Scaffolding Hazards - Avoiding Common Mistakes
Learn how to prevent the basic scaffold hazards
By Joe O'Connor
Many employers ignore Occupational Safety and Health Administration's (OSHA) regulations. Have you ever heard another mason contractor express the feeling that standards, such as the OSHA's scaffolding requirements, are set by bureaucrats in Washington? What does OSHA really know about the hazards of working with scaffolds? Mason contractors are on scaffolds all the time and know how to use them safely. Besides, experience is said to be the best teacher. People learn by their accomplishments and mistakes.
Unfortunately, when it comes to safety, errors can be fatal! Don't subscribe to a negative OSHA philosophy. The statistics OSHA uses to set standards are actual cases. The requirements established target actions that would have prevented fatalities or injuries. If you must depend on experience, look at others mistakes and avoid them.
The following are a few cases selected from an accident investigation search of OSHA's database for mason contractors using the keyword scaffolds. They illustrate the need for protection against scaffolding hazards.
- Electric Shock - Contact with Overhead Line through Scaffold
- Employee Killed in Scaffold Collapse
- Employee Killed When Box Falls
- Employee Breaks His Back in Fall From Scaffolding
- Employee Killed in Fall From Scaffolding
- Employee Injured After Being Struck By Collapsing Scaffold
- Employee Dies in Fall Through Scaffolding
- Employee Killed By Falling Scaffold
- Six Employees Injured When Scaffold Collapses
- Construction Employee Killed in Fall From Scaffold
Electricity is a major hazard when using scaffolds. Electrical lines are generally elevated to keep individuals a safe distance away. The purpose of the scaffold is obviously to allow one to work at these heights which brings workers close to this hazard.
On November 24, 1986, seven employees of a masonry company were erecting a brick wall from a tubular, welded-frame scaffold approximately 24 feet high. The scaffold had been constructed approximately 21 inches across from a 7,620-volt power line. A laborer carried a piece of wire reinforcement (10 feet long by 8 inches wide) along the top section of the scaffold and contacted the power line with it. The laborer, who was wearing leather gloves, received an electric shock and dropped the wire reinforcement, which fell across the power line and simultaneously contacted the metal rail of the scaffold, energizing the entire scaffold. A 20-year-old bricklayer standing on the work platform in contact with the main scaffold was electrocuted.
OSHA requires that scaffolds and workers maintain a proper clearance from power lines. 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 power lines. The required clearance from uninsulated lines is 10 feet if the voltage is less than 50 kilovolts (kV) and 10 feet plus 4 inches for every 1 kV over 50 kV. All overhead outdoor lines should be treated as uninsulated.
Overloading scaffolds is another major hazard. The mason industry by nature requires heavy loads on scaffolds. Too often contractors place excessive strain on scaffolds as shown by the following case.
Last August a scaffold collapsed in Massachusetts killing two workers. The accident investigation showed that the scaffold was overloaded with brick, debris and excess scaffold planking. None of the workers had received training nor was the scaffold inspected by a competent person. In addition, a cross bracing was missing from the base of the scaffold.
Each scaffold and scaffold component must be able to support its own weight and at least 4 times the maximum intended load applied or transmitted to it. On suspended scaffolds the suspension rope, including connecting hardware, must be capable of supporting at least 6 times the maximum intended load. A competent person must be present when the scaffold is erected to insure it can take the intended load and that it is erected properly. The requirement for worker training and a daily inspection by a competent person could have prevented the missing brace and accumulation of debris.
The most common hazard on scaffolding is the potential for falling. The following case demonstrates a violation frequently seen when workers use a scaffold. A crew was working on a scaffold applying stucco to a six-story college dormitory. An employee on the fifth floor stepped on a guardrail to access the next level of the scaffold. The guardrail gave way allowing the employee to fall 48 feet to his death.
To prevent this type of fall OSHA requires employees to use an appropriate access for any scaffold higher then 2 feet. Climbing on any part of the frame is prohibited. Appropriate access can include a ladder built into the scaffold, which meets OSHA ladder specifications, or an attached ladder.
In reviewing this case, another comment should be made about fall protection. OSHA requires proper fall protection on all scaffolds over 10 feet. A personal fall arrest system or guardrail system must be in place. The guardrail here was loosely attached. It did not meet the specifications. Points to consider for the guardrail system are: insure guardrails are capable of withstanding a 200 lb. force, midrails can withstand a 150 lb. force, and netting, screens or some other form of falling object protection are in place.
Paying attention to these basic hazards can prevent the same occurrence on your jobsites. Review the Scaffold standards in the Code of Federal Regulations (CFR) 29 Subpart L and observe all precautions. Special attention should be given to any requirement that will help you avoid overloading a scaffold, protecting workers from falls and falling objects and staying clear of electricity.
About the Author
Joseph O'Connor is Vice President and Director of INTEC, Inc. He currently serves as a national representative for various employer organizations participating in OSHA-ACCOSH work groups and ANSI committees.
