaking,
or taking permanent deformation.
(8) Snap-hooks shall be sized to be compatible with the member to
which they are connected so as to prevent unintentional disengagement of
the snap-hook by depression of the snap-hook keeper by the connected
member, or shall be a locking type snap-hook designed and used to
prevent disengagement of the snap-hook by the contact of the snaphook
keeper by the connected member.
(9) Horizontal lifelines, where used, shall be designed, and
installed as part of a complete personal fall arrest system, which
maintains a safety factor of at least two, under the supervision of a
qualified person.
(10) Anchorages to which personal fall arrest equipment is attached
shall be capable of supporting at least 5,000 pounds (22.2 kN) per
employee attached, or shall be designed, installed, and used as part of
a complete personal fall arrest system which maintains a safety factor
of at least two, under the supervision of a qualified person.
(11) Ropes and straps (webbing) used in lanyards, lifelines, and
strength components of body belts and body harnesses, shall be made from
synthetic fibers or wire rope.
(d) System performance criteria. (1) Personal fall arrest systems
shall, when stopping a fall:
(i) Limit maximum arresting force on an employee to 900 pounds (4
kN) when used with a body belt;
(ii) Limit maximum arresting force on an employee to 1,800 pounds (8
kN) when used with a body harness;
(iii) Bring an employee to a complete stop and limit maximum
deceleration distance an employee travels to 3.5 feet (1.07 m); and
(iv) Shall have sufficient strength to withstand twice the potential
impact energy of an employee free falling a distance of six feet (1.8
m), or the free fall distance permitted by the system, whichever is
less.
(2)(i) When used by employees having a combined person and tool
weight of less than 310 pounds (140 kg), personal fall arrest systems
which meet the criteria and protocols contained in paragraphs (b), (c)
and (d) in section II of this appendix shall be considered as complying
with the provisions of paragraphs (d)(1)(i) through (d)(1)(iv) above.
(ii) When used by employees having a combined tool and body weight
of 310 pounds (140 kg) or more, personal fall arrest systems which meet
the criteria and protocols contained in paragraphs (b), (c) and (d) in
section II may be considered as complying with the provisions of
paragraphs (d)(1)(i) through (d)(1)(iv) provided that the criteria and
protocols are modified appropriately to provide proper protection for
such heavier weights.
(e) Care and use. (1) Snap-hooks, unless of a locking type designed
and used to prevent disengagement from the following connections, shall
not be engaged:
(i) Directly to webbing, rope or wire rope;
(ii) To each other;
(iii) To a dee-ring to which another snap-hook or other connector is
attached;
(iv) To a horizontal lifeline; or
(v) To any object which is incompatibly shaped or dimensioned in
relation to the snap-hook such that the connected object could depress
the snap-hook keeper a sufficient amount to release itself.
(2) Devices used to connect to a horizontal lifeline which may
become a vertical lifeline shall be capable of locking in either
direction on the lifeline.
(3) Personal fall arrest systems shall be rigged such that an
employee can neither
[[Page 176]]
free fall more than six feet (1.8 m), nor contact any lower level.
(4) The attachment point of the body belt shall be located in the
center of the wearer's back. The attachment point of the body harness
shall be located in the center of the wearer's back near shoulder level,
or above the wearer's head.
(5) When vertical lifelines are used, each employee shall be
provided with a separate lifeline.
(6) Personal fall arrest systems or components shall be used only
for employee fall protection.
(7) Personal fall arrest systems or components subjected to impact
loading shall be immediately removed from service and shall not be used
again for employee protection unless inspected and determined by a
competent person to be undamaged and suitable for reuse.
(8) The employer shall provide for prompt rescue of employees in the
event of a fall or shall assure the self-rescue capability of employees.
(9) Before using a personal fall arrest system, and after any
component or system is changed, employees shall be trained in accordance
with the requirements of paragraph 1910.66(i)(1), in the safe use of the
system.
(f) Inspections. Personal fall arrest systems shall be inspected
prior to each use for mildew, wear, damage and other deterioration, and
defective components shall be removed from service if their strength or
function may be adversely affected.
II. Test methods for personal fall arrest systems (non-mandatory)--
(a) General. Paragraphs (b), (c), (d) and (e), of this section II set
forth test procedures which may be used to determine compliance with the
requirements in paragraph (d)(1)(i) through (d)(1)(iv) of section I of
this appendix.
(b) General conditions for all tests in section II. (1) Lifelines,
lanyards and deceleration devices should be attached to an anchorage and
connected to the body-belt or body harness in the same manner as they
would be when used to protect employees.
(2) The anchorage should be rigid, and should not have a deflection
greater than .04 inches (1 mm) when a force of 2,250 pounds (10 kN) is
applied.
(3) The frequency response of the load measuring instrumentation
should be 120 Hz.
(4) The test weight used in the strength and force tests should be a
rigid, metal, cylindrical or torso-shaped object with a girth of 38
inches plus or minus four inches (96 cm plus or minus 10 cm).
(5) The lanyard or lifeline used to create the free fall distance
should be supplied with the system, or in its absence, the least elastic
lanyard or lifeline available to be used with the system.
(6) The test weight for each test should be hoisted to the required
level and should be quickly released without having any appreciable
motion imparted to it.
(7) The system's performance should be evaluated taking into account
the range of environmental conditions for which it is designed to be
used.
(8) Following the test, the system need not be capable of further
operation.
(c) Strength test. (1) During the testing of all systems, a test
weight of 300 pounds plus or minus five pounds (135 kg plus or minus 2.5
kg) should be used. (See paragraph (b)(4), above.)
(2) The test consists of dropping the test weight once. A new unused
system should be used for each test.
(3) For lanyard systems, the lanyard length should be six feet plus
or minus two inches (1.83 m plus or minus 5 cm) as measured from the
fixed anchorage to the attachment on the body belt or body harness.
(4) For rope-grab-type deceleration systems, the length of the
lifeline above the centerline of the grabbing mechanism to the
lifeline's anchorage point should not exceed two feet (0.61 m).
(5) For lanyard systems, for systems with deceleration devices which
do not automatically limit free fall distance to two feet (0.61 m) or
less, and for systems with deceleration devices which have a connection
distance in excess of one foot (0.3 m) (measured between the centerline
of the lifeline and the attachment point to the body belt or harness),
the test weight should be rigged to free fall a distance of 7.5 feet
(2.3 m) from a point that is 1.5 feet (46 cm) above the anchorage point,
to its hanging location (six feet below the anchorage). The test weight
should fall without interference, obstruction, or hitting the floor or
ground during the test. In some cases a non-elastic wire lanyard of
sufficient length may need to be added to the system (for test purposes)
to create the necessary free fall distance.
(6) For deceleration device systems with integral lifelines or
lanyards which automatically limit free fall distance to two feet (0.61
m) or less, the test weight should be rigged to free fall a distance of
four feet (1.22 m).
(7) Any weight which detaches from the belt or harness should
constitute failure for the strength test.
(d) Force test--(1) General. The test consists of dropping the
respective test weight specified in (d)(2)(i) or (d)(3)(i) once. A new,
unused system should be used for each test.
(2) For lanyard systems. (i) A test weight of 220 pounds plus or
minus three pounds (100 kg plus or minus 1.6 kg) should be used. (See
paragraph (b)(4), above.)
(ii) Lanyard length should be six feet plus or minus two inches
(1.83 m plus or minus 5 cm) as measured from the fixed anchorage to the
attachment on the body belt or body harness.
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(iii) The test weight should fall free from the anchorage level to
its hanging location (a total of six feet (1.83 m) free fall distance)
without interference, obstruction, or hitting the floor or ground during
the test.
(3) For all other systems. (i) A test weight of 220 pounds plus or
minus three pounds (100 kg plus or minus 1.6 kg) should be used. (See
paragraph (b)(4), above.)
(ii) The free fall distance to be used in the test should be the
maximum fall distance physically permitted by the system during normal
use conditions, up to a maximum free fall distance for the test weight
of six feet (1.83 m), except as follows:
(A) For deceleration systems which have a connection link or
lanyard, the test weight should free fall a distance equal to the
connection distance (measured between the centerline of the lifeline and
the attachment point to the body belt or harness).
(B) For deceleration device systems with integral lifelines or
lanyards which automatically limit free fall distance to two feet (0.61
m) or less, the test weight should free fall a distance equal to that
permitted by the system in normal use. (For example, to test a system
with a self-retracting lifeline or lanyard, the test weight should be
supported and the system allowed to retract the lifeline or lanyard as
it would in normal use. The test weight would then be released and the
force and deceleration distance measured).
(4) A system fails the force test if the recorded maximum arresting
force exceeds 1,260 pounds (15.6 kN) when using a body belt, and/or
exceeds 2,520 pounds (11.2 kN) when using a body harness.
(5) The maximum elongation and deceleration distance should be
recorded during the force test.
(e) Deceleration device tests--(1) General. The device should be
evaluated or tested under the environmental conditions, (such as rain,
ice, grease, dirt, type of lifeline, etc.), for which the device is
designed.
(2) Rope-grab-type deceleration devices. (i) Devices should be moved
on a lifeline 1,000 times over the same length of line a distance of not
less than one foot (30.5 cm), and the mechanism should lock each time.
(ii) Unless the device is permanently marked to indicate the type(s)
of lifeline which must be used, several types (different diameters and
different materials), of lifelines should be used to test the device.
(3) Other self-activatinq-type deceleration devices. The locking
mechanisms of other self-activating-type deceleration devices designed
for more than one arrest should lock each of 1,000 times as they would
in normal service.
III. Additional non-mandatory guidelines for personal fall arrest
systems. The following information constitutes additional guidelines for
use in complying with requirements for a personal fall arrest system.
(a) Selection and use considerations. The kind of personal fall
arrest system selected should match the particular work situation, and
any possible free fall distance should be kept to a minimum.
Consideration should be given to the particular work environment. For
example, the presence of acids, dirt, moisture, oil, grease, etc., and
their effect on the system, should be evaluated. Hot or cold
environments may also have an adverse affect on the system. Wire rope
should not be used where an electrical hazard is anticipated. As
required by the standard, the employer must plan to have means available
to promptly rescue an employee should a fall occur, since the suspended
employee may not be able to reach a work level independently.
Where lanyards, connectors, and lifelines are subject to damage by
work operations such as welding, chemical cleaning, and sandblasting,
the component should be protected, or other securing systems should be
used. The employer should fully evaluate the work conditions and
environment (including seasonal weather changes) before selecting the
appropriate personal fall protection system. Once in use, the system's
effectiveness should be monitored. In some cases, a program for cleaning
and maintenance of the system may be necessary.
(b) Testing considerations. Before purchasing or putting into use a
personal fall arrest system, an employer should obtain from the supplier
information about the system based on its performance during testing so
that the employer can know if the system meets this standard. Testing
should be done using recognized test methods. Section II of this
appendix C contains test methods recognized for evaluating the
performance of fall arrest systems. Not all systems may need to be
individually tested; the performance of some systems may be based on
data and calculations derived from testing of similar systems, provided
that enough information is available to demonstrate similarity of
function and design.
(c) Component compatibility considerations. Ideally, a personal fall
arrest system is designed, tested, and supplied as a complete system.
However, it is common practice for lanyards, connectors, lifelines,
deceleration devices, body belts and body harnesses to be interchanged
since some components wear out before others. The employer and employee
should realize that not all components are interchangeable. For
instance, a lanyard should not be connected between a body belt (or
harness) and a deceleration device of the self-retracting type since
this can result in additional free fall for which the system was not
designed. Any substitution or change to a personal fall arrest system
should be fully evaluated or tested by a competent person to determine
that it meets the
[[Page 178]]
standard, before the modified system is put in use.
(d) Employee training considerations. Thorough employee training in
the selection and use of personal fall arrest systems is imperative. As
stated in the standard, before the equipment is used, employees must be
trained in the safe use of the system. This should include the
following: Application limits; proper anchoring and tie-off techniques;
estimation of free fall distance, including determination of
deceleration distance, and total fall distance to prevent striking a
lower level; methods of use; and inspection and storage of the system.
Careless or improper use of the equipment can result in serious injury
or death. Employers and employees should become familiar with the
material in this appendix, as well as manufacturer's recommendations,
before a system is used. Of uppermost importance is the reduction in
strength caused by certain tie-offs (such as using knots, tying around
sharp edges, etc.) and maximum permitted free fall distance. Also, to be
stressed are the importance of inspections prior to use, the limitations
of the equipment, and unique conditions at the worksite which may be
important in determining the type of system to use.
(e) Instruction considerations. Employers should obtain
comprehensive instructions from the supplier as to the system's proper
use and application, including, where applicable:
(1) The force measured during the sample force test;
(2) The maximum elongation measured for lanyards during the force
test;
(3) The deceleration distance measured for deceleration devices
during the force test;
(4) Caution statements on critical use limitations;
(5) Application limits;
(6) Proper hook-up, anchoring and tie-off techniques, including the
proper dee-ring or other attachment point to use on the body belt and
harness for fall arrest;
(7) Proper climbing techniques;
(8) Methods of inspection, use, cleaning, and storage; and
(9) Specific lifelines which may be used. This information should be
provided to employees during training.
(f) Inspection considerations. As stated in the standard (section I,
Paragraph (f)), personal fall arrest systems must be regularly
inspected. Any component with any significant defect, such as cuts,
tears, abrasions, mold, or undue stretching; alterations or additions
which might affect its efficiency; damage due to deterioration; contact
with fire, acids, or other corrosives; distorted hooks or faulty hook
springs; tongues unfitted to the shoulder of buckles; loose or damaged
mountings; non-functioning parts; or wearing or internal deterioration
in the ropes must be withdrawn from service immediately, and should be
tagged or marked as unusable, or destroyed.
(g) Rescue considerations. As required by the standard (section I,
Paragraph (e)(8)), when personal fall arrest systems are used, the
employer must assure that employees can be promptly rescued or can
rescue themselves should a fall occur. The availability of rescue
personnel, ladders or other rescue equipment should be evaluated. In
some situations, equipment which allows employees to rescue themselves
after the fall has been arrested may be desirable, such as devices which
have descent capability.
(h) Tie-off considerations. (1) One of the most important aspects of
personal fall protection systems is fully planning the system before it
is put into use. Probably the most overlooked component is planning for
suitable anchorage points. Such planning should ideally be done before
the structure or building is constructed so that anchorage points can be
incorporated during construction for use later for window cleaning or
other building maintenance. If properly planned, these anchorage points
may be used during construction, as well as afterwards.
(2) Employers and employees should at all times be aware that the
strength of a personal fall arrest system is based on its being attached
to an anchoring system which does not significantly reduce the strength
of the system (such as a properly dimensioned eye-bolt/snap-hook
anchorage). Therefore, if a means of attachment is used that will reduce
the strength of the system, that component should be replaced by a
stronger one, but one that will also maintain the appropriate maximum
arrest force characteristics.
(3) Tie-off using a knot in a rope lanyard or lifeline (at any
location) can reduce the lifeline or lanyard strength by 50 percent or
more. Therefore, a stronger lanyard or lifeline should be used to
compensate for the weakening effect of the knot, or the lanyard length
should be reduced (or the tie-off location raised) to minimize free fall
distance, or the lanyard or lifeline should be replaced by one which has
an appropriately incorporated connector to eliminate the need for a
knot.
(4) Tie-off of a rope lanyard or lifeline around an ``H'' or ``I''
beam or similar support can reduce its strength as much as 70 percent
due to the cutting action of the beam edges. Therefore, use should be
made of a webbing lanyard or wire core lifeline around the beam; or the
lanyard or lifeline should be protected from the edge; or free fall
distance should be greatly minimized.
(5) Tie-off where the line passes over or around rough or sharp
surfaces reduces strength drastically. Such a tie-off should be avoided
or an alternative tie-off rigging should be used. Such alternatives may
include use of a snap-hook/dee ring connection, wire rope tie-off, an
effective padding of the
[[Page 179]]
surfaces, or an abrasion-resistance strap around or over the problem
surface.
(6) Horizontal lifelines may, depending on their geometry and angle
of sag, be subjected to greater loads than the impact load imposed by an
attached component. When the angle of horizontal lifeline sag is less
than 30 degrees, the impact force imparted to the lifeline by an
attached lanyard is greatly amplified. For example, with a sag angle of
15 degrees, the force amplification is about 2:1 and at 5 degrees sag,
it is about 6:1. Depending on the angle of sag, and the line's
elasticity, the strength of the horizontal lifeline and the anchorages
to which it is attached should be increased a number of times over that
of the lanyard. Extreme care should be taken in considering a horizontal
lifeline for multiple tie-offs. The reason for this is that in multiple
tie-offs to a horizontal lifeline, if one employee falls, the movement
of the falling employee and the horizontal lifeline during arrest of the
fall may cause other employees to also fall. Horizontal lifeline and
anchorage strength should be increased for each additional employee to
be tied-off. For these and other reasons, the design of systems using
horizontal lifelines must only be done by qualified persons. Testing of
installed lifelines and anchors prior to use is recommended.
(7) The strength of an eye-bolt is rated along the axis of the bolt
and its strength is greatly reduced if the force is applied at an angle
to this axis (in the direction of shear). Also, care should be exercised
in selecting the proper diameter of the eye to avoid accidental
disengagement of snap-hooks not designed to be compatible for the
connection.
(8) Due to the significant reduction in the strength of the
lifeline/lanyard (in some cases, as much as a 70 percent reduction), the
sliding hitch knot should not be used for lifeline/lanyard connections
except in emergency situations where no other available system is
practical. The ``one-and-one'' sliding hitch knot should never be used
because it is unreliable in stopping a fall. The ``two-and-two,'' or
``three-and-three'' knot (preferable), may be used in emergency situa-
tions; however, care should be taken to limit free fall distance to a
minimum because of reduced lifeline/lanyard strength.
(i) Vertical lifeline considerations. As required by the standard,
each employee must have a separate lifeline when the lifeline is
vertical. The reason for this is that in multiple tie-offs to a single
lifeline, if one employee falls, the movement of the lifeline during the
arrest of the fall may pull other employees' lanyards, causing them to
fall as well.
(j) Snap-hook considerations. Although not required by this standard
for all connections, locking snap-hooks designed for connection to
suitable objects (of sufficient strength) are highly recommended in lieu
of the non-locking type. Locking snap-hooks incorporate a positive
locking mechanism in addition to the spring loaded keeper, which will
not allow the keeper to open under moderate pressure without someone
first releasing the mechanism. Such a feature, properly designed,
effectively prevents roll-out from occurring.
As required by the standard (section I, paragraph (e)(1)) the
following connections must be avoided (unless properly designed locking
snap-hooks are used) because they are conditions which can result in
roll-out when a nonlocking snap-hook is used:
<bullet<ls-thn-eq> Direct connection of a snap-hook to a horizontal
lifeline.
<bullet<ls-thn-eq> Two (or more) snap-hooks connected to one dee-
ring.
<bullet<ls-thn-eq> Two snap-hooks connected to each other.
<bullet<ls-thn-eq> A snap-hook connected back on its integral
lanyard.
<bullet<ls-thn-eq> A snap-hook connected to a webbing loop or
webbing lanyard.
<bullet<ls-thn-eq> Improper dimensions of the dee-ring, rebar, or
other connection point in relation to the snap-hook dimensions which
would allow the snap-hook keeper to be depressed by a turning motion of
the snap-hook.
(k) Free fall considerations. The employer and employee should at
all times be aware that a system's maximum arresting force is evaluated
under normal use conditions established by the manufacturer, and in no
case using a free fall distance in excess of six feet (1.8 m). A few
extra feet of free fall can significantly increase the arresting force
on the employee, possibly to the point of causing injury. Because of
this, the free fall distance should be kept at a minimum, and, as
required by the standard, in no case greater than six feet (1.8 m). To
help assure this, the tie-off attachment point to the lifeline or anchor
should be located at or above the connection point of the fall arrest
equipment to belt or harness. (Since otherwise additional free fall
distance is added to the length of the connecting means (i.e. lanyard)).
Attaching to the working surface will often result in a free fall
greater than six feet (1.8 m). For instance, if a six foot (1.8 m)
lanyard is used, the total free fall distance will be the distance from
the working level to the body belt (or harness) attachment point plus
the six feet (1.8 m) of lanyard length. Another important consideration
is that the arresting force which the fall system must withstand also
goes up with greater distances of free fall, possibly exceeding the
strength of the system.
(l) Elongation and deceleration distance considerations. Other
factors involved in a proper tie-off are elongation and deceleration
distance. During the arresting of a fall, a lanyard will experience a
length of stretching or elongation, whereas activation of a deceleration
device will result in a certain stopping distance. These distances
should be available
[[Page 180]]
with the lanyard or device's instructions and must be added to the free
fall distance to arrive at the total fall distance before an employee is
fully stopped. The additional stopping distance may be very significant
if the lanyard or deceleration device is attached near or at the end of
a long lifeline, which may itself add considerable distance due to its
own elongation. As required by the standard, sufficient distance to
allow for all of these factors must also be maintained between the
employee and obstructions below, to prevent an injury due to impact
before the system fully arrests the fall. In addition, a minimum of 12
feet (3.7 m) of lifeline should be allowed below the securing point of a
rope grab type deceleration device, and the end terminated to prevent
the device from sliding off the lifeline. Alternatively, the lifeline
should extend to the ground or the next working level below. These
measures are suggested to prevent the worker from inadvertently moving
past the end of the lifeline and having the rope grab become disengaged
from the lifeline.
(m) Obstruction considerations. The location of the tie-off should
also consider the hazard of obstructions in the potential fall path of
the employee. Tie-offs which minimize the possibilities of exaggerated
swinging should be considered. In addition, when a body belt is used,
the employee's body will go through a horizontal position to a jack-
knifed position during the arrest of all falls. Thus, obstructions which
might interfere with this motion should be avoided or a severe injury
could occur.
(n) Other considerations. Because of the design of some personal
fall arrest systems, additional considerations may be required for
proper tie-off. For example, heavy deceleration devices of the self-
retracting type should be secured overhead in order to avoid the weight
of the device having to be supported by the employee. Also, if
selfretracting equipment is connected to a horizontal lifeline, the sag
in the lifeline should be minimized to prevent the device from sliding
down the lifeline to a position which creates a swing hazard during fall
arrest. In all cases, manufacturer's instructions should be followed.
Appendix D to Sec. 1910.66--Existing Installations (Mandatory)
Use of the Appendix
Appendix D sets out the mandatory building and equipment
requirements for applicable permanent installations completed after
August 27, 1971, and no later than July 23, 1990 which are exempt from
the paragraphs (a), (b)(1), (b)(2), (c), (d), (e), and (f) of this
standard. The requirements in appendix D are essentially the same as
unrevised building and equipment provisions which previously were
designated as 29 CFR 1910.66 (a), (b), (c) and (d) and which were
effective on August 27, 1971.
Note: All existing installations subject to this appendix shall also
comply with paragraphs (g), (h), (i), (j) and appendix C of the standard
29 CFR 1910.66.
(a) Definitions applicable to this appendix--(1) Angulated roping. A
system of platform suspension in which the upper wire rope sheaves or
suspension points are closer to the plane of the building face than the
corresponding attachment points on the platform, thus causing the
platform to press against the face of the building during its vertical
travel.
(2) ANSI. American National Standards Institute.
(3) Babbitted fastenings. The method of providing wire rope
attachments in which the ends of the wire strands are bent back and are
held in a tapered socket by means of poured molten babbitt metal.
(4) Brake--disc type. A brake in which the holding effect is
obtained by frictional resistance between one or more faces of discs
keyed to the rotating member to be held and fixed discs keyed to the
stationary or housing member (pressure between the discs being applied
axially).
(5) Brake--self-energizing band type. An essentially undirectional
brake in which the holding effect is obtained by the snubbing action of
a flexible band wrapped about a cylindrical wheel or drum affixed to the
rotating member to be held, the connections and linkages being so
arranged that the motion of the brake wheel or drum will act to increase
the tension or holding force of the band.
(6) Brake--shoe type. A brake in which the holding effect is
obtained by applying the direct pressure of two or more segmental
friction elements held to a stationary member against a cylindrical
wheel or drum affixed to the rotating member to be held.
(7) Building face rollers. A specialized form of guide roller
designed to contact a portion of the outer face or wall structure of the
building, and to assist in stabilizing the operators' platform during
vertical travel.
(8) Continuous pressure. Operation by means of buttons or switches,
any one of which may be used to control the movement of the working
platform or roof car, only as long as the button or switch is manually
maintained in the actuating position.
(9) Control. A system governing starting, stopping, direction,
acceleration, speed, and retardation of moving members.
(10) Controller. A device or group of devices, usually contained in
a single enclosure, which serves to control in some predetermined manner
the apparatus to which it is connected.
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(11) Electrical ground. A conducting connection between an
electrical circuit or equipment and the earth, or some conducting body
which serves in place of the earth.
(12) Guide roller. A rotating, bearing-mounted, generally
cylindrical member, operating separately or as part of a guide shoe
assembly, attached to the platform, and providing rolling contact with
building guideways, or other building contact members.
(13) Guide shoe. An assembly of rollers, slide members, or the
equivalent, attached as a unit to the operators' platform, and designed
to engage with the building members provided for the vertical guidance
of the operators' platform.
(14) Interlock. A device actuated by the operation of some other
device with which it is directly associated, to govern succeeding
operations of the same or allied devices.
(15) Operating device. A pushbutton, lever, or other manual device
used to actuate a control.
(16) Powered platform. Equipment to provide access to the exterior
of a building for maintenance, consisting of a suspended power-operated
working platform, a roof car, or other suspension means, and the
requisite operating and control devices.
(17) Rated load. The combined weight of employees, tools, equipment,
and other material which the working platform is designed and installed
to lift.
(18) Relay, direction. An electrically energized contactor
responsive to an initiating control circuit, which in turn causes a
moving member to travel in a particular direction.
(19) Relay, potential for vertical travel. An electrically energized
contactor responsive to initiating control circuit, which in turn
controls the operation of a moving member in both directions. This relay
usually operates in conjunction with direction relays, as covered under
the definition, ``relay, direction.''
(20) Roof car. A structure for the suspension of a working platform,
providing for its horizontal movement to working positions.
(21) Roof-powered platform. A powered platform having the raising
and lowering mechanism located on a roof car.
(22) Self-powered platform. A powered platform having the raising
and lowering mechanism located on the working platform.
(23) Traveling cable. A cable made up of electrical or communication
conductors or both, and providing electrical connection between the
working platform and the roof car or other fixed point.
(24) Weatherproof. Equipment so constructed or protected that
exposure to the weather will not interfere with its proper operation.
(25) Working platform. The suspended structure arranged for vertical
travel which provides access to the exterior of the building or
structure.
(26) Yield point. The stress at which the material exhibits a
permanent set of 0.2 percent.
(27) Zinced fastenings. The method of providing wire rope
attachments in which the splayed or fanned wire ends are held in a
tapered socket by means of poured molten zinc.
(b) General requirements. (1) Design requirements. All powered
platform installations for exterior building maintenance completed as of
August 27, 1971, but no later than [insert date, 180 days after the
effective date], shall meet all of the design, construction and
installation requirements of Part II and III of the ``American National
Standard Safety Requirements for Powered Platforms for Exterior Building
Maintenance ANSI A120.1-1970'' and of this appendix. References shall be
made to appropriate parts of ANSI A120.1-1970 for detail specifications
for equipment and special installations.
(2) Limitation. The requirements of this appendix apply only to
electric powered platforms. It is not the intent of this appendix to
prohibit the use of other types of power. Installation of powered
platforms using other types of power is permitted, provided such
platforms have adequate protective devices for the type of power used,
and otherwise provide for reasonable safety of life and limb to users of
equipment and to others who may be exposed.
(3) Types of powered platforms. (i) For the purpose of applying this
appendix, powered platforms are divided into two basic types, Type F and
Type T.
(ii) Powered platforms designated as Type F shall meet all the
requirements in Part II of ANSI A 120.1-1970, American National Standard
Safety Requirements for Powered Platforms for Exterior Building
Maintenance. A basic requirement of Type F equipment is that the work
platform is suspended by at least four wire ropes and designed so that
failure of any one wire rope will not substantially alter the normal
position of the working platform. Another basic requirement of Type F
equipment is that only one layer of hoisting rope is permitted on
winding drums. Type F powered platforms may be either roof-powered or
self-powered.
(iii) Powered platforms designated as Type T shall meet all the
requirements in Part III of ANSI A120.1-1970 American National Standard
Safety Requirements for Powered Platforms for Exterior Building
Maintenance, except for section 28, Safety Belts and Life Lines. A basic
requirement of Type T equipment is that the working platform is
suspended by at least two wire ropes. Failure of one wire rope would not
permit the working platform to fall to the ground, but would upset its
normal position. Type T powered
[[Page 182]]
platforms may be either roof-powered or self-powered.
(iv) The requirements of this section apply to powered platforms
with winding drum type hoisting machines. It is not the intent of this
section to prohibit powered platforms using other types of hoisting
machines such as, but not limited to, traction drum hoisting machines,
air powered machines, hydraulic powered machines, and internal
combustion machines. Installation of powered platforms with other types
of hoisting machines is permitted, provided adequate protective devices
are used, and provided reasonable safety of life and limb to users of
the equipment and to others who may be exposed is assured.
(v) Both Type F and Type T powered platforms shall comply with the
requirements of appendix C of this standard.
(c) Type F powered platforms--(1) Roof car, general. (i) A roof car
shall be provided whenever it is necessary to move the working platform
horizontally to working or storage positions.
(ii) The maximum rated speed at which a power traversed roof car may
be moved in a horizontal direction shall be 50 feet per minute.
(2) Movement and positioning of roof car. (i) Provision shall be
made to protect against having the roof car leave the roof or enter roof
areas not designed for travel.
(ii) The horizontal motion of the roof cars shall be positively
controlled so as to insure proper movement and positioning of the roof
car.
(iii) Roof car positioning devices shall be provided to insure that
the working platform is placed and retained in proper position for
vertical travel and during storage.
(iv) Mechanical stops shall be provided to prevent the traversing of
the roof car beyond its normal limits of travel. Such stops shall be
capable of withstanding a force equal to 100 percent of the inertial
effect of the roof car in motion with traversing power applied.
(v)(a) The operating device of a power-operated roof car for
traversing shall be located on the roof car, the working platform, or
both, and shall be of the continuous pressure weather-proof electric
type. If more than one operating device is provided, they shall be so
arranged that traversing is possible only from one operating device at a
time.
(b) The operating device shall be so connected that it is not
operable until:
(1) The working platform is located at its uppermost position of
travel and is not in contact with the building face or fixed vertical
guides in the face of the building; and
(2) All protective devices and interlocks are in a position for
traversing.
(3) Roof car stability. Roof car stability shall be determined by
either paragraph (c)(3) (i) or (ii) of this appendix, whichever is
greater.
(i) The roof car shall be continuously stable, considering
overturning moment as determined by 125 percent rated load, plus maximum
dead load and the prescribed wind loading.
(ii) The roof car and its anchorages shall be capable of resisting
accidental over-tensioning of the wire ropes suspending the working
platform and this calculated value shall include the effect of one and
one-half times the value. For this calculation, the simultaneous effect
of one-half wind load shall be included, and the design stresses shall
not exceed those referred to in paragraph (b)(1) of this appendix.
(iii) If the load on the motors is at any time in excess of three
times that required for lifting the working platform with its rated load
the motor shall stall.
(4) Access to the roof car. Safe access to the roof car and from the
roof car to the working platform shall be provided. If the access to the
roof car at any point of its travel is not over the roof area or where
otherwise necessary for safety, self-closing, self-locking gates shall
be provided. Applicable provisions of the American National Standard
Safety Requirements for Floor and Wall Openings, Railings and Toeboard,
A12.1-1967, shall apply.
(5) Means for maintenance, repair, and storage. Means shall be
provided to run the roof car away from the roof perimeter, where
necessary, and to provide a safe area for maintenance, repairs, and
storage. Provisions shall be made to secure the machine in the stored
position. For stored machines subject to wind forces, see special design
and anchorage requirements for ``wind forces'' in Part II, section
10.5.1.1 of ANSI A120.1-1970 American National Standard Safety
Requirements for Powered Platforms for Exterior Building Maintenance.
(6) General requirements for working platforms. The working platform
shall be of girder or truss construction and shall be adequate to
support its rated load under any position of loading, and comply with
the provisions set forth in section 10 of ANSI A120.1-1970, American
National Standard Safety Requirements for Powered Platforms for Exterior
Building Maintenance.
(7) Load rating plate. Each working platform shall bear a
manufacturer's load rating plate, conspicuously posted; stating the
maximum permissible rated load. Load rating plates shall be made of
noncorrosive material and shall have letters and figures stamped,
etched, or cast on the surface. The minimum height of the letters and
figures shall be one-fourth inch.
(8) Minimum size. The working platform shall have a minimum net
width of 24 inches.
(9) Guardrails. Working platforms shall be furnished with permanent
guard rails not
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less than 36 inches high, and not more than 42 inches high at the front
(building side). At the rear, and on the sides, the rail shall not be
less than 42 inches high. An intermediate guardrail shall be provided
around the entire platform between the top guardrail and the toeboard.
(10) Toeboards. A four-inch toeboard shall be provided along all
sides of the working platform.
(11) Open spaces between guardrails and toeboards. The spaces
between the intermediate guardrail and platform toeboard on the building
side of the working platform, and between the top guardrail and the
toeboard on other sides of the platform, shall be filled with metalic
mesh or similar material that will reject a ball one inch in diameter.
The installed mesh shall be capable of withstanding a load of 100 pounds
applied horizontally over any area of 144 square inches. If the space
between the platform and the building face does not exceed eight inches,
and the platform is restrained by guides, the mesh may be omitted on the
front side.
(12) Flooring. The platform flooring shall be of the nonskid type,
and if of open construction, shall reject a \9/16\-inch diameter ball,
or be provided with a screen below the floor to reject a \9/16\-inch
diameter ball.
(13) Access gates. Where access gates are provided, they shall be
self-closing and self-locking.
(14) Operating device for vertical movement of the working platform.
(i) The normal operating device for the working platform shall be
located on the working platform and shall be of the continuous pressure
weatherproof electric type.
(ii) The operating device shall be operable only when all electrical
protective devices and interlocks on the working platform are in
position for normal service and, the roof car, if provided, is at an
established operating point.
(15) Emergency electric operative device. (i) In addition, on roof-
powered platforms, an emergency electric operating device shall be
provided near the hoisting machine for use in the event of failure of
the normal operating device for the working platform, or failure of the
traveling cable system. The emergency operating device shall be mounted
in a locked compartment and shall have a legend mounted thereon reading:
``For Emergency Operation Only. Establish Communication With Personnel
on Working Platform Before Use.''
(ii) A key for unlocking the compartment housing the emergency
operating device shall be mounted in a break-glass receptacle located
near the emergency operating device.
(16) Manual cranking for emergency operation. Emergency operation of
the main drive machine may be provided to allow manual cranking. This
provision for manual operation shall be designed so that not more than
two persons will be required to perform this operation. The access to
this provision shall include a means to automatically make the machine
inoperative electrically while under the emergency manual operation. The
design shall be such that the emergency brake is operative at or below
governor tripping speed during manual operation.
(17) Arrangement and guarding of hoisting equipment. (i) Hoisting
equipment shall consist of a power-driven drum or drum contained in the
roof car (roof-powered platforms) or contained on the working platform
(self-powered platform).
(ii) The hoisting equipment shall be power-operated in both up and
down directions.
(iii) Guard or other protective devices shall be installed wherever
rotating shafts or other mechanisms or gears may expose personnel to a
hazard.
(iv) Friction devices or clutches shall not be used for connecting
the main driving mechanism to the drum or drums. Belt or chain-driven
machines are prohibited.
(18) Hoisting motors. (i) Hoisting motors shall be electric and of
weather-proof construction.
(ii) Hoisting motors shall be in conformance with applicable
provisions of paragraph (c)(22) of this appendix, Electric Wiring and
Equipment.
(iii) Hoisting motors shall be directly connected to the hoisting
machinery. Motor couplings, if used, shall be of steel construction.
(19) Brakes. The hoisting machine(s) shall have two independent
braking means, each designed to stop and hold the working platform with
125 percent of rated load.
(20) Hoisting ropes and rope connections. (i) Working platforms
shall be suspended by wire ropes of either 6x19 or 6x37 classification,
preformed or nonpreformed.
(ii) [Reserved]
(iii) The minimum factor of safety shall be 10, and shall be
calculated by the following formula:
F = SxN/W
Where
S = Manufacturer's rated breaking strength of one rope.
N = Number of ropes under load.
W = Maximum static load on all ropes with the platform and its rated
load at any point of its travel.
(iv) Hoisting ropes shall be sized to conform with the required
factor of safety, but in no case shall the size be less than \5/16\ inch
diameter.
(v) Winding drums shall have at least three turns of rope remaining
when the platform has landed at the lowest possible point of its travel.
[[Page 184]]
(vi) The lengthening or repairing of wire rope by the joining of two
or more lengths is prohibited.
(vii) The nondrum ends of the hoisting ropes shall be provided with
individual shackle rods which will permit individual adjustment of rope
lengths, if required.
(viii) More than two reverse bends in each rope is prohibited.
(21) Rope tag data. (i) A metal data tag shall be securely attached
to one of the wire rope fastenings. This data tag shall bear the
following wire rope data:
(a) The diameter in inches.
(b) Construction classification.
(c) Whether nonpreformed or preformed.
(d) The grade of material used.
(e) The manufacturer's rated breaking strength.
(f) Name of the manufacturer of the rope.
(g) The month and year the ropes were installed.
(22) Electrical wiring and equipment. (i) All electrical equipment
and wiring shall conform to the requirements of the National Electrical
Code, NFPA 70-1971; ANSI C1-1971 (Rev. of C1-1968), except as modified
by ANSI A120.1-1970 ``American National Standard Safety Requirements for
Powered Platforms for Exterior Building Maintenance.'' For detail design
specifications for electrical equipment, see Part 2, ANSI A120.1-1970.
(ii) All motors and operation and control equipment shall be
supplied from a single power source.
(iii) The power supply for the powered platform shall be an
independent circuit supplied through a fused disconnect switch.
(iv) Electrical conductor parts of the power supply system shall be
protected against accidental contact.
(v) Electrical grounding shall be provided.
(a) Provisions for electrical grounding shall be included with the
power-supply system.
(b) Controller cabinets, motor frames, hoisting machines, the
working platform, roof car and roof car track system, and noncurrent
carrying parts of electrical equipment, where provided, shall be
grounded.
(c) The controller, where used, shall be so designed and installed
that a single ground or short circuit will not prevent both the normal
and final stopping device from stopping the working platform.
(d) Means shall be provided on the roof car and working platform for
grounding portable electric tools.
(e) The working platform shall be grounded through a grounding
connection in a traveling cable. Electrically powered tools utilized on
the working platform shall be grounded.
(vi) Electrical receptacles located on the roof or other exterior
location shall be of a weatherproof type and shall be located so as not
to be subject to contact with water or accumulated snow. The receptacles
shall be grounded and the electric cable shall include a grounding
conductor. The receptacle and plug shall be a type designed to avoid
hazard to persons inserting or withdrawing the plug. Provision shall be
made to prevent application of cable strain directly to the plug and
receptacle.
(vii) Electric runway conductor systems shall be of the type
designed for use in exterior locations and shall be located so as not to
be subject to contact with water or accumulated snow. The conductors,
collectors, and disconnecting means shall conform to the same
requirements as those for cranes and hoists in Article 610 of the
National Electrical Code, NFPA 70-1971; ANSI C1-1971 (Rev. of C1-1968).
A grounded conductor shall parallel the power conductors and be so
connected that it cannot be opened by the disconnecting means. The
system shall be designed to avoid hazard to persons in the area.
(viii) Electrical protective devices and interlocks of the
weatherproof type shall be provided.
(ix) Where the installation includes a roof car, electric contact(s)
shall be provided and so connected that the operating devices for the
working platform shall be operative only when the roof car is located
and mechanically retained at an established operating point.
(x) Where the powered platform includes a powered-operated roof car,
the operating device for the roof car shall be inoperative when the roof
car is mechanically retained at an established operating point.
(xi) An electric contact shall be provided and so connected that it
will cause the down direction relay for vertical travel to open if the
tension in the traveling cable exceeds safe limits.
(xii) An automatic overload device shall be provided to cut off the
electrical power to the circuit in all hoisting motors for travel in the
up direction, should the load applied to the hoisting ropes at either
end of the working platform exceed 125 percent of its normal tension
with rated load, as shown on the manufacturer's data plate on the
working platform.
(xiii) An automatic device shall be provided for each hoisting rope
which will cut off the electrical power to the hoisting motor or motors
in the down direction and apply the brakes if any hoisting rope becomes
slack.
(xiv) Upper and lower directional limit devices shall be provided to
prevent the travel of the working platform beyond the normal upper and
lower limits of travel.
(xv) Operation of a directional limit device shall prevent further
motion in the appropriate direction, if the normal limit of travel has
been reached.
(xvi) Directional limit devices, if driven from the hoisting machine
by chains, tapes,
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or cables, shall incorporate a device to disconnect the electric power
from the hoisting machine and apply both the primary and secondary
brakes in the event of failure of the driving means.
(xvii) Final terminal stopping devices of the working platform:
(a) Final terminal stopping devices for the working platform shall
be provided as a secondary means of preventing the working platform from
over-traveling at the terminals.
(b) The device shall be set to function as close to each terminal
landing as practical, but in such a way that under normal operating
conditions it will not function when the working platform is stopped by
the normal terminal stopping device.
(c) Operation of the final terminal stopping device shall open the
potential relay for vertical travel, thereby disconnecting the electric
power from the hoisting machine, and applying both the primary and
secondary brakes.
(d) The final terminal stopping device for the upper limit of travel
shall be mounted so that it is operated directly by the motion of the
working platform itself.
(xviii) Emergency stop switches shall be provided in or adjacent to
each operating device.
(xix) Emergency stop switches shall:
(a) Have red operating buttons or handles.
(b) Be conspicuously and permanently marked ``Stop.''
(c) Be the manually opened and manually closed type.
(d) Be positively opened with the opening not solely dependent on
springs.
(xx) The manual operation of an emergency stop switch associated
with an operating device for the working platform shall open the
potential relay for vertical travel, thereby disconnecting the electric
power from the hoisting machine and applying both the primary and
secondary brakes.
(xxi) The manual operation of the emergency stop switch associated
with the operating device for a power-driven roof car shall cause the
electrical power to the traverse machine to be interrupted, and the
traverse machine brake to apply.
(23) Requirements for emergency communications. (i) Communication
equipment shall be provided for each powered platform for use in an
emergency.
(ii) Two-way communication shall be established between personnel on
the roof and personnel on the stalled working platform before any
emergency operation of the working platform is undertaken by personnel
on the roof.
(iii) The equipment shall permit two-way voice communication between
the working platform and
(a) Designated personnel continuously available while the powered
platform is in use; and
(b) Designated personnel on roof-powered platforms, undertaking
emergency operation of the working platform by means of the emergency
operating device located near the hoisting machine.
(iv) The emergency communication equipment shall be one of the
following types:
(a) Telephone connected to the central telephone exchange system; or
(b) Telephones on a limited system or an approved two-way radio
system, provided designated personnel are available to receive a message
during the time the powered platform is in use.
(d) Type T powered platforms--(1) Roof car. The requirements of
paragraphs (c)(1) through (c)(5) of this appendix shall apply to Type T
powered platforms.
(2) Working platform. The requirements of paragraphs (c)(6) through
(c)(16) of this appendix apply to Type T powered platforms.
(i) The working platform shall be suspended by at least two wire
ropes.
(ii) The maximum rated speed at which the working platform of self-
powered platforms may be moved in a vertical direction shall not exceed
35 feet per minute.
(3) Hoisting equipment. The requirements of paragraphs (c) (17) and
(18) of this appendix shall apply to Type T powered platforms.
(4) Brakes. Brakes requirements of paragraph (c)(19) of this
appendix shall apply.
(5) Hoisting ropes and rope connections. (i) Paragraphs (c)(20) (i)
through (vi) and (viii) of this appendix shall apply to Type T powered
platforms.
(ii) Adjustable shackle rods in subparagraph (c)(20)(vii) of this
appendix shall apply to Type T powered platforms, if the working
platform is suspended by more than two wire ropes.
(6) Electrical wiring and equipment. (i) The requirements of
paragraphs (c)(22) (i) through (vi) of this appendix shall apply to Type
T powered platforms. ``Circuit protection limitation,'' ``powered
platform electrical service system,'' all operating services and control
equipment shall comply with the specifications contained in Part 2,
section 26, ANSI A120.1-1970.
(ii) For electrical protective devices the requirements of
paragraphs (c)(22) (i) through (viii) of this appendix shall apply to
Type T powered platforms. Requirements for the ``circuit potential
limitation'' shall be in accordance with specifications contained in
Part 2, section 26, of ANSI A120.1-1970.
(7) Emergency communications. All the requirements of paragraph
(c)(23) of this appendix shall apply to Type T powered platforms.
[54 FR 31456, July 28, 1989, as amended at 61 FR 9235, Mar. 7, 1996]
[[Page 186]]
Effective Date Note: At 72 FR 7190, Feb. 14, 2007, Appendix D to
Sec. 1910.66 was amended by revising paragraph (c)(22)(i) and in the
second sentence of paragraph (c)(22)(vii), the words ``Article 610 of
the National Electrical Code, NFPA 70-1971; ANSI C1-1971 (Rev. of C1-
1968)'' were revised to read ``Subpart S of this Part.'', effective Aug.
13, 2007. For the convenience of the user, the revised text is set forth
as follows:
Sec. 1910.66 Powered platforms for building maintenance.
* * * * *
Appendix D to Sec. 1910.66--Existing Installations (Mandatory)
* * * * *
(c) * * *
(22) * * * (i) All electrical equipment and wiring shall conform to
the requirements of Subpart S of this Part, except as modified by ANSI
A120.1--1970 ``American National Standard Safety Requirements for
Powered Platforms for Exterior Building Maintenance'' (see Sec.
1910.6). For detail design specifications for electrical equipment, see
Part 2, ANSI A120.1-1970.
* * * * *
