Figure 1. Metal scaffold contacting an overhead power line.
Just The “FACS” Safety Notes
When scaffolds, conductive tools, or other materials contact overhead power lines (see Figure 1), workers receive serious and often fatal injuries. Data from the NIOSH National Traumatic Occupational Fatalities (NTOF) data base indicate that nearly 6,500 traumatic work-related deaths occur each year in the United States; an estimated 7% of these fatalities are electrocutions [NIOSH 1991]. The NTOF data base also shows that from 1980 through 1986, at least 25 deaths resulted when workers contacted overhead power lines while erecting or moving scaffolds or while using conductive tool on scaffolds.
Figure 1. Metal scaffold contacting an overhead
power line.
OSHA has proposed revisions to the current safety regulations to prevent workers from placing scaffolds where they might contact overhead power lines or other energized circuits [51 Fed. Reg. 42706 (1986)]. These proposed regulations require that the following minimum clearances be maintained between scaffolds and exposed, energized power lines:
On June 17, 1986, a 28-year-old painter and a 33-year-old carpenter were painting church windows from a tubular, welded-frame scaffold approximately 25 feet high and mounted on rubber casters. After the workers had completed one side of the church, they attempted to move the scaffold to another location to continue painting. The workers passed the scaffold under a 12,000-volt power line that was approximately 30 feet above ground level. They then changed direction and tried to pass the scaffold under the same power line at a point that was only 24 feet above ground level. The scaffold contacted one phase of the power line, providing a path to the ground for the electric current. The two workers grasping the scaffold were electrocuted [NIOSH 1986e].
On August 27, 1986, a company owner and six workers were painting a concrete silo. A 5- by 7-foot tubular, welded-frame scaffold was erected to reach the top of the silo approximately 6 feet across from a 7,200-volt power line. Workers were using 8-foot aluminum poles with rollers to paint the side of the silo. A 19-year-old laborer who was painting from the scaffold pulled the aluminum pole back onto the scaffold to load more paint onto the roller. In doing so, he contacted the power line with the aluminum pole and was electrocuted [NIOSH 1986g].
On October 31, 1986, a crew of four painters (aged 56, 37, 37, and 31) completed painting one side of a three-story structure. The crew was using a five-tier, tubular, welded-frame scaffold mounted on 5-inch, rubber-clad aluminum wheels. The painters and the crew chief attempted to move the 28.5-foot scaffold to the other side of the structure. The scaffold contacted one phase of a 12,000-volt power line that was approximately 27.5 feet above the ground. The contact created a path to the ground for the electric current. The four painters were electrocuted and the crew chief was severely burned [NIOSH 1986a].
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 [NIOSH 1986f].
On June 5, 1987, a seven-tier, tubular, welded-frame scaffold (31 feet high) was erected to paint a 33-foot-high sign at the entrance of a new shopping mall. After the sign had been partially painted, the scaffold was moved to allow concrete to be placed in the area around the sign. The scaffold was positioned approximately 10 feet horizontally from a 13,750-volt overhead power line. Several days later, the crew of seven workers (carpenters, laborers, and painters) were instructed to replace the scaffold and finish painting the sign. The crew positioned themselves around the scaffold and attempted to lift it approximately 5 inches onto the newly constructed concrete pad. As they were lifting the scaffold, the top section partially separated from the adjoining section, toppled over, and contacted the power line. A 28-year-old carpenter and a 31-year-old laborer were electrocuted. The other five workers were hospitalized with electrical burns [NIOSH 1987b].
On September 25, 1989, six workers were using a mobile, elevated work platform to install aluminum siding on a warehouse under construction. The platform measured 25.5 feet from ground level to the top guardrail. Approximately 3 days before the incident, the crew had passed the platform under a 69,000-volt overhead power line located 34 feet above the ground. On the day of the incident, the crew tried to pass the platform under the same power line at a different location where the power line was only 27 feet above ground level. In addition, fill dirt brought into this location for landscaping caused the ground level to slope upward approximately 1.5 feet. As the crew passed the platform under the power line, the top guardrail contacted the bottom phase of the power line. Three crew members (a 30-year-old laborer and two steel workers aged 34 and 38) were electrocuted; three others were seriously burned [NIOSH 1990b].