Safe Solutions

It was a sweltering summer day in late August, and the roofing crews from APF Roofing Co. were busy.

Jim, a foreman with APF Roofing, and his crew were installing a single-ply roof system on a small office building. The workers were using a variety of tools, including electrically powered reciprocating saws and drills and hot-air blowers.

Earlier, Jim had met with the building owner to discuss possible safety hazards specific to the job site. Jim had inspected the deck's underside for potentially hazardous conditions and combustible materials, such as insulation, and also spotted some electrical conduit.

Jim used bright orange spray paint to mark the roof areas under which the conduit was located so the workers would know not to penetrate those areas with cutting tools. Jim also made sure circuits would be turned off in the areas where his crew was going to be working. All electrical cords the crew was going to use were inspected for damage and declared safe by a competent person.

In addition, Jim noted the closest power lines were 20 feet away from the roof. The Occupational Safety and Health Administration requires that roofing workers and equipment maintain a minimum distance of 10 feet from power lines. Jim also noted there were no rooftop panels containing electrical equipment.

Before work began, Jim checked for any combustible substrates or other materials that could be ignited by the hot-air blowers. He made sure there were enough fire extinguishers nearby and that workers were wearing appropriate personal protective equipment.

Jim also checked that appropriate fall protection was in place and all equipment was in good operating condition. Jim was satisfied the building was safe and ready for his crew to begin work.

Jim and his crew worked steadily through the morning. Just before lunch, Jim realized they needed a portable generator. He sent a new roofing worker, Mike, down to the truck to get one.

Mike went to the truck and found a generator. The generator had no ground fault circuit interrupter (GFCI), but Mike did not know a GFCI is critical when electrically powered tools and equipment are being used.

A GFCI is a sensitive circuit breaker that compares the amount of current traveling to and from electrical equipment. If the current traveling from an electrical source is different from the current returning, the GFCI trips the circuit, preventing electrical shock.

When the workers got the generator on the roof, Mike plugged an electric saw into it and began cutting through an old piece of roof deck.

A moment later, an electrical shock jolted through Mike, and he collapsed onto the deck. Jim reacted quickly, telling one of the other workers to call 911.

A few minutes later, an ambulance arrived. The paramedics examined Mike and said he should be examined by a doctor. They transported him to the hospital.

In the meantime, Jim called APF Roofing's owner, Simon, and explained what had happened. Then, Jim had the generator tagged and removed from service.

Jim met Simon at the hospital. The doctor told them Mike was fine but should go home and rest. Simon drove Mike home and, on his way back to the office, realized it had been a while since APF Roofing had held a safety training session about electrical hazards.

Back at the office, Simon placed a call to a roofing contractors association and spoke to a safety consultant. The following week, an instructor from the association visited APF Roofing and guided the workers through the first in a series of safety training sessions. During the session, the instructor talked about the importance of using a GFCI.

The crews learned that a power source, such as a generator, should have a built-in GFCI. If it does not, a portable GFCI must be plugged into the power source. Extension cords should then be plugged directly into the portable GFCI and tools connected to the extension cords.

The instructor also explained that an electrical shock or burn occurs when a part of a person's body completes a circuit, connecting a power source with the ground. Mike had been holding a defective electrically powered saw that had been plugged into a generator with no GFCI. If the generator had had a GFCI, it would have sensed the defect in the saw and tripped the circuit, preventing the saw from shocking Mike.

Simon, Jim and the crews learned that though electrically powered tools and equipment can help complete a job, electricity is something that must be handled with caution.

Peter Greenbaum is NRCA's director of education and training media.