Skip Navigation

Course 813 - Construction Worksite Safety

1    2    3    4    5    6    7    8    9    10    11    Course Homepage     Final Exam      Contact Instructor     Website Homepage
Safety guides and audits to make your job as a safety professional easier

Scaffolds and Aerial Lifts

Introduction

scaffold

When scaffolds and aerial lifts are not erected or used properly, fall hazards can occur. About 2.3 million construction workers frequently work on scaffolds. Protecting workers from scaffold-related accidents would prevent an estimated 4,500 injuries and 50 fatalities each year.

Unsafe scaffolding procedures can cause accidents, serious injuries and even death. Accidents involving scaffolding mainly involve:

  • workers falling
  • incorrect operating procedures
  • environmental conditions
  • falling materials

Training and Retraining

Training in scaffold safety should be provided for both supported and suspended scaffolding in addition to general requirements for capacity and platform construction, safe access, fall protection, falling object protection, safe use, and training.

Workers should be retrained if any of the following conditions occur:

  • An accident occurs during scaffold or aerial lift use.
  • Workplace hazards involving scaffolds or aerial lifts are discovered.
  • A different type of scaffold or aerial lift is used.

Employers are also required to retrain workers who they observe working improperly on scaffolds or operating aerial lifts.

Supported Scaffolds

exposure
Supported Scaffolds
(Click to Enlarge)

Supported scaffolds: Consist of one or more platforms supported by outrigger beams, brackets, poles, legs, uprights, posts, frames, or similar rigid support.

Frame Scaffold or Fabricated Frame: Platform(s) supported on fabricated end frames with integral posts, horizontal bearers, and intermediate members.

Manually Propelled/Mobile: Unpowered, portable, caster- or wheel-mounted supported scaffold.

Pump Jack: Platform supported by vertical poles and movable support brackets.

Ladder Jack: Platform resting on brackets attached to ladders.

Check out this OSHA video describing the hazards of working on supported scaffolds.
(Click to play video)

Tube and Coupler: Platform(s) supported by tubing, erected with coupling devices connecting uprights, braces, bearers, and runners.

Pole: Posts with fixed connection points that accept runners, bearers, and diagonals, also made of wood, that can be interconnected at predetermined levels.

Specialty: Scaffold types designed for a narrow and very specific range of applications. Includes plasterers', decorators', and other large-area scaffolds; bricklayers' square scaffolds; horse scaffolds; outrigger scaffolds; step, platform, and trestle ladder scaffolds; form and carpenter's bracket scaffolds; window jack scaffolds; crawling boards and chicken ladders; and roof bracket scaffolds.

Suspension Scaffolds

Suspended scaffolds are platforms suspended by ropes, or other non-rigid means, from an overhead structure.

Two-point (swing stage): Platform supported by hangers (stirrups) suspended by two ropes from overhead supports and equipped with a means to permit the platform to be raised and lowered.

Single-point Adjustable: Platform suspended by one rope from an overhead support and equipped with a means to permit the platform to be moved to desired working levels.

Catenary: Platform supported by two essentially horizontal and parallel ropes attached to structural members of a building. Additional vertical pickups may also provide support.

Multi-point Adjustable: Platform(s) suspended by more than two ropes from overhead supports and equipped with a means to permit the platform to be raised and lowered. Includes chimney hoists.

Interior Hung: Platform suspended from the ceiling or roof structure by fixed-length supports.

Needle Beam: A platform suspended from needle beams.

Multi-level: Two-point or multi-point adjustable suspension scaffold with a series of platforms at various levels resting on common stirrups.

Float (ship): Braced platform resting on two parallel bearers and hung from overhead supports by ropes of fixed length.

Recommended Precautions: Supported and Suspended Scaffolds

scaffold
Scaffolds can only be erected, moved, dismantled or altered under the supervision of a competent person.

Recommended precautions to take while working with scaffolds include:

  • Make sure employees are instructed about the hazards of using diagonal braces as fall protection. Scaffolds should be accessed by using ladders and stairwells. Crossbracing should not be used.
  • Make sure scaffolds are sound, rigid and sufficient to carry its own weight plus four times the maximum intended load without settling or displacement.
  • Ensure scaffolds are erected on solid footing.
  • Do not support scaffolds or planks with unstable objects, such as barrels, boxes, loose bricks or concrete blocks. Ladders, boxes, barrels, buckets or other makeshift platforms should not be used to raise work height. Extra material should not be used to build up on scaffold platforms.
  • Ensure scaffolds are erected, moved, dismantled or altered under the supervision of a competent person.
  • scaffold
    Click to Enlarge
  • Never use scaffold accessories such as braces, brackets, trusses, screw legs or ladders that are damaged or weakened from any cause. Make sure they are immediately repaired or replaced.
  • Tightly plank scaffold platforms with scaffold plank grade material or equivalent. All scaffolds should be fully planked.
  • Make sure a competent person inspects the scaffolding and, at designated intervals, repeat the inspection.
  • Ensure a competent person inspects rigging on suspension scaffolds before each shift and after any occurrence that could affect structural integrity to ensure that all connections are tight and that no damage to the rigging has occurred since its last use.
  • Check that synthetic and natural rope used in suspension scaffolding is protected from heat-producing sources.
  • Always check to make sure scaffolds are at least 10 feet from electric power lines at all times. Equip scaffolds with guardrails, midrails and toeboards, as required.
  • Ensure damaged parts that affect the strength of the scaffold are taken out of service. Make sure scaffolds are not moved horizontally while workers are on them unless they are designed to be mobile and workers have been trained in the proper procedures.
  • Do not allow employees to work on scaffolds when covered with snow, ice, or other slippery materials. Employees are not permitted to work on scaffolds in bad weather or high winds unless a competent person has determined it is safe to do so.
  • Scaffolds should not be loaded with more weight than they were designed to support.

For a complete course on scaffold safety, take OSHAcademy Course 803, Scaffold Safety Program Management and Course 804, Safe Scaffold Erection and Inspection.

You may also want to visit OSHA’s Safety and Health Topics: Scaffolding web page.

Aerial Lifts

lifts

Aerial lifts are vehicle-mounted, boom-supported aerial platforms, such as cherry pickers or bucket trucks, used to access utility lines and other aboveground job sites. The major causes of fatalities are falls, electrocutions, and collapses or tip overs.

Aerial lifts have replaced ladders and scaffolding on many job sites due to their mobility and flexibility. They may be made of metal, fiberglass-reinforced plastic, or other materials. They may be powered or manually operated, and are considered to be aerial lifts whether or not they can rotate around a primarily vertical axis.

Employers must take measures to ensure the safe use of aerial lifts by their workers if they are required to use this equipment in the course of their employment.

Aerial Lift Training
training

Only trained and authorized persons are allowed to operate an aerial lift. Training should include the following:

  • explanations of electrical, fall, and falling object hazards
  • procedures for dealing with hazards
  • recognizing and avoiding unsafe conditions in the work setting
  • instructions for correct operation of the lift (including maximum intended load and load capacity)
  • demonstrations of the skills and knowledge needed to operate an aerial lift before operating it on the job
  • when and how to perform inspections
  • manufacturer's requirements

Type of Aerial Lifts

lifts

Manually-propelled elevating aerial platforms: When employees use manually propelled elevating aerial platforms as covered by ANSI/SIA A92.3-1990, the manufacturer’s operating manual must be with the equipment. You must follow all operating and maintenance instructions and recommendations of the manufacturer.

Boom-supported elevating work platforms: When employees use boom supported elevating work platforms as covered by ANSI/SIA A92.5-1992, the manufacturer’s operating manual must be with the equipment. Follow all operating and maintenance instructions and recommendations of the manufacturer.

Vehicle-mounted elevating and rotating lifts [ANSI A92.2 devices]: Platforms other than buckets or baskets must include guardrail systems with guardrails, midrails, and toeboards. Each person who works on a boom-supported platform must use a personal fall-protection system that includes a body harness and a lanyard attached to the boom or basket.

Scissor lifts: When employees use self-propelled elevating aerial platforms (scissor lifts), as covered by ANSI/SIA A92.6-1990, the manufacturer’s operating manual must be with the equipment. Follow all operating and maintenance instructions and recommendations of the manufacturer.

Aerial Lift Safe Work Practices

lifts
This tip-over caused a fatality.

To make sure you are not injured while operating an aerial lift, follow these safe work practices:

  • Make sure that workers who operate aerial lifts are properly trained in the safe use of the equipment.
  • Maintain and operate elevating work platforms according to the manufacturer's instructions.
  • Never override hydraulic, mechanical, or electrical safety devices.
  • Never move the equipment with workers in an elevated platform unless this is permitted by the manufacturer.
  • Do not allow workers to position themselves between overhead hazards, such as joists and beams, and the rails of the basket. Movement of the lift could crush the worker(s).
  • Maintain a minimum clearance of at least 10 feet, or 3 meters, away from the nearest energized overhead lines.
  • Always treat power lines, wires and other conductors as energized, even if they are down or appear to be insulated.
  • Use a body harness or restraining belt with a lanyard attached to the boom or basket to prevent the worker(s) from being ejected or pulled from the basket.
  • Set the brakes and use wheel chocks when on an incline.
  • Use outriggers, if provided.
  • Do not exceed the load limits of the equipment. Allow for the combined weight of the worker, tools and materials.

You may also want to visit OSHA’s Fact Sheet for Aerial Lifts and 29 CFR 1926.453, Aerial lifts.

Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Employers should _____ workers who they observe working on scaffolds or aerial lifts improperly.

2. Scaffolds should be accessed by using _____ and not ______.

3. You notice workers on a supported scaffold while it is snowing. What do you tell the workers?

4. You notice workers on an aerial lift are working within 10 ft of a high voltage line. What do you tell the workers?

5. Use a _____ to the aerial lift boom or basket to prevent the worker(s) from being ejected or pulled from the basket.


Have a great day!

Important! You will receive an "error" message unless all questions are answered.