Eyes on the Sky at the First Crane Jump Since a Collapse MARCH 30, 2008 by Manny Fernandez

Throughout New York City’s building boom, so-called crane jumps, an intricate procedure in which a crane is jacked up to raise its height, have been a frequent and little-noticed routine at construction sites.

But the scene on Saturday at a Brooklyn construction site was anything but routine.

City buildings inspectors, safety managers, police officers, construction workers, pedestrians, motorists and reporters waited below a 153-foot crane near Flatbush Avenue in Downtown Brooklyn, looking up with varying degrees of anticipation, confidence and anxiety. They were watching what was supposed to be the first crane jump in the city since March 15, when a construction crane collapsed on the East Side of Manhattan and killed seven people during a similar operation.

But after hours of prep work, caution ruled the day, and it was the weather that had the last word.

The yellow tower crane — a four-sided steel lattice tower topped by a cab and swinging arm, or boom — sat on Myrtle Avenue, between Flatbush Avenue and Prince Street. It has been erecting a 38-story, $152 million condominium building at 150 Myrtle Avenue called Toren, which means “tower” in Dutch.

Thomas Auringer, owner of U.S. Crane and Rigging L.L.C., which was conducting and overseeing the extension of the crane, had planned to add five 20-foot sections on Saturday and Sunday, raising it by 100 feet so work could continue on the upper floors of the unfinished building, which rises about 13 or 14 stories now.

Mr. Auringer, in an orange hard hat, was asked how much time was needed to install one section. “As long as it takes,” he said, explaining that he did not want to rush the job.

In the wake of the collapse on the East Side, the city ordered sweeping changes in the way it regulated tower cranes and crane jumps. The new regulations issued by the Department of Buildings require a city inspector to be present every time a crane is erected, jumped or dismantled, and also require an additional safety meeting with workers involved before each jump.

Crane jumps are a slow-motion ballet of steel, rope, cable, man and machine. At 10 a.m., the crane’s boom turned and used its hook to pick up a three-sided steel frame. That frame was slowly hoisted on cables by the crane’s hook and set around the tower. The outer frame serves as a kind of elevator, lifting the top part of the crane using hydraulic pistons so a new section can be inserted and bolted into place.

It took hours just to lift and secure the outer frame.

The atmosphere outside the construction site’s chain-link fence as all this unfolded was relaxed. A man in a white hard hat smoked a cigar. Traffic on the block was diverted much of the time, but buses were occasionally let through, and men, women and children walked on the sidewalk directly across from the crane.

Donald Capoccia, managing principal of BFC Partners, the building’s developer, arrived to watch the process. “They know exactly what they’re doing up there,” Mr. Capoccia said.

A group of men who had climbed the middle of the tower did their work on Saturday about 13 stories above a chilly Brooklyn, balancing themselves on the tower’s latticed steel and on the steel collar that attached the crane to the building. Investigators believe that a steel collar on the East Side crane broke loose during a crane jump and fell from the 18th floor, knocking out a lower collar and destabilizing the crane.

But the collar did not seem to concern workers. The weather did.

Wind, it seems, is the enemy of the crane jump. The city building code states that no crane operator can start an operation when the wind speed exceeds 30 miles per hour, and according to the manufacturer guidelines, the wind speed threshold of the crane used on Saturday was 24.6 m.p.h.

Shortly after 11 a.m., as the wind gently rocked the traffic signals and blew bursts of dust into bystanders’ eyes, Mr. Auringer got on his walkie-talkie and asked the man in the crane’s cab about the wind. The cab, high up the tower, was outfitted with wind sensors. The wind speed was about 11 m.p.h., with gusts up to 13 m.p.h.

But the situation changed later in the day, when the wind grew stronger.

It was gusting between 19 and 26 m.p.h., and one gust came in at 37 m.p.h., Mr. Auringer said. About 5 p.m., the jump was called off and postponed until Sunday. Not one of the five new sections had been inserted.

“We had enough time to do a section, but we decided to call it,” he said. “Weather runs our business. And if it’s not safe, we don’t work. This is standard procedure.”

A version of this article appears in print on , on Page A26 of the New York edition with the headline: Eyes on the Sky at the First Crane Jump Since a Collapse.