Powered platforms maintenance

Yes — 1910.66(a) covers permanent powered platform installations dedicated to interior or exterior building maintenance of a specific structure or group of structures. The rule does not cover temporary suspended (swinging) scaffolds used for short-term building service or suspended scaffolds used for construction, which are covered under 29 CFR 1910 Subpart D and 29 CFR 1926 Subpart L.

New installations and major modifications completed after July 23, 1990, are treated as "new installations" and must meet the full requirements in 1910.66. See the application for new installations at 1910.66(b)(1).

Existing permanent installations completed before July 23, 1990, must comply with paragraphs (g), (h), (i), (j), and appendix C to subpart I, while those completed after August 27, 1971 and before July 23, 1990 must also comply with Appendix D of 1910.66. See the existing installations rules at 1910.66(b)(2).

Building owners must give a written statement that the installation meets the requirements of paragraphs (e)(1) and (f)(1) and any additional design criteria relating to load capacities, stability factors, maximum horizontal forces, design of hoists/wire rope/stabilization systems, and electrical wiring and equipment. Employers cannot allow use until they receive that written assurance; see 1910.66(c)(1).

The building owner's assurance must be based on the results of a field test of the installation and any other relevant information such as test data, equipment specifications, and verification by a registered professional engineer. See the field-test and verification requirement at 1910.66(c)(2).

Building owners must inform the employer in writing that the installation has been inspected, tested, and maintained in compliance with paragraphs (g) and (h), and that all anchorages meet the requirements of 1910.140(c)(13) — see 1910.140(c)(13) for the anchorage criteria.

No — the employer must not permit employees to use the installation before receiving the written assurance from the building owner that the installation meets the requirements in 1910.66(c)(1) and (c)(3). See the explicit prohibition at 1910.66(c)(4).

A registered professional engineer experienced in such designs must design the structural supports, tie-downs, tie-in guides, anchoring devices, and any affected parts of the building that are part of the installation. This requirement is stated in 1910.66(e)(1)(i).

It means exterior powered platform installations must be designed and installed so they remain safe and functional under local weather conditions (wind, snow, ice, etc.) expected at that site. The standard requires this capability in 1910.66(e)(1)(ii).

The building installation must provide safe access to and egress from the powered-platform equipment and enough space to carry out required maintenance safely. See the access and maintenance-space requirement at 1910.66(e)(1)(iii).

The affected parts of the building must be capable of sustaining all loads the equipment imposes, and platforms must have a stated rated load (the weight of workers, tools, and materials permitted) identified on the load rating plate. See 1910.66(e)(1)(iv) and the definitions of "platform rated load" in 1910.66(d).

Yes — the affected parts of the building must be designed so that the equipment can be used without exposing employees to hazardous conditions. This obligation is in 1910.66(e)(1)(v).

Tie-in guides are required on the exterior of each building unless one of the exceptions in 1910.66(e)(2)(ii) or (iii) applies. See the tie-in guide requirement at 1910.66(e)(2)(i).

Tie-in guides may be omitted for up to the uppermost 75 feet of the building if angulated roping is used and an angulation force of at least 10 pounds is maintained under all loading conditions. See the angulated-rope exception and force requirement at 1910.66(e)(2)(ii).

An intermittent stabilization system used in place of continuous tie-in guides must keep the equipment in continuous contact with the building façade, prevent sudden horizontal movement of the platform, and must meet the specific requirements for such systems in 1910.66(e)(2)(iii)(A).

A field test must be conducted before placing a new installation into service and after any major alteration to an existing installation, per the requirement referenced in 1910.66(c)(2) and the testing/inspection provisions in 1910.66(g)(1).

Design criteria for hoisting and supporting equipment, stabilization systems, and electrical wiring/equipment must be met as described in paragraph (f)(1) and by the building-owner assurances required in 1910.66(c)(1) and 1910.66(f)(1). A registered professional engineer typically documents and verifies compliance with these criteria.

A "competent person" is someone who, because of training and experience, can identify hazardous or dangerous conditions in powered platform installations and can train employees to identify those conditions. That definition appears in 1910.66(d).

It means that anchorages used for the powered-platform installation must meet the strength and design criteria required for personal fall arrest systems in 1910.140(c)(13), and the building owner must confirm that in writing as part of the assurance required by 1910.66(c)(3).

Appendix D applies to permanent installations that were completed after August 27, 1971 and before July 23, 1990, in addition to the other retroactive compliance provisions; see 1910.66(b)(2)(ii) and 1910.66appendixD.

The building owner is responsible for inspecting, testing, and maintaining installations in compliance with paragraphs (g) and (h), and must provide the employer a written statement confirming that work and anchorage compliance before employees use the system. Employers must not allow employees to use the equipment until they receive that written assurance under 1910.66(c)(2)–(4).

"Continuous pressure" means a control that only operates while the operator maintains constant manual actuation (the control must be continuously pressed or held to function). This definition is found in 1910.66(d).

Yes — platforms must have a stated rated load (the maximum combined weight of workers, tools, and materials permitted) and the affected building parts must be able to sustain the imposed loads; this is referenced in the design and load requirements at 1910.66(e)(1)(iv) and the definition of "platform rated load" in 1910.66(d).

Yes — if there is potential for head injury from falling objects while using powered platforms, employers must require protective helmets that meet applicable consensus standards. The platform design requirement to prevent exposing employees to hazardous conditions is in 1910.66(e)(1)(v), and OSHA's interpretation on head protection for crane/hoist operations explains that helmets are required where there is a potential for falling-object hazards (see the head-protection letter at https://www.osha.gov/laws-regs/standardinterpretations/2024-06-06-2).

After any major alteration, the installation must undergo the required field test and any inspections or tests specified in paragraphs (g) and (h), the building owner must base assurances on that testing and provide written confirmation, and the employer must receive that written assurance before allowing employee use; see 1910.66(c)(2)–(4).

The maximum vertical interval between building anchors is three floors or 50 feet (15.3 m), whichever is less. This requirement is in 1910.66(e)(2)(iii)(A)(1).

• Make sure anchor spacing on tall facades follows this limit so stabilizer ties can be attached at each required interval.

Building anchors must be located vertically so that attaching the stabilizer ties will not cause the platform suspension ropes to angulate the platform horizontally across the building face, and they must be positioned horizontally so they are symmetrical about the platform suspension ropes. See 1910.66(e)(2)(iii)(A)(2).

• In practice, this means anchor placement should mirror the suspension rope layout and avoid offsets that would tilt the platform.

Yes—building anchors must be easily visible to employees and must allow a stabilizer tie attachment for each of the platform suspension ropes at each vertical interval; if a platform uses more than two suspension ropes, only the two building-side suspension ropes at the platform ends need stabilizer attachments. See 1910.66(e)(2)(iii)(A)(3).

• Make anchors visible (painted, labeled, or otherwise obvious) and provide tie points on the building side ropes as required.

No—external building anchors that extend beyond the face of the building must be free of sharp edges or points, and where cables, suspension wire ropes, and lifelines may contact the building face, external anchors must not interfere with their handling or operation. See 1910.66(e)(2)(iii)(A)(4).

• Inspect anchor hardware for burrs or protrusions and ensure clear rope paths to prevent chafing or snags.

Anchors and components of an intermittent stabilization system must be capable of sustaining without failure at least four times the maximum anticipated load applied or transmitted to those components and anchors. See 1910.66(e)(2)(iii)(A)(5).

• Use engineering calculations to determine the maximum anticipated load and select anchors/components rated to at least 4× that load.

Each building anchor must meet the applicable wind-load resistance requirements; when two anchors share wind load, each anchor must have a minimum design wind load capacity of 300 pounds (1334 N). If anchor spacing differs from the suspension rope spacing or the building requires different suspension spacings on one platform, then at least one building anchor and stabilizer tie must be capable of sustaining the specified wind loads. See 1910.66(e)(2)(iii)(A)(6).

• Confirm anchor wind-load capacity with the design engineer, and where spacing discrepancies exist, ensure a single anchor can handle the wind load as required.

Guide-button systems must be coordinated with the platform-mounted guide equipment, placed horizontally and vertically so guide tracks on the platform properly engage the buttons, have two guide buttons engaging each guide track at all times except at initial engagement, be free of sharp edges where they extend beyond the building face, and have buttons, connections and seals capable of sustaining at least the weight of the platform (or have track features to prevent weight transfer), with a minimum design load of 300 pounds per building anchor. See 1910.66(e)(2)(iii)(B) and 1910.66(e)(2)(iii)(B)(6).

• Verify button placement and strength during design and testing so guide tracks remain engaged and do not transmit platform weight to undersized buttons.

A system using angulated roping and building-face rollers is acceptable only where the suspended portion of the equipment does not exceed 130 feet (39.6 m) above a safe surface or ground level, and where the platform maintains at least a 10-pound (44.4 N) angulation force on the building facade. See 1910.66(e)(2)(iii)(C).

• If your installation exceeds 130 feet or cannot maintain the 10-pound angulation, select a different stabilization system.

Yes—tie-in guides for building interiors may be eliminated if a registered professional engineer determines that an alternative stabilization system (including the systems in 1910.66(e)(2)(iii) or platform tie-off at each workstation) will provide equivalent safety. See 1910.66(e)(2)(iv).

• Keep the engineer's justification on file and implement the alternative exactly as specified by the engineer.

Employees working on roofs while performing building maintenance must be protected by a perimeter guarding system that meets the requirements of 1910.23(c)(1). See 1910.66(e)(3)(i).

• The perimeter guard must be placed no more than 6 inches inboard of the inside face of a parapet or roof curb and not more than an 18-inch setback from the exterior building face, per 1910.66(e)(3)(ii).
• For practical guidance about when roof fall protection is required for low-slope roofs, see OSHA's interpretation on fall protection on low slope roofs (June 6, 2024) at https://www.osha.gov/laws-regs/standardinterpretations/2024-06-06-1.

Operational areas for trackless-type equipment must have structural stops (such as curbs) to prevent equipment from traveling outside intended areas and to prevent crushing or shearing hazards, and means must be provided to traverse all carriages and their suspended equipment to a safe area for maintenance and storage. See 1910.66(e)(4) and 1910.66(e)(5).

• Provide physical curbs/stops and clear, safe access routes for maintenance personnel to reach carriages and equipment.

If an elevated track system is located four feet (1.2 m) or more above a safe surface and traversed by carriage-supported equipment, it must either be provided with a walkway and guardrail system or the working platform must be capable of being lowered as part of normal operation to the lower safe surface and have a safe means of access/egress. See 1910.66(e)(6)(i)–(ii).

• Choose the option that best fits the installation and ensure guardrails or lowering mechanisms meet the standard's safety requirements.

Tie-down anchors, fasteners, and the structures they affect must be resistant to corrosion. See 1910.66(e)(7).

• Use corrosion-resistant materials or protective coatings and include corrosion checks in inspection/maintenance programs.

Hanging lifelines and all cables not in tension must be stabilized at each 200-foot (61 m) interval of vertical travel beyond an initial 200-foot distance. Hanging cables that are in constant tension must be stabilized when vertical travel exceeds an initial 600-foot (183 m) distance and at further intervals of 600 feet (183 m) or less. See 1910.66(e)(8)(i)–(ii).

• Plan stabilization points during design and verify them during installation to limit uncontrolled cable movement.

You must develop and implement a written emergency action plan for each kind of working-platform operation that explains emergency procedures for power failures, equipment failures, and other emergencies (including building escape routes and alarms), and employers must review with each employee the parts of the plan they must know upon initial assignment and whenever the plan changes. See 1910.66(e)(9) and 1910.66(e)(10).

• Train and document employee briefings on the plan at hiring and when procedures change.

Building electrical installations for working platforms must comply with 1910.302–1910.308 unless otherwise specified; the wiring must be sized so voltage drop under full load is no more than 5% at any power outlet used by the equipment; the equipment power circuit must be independent (except for hand-tool circuits used with the equipment) and may be on the emergency system; a lockable disconnect switch must be provided and located conveniently for the equipment operator; the disconnect must be locked ON when equipment is in use; and an effective two-way voice communication system must be provided between operators and persons stationed in the building. See 1910.66(e)(11) and its subparts such as 1910.66(e)(11)(i) through 1910.66(e)(11)(vi).

• Confirm a qualified electrician designs the circuit to meet voltage-drop and isolation requirements and install the required locked disconnect and communications system.

Equipment installations must be designed by or under the direction of a registered professional engineer experienced in such design; the design must provide a minimum live load of 250 pounds (113.6 kg) for each occupant of a suspended or supported platform; equipment exposed to wind when not in service must withstand winds of at least 100 miles per hour at 30 feet above grade; and equipment exposed to wind in service must withstand winds of at least 50 miles per hour for all elevations. See 1910.66(f)(1)(i)–(iv).

• Work with a registered professional engineer to document live-load and wind-resistance calculations in the design record.

Bolted connections must be self-locking or otherwise secured to prevent loss of the connections by vibration. See 1910.66(f)(2).

• Use locking nuts, safety wire, thread-lock compounds, or other positive-retention methods, and inspect them regularly.

Carriages used to suspend elevated building maintenance equipment must control horizontal movement to ensure safe movement and accurate positioning, powered carriages must not exceed a traversing speed of 50 feet per minute, manually initiated traversing on a smooth level surface must not require more than 40 pounds of horizontal force, structural stops/curbs must prevent carriage travel beyond designed limits, traversing controls for powered carriages must be continuous-pressure and arranged so only one control station operates at a time, an emergency stop device must be provided on each end of a powered carriage, and traversing of a carriage is not possible unless the suspended portion is at its uppermost designed position and free of contact with the building. See 1910.66(f)(3)(i) and related subparagraphs.

• Ensure carriage controls, emergency stops, and interlocks are tested regularly and that operators understand the control logic.

Underfoot-supported carriages must have a stability factor against overturning of not less than two for horizontal traversing (including impact and wind effects), and the carriages and their anchorages must be capable of resisting accidental over-tensioning of the wire ropes suspending the working platform; this calculated value must include the effect of one and one-half times the stall capacity of the hoist motor. See 1910.66(f)(3)(i)(G)(1)–(2).

• Validate stability and anchor strength with the design engineer and include worst-case scenario forces (wind, impact, over-tension) in calculations.

If employees are in areas where there is potential for head injury from falling objects—such as when a crane or hoist lifts loads in the vicinity—head protection is required under 29 CFR 1910.135(a)(1). OSHA's letter of interpretation clarifying that crane operators and nearby workers need head protection when exposed to overhead falling hazards is available at https://www.osha.gov/laws-regs/standardinterpretations/2024-06-06-2.

• Perform a hazard assessment and require ANSI Z89.1-compliant helmets where overhead hazards exist.

You must prevent vertical movement of a roof carriage unless its tie-down to the building is engaged when the carriage relies on the tie-down for stability. The standard requires that "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" (see 1910.66(f)(3)(i)(G)(3)). Practical steps to comply:

• Verify whether a carriage’s stability depends on a tied-down anchor. If it does, install an interlock that physically or electrically prevents hoist-up or hoist-down commands until the tie-down is engaged.
• Test the interlock regularly and document tests so you can show the device is working as required.
• Combine this requirement with other stability controls (for example, tie-down strength and anchorage design) required elsewhere in 1910.66 to ensure overall overturn protection.

Working platforms must have a top guardrail, midrail, and toeboard sized and tested to resist specified loads. The rule states that "Each working platform of a suspended unit shall be provided with a guardrail system on all sides" consisting of a top guardrail, midrail, and toeboard, with numeric strength and dimension requirements in 1910.66(f)(5)(i)(G). Key requirements to follow:

• Top guardrail: minimum 36 inches (914 mm) high and able to withstand at least a 100-pound (444 N) downward or outward force (1910.66(f)(5)(i)(G)(2)).
• Midrail: must withstand at least a 75-pound (333 N) downward or outward force (1910.66(f)(5)(i)(G)(3)).
• Panel/closure areas: areas between guardrail and toeboard and between midrail and toeboard must resist a 100-pound horizontal load applied over any 1 sq. ft. area (1910.66(f)(5)(i)(G)(4)).
• Toeboard: must resist a 50-pound force and be at least 3.5 inches high from top edge to platform floor, be securely fastened at the platform edge with no more than 1/2 inch clearance, and be solid or have openings no larger than 1 inch (1910.66(f)(5)(i)(G)(5), 1910.66(f)(5)(i)(G)(6), 1910.66(f)(5)(i)(G)(7), 1910.66(f)(5)(i)(G)(8)).

Follow these dimensional and strength specs exactly or use an equivalent method that provides the same level of protection; document inspections and repairs of guardrail and toeboard components as part of your platform maintenance program.

A hoisting machine must have a primary brake directly on the drive train that auto-sets on power interruption, plus at least one independent secondary (emergency) brake that will stop and hold the load if the primary fails. The rule requires each hoisting machine to be provided with a primary brake and at least one independent secondary brake, each capable of stopping and holding not less than 125 percent of the lifting capacity of the hoist, and further specifies that the primary brake be directly connected to the drive train and automatically set when power to the prime mover is interrupted (1910.66(f)(4)(ix), 1910.66(f)(4)(ix)(A)). Additionally, the secondary brake must be an automatic emergency type that does not engage before the hoist is stopped by the primary brake and, when actuated, must stop and hold the platform within 24 inches (609.6 mm) vertically (1910.66(f)(4)(ix)(B), 1910.66(f)(4)(ix)(B)(2)). Practical compliance tips:

• Specify brakes rated to at least 125% of hoist capacity and verify installation so the primary brake is directly coupled to the drive train (no belts, chains, clutches, or set-screws in the primary connection).
• Test both brakes under load and record the stopping distance for the secondary brake to confirm it holds within 24 inches.
• Ensure the primary brake will automatically set on power loss by inspection and by functional testing following manufacturer and company procedures.

Transportable outriggers must be secured to a verified building anchorage designed with a stability factor of at least four and be engineered for lateral and ultimate loads as specified. The standard says each transportable outrigger "shall be secured with a tie-down to a verified anchorage on the building during the entire period of its use" and that the anchorage be designed to have a stability factor of not less than four against overturning or upsetting (1910.66(f)(3)(ii)(C)). It also requires lateral stability to resist an accidental lateral load of not less than 70 percent of the hoist’s rated load (1910.66(f)(3)(ii)(E)) and that each outrigger be designed to support an ultimate load of not less than four times the rated load of the hoist (1910.66(f)(3)(ii)(F)). Practical actions:

• Use a qualified engineer to verify anchorage capacity and document the anchorage design showing the factor-of-four stability against overturning.
• Ensure tie-back ropes are equivalent in strength to suspension ropes and are installed parallel to the outrigger centerline as required by 1910.66(f)(3)(ii)(H) and 1910.66(f)(3)(ii)(I).
• Keep records of anchorage verification, outrigger load ratings, and periodic inspections as part of your suspended-platform safety program.