Scaffold and Aerial Lift Safety by KTA
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Scaffold and Aerial Lift Safety by KTA
- 1. Scaffold and Aerial Lift Safety • Stan Liang, CIH, CSP, CET • KTA-Tator, Inc.
- 2. Webinar Objectives Brief overview of the following: OSHA Scaffold Standard Safe work practices for the use of scaffolds, aerial lifts, and scissor lifts Resources for additional information
- 3. Scaffolds/Aerial lifts • Hazards – Falls – Falling objects – Structural instability – Electrocution – Overloading
- 4. Scaffolds 29 CFR 1926 – Subpart L • 1926.450 – Scope, application, and definitions • 1926.451 – General requirements • 1926.452 – Requirements applicable to specific types of scaffolds • 1926.453 – Aerial lifts • 1926.454 – Training requirements
- 5. 29 CFR 1926 – Subpart L Appendices • Appendix A – Scaffold specifications • Appendix B – Fall protection for scaffold erectors and dismantlers • Appendix C – National consensus standards • Appendix D – Training topics for scaffold erectors and dismantlers • Appendix E – Drawings and illustrations
- 6. Competent Person • One who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous or dangerous to employees and has authorization to take prompt corrective measures to eliminate them.
- 7. Qualified Person • One who by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience has successfully demonstrated his or her ability to solve or resolve problems related to the subject matter, work, or the project.
- 8. General Requirements – Support its own weight and 4 times the maximum intended load – Suspension rope and connecting hardware support 6 times the maximum intended load
- 9. General Requirements – Stall load of scaffold hoist not to exceed 3 times the rated load – Designed by a qualified person and loaded according to design
- 10. General Requirements Scaffold Platform Construction • Platforms must be fully decked and planked • Platform must be at least 18 inches wide • Planks must be in good condition
- 11. General Requirements Scaffold Platform Construction • Each abutted end shall rest on a separate support surface • Platforms overlap not less than 12” and only over supports • Platforms that rest on a bearer at an angle other than a right angle must be laid first
- 12. General Requirements Scaffold Platform Construction • The end of the platform must extend at least 6 inches beyond the support; or • Restrained by hooks, cleats or other means
- 13. General Requirements Scaffold Platform Construction • Platforms 10 feet long or less extend no more than 12 inches past the support • Platforms more than 10 feet long extend no more than 18 inches
- 14. General Requirements Scaffold Construction • Scaffold components manufactured by different manufacturers shall not be used together unless: – Components fit together without force – Scaffold's structural integrity is maintained by the user – Competent person determines the resulting scaffold is structurally sound
- 15. General Requirements Scaffolds Construction • Components of dissimilar metals can not be intermixed
- 16. General Requirements Supported Scaffolds • Fully planked • Bear on adequate foundations • Plumbed and braced • Unstable objects not used as work platforms
- 17. General Requirements Suspended Scaffolds • Support devices must support 4 times the imposed load • Direct connection evaluated by a competent person
- 18. General Requirements Suspended Scaffolds • Counterweights made of non-flowable material • Counterweights secured and not removed until scaffold is disassembled • Tiebacks secured to sound anchorage • Single tiebacks installed at an angle prohibited
- 19. General Requirements Suspended Scaffolds • Minimum lengths for suspension ropes on hoists • No repaired wire rope • Ropes inspected by a competent person prior to each shift
- 20. General Requirements Suspended Scaffolds • No gasoline powered equipment or hoist • Automatic brakes on powered and manual hoists • Positive crank force required for descent • Tied to prevent swaying • Safety devices not used as platforms
- 21. Scaffold Access • Access must be provided when platforms are more than 2 feet below or above a point of access • Cross braces can not be used as a point of access
- 22. Scaffold Access • Hook on attachable ladders: – Specifically designed for the type of scaffold – Rest platforms at 35 foot intervals when more than 35 feet high
- 23. Scaffold Use • Do not overload scaffold • Platform can not deflect more than 1/60 of the span when loaded • Inspect scaffolds prior to each shift or after an event which may have damaged the scaffold • Do not move the scaffold when occupied unless designed for such use • Shore or lean-to scaffolds can not be used.
- 25. Scaffold Use • Scaffolds must be erected, moved, and dismantled only under the supervision of a competent person • Erecting, moving, or dismantling scaffolding must be performed by trained employees selected for such work by the competent person
- 26. Scaffold Use • Employees are prohibited from working on scaffolds covered with snow, ice, or slippery materials • Tag lines or equivalent means must be used to prevent swinging loads from contacting the scaffold • Work on scaffolds is prohibited in high winds. • Debris can not accumulate on platforms.
- 29. Power Line Clearances Voltages Minimum Distance Less than 300 volts 3 feet (0.9m) 300 volts to 50kV 10 feet (3.1m) More than 50kV 10 feet (3.1m) plus 0.4 inches for each kV over 50kV
- 30. Power Line Clearances Voltages Minimum Distance Less than 50kV 10 feet (3.1m) More than 50kV 10 feet (3.1m) plus 0.4 inches (1cm) for each 1kV over 50kV
- 31. Power Line Clearance Alternatives • Two times the length of the insulator • Notify utility company in advance and: – De-energize the power lines; – Relocate the lines; or – Install protective covering to prevent accidental contact
- 32. Fall Protection • Fall protection is required when employees are more than 10 feet above a lower level • Fall protection is required for erection or dismantling of scaffolds, if the competent person determines it is feasible
- 33. Fall Protection Methods • Boatswain’s chair, catenary scaffold – personal fall arrest • Single or two point adjustable suspension scaffold – personal fall arrest and a guardrail • All other scaffolds – personal fall arrest or a guardrail
- 34. Fall Protection • Each employee on a walkway within a scaffold must be protected by a guardrail system installed within 9 1/2 inches of and along each walkway
- 35. Personal Fall Arrest Vertical Life Lines • Can not be used if overhead components are part of a single point or two point adjustable scaffold • Attached to an anchorage independent of the scaffold • Protected from sharp edges and abrasion
- 36. Personal Fall Arrest Horizontal Lifelines • Can not be attached only to suspension ropes • Independent anchorages are mandatory on all suspended scaffolds, except for two- point suspension scaffolds
- 37. Additional Requirements for Personal Fall Arrest • If lanyards or lifelines are connected directly to a two-point suspension scaffold, the scaffold must be provided with additional independent support lines • Vertical lifelines, independent support lines and suspension ropes shall not be tied to each other or share common anchorage points
- 38. Fall Protection Guardrails • Guardrails must be installed on all open sides • Guardrails must be installed prior to use • Top rail height must be between 38 inches and 45 inches • Where personal fall arrest is also used, top rail height must be between 36 inches and 45 inches
- 39. Fall Protection Guardrails • Intermediate members must be not more than 19 inches apart • Mid rails, screens, or mesh must be used • Screens or mesh, if used, must extend along the entire opening between supports and from the top rail to the platform
- 40. Fall Protection Guardrails • Top rail must withstand 200 pounds of force (100 pounds for single-point and two-point adjustable suspension scaffolds) • When maximum force is applied, the top rail must not deflect below minimum permissible height • Mid rails, screens, mesh, and intermediate members must withstand a force of 150 pounds (75 pounds for single-point and two-point adjustable suspension scaffolds)
- 41. Fall Protection Guardrails – Cross Bracing • Can be used in place of a mid rail when the crossing point is between 20 inches and 30 inches above the work platform • Can be used instead of a top rail when the crossing point is between 38 inches and 48 inches above the work platform • Upright end points must be more than 48 inches apart
- 42. Falling Object Protection Options • Barricading the work areas below • Install toe board on scaffold platforms • Install canopies or debris nets to protect workers below the platform
- 43. Requirements for Specific Scaffolds • Tube and coupler scaffolds • Mobile scaffolds • Containment platforms • Two-point suspension scaffolds • Singe-point suspension scaffolds • Pik boards
- 44. Tube and Coupler Scaffolds • Designed by a P.E. if over 125 feet • Requirements for couplers and bracing
- 45. Containment Platforms • Containment platforms must comply with 1926. Subpart L.
- 46. Mobile Scaffolds •Must be plumb, level, and squared •Wheels must be able to be locked •Scaffold must be leveled using screw jacks • Caster stems and wheel stems shall be pinned or otherwise secured
- 47. Mobile Scaffolds • Manual force to move the scaffold must be applied no more than 5 feet above the supporting surface • Power systems used to move the scaffolds must be designed for such use
- 48. Mobile Scaffolds • Employees can only ride mobile scaffolds under the following conditions: – Surface is within 3 degrees of level – Height to base width is two to one or less – Outrigger frames, when used, are installed on both sides – Speed does not exceed one foot per second when power systems are used – No employee is on any part of the scaffold that extends outward beyond wheels, casters, or other supports
- 49. Two Point Suspension Scaffolds •Can not be connected together during raising and lowering operations unless the connections are articulated and hoists properly sized •Can not be more than 36 inches wide unless designed by a qualified person to prevent unstable conditions
- 50. Single Point Suspension Scaffolds •Use of a safety hook (hook with a latch), if a boatswain’s chair is used •Supporting rope must be kept vertical
- 51. Pik Boards –Safety ropes or clips on stirrups used to suspend the platform from the cables –Minimum width of the pik boards must be at least 18" - Pik secured to hangers at both ends
- 52. Training • Employees using scaffolds must receive training from a qualified person that covers: – Nature of electrical, fall, and falling object hazards – Use of scaffold – Maximum intended load and load carrying capabilities of the scaffold – Requirements of subpart L
- 53. Training • OSHA has separate training requirements for workers engaged in the following: – Erecting – Disassembling – Moving – Repairing – Maintenance – Inspection
- 54. Training • Employees engaged in activities other than use must receive training from a qualified person that covers: – Nature of electrical, fall, and falling object hazards – Correct procedures – Design criteria, load capacity, and intended use – Requirements of subpart L
- 55. Retraining • Required if an employee lacks the skill or understanding needed for safe work involving scaffolds • Retraining is also required when: – Additional or new hazards exist – Changes occur in the type of scaffold and fall protection – Where there are inadequacies in an employee’s work practices
- 56. OSHA Aerial Lift Requirements Training • Operated only by authorized persons • According to an OSHA letter of interpretation training is required • Training requirements enforced by OSHA would be based on industry standards as defined in ANSI Standard A92.2
- 57. OSHA Aerial Lift Requirements Training • ANSI Standard A92.2 training requirements include: – Instruction in safe operation including the operator’s manual, user’s work instruction, and other applicable ANSI standards – Hands on training must also be included
- 58. OSHA Aerial Lift Requirements Fall Protection • Fall protection must be worn when in the basket • A short lanyard (e.g. 3 to 4 foot lanyard) should be used for restraint • Employees must always stand firmly on the floor of the basket (not the guardrails)
- 59. OSHA Aerial Lift Requirements • Must be provided with upper and lower controls • Lower controls to be operated only in emergencies or with permission of workers in the basket • Test controls daily prior to use
- 60. OSHA Aerial Lift Requirements • Place outriggers on solid surface or pads • Load limits specified by the manufacturer must not be exceeded • Boom must not be elevated when lift is moving
- 61. OSHA Scissor Lift Requirements • Requirements for mobile scaffolds apply • If guard rails are in place, no additional fall protection is required
- 62. Additional Information • www.osha.gov – 29 CFR 1926 Subpart L (Scaffold Standard) – CPL 02-01-023 [CPL 2-1.23] (Compliance Directive) – Scaffolding Construction e-Tool – Letters of interpretation • www.scaffold.org (Scaffold Industry Association) • http://www.ansi.org (American National Standard Institute) – A92 (SIA): Scaffolds and other elevating devices
- 63. Questions
Notas del editor
- This webinar is intended to provide a brief overview of OSHA requirements for the use of scaffolds, aerial lifts, and scissor lifts. For participants interested in additional information, resources available from OSHA and organizations such as the Scaffold Industry Association and the American National Standards Institute will be discussed at the end of this webinar. Attendees of this webinar should be aware that OSHA has specific training requirements for scaffolds, aerial lifts, and scissor lifts which are not addressed in this overview webinar.
- Typical hazards when using scaffolds, aerial lifts, and scissor lifts are falls, falling objects, structural instability (such as an improperly secured scaffold tipping over), electrocution (when workers on the scaffold are exposed to energized power lines), and overloading. Accidents involving scaffolds, aerial lifts, and scissor lifts are a common cause of fatalities on construction sites. Approximately 9% of all construction fatalities involve scaffolds and aerial lifts. Scaffolding related citations are also the top 1 or 2 type of citations OSHA issues in construction annually.
- Subpart L of 29 CFR 1926 addresses OHSA’s requirements for scaffolds. The sections of Subpart L include the following: 1926.450 – Scope, application and definitions 1926.451 – General requirements 1926.452 – Requirements applicable to specific types of scaffolds 1926.453 – Aerial lifts 1926.454 – Training requirements
- Subpart L also contains several appendices which provide non-mandatory guidance, including: Appendix A – Scaffold specifications (such as those for scaffold grade lumber) Appendix B – Fall protection for scaffold erectors and dismantlers Appendix C – National consensus standards Appendix D – Training topics for scaffold erectors and dismantlers Appendix E – Drawings and illustrations (for various types of scaffolds)
- Many of the key requirements of the OSHA Construction Industry Standards including scaffolds must be addressed by a competent person. 29 CFR 1926.32 defines a competent person as one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees and has authorization to take prompt corrective measures to eliminate them. Note that you can have a person on site that is very knowledgeable of scaffolding hazards and controls, but if they are not authorized to immediately mandate corrective action, they can not be considered the Competent Person.
- Other key requirements of the scaffold Standards, such as scaffold design, must be addressed by a qualified person. 29 CFR 1926.32 defines a qualified person as one who by possession of a recognized degree, certificate or professional standing, or by extensive knowledge, training, or experience has successfully demonstrated their ability to solve or resolve problems related to the subject matter, work, or the project. It is up to the employer to determine who has the appropriate qualifications to fulfill this role.
- OSHA’s general requirements applicable to all scaffolds include the following: Scaffold and scaffold components must support their own weight and four times the maximum intended load. Suspension rope and hardware must support six times the maximum intended load.
- The stall load of a scaffold hoist must not exceed three times its rated load Scaffolds must be designed by a qualified person and built and loaded according to that design. For instance, point loading of a scaffold by placing a load in the center of the span of a stage may create loading that exceeds the design criteria.
- Platforms must be fully decked and planked. Platform and walkways must be at least 18 inches wide. Where the use of platforms at least 18 inches wide is not feasible, they must be as wide as possible and workers must be protected from resulting fall hazards by personal fall arrest and/or guardrails if an 18 inch wide walkway is not feasible. Planks must be in good condition. They must not be broken, cracked, warped, or painted. If lumber is used, the plank must be stamped ‘Scaffold Grade.’
- For scaffold platform ends that abut (or the ends touch but are not overlapped), each end shall rest on a separate support surface. For platform ends that overlap, the length of the overlap must be at least 12”. The overlap must be over a support. On direction changes, platforms that rest on a bearer at an angle other than a right angle must be laid first The overlap in this slide is less than 12 inches and is not over the support or bearer, which is not compliant with OSHA. This increases the risk that the platform will slip off.
- The end of the platform must extend at least 6 inches beyond the support; or restrained by hooks, cleats or other means. This picture represents an unsafe practice as neither the OSHA requirement is met in this case and the end of the platform could slip off.
- Platforms 10 feet long or less can extend no more than 12 inches past the support. If the platforms are more than 10 feet long they can extend no more than 18 inches past the support. These limits can be exceeded only if the cantilevered, or portion of the platform that extends beyond the scaffold, can support the weight of employees or materials without tipping or if a guardrail is used to block access to this area of the platform. We can see in this picture that there is an obvious exposure to a fall hazard because the employee is standing on a platform that extends too far from the support.
- Scaffold components manufactured by different manufacturers shall not be used together unless: Components fit together without force; Scaffold's structural integrity is maintained by the user; and The competent person determines the resulting scaffold is structurally sound
- Scaffold components made of dissimilar metals shall not be inter mixed due to galvanic action (or electrical current between dissimilar metals which results in corrosion). Connection of such components is permitted if a competent person has determined that galvanic action will not reduce the strength below OSHA requirements or 4 times the maximum intended load for scaffold components.
- Supported scaffolds, such as ‘system scaffolds’ or tube and coupler type, must bear on adequate foundations, and be plumbed (or kept straight) and braced. Scaffolds are not permitted to stand on unstable objects. The scaffold in this slide is an obvious example of a scaffold on an inadequate foundation.
- OSHA requirements for suspended scaffolds such as two point suspended scaffolds include the following Support devices must support 4 times the imposed load; and Direct connections must be evaluated by the competent person Due to the age of the structural member, this picture represents an example of direct connection location that should be evaluated by the competent person before it is used to support the weight of a scaffold.
- Counterweights must be made of a non-flowable material. Examples of materials which should not be used are sand and gravel. Counterweights must be secured, and can not be removed until the scaffold is disassembled Tiebacks must be secured to a sound anchorage on the building or structure; and Single tiebacks installed at an angle other than 90 degrees are prohibited This picture shows an unsafe practice since the tieback is not at a 90 degree angle to the parapet of the building.
- Minimum lengths are required for suspension ropes on hoists. For winding drum hoists there must be at least four wraps left on the drum at the lowest point of travel; Repaired wire rope is prohibited; and Ropes must be inspected by a competent person prior to each work shift and after every incident which could affect the rope’s integrity
- No gasoline powered equipment and hoists are permitted on suspended scaffolds (due to the hazard of carbon monoxide from engine exhaust); Automatic brakes must be provided on powered and manual hoists; A positive crank force is required to descend for manual hoists. In other words, a manual hoist should not lower unless the crank is turned. The scaffold must be tied to prevent swaying; and Devices whose sole function is to provide emergency escape and rescue are not permitted to be used as platforms.
- Access must be provided when platforms are more than 2 feet below or above a point of access. Access can be provided by: Portable ladders; Hook-on ladders; Stair towers; Stairway-type ladders; Ramps and walkways; and Integral prefabricated scaffold access Use of cross bracing, as seen in this photo is not permitted.
- If hook on or attachable ladders are used they must be: Specifically designed for the type of scaffold; and Provided with rest platforms at 35 foot intervals when more than 35 feet high to prevent workers from getting exhausted before reaching the top. Climber exhaustion can be a cause of falls from ladders.
- General OSHA requirements for scaffold use include the following: Do not overload scaffolds in excess of their maximum intended loads or rated capacities, whichever is less. When designing scaffolds, it is assumed that each occupant will weigh 250 pounds, including any tools or equipment that they are carrying. Platforms can not deflect more than 1/60 of the span when loaded. For example, a 10 foot long platform can not deflect more than 2 inches. Inspect scaffolds prior to each shift, and after any event such as high winds, which may have damaged the scaffold. Scaffolds can not be moved when occupied unless designed for such use by a registered professional engineer. Shore or lean-to scaffolds can not be used. This is a type of scaffold that is supported primarily by leaning against a building or structure.
- Any part of a scaffold damaged or weakened must be immediately repaired, braced, or removed from service until repaired. This picture shows a make shift repair that would not comply with the OSHA standard
- Scaffolds must be erected, moved, and dismantled only under the supervision of a competent person. The competent person must be qualified in scaffold erection, moving, dismantling, or alterations. Erecting, moving, or dismantling scaffolding must be performed by trained employees selected for such work by the competent person.
- Employees are prohibited from working on scaffolds covered with snow, ice, or slippery materials (except as needed to clear such hazards). Tag lines or equivalent means must be used to prevent swinging loads being hoisted onto the platform from damaging the platform. Work on scaffolds is prohibited in high winds. The competent person determines when wind conditions make scaffold use unsafe. OSHA does not have a specific wind speed limit. Debris can not be allowed to accumulate on the platform and create a slip or trip hazard.
- Makeshift devices, as seen in this picture, can not be used to increase the working level height.
- Ladders can not be used to increase working level height unless the following requirements are met: Scaffolds secured to prevent movement Ladders secured to prevent movement Both ladder legs must be on the same platform or other means provided to stabilize the ladder against unequal platform deflection. For example, if each set of legs of a step ladder are on separate platforms, use of the step ladder could cause one of the platforms to move resulting in a fall hazard.
- A common cause of scaffold accidents is the accidental contact of workers with overhead power lines. This slide shows minimum clearances for insulated power lines.
- This slide shows minimum clearances for un-insulated power lines. Most power lines are un-insulated.
- OSHA permits the following alternatives for minimum clearances: The clearance can be two times the length of the insulator. However the distance can never be less than 10 feet. The clearance can also be reduced if the utility company is notified in advance and they take one of the following actions: - De-energize the power lines; - Relocate the power lines; or - Install protective coverings to prevent accidental contact.
- Fall protection is required when employees on a scaffold are more than 10 feet above a lower level. Note that this rule is specifically for scaffolds on construction sites. In other cases on construction work places, the OSHA enforces a six foot threshold. For work places regulated under OSHA General Industry Standards there is 4 foot threshold for fall protection (when on a walk way). Fall protection is required for erection and dismantling of the scaffold, if the competent person determines that it is feasible and does not create a greater hazard.
- The scaffold standard mandates the use of certain types of fall protection methods for specific scaffolds. Methods mandated for some common types of scaffolds are: Boatswain’s chairs and catenary scaffolds (which includes pik boards) – personal fall arrest system (such as a full-body harness and shock absorbing lanyard to an approved anchorage); Single or two point adjustable suspension scaffolds – personal fall arrest and a guardrail; and For scaffolds which are not specifically addressed (such as tube and coupler scaffolds), personal fall arrest or a guardrail can be used.
- Each employee on a walkway within a scaffold must be protected by a guardrail system installed within 9 1/2 inches of and along each walkway. It is obvious in this picture that this employee on a walkway is not provided with the fall protection required by OSHA.
- Where vertical lifelines are used in conjunction with scaffolds, OSHA places the following restrictions: Vertical lifelines can not be used if overhead components (such as overhead protection or additional platform levels) are part of a single point or two point adjustable scaffold; They must be attached to an anchorage that is independent of the scaffold; and They must be protected from sharp edges and abrasion
- OSHA requirements for horizontal lifelines are as follows: Can not be attached only to suspension ropes; Independent anchorages are mandatory for all types of suspended scaffolds except for two-point suspension scaffolds. This exception will be discussed further.
- If lanyards or lifelines are connected directly to a two-point suspension scaffold, the scaffold must be provided with additional independent support lines (such as providing a second set of suspension ropes with separate anchor points). Vertical lifelines, independent support lines, and suspension ropes shall not be tied to each other or share common anchorage points. These requirements ensure that failure of scaffolding will not affect the personal fall arrest system. Many fatalities have occurred when workers were tied off directly to the scaffold or its suspension ropes when the scaffold failed.
- Guardrails, where used, must be installed on all open sides. Guardrails must be installed prior to use (except for erection or dismantling crews). The top rail height must be between 38 inches and 45 inches. Where personal fall arrest is also used (such as two-point suspension scaffolds), the top rail height must be between 36 inches and 45 inches.
- Intermediate members of guardrails (or vertical supports) must be not more than 19 inches apart. Mid rails, screens, or mesh must be used. Screens or mesh, if used, must extend along the entire opening between supports and from the top rail to the platform.
- The top rail must be able to withstand a 200 pound force applied in a horizontal or downward direction. Top rails for single-point and two-point adjustable scaffolds must be able to withstand a force of 100 pounds. When the maximum force is applied to the top rail, it must not deflect below 38 inches (36 inches if personal fall arrest is used). Mid rails, screens, mesh, and intermediate members must withstand a force of 150 pounds applied downward or horizontally. For single-point and two-point suspension scaffolds, a 75 pound force must be withstood.
- Cross bracing on tube and coupler scaffolds can be used in lieu of top or mid rails under the following conditions: Used in place of a mid rail if the cross bracing is between 20 inches and 30 inches above the work platform Used in place of a top rail if the cross bracing is between 38 and 48 inches above the work platform Upright end points must be more than 48 inches apart
- Many injuries and fatalities occur when objects fall from scaffolds and strike workers below. The following options are available to employers to protect workers from objects falling off scaffolds: The work areas below can be barricaded and employees not permitted to enter the work area. Toe boards can be installed on scaffold platforms. If materials are piled higher than the toe board, paneling must extend from the toe board to the top rail. Toe boards must be at least 3 1/2 inches high and able to withstand a force of 50 pounds (in a downward or horizontal direction). Canopies over walk ways or debris nets can be installed to protect workers below.
- OSHA has additional regulations that apply to specific types of scaffolding. Our discussion will focus on the more common types of scaffolds including ‘system’ or tube and coupler scaffolds, mobile scaffolds, containment platforms, two-point suspension scaffolds, single-point suspension scaffolds, and pik boards.
- OSHA has specific requirements for construction of tube and coupler scaffolds such as: Design by a Registered Professional Engineer if the height exceeds 125 feet; and Various requirements for scaffold bracing and couplers, Manufactured ‘system scaffolds’ like Safeway or Harsco ‘Quick Erect Scaffolds’ are replacing much of the more labor-intensive tube and coupler scaffolds. These vendors usually provide the Qualified Person to design the job-specific scaffold.
- According to OSHA letters of interpretation dated August 6, 2002 and April 21, 2004 OSHA regulates temporary containment platforms under 29 CFR 1926 Subpart L.
- OSHA also has specific requirements for mobile scaffolds including the following: • Must be plumb (or straight), level, and squared; • Wheels must be able to be locked to prevent movement when unit is stationary; • The scaffold must be leveled using screw jacks; and • Caster stems and wheel stems shall be pinned or otherwise secured in the scaffold legs.
- If manual force is used to move the scaffold, it should be applied as close to the supporting surface as possible but no more than 5 feet above. Power systems used to move scaffolds must be designed for such use. Forklifts, trucks, or similar motor vehicles can not be used unless the scaffold is designed for that type of propulsion.
- Employees can only ride mobile scaffolds under the following conditions: –Surface is within 3 degrees of level; –The ratio of the height of the scaffold to the base width of the scaffold is two to one or less; –Outrigger frames, when used, are installed on both sides; –Speed does not exceed one foot per second, when power systems are used; and –No employee is on any part of the scaffold that extends outward beyond wheels, casters, or other supports. These requirements (such as making sure that the scaffold is not too high relative to the width of the base) are intended to ensure scaffold stability to minimize the risk of tip over during movement.
- Another common type of scaffold is a two-point adjustable suspension scaffold. Some additional requirements for this type of suspended scaffold include the following: Two-point suspension scaffolds can not be connected together during raising and lowering operations unless the connections are articulated and hoists properly sized. Platforms can not be more than 36 inches wide (unless designed by a qualified person to prevent unstable conditions).
- Another common type of scaffold is the single point suspension scaffold such as boatswain’s chairs and spider baskets. Key requirements specific to this type of scaffold include: Use of a safety hook (such as a hook with a latch), if a boatswain’s chair is used; and Keeping the supporting rope vertical.
- Pik boards are the most common type of scaffold on bridge painting projects. They are classified by OSHA as catenary scaffolds. Key requirements include: Safety ropes or clips on stirrups (or hooks) used to suspend the platform from the cables. In other words, if the hooks used to suspend the platform from the cable are open, the platform hook can bounce off of the cable; Minimum width of the pik boards must be at least 18“; and The platform should also be secured to the hangars at both ends. This is to prevent the pik board from slipping off. We can see in this photo that personal fall arrest equipment is not being used as required for this type of scaffold.
- OSHA requires that employees using scaffolds must receive training from a qualified person. This training must cover: Nature of electrical, fall, and falling object hazards; Procedures for use of scaffold and handling of materials on the scaffold; Maximum intended load and load carrying capabilities of scaffold; and Requirements of subpart L
- OSHA has separate training requirements for workers engaged in the following: Erecting Disassembling Moving Repairing Maintaining Inspecting
- Employees engaged in these activities must receive training from a qualified person that covers: Nature of electrical, fall, and falling object hazards; Correct procedures for the designated task, like scaffold erection; Design criteria, load capacity, and intended use; and Requirements of subpart L
- Retraining is required if an employee lacks the skill or understanding needed for safe work involving scaffolds. Retraining is performed until proficiency is established. Retraining is also required when: Additional or new hazards exists; Changes occur in the type of scaffold and fall protection; and Where there are inadequacies in an employee’s work
- According to an OSHA letter of interpretation (dated October 23, 1992), persons authorized to operate aerial lifts must be trained. However, the OSHA standards do not provide specific guidance on what constitutes ‘OSHA compliant’ training. According to this letter of interpretation, training requirements enforced by OSHA would be based on industry standards of practice as defined in ANSI Standard A92.2
- The training requirements of the ANSI Standard A92.2 include the following: Instruction in safe operation including the operator’s manual, user’s work instructions, and other applicable ANSI standards. For example, if using a snooper truck to inspect a bridge, requirements of ANSI A92.8 (Vehicle Mounted Bridge Inspection and Maintenance Devices) would have to be addressed in the training. Hands on training must also be included. This training should be sufficient to demonstrate the trainee’s proficiency to safely operate the equipment.
- Fall protection requirements for aerial lifts include the following: Fall protection must be worn and attached to an anchorage on the boom or basket. A letter of interpretation dated August 18, 1995 indicates that the purpose of fall protection is protect employees from being bounced out of the basket or from climbing out of the basket. A short lanyard (for example, 3 to 4 feet in length) should be used. Employees must always stand firmly on the floor of the basket (not the guardrails as seen in this picture).
- OSHA requirements for aerial lift controls include the following: Aerial lifts must be provided with upper and lower controls. Lower controls are only to be used in an emergency or when personnel in the basket give their permission. Controls must be tested daily prior to use.
- Other OSHA requirements for operation of aerial lifts include the following: Outriggers must be placed on a solid surface or pads; Manufacturer load limits must not be exceeded. Load capacity includes total combined weight of personnel, tools, and accessories; and The boom must not be elevated when lift is moving unless equipment is designed for this type of operation.
- According to an OSHA letter of interpretation, dated February 3, 2000, scissor lifts are regulated as mobile scaffolds. As long as guard rails are in place or employees do not stand on guardrails or ladders and makeshift devices, no additional fall protection is required.
- This presentation only provides a brief overview of what is required for OSHA compliance when using scaffolds, aerial lifts, and scissor lifts. The following additional resources are available for free on www. osha.gov: 29 CFR 1926 Subpart L (Scaffolds) CPL 02-01-023 (Scaffold Compliance Directive) which provides additional information on OSHA’s interpretation of and enforcement procedures for scaffold standard requirements; Scaffolding Construction e-Tool which provides an overview and explanation of OSHA scaffold standards (as well as links to specific requirements of the scaffold standard) and Various letters of interpretation which provide additional information on how OSHA standards apply. Additional information on safe use practices can be found on the Scaffold Industry Association and the American National Standards Institute websites. The Scaffold Industry Association website has various publications available for sale and for free as well as information on scaffold training courses. The ANSI A92 scaffold standards are available for purchase from the ANSI website. As discussed previously in this webinar, OSHA requires that aerial lifts must be in compliance with the applicable A92 standard.