Back to Basics, Construction

Back to Basics: Scaffolding Safety

Back to Basics is a weekly feature that highlights important but possibly overlooked information that any EHS professional should know. This week, we examine OSHA’s recommendations for scaffolding safety.

Many industries deploy scaffolding to get work done, specifically in construction, where millions of employees use scaffolding on a regular basis. According to OSHA, the Bureau of Labor Statistics’ Census of Fatal Occupational Injuries (CFOI) reported 52 fatal falls to lower levels from scaffolding in 2021, and in FY 2022, scaffolding citations were listed at number five on OSHA’s top 10 most-violated workplace standards.

Hazards

OSHA defines a scaffold as an elevated, temporary work platform, of which there are two basic types. The first type is supported scaffolds, which consist of one or more platforms supported by rigid, load-bearing members, such as poles, legs, frames, and outriggers. The second type is suspended scaffolds, which are one or more platforms suspended by ropes or other non-rigid, overhead support. Scissor lifts and aerial lifts, along with other types of equipment, are considered to be other types of supported scaffolds.

Workers can be exposed to many hazards when working around scaffolding, including falls from elevation, due to the lack of fall protection. The scaffolding could collapse, which is caused by instability or overloading. Employees can be struck by falling tools, work materials, or debris, or they can be potentially electrocuted due to the proximity of the scaffolding to the overhead power lines.

Scaffolding workers

There are three main groups of people who work with scaffolding, the erectors and dismantlers, the users, and the designers, OSHA states. Erectors and dismantlers are workers whose main job involves assembling and disassembling scaffolding before other work can begin, and after the work, or a portion of it, has been completed. These workers must be trained by a competent person who is capable of identifying existing and predictable hazards and has the authorization to take prompt corrective measures to eliminate those hazards.

According to OSHA, scaffolds must be designed by a qualified person and be constructed and loaded in accordance with that design. A qualified person in this scenario is one who possesses a recognized degree, certificate, or professional standing, or someone who by extensive knowledge, training, and experience has successfully demonstrated their ability to solve or resolve problems relating to scaffolding.

The qualified person must do adequate preplanning to assure the safe erection and use of the scaffold. Preplanning must include determining the necessary type of scaffolding for the job, the maximum load for the scaffold, assuring a good foundation, and avoiding electrical hazards. The common hazards that erectors and dismantlers face include access, collapse, electrical, fall, instability, and struck-by hazards.

OSHA says scaffold users are workers whose work requires them to be supported by scaffolding to access the area of a structure where that work is performed. Employers must have a qualified person to train each employee who performs work while on scaffolding. Workers must be trained to recognize the hazards associated with the type of scaffolding being used and to understand the procedures to control and minimize those hazards.

Scaffold designers are workers who are qualified to design scaffolds. For certain kinds, these workers must also be registered professional engineers. Non-mobile scaffolds must not be moved horizontally with workers on them unless a registered professional engineer designed the scaffold specifically for that kind of movement. The following kinds of scaffolding must be designed by a registered professional engineer, and shall be constructed and loaded according to that design:

  • Pole scaffolds over 60 feet high
  • Tube and coupler scaffolds over 125 feet high
  • Fabricated frame scaffolds, including tubular welded frame scaffolds, welded end frame scaffolds, and walk-through frame scaffolds, over 125 feet high
  • Outrigger scaffolds and their components

Construction industry requirements

The general requirements for scaffolding in construction are outlined in OSHA’s standard. Scaffolding must be capable of supporting its own weight and at least four times the maximum intended load applied or transmitted to it, without failure.

The direct connections to roofs and floors, and counterweights used to balance adjustable suspension scaffolds, must be capable of resisting at least four times the tipping moment imposed by the scaffold operating at the rated load of the hoist. Alternatively, they must withstand a minimum of 1.5 times the tipping moment imposed by the scaffold operating at the stall load of the hoist, whichever is greater.

OSHA requires that each suspension rope, including connecting hardware, for non-adjustable or adjustable suspension scaffolds should be capable of supporting at least six times the maximum intended load applied or transmitted to that rope without failure. For adjustable suspension scaffolds, this can apply with the scaffold operating at either the rated load of the hoist, or two times minimum the stall load of the hoist, again whichever is greater. The stall load of any scaffold must not exceed three times its rated load.

In terms of access, the following must be used when scaffold platforms are more than 2 feet above or below a point of access:

  • Portable ladders
  • Hook-on ladders
  • Attachable ladders
  • Stair towers (scaffold stairways/towers)
  • Stairway-type ladders, such as ladder stands
  • Ramps
  • Walkways
  • Integral prefabricated scaffold access
  • Direct access from another scaffold, structure, or personnel hoist

When it comes to using scaffolding, employers must ensure that scaffolds and scaffold components are not loaded in excess of their maximum intended loads or rated capacities, whichever is less. OSHA emphasizes that the use of shore or lean-to scaffolds is prohibited.

Scaffolds and their components must be inspected for visible defects by a competent person before each work shift, and after any occurrence which could have affected a scaffold’s structural integrity. If any part of a scaffold is damaged or weakened so that its strength is less than required, it must immediately be repaired or replaced, braced to meet those provisions, or removed from service until it is fixed.

Scaffolds must not be erected, used, dismantled, altered, or moved such that they or any conductive material handled on them might come closer to exposed and energized powerlines. OSHA provides minimum distance guidelines for insulated and uninsulated lines depending on the voltage. The exception is that scaffolds and materials may be closer to power lines when such clearance is necessary for the job, and only after the utility company or electrical system operator has been notified and deenergized or relocated the lines, or installed protective coverings to prevent accidental contact.

Employers must make sure that workers are not allowed to work on scaffolds covered with snow, ice, or other slippery material except as necessary to remove such materials. Work on or from scaffolds is also not allowed during storms or high winds unless a competent person has determined that it is safe for workers to be on the scaffold and those workers are protected by a personal fall arrest system or wind screens. Wind screens are not to be used unless the scaffold is secured against the anticipated wind forces.

Suspension ropes must be shielded from heat-producing processes and from acids or other corrosive substances. They can also be treated to protect against corrosive substances or be made of a material that will not be damaged by the substance being used on the scaffold. Debris must not be allowed to accumulate on platforms, and makeshift devices, like boxes or barrels, cannot be used on scaffolding to increase the working level height of employees.

Each employee on a scaffold more than 10 feet above a lower level must have fall protection to keep them from falling to that lower level. A competent person must determine the feasibility and safety of providing fall protection for employees erecting and dismantling supported scaffolds. Employers are also required to provide fall protection for employees erecting or dismantling supported scaffolds where the installation and use of such protection is feasible and does not create a greater hazard.

For more details, click here for OSHA’s standards and recommendations for scaffolding safety.