In the wake of a disaster that left a major facility with massive damage and dust up to its cooling towers, the telecommunications company moved swiftly to rebuild this Manhattan location. The consulting firm improved on the original by rethinking mechanical room location, improving redundancy, and expanding the life safety system. Now, the building is ready to serve its occupants better, in case of emergency or just another day at the office.

Among the damage from the 9/11 World Trade Center attacks was Verizon's 140 West Street facility in lower Manhattan. Located just across the street from Ground Zero, the original New York Telephone Company headquarters building, constructed in 1926, suffered major damage. Falling steel pierced its walls and facade, tearing open gaping holes. Water from fire hoses and broken water mains flooded its basement vaults, which shorted out cables not already severed by the fallen steel, destroyed the electrical switchgear, ripped loose fuel tanks, and severely compromised the chiller plant. On the exterior, mountains of debris several stories high blocked the ducts, and a thick coating of dust blanketed everything, up to the rooftop cooling towers.

As one of Verizon's largest office buildings in the United States, and its largest switching center in NYC, the 1 million-sq-ft, 32-story structure is a critical telecommunications facility, serving some 300,000 voice lines and 3.5 million data circuits, as well as circuits connected to other telecommunications companies. Within a month, Verizon launched a reconstruction program to both repair the historic structure and improve its systems to better meet present and future needs. Consulting engineers Syska Hennessy Group joined the effort, initially to evaluate the condition of the building, and then to assess the space and develop several options to rehabilitate and/or replace the systems.

The team's objective was to create a state-of-the-art telecommunications center in a landmark building, with a complete infrastructure upgrade that would suit both the telecommunication functions on the lower floors and the administrative functions on the upper ones. Syska Hennessy Group was responsible for the design of mechanical, electrical, plumbing, fire protection, life safety, and central utilities systems.

All the new MEP systems and equipment were designed to furnish the capacity and flexibility necessary for the possible addition of telecommunications equipment in the future. Another key goal was to provide backup for the systems by building in redundancy and to make provisions for essential MEP services to be brought in from outside in the event of emergencies.

The design team also had to contend with a number of other challenges. First, the work had to be carried out expeditiously to complete the rehabilitation as soon as possible. In order to move it along quickly according to construction priorities, the team broke the work down into individual design and construction packages. For example, they issued design documents for the 17th floor, where the new fan farm would be located, as a single package.

Furthermore, the critical nature of the building meant that telecommunication operations could not be interrupted and that existing systems had to keep functioning while the new ones were being built and integrated into the structure. Thus, the new chiller plant on the first floor had to be constructed while the electrical service was maintained just below it, so work could not be performed in that area. In addition, the plant was designed for installation while a satellite chiller plant was kept in operation. Finally, because the building has landmark status, specific guidelines to avoid interfering with its historic features also came into play.

GREATER COOLING REQUIREMENTS

Technological changes that permit a larger number of processes executed by ever-smaller equipment have led to higher electrical loads per square foot and the need for greater cooling in a building of this type. Therefore, an entirely new central refrigeration plant was built to produce all the chilled water required for cooling the facility.

Redundancy was built into the plant by utilizing four 800-ton-capacity electric centrifugal chillers with associated chilled and condenser water pumps for an N + 1 capacity. The design also allows for the future connection up to 1,600 tons of additional capacity should the cooling load grow in the future. The plant includes two plate-and-frame-type heat exchangers to provide free cooling when outdoor conditions permit. To prevent damage or outage in case of flooding, the plant was located on the first floor, rather than in the basement where the previous one had been.

Each of the telecommunications floors from three to ten received two mechanical equipment rooms (MERs), at diagonally opposite corners, to reduce the risk of losing both in the event of an emergency. Each of the MERs includes two AHUs, either one of which is capable of handling the entire design load. In this state-of-the-art cooling system, the air is distributed beneath raised floors, leaving the maximum space free to house switching equipment. To protect the telecommunications equipment, water risers run through the MERs rather than through the telecomm space.