Those inconvenient facts, however, are dwarfed by the notion that this is a story of technology and innovation, as two national media outlets pronounce. Indeed, it may be an important technological innovation, but even innovations come with costs, controversies, and questions, and those shouldn't be forgotten.
Gizmodo on 10/23/13 published Inside the NYC Super-Factory Building America's Tallest Prefab Tower:
In a corner of the Brooklyn Navy Yard, on a factory floor that resembles an oversized assembly line, workers are building entire apartments in days. Most New Yorkers might not realize it, but the tallest prefab building in the country—and maybe the world—is currently taking shape not far from where they live. Gizmodo recently got a chance to visit the space and watch it come together.In Fast Company
...In a massive warehouse on the northern side of the Yard, FCS has set up one of the largest prefab factories on the planet: A perfectly-engineered assembly line where roughly 100 workers are putting together 930 modules that will eventually become B2.
One of the biggest hurdles with prefab isn’t just structural integrity or waterproofing, but the workers themselves: Prefab has long been perceived as a way for developers to avoid paying construction workers and, thus, to bypass unions altogether. So one of FCS’s biggest successes has actually been a legal one: The formation of a new, non-jurisdictional “Modular Division,” made up of union carpenters, iron workers, painters, plumbers, electricians, and more. It’s this agreement that makes it possible to use 100 percent union labor at the Navy Yard site, where small teams from each trade work on assembling each module simultaneously.
...This is a problem that the engineers at FCS (and Arup, the collaborating engineering firm) are quite proud of solving; when the workers install the modules later this year, they’ll also construct a framing lattice of extra steel cross-bracing inside the warren of boxes.
...What will happen to this buzzing factory space when all 930 modules are complete? Roger Krulak, a Senior Vice President at Forest City Ratner who gave us a tour of the factory, explains that B2 is a case study—if all goes according to plan, it’ll serve as a model for other urban developments throughout the city.
FastCo.Exist published New York's Newest Skyscraper Is 32 Floors Of Prefab Apartments That Click Together:
Nowhere is this scenario more promising than in Brooklyn's Navy Yard, an industrial park where one factory is churning out extremely precise, 450- to 950-square-foot apartments that will click and seal together to form the largest modular high-rise building in the world. At 32 stories of stacked modular apartments, developer Forest City Ratner's "B2" building will surpass in height the 24-story student dorm erected in Wolverhampton, England, in 2009, then hailed as the tallest modular building of its kind. This past month, Co.Exist got a look inside at the reportedly faster and more efficient building process that could shape the cities we live in for years to come.Apartment RenderingHow long will it take?
Inside Building 293, a massive, cadet blue shipping container of a warehouse, teams of 10 to 15 union workers are prefabricating one floor at a time. When completed, a finished module will include a kitchen stocked with new appliances and a full bathroom. In fact, the only unfinished elements after the "mods" are trucked two miles over to Dean Street will be the plumbing connections, which plumbers can simply snap together from a kit packed inside the walls. Everything else, including hallways, stairs, and five phases of modular construction from the inside out to the façade, will be done at the factory.
Modular assembly is often compared to the kind of line assembly popularized by Henry Ford's T-Birds, but B2 is actually being constructed by a different process altogether. Instead of individual workers putting together piecemeal parts, FCS Modular and its Swedish partner Skanska decided on using a system called "group technology workcells," in which multidisciplinary groups of cross-trained tradesmen work on different parts of the floor simultaneously. It's the same way airplane engines are constructed, Roger Krulak, a senior vice president at Forest City Ratner (FCR), explains.
The article states:
Because of innovations like these, FCR claims to have "cracked the code" to modular building on a new scale. The company says that B2 will be built in 18 months, or two-thirds the time it would take for conventional construction. Stacking the mods onsite, like one might build a Lego tower, will happen on a speedy rolling basis: As metal chassis come into the factory, finished mods go out by truck, and are lowered behind the Barclays Center onto the new structure by crane. The group has also pledged that its prefab process will save money and reduce the construction waste that occurs when building from the ground up by 70% to 90%.If it takes 18 months, then they've adjusted the start by six months, since right now it looks to be a two-year project from the groundbreaking.
How many workers?
The article explains that Forest City is not actually employing all the workers it once promised:
Last year, FCR revealed the plan for B2, which now will dedicate 50% of its 363 rental units to low-income tenants and will eventually employ 125 union tradesmen during construction (it currently has 72). Using all-union labor in modular construction was something the company claims was essential to the process. Whether cooperation with the trades continues will likely have a hand in determining the future of modular in New York.The sealant
The article explains an innovation:
Another key feature of FCR'S code is how the mods will actually fit and join together. To secure the building from winds and seismic shifts, it will feature both a steel brace and a conventional foundation--a hybrid of modular and traditional construction methods. But a more radical innovation takes place in between the mods, when they are joined together by rubber sealant, like the connections between subway cars. The sealant goes on the façade in one of the final steps before the mod is trucked out. The apartments, meanwhile, require zero welding.