Safe Solutions

During the five years Ray has worked for Standard Roofing, he has gained considerable experience as a roof mechanic and undergone numerous safety training classes. Standard Roofing's owner, Jack, is committed to safe work practices and proud of his company's safety record.

One morning, Ray and his crew were at work on a mall's roof. A rented boom truck and an operator, whom Jack had hired, were on-site to load materials to the roof.

Steve, Standard Roofing's foreman, noticed there was no insulating blanket covering the nearby overhead power lines; the electric utility company said it would install the blanket. He wasn't prepared to assume the power lines were de-energized and was reluctant to allow the operator to begin loading. The operator, however, explained that with the assistance of a Standard Roofing worker, he could keep the boom a safe distance from the power lines. Steve was convinced and chose Ray to watch the boom and warn the operator if it got close to the power lines. Standing on the ground, the operator controlled the boom using rubber-coated hand controls mounted on the truck's side. He and Ray made sure they had a clear line of sight of each other.

Work progressed through the morning, and it soon was time for lunch. As the operator eased the boom away from the roof, he miscalculated, and the boom contacted a power line that had 7,200 volts (7.2 kV) surging through it.

Ray noticed the operator was unable to let go of the hand controls. Ray looked up at the boom and realized an electrical current was passing through it. He reacted immediately by charging at the operator and kicking him in the chest, knocking him free from the hand controls.

The operator gasped and collapsed on the ground, unconscious. A crew member grabbed a cell phone and called for emergency medical assistance. Steve ordered everyone away from the work area—the boom still was in contact with the power line. Moments later, the truck's tires ignited, and the truck began to burn.

The operator regained consciousness just as an ambulance arrived. The medical team examined him and found he had suffered burns to one hand but otherwise was in good condition.

After being notified about the emergency, the captain at the fire station dispatched his crew and notified the electric utility company that owned the power line. When the crews from the fire department and utility company arrived, they de-energized the power line and extinguished the fire. Apart from the crane operator's burned hand, there were no other injuries.

Jack arrived at the job site and learned about the operator's miscalculation and Steve's poor judgment. Later that day, after consulting his company's safety manual, Jack realized Steve and the crew had neglected to follow other critical safety regulations. Jack was grateful for Ray's quick thinking—he had saved the operator. But Jack was concerned Ray and the crane operator could have been seriously hurt or killed. Jack knew if proper precautions had been taken, heroics wouldn't have been necessary.

Instead, as mentioned in the company safety manual, Jack should have trained his employees about Occupational Safety and Health Administration (OSHA) regulations 29 CFR 1910.333 (c)(3) and 29 CFR 1926.550 (a)(15). The regulations require workers and employers to consider all overhead power lines energized until the owner of the lines or electric utility company indicates the lines are not energized and have been visibly grounded.

According to OSHA, employers should ensure overhead power lines are de-energized or separated from the boom and its load by de-energizing and visibly grounding electrical distribution and transmission lines at the point of work and/or using insulated barriers that are not part of the boom to prevent contact with the lines.

If power lines are not de-energized, a boom or crane can be operated in the area only if a safe minimum clearance is maintained—at least 10 feet (3 m) for lines rated 50,000 volts (50 kV) or less; at least 10 feet (3 m) plus 0.4 of an inch (10 mm) for each kilovolt above 50,000 volts (50 kV); or twice the length of the line insulator (but never less than 10 feet [3 m]).

It's critical workers who operate cranes and other boomed vehicles are trained in safe operating procedures. A worker should understand the limitations of devices such as boom guards, insulated lines, ground rods, nonconductive links and proximity warning devices. They should recognize these devices are not substitutes for de-energizing and grounding lines and maintaining safe clearance.

Jack knew he would have to rent cranes and hire crane operators in the future. But he decided to always ensure the operators properly were trained and Standard Roofing crews knew the potential hazards, as well.

Peter Greenbaum is NRCA's manager of education programs.