I haven't gotten answers yet.
The latest Construction Alert issued on July 18 by the Empire State Development Corporation (and prepared by developer Forest City Ratner) indicates that "subject to receipt of permits, a third shift may be instituted during this reporting period, from 11 PM – 7 AM, Monday –Friday only."
(There have been no previous third shifts for arena construction, but there have long been some disruptive overnight shifts regarding utility work at the boundaries of the project. For example, see this video.)
Some readers asked me about this, so I queried the Empire State Development Corporation about it, and was told to ask Forest City. (The ESDC said in June that working a second shift "ensures maximum productivity.")
So I asked the developer for the rationale for the third shift, and the safeguards planned.
And I asked the Department of Buildings if a permit had been granted, and what safeguards would be required.
Both sets of queries are pending.
Final EIS discloses possibility
I then took a look at the Final Environmental Impact Statement, Construction Impacts chapter, which did allow for the possibility:
It is anticipated that construction activities for the buildings and the arena would generally take place Monday through Friday with exceptions that are discussed separately below. In accordance with city laws and regulations, construction work would generally begin at 7 AM on weekdays, with some workers arriving to prepare work areas between 6 AM and 7 AM. Normally, work would end at 3:30 PM. It is anticipated that the workday would be extended for specific trades to complete some specific tasks beyond normal work hours... The extended workday would generally last until about 6 PM and would not include all construction workers on-site, but just those involved in the specific task. Extended workdays are expected to occur about 40 percent of the weekdays over the course of construction.
Over the course of construction, it is expected that evening and night work would be required. For example, certain of the transit improvements may involve street openings at the intersection of Flatbush and Atlantic Avenues, and this would likely be allowed only during the late evening and night when traffic is at its lightest. In addition, some of the larger construction tasks within the Vanderbilt Yard and the arena may require continuous periods of time to complete. So as not to interfere with the LIRR train schedule, LIRR work would be scheduled to start after the Yard has been vacated to meet the evening rush hour and be completed before trains return from the morning rush hour.(Emphases added)
...When work is required outside of normal construction hours, the proper approvals would be obtained from the appropriate agencies. A noise control plan would be developed and implemented to minimize intrusive noise emanating into nearby areas and affecting sensitive receptors. The noise control plan would include such restrictions as the prohibition, where possible, against placing generators at the property line and engaging in unnecessary loud activities at night.
So I also asked what "larger construction task" was involved.
Atlantic Yards FEIS Chapter 17, Construction Impacts
FINAL Atlantic Yards Construction Alert 7-18-2011