Crane Accidents Are Not Tied To Machine Age, Study Says
A crane's age is not an indicator of its physical fitness, according to a new study by Dallas-based forensic firm Haag Engineering. The results fly in the face of laws in Singapore and pending legislation in New York City, as other cities contemplate forcing crane owners to upgrade aging fleets.
"Bottom line, there is absolutely no correlation between age and accidents," said Jim Wiethorn, chairman and principal at Haag, who spoke at the Specialized Carriers & Rigging Association's annual meeting, held on April 22-26 in Boca Raton, Fla.
The lead author of the study, "Crane Accidents: A Study of Causes and Trends To Create a Safer Work Environment," added that his firm reviewed more than 500 crane accidents, from 1983 to 2013. In June, Haag will sell the full study, which details accident causes, for $249.
Regulators have argued that aging crane fleets pose higher risks to the public.
"As building in New York City continues to accelerate, we must encourage crane manufacturers to supply the construction industry with modernized equipment," said former Mayor Michael Bloomberg last December, when proposing the city ordinance, which is still pending.
Proponents frequently cite Singapore, which requires contractors to retire machines when they reach a certain age. Depending on the crane's capacity, the provision kicks in between 20 and 30 years of service. An extension can be granted if an inspection demonstrates the crane is safe to operate. Jurisdictions in the U.S. and Canada have considered similar measures.
Health and safety officials in Singapore have said the laws emerged out of accidents in the region that resulted from "fatigue stresses as a result of prolonged years of service," according to the country's Ministry of Manpower. However, Wiethorn contended Singapore's age laws are more focused on protecting against foreign competition than public safety.
Importance of Maintenance
Crane experts at last month's meeting viewed such laws as reactionary, often masking other problems—for example, poorly maintained machinery.
"Time does not weather a crane; maintenance and application do," said Zack Parnell, COO and vice president of Woodland, Wash.-based Industrial Training International. "New cranes have accidents all the time," added Rob Weiss, president of Cranes Inc., a Maspeth, N.Y.-based rental outfit. In several recent crane accidents in New York City, "it was maintenance, not age," that caused them, he said.
The city's Dept. of Buildings already has banned two tower-crane models built in the 1970s and 1980s—36 units in all—after "they were identified to have documented performance and safety issues," according to the department. Two such cranes erected at the World Trade Center site dropped loads due to faulty hoist drums, the city determined. The Link-Belt and Favco brand units are no longer supported by a manufacturer. Cranes Inc. owns five of those units, one of which is now working across the Hudson River, in Hoboken, N.J.
Machinery bans could hike construction costs, Weiss noted. For the 36 banned cranes, "the industry just doesn't have the money to purchase $120 million in new cranes," he said. Further, a new tower crane of the same size rents for $80,000 to $100,000 a month, while the older units rent for $35,000 to $40,000. "The cost impact to the steel industry has been dramatic," Weiss said. "It's name-your-own-price now in New York City."
On the other hand, keeping vintage cranes alive also can produce diminishing returns, Wiethorn acknowledged at the meeting. "Life expectancy is directly related to economic value," he said. "With age, it is going to cost a little bit more." Attendees asked him at what age it makes financial sense to scrap a crane, and Wiethorn replied, "You'll have to read the study, but it is getting into the 30s and 40s."
Flight Recorders Considered Risky
Crane owners, manufacturers and insurers also debated the question of whether machines should be equipped with black boxes that record lift data, which is a notion that is part of the pending legislation in New York City.
Currently, no standard yet exists for these devices. Tadano rough-terrain cranes, for example, record the past 50 lifts, with such details as date, time, load moment, boom length, boom angle and outrigger placement, among others. They also record the 10 heaviest lifts. However, Tadano does not provide the user access to this information. Some brands record even less data, if any.
Crane owners said they didn't want the liability of a black box, even if the data could exonerate them in court.
Bob Moore, chief legal officer for NationsBuilders Insurance Services Inc., said that a flight recorder, similar to what aircraft use, would be a reasonable solution if it were limited to just a few hours of data and handled by a trained professional, to avoid tampering.
"You want to have the data so you can have an accident investigation," he said.
