OSU and the Columbus, Ohio, OSHA office hosted this fourth annual safety event in the Fawcett Center on the OSU campus. The event attracted approximately 300 people and offered educational sessions in three tracks for EHS professionals, workers and OSU students.
Merrill presented his leadership-track session, “Managing Crane Safety,” to cover the basics of safe crane operations on work sites. He opened the presentation by scrolling through photographs of crane accidents, which depicted cranes landing on cars, cranes bent over buildings, cranes crushing equipment and more.
“The reason that I show these slides is because lifting stuff is a dangerous business,” he said. “You’ve got to know what you’re doing.”
In addition to carrying the greatest potential for accidents, Merrill said, cranes typically are the most important and expensive piece of equipment on the jobsite. He added that crane accidents are the most costly, whether that cost is measured in money or human lives. And these incidents usually are preventable.
“Ninety percent of crane accidents are caused by operator error,” he said. “Very, very seldom does a crane break. Most cranes are put into a situation where it is going to be broken. It’s not going to break on its own.”
Merrill gave a breakdown of some of the people on the jobsite responsible for crane safety: The site supervisor has overall responsibility for the lift, must supervise plans of operations, provide accurate load weight information, ensure capability of the rigging crew, designate competent signalers and maintain the jobsite plan, lift plan and overall safety on the site.
The crane operator, meanwhile, is responsible for crane safety and operations. Operators are responsible for the crane’s proper maintenance and inspection, manufacturer guidelines, logbooks, records and verifying that all safety equipment on crane is functional. In short, he or she has to know the crane.
“In the crane world, the manufacturer is the one who dictates what you can and can’t do with that crane,” Merrill explained. “The crane operator knows how to read load charts. You think that’s a common thing, but I can tell you there are many people running cranes for many years and don’t even know what load chart is.”
Selecting a Crane
“You’ve got to size a crane based on what your job is,” Merrill said.
Too often, he explained, a construction company owner will call and request, for example, a 50-ton crane, completely convinced this is the equipment he needs. But there are many factors that come into play and affect what, where and how much a crane can lift. Lifting a load farther out from the crane, for example, changes how much weight the crane safely can lift. And when calculating the radius, the building location and crane’s boom placement must be taken into account to ensure there is room to lift the load to the top of the building.
“This is why your operator knowing how to read the load chart is so important,” Merrill stressed. After all, he added, a crane one degree out of level can lose 10 percent of capacity.
“This is how accidents happen every day in the crane world, because people don’t know what they don’t know. This is why having certified officers is so, so important.”
Merrill also stressed the importance of developing more detailed standards to help reduce crane incidents. When commenting on when OSHA’s proposed cranes and derricks standard might become a final rule, Merrill said, “Yes, God, please, as soon as we can. Anyone who’s in the business wants a new standard, wants new rules, because quite frankly it makes our job easier [to have set rules] when we take a crane on the jobsite.”
“Know What You Don’t Know”
Merrill also offered the following crane safety tips:
• Determine whether the crane operator is competent. Ask how much experience this employee has, if he or she has ever run this type of crane before in this type of operation and if they are CCO-certified.
• Determine ground stability. Using a crane on solid concrete versus sand, gravel or backfill can vastly change the operations. “This is why when someone comes to your jobsite and says, ‘What’s underneath there,’ we’re serious,” he said. “The ground pressure these cranes exert is tremendous – there could be a hole there you don’t know about.”
• Determine load capacity. The crane’s load chart specifies the rated maximum capacity of the crane for every possible configuration and situation. Never use signs of tipping to determine capacity limits.
• Understand you can damage a crane without it tipping. Merrill explained that a crane could be overloaded or overstressed before any signs of tipping are evident. The crane therefore may go from a stable to unstable condition with no marked change in the operator’s perception of machine condition. “Once tipping starts, it may happen so quickly that recovery is impossible,” Merrill said.
• Balance is important. “That’s how a crane works, it’s all about balance: I’ve got more weight behind me than the load,” Merrill said. The tipping axis is closets to the center of gravity.
• Don’t discount wind. “Wind is always a huge, huge issue,” he added. Wind was a factor in the 1999 Big Blue crane accident in Milwaukee, where three workers died when the crane came crashing down at the construction of the baseball stadium Miller Park.
• Never attempt side loading. “The booms on these cranes are designed to be compressed straight up and down, not bent sideways,” Merrill said.
• Beware of power lines. Power lines are the No. 1 cause of death in the crane industry, Merrill said. “If you learn nothing else in this today, understand that no power line is insulated,” he warned. “The current will jump from one conductor to another … Electricity is not our friend.”
“This is how bad stuff happens,” Merrill said of crane incidents. “People don’t know what they don’t know.”