Citing safety concerns at the World Trade Center and other sites, New York City Mayor Michael Bloomberg (R) has proposed a new law that would ban all mobile and tower cranes from operating in the city when they reach a certain age—in most cases, 25 years—and require all cranes, young and old, to be equipped with load-cycle counters. Opponents argue that the age of a machine is not an indicator of its safeness, citing a 2007 study in California that reached the same conclusion.
The bill came out of two near-misses at the World Trade Center site. In October 2011, a 40-year-old tower crane dropped a 14,000-lb load 100 ft. In February 2012, a 33-year-old tower crane dropped a 48,000-lb load nearly 500 ft. In both cases, the city determined the vintage cranes' hoist drums failed, lacking hydraulic check valves and other fail-safes to stop the free falls. "After these incidents is when the department started looking into this legislation," says a spokeswoman for the buildings department.
New York City is not the first jurisdiction to float the idea. Singapore requires cranes to be scrapped after roughly 25 years, mainly to ensure the cranes are not fatigued. In 2007, an engineer in California proposed an amendment to the state's safety code that would have banned tower cranes older than 20 years. The state denied the request, ruling that inspections are sufficient to catch unsafe equipment. Age alone, state officials concluded, "does not determine whether a crane can continue to be operated safely."
The New York City bill also aims to advance lifting technology, such as flight recorders and electric drives. However, opponents say manufacturers' data-loggers are crude devices that lack sufficient memory and that there is no industry standard for how to measure the fatigue factor of a pick. Under the proposal, equipment owners would be charged with keeping a detailed record of every lift for the life of a crane.