Above and Beyond Two owners of large tower crane fleets cut risks by stepping up safety programs
...with Dunn’s fleet of royal-blue cranes towering above the skyline, It is believed to be the country’s largest fleet of tower cranes owned by a general contractor. Made by Spanish manufacturer Linden Comansa, the iconic cranes have a signature “flat top” design that uses no overhead pendants to support the jib.
What locals don’t notice is the invisible database that now connects these cranes. Dunn began the initiative began three years ago for general safety compliance and expanded it last year for the hoisting fleet.
“In the past, when technicians go out to inspect a crane, they have a paper report that they fill out, and basically it’s filed away,” says Cory Hall, safety manager of J.E. Dunn Logistics, adding that the firm inspects its tower cranes every six weeks or 300 hours. Federal guidelines only require annual inspections. The company also performs nondestructive testing of structural components after each project.
Dunn tracks its safety compliance with a software program called DBO2. In 2008, it asked the program’s San Carlos, Calif., supplier to tailor the software for use with the hoisting fleet. “We can pull statistics and data, everything from fall protection to crane inspection,” says Hall. “Once a crane is moved, those statistics…follow that crane to the next job.”
The equipment is hooked up to mobile GPS trackers, too. That may sound especially strange for tower cranes—which typically work from a stationary position. But the tracking devices monitor essential data, such as load testing. Every day, Dunn requires its operators to test the crane to 110% of maximum capacity as part of their startup routine. Industry standards only require this procedure when the crane is first set up.
It works like this: A rigger on the ground hooks up a test block that weighs the same at the crane’s maximum rating. Tethered to it is a smaller “pup” weight that adds 10% more. The operator lifts the test weight, and when the chains pull tight on the pup, the crane’s limit switch trips, shutting it down. If not, the operator knows something is wrong.
The method is controversial among some crane experts because it potentially exposes the crane to premature fatigue. But it is perfectly legal as long as the manufacturer does not prohibit it. Operators say they like the assurance: “If anything [bad] happened, it would be on me,” says Terry Pierce, a crane operator for Dunn. “You don’t get any second chances.”
E-mails fire away to Hall’s staff whenever a switch is tripped—so they know if an operator does not perform daily load tests. “When the contact goes in, it sends a signal to the GPS system,” says Hague. Only technicians are allowed to adjust the switches, which are calibrated for every job. If an operator tries to cheat, Hall says, “It’s an automatic no-questions-asked [situation]…that operator is dismissed within the hour.”
Tagged Out With 550 machines, Morrow is believed to run the largest rental fleet of tower cranes in the U.S. But even so, Morrow’s management team says the company could be doing more to improve safety tomorrow.
“We have to change as an industry,” explains Juhren, who also chairs the American National Standards Institute’s B30.3 committee on tower cranes, which publishes best practices for those machines. “For years, it was just assumed that we did what we said we had to do.”
Years ago, Morrow already had developed a QC program—an internal mechanism for tracking its crane parts. “But we never really had a QA program,” says Juhren.
In 2008, the company developed a system of blue, red and green tags that inspectors must sign...
