American ingenuity reflected in 9/11 Memorial

NEW YORK — Within the first three and a half months of opening, the National September 11 Memorial had more than one million visitors. The 9/11 Memorial is a tribute of remembrance to the nearly 3,000 people killed in the terror attacks of September 11, 2001, and February 26, 1993. At the heart of the memorial are enormous twin reflecting pools, which are set in the footprints of the Twin Towers and feature the largest manmade waterfalls in North America. Bronze parapets inscribed with the victims’ names line the perimeter of the pools.  

NEW YORK — Within the first three and a half months of opening, the National September 11 Memorial had more than one million visitors. The 9/11 Memorial is a tribute of remembrance to the nearly 3,000 people killed in the terror attacks of September 11, 2001, and February 26, 1993. At the heart of the memorial are enormous twin reflecting pools, which are set in the footprints of the Twin Towers and feature the largest manmade waterfalls in North America. Bronze parapets inscribed with the victims’ names line the perimeter of the pools.

(Photo Credit: Amy Dreher, 9/11 Memorial)

Facing a monumental project, the Port Authority of New York and New Jersey needed a team of contractors with determination and dedication. New York-based contractors 4 J’s Plumbing & Heating Corp., Fresh Meadow Mechanical Corp. and KSW Inc. were selected to install the piping for the reflecting pools, and heating and cooling system. To complete the job on time and resolve space and safety issues on site, Victaulic grooved mechanical pipe-joining systems were specified.

Unprecedented challenges

Each of the memorial’s reflecting pools is about an acre in size, and contains about 560,000 gallons of water. About 52,000 gallons of water ringlets cascade over the edges of the fountains every minute. The pools, which sink 30 feet into the footprints of the north and south towers of the World Trade Center, are located in an 8-acre plaza. The mechanical rooms housing the pumps for the waterfalls are located 50 feet below plaza level, directly beneath the pools.

4 J’s Associates LLC, a joint venture of 4 J’s Plumbing & Heating Corp. and Fresh Meadow Mechanical Corp., was tasked with the piping installation for the memorial. KSW Inc. was responsible for the installation of a heating and cooling system as well as the chiller plant.

Construction of the reflecting pools proved to be a project of unprecedented size, and not just for the contractors involved.

“[The Port Authority] asked if we’ve ever done a fountain project this large, and I said I don’t think anyone has done a fountain project this large,” said Daniel Justus, president of 4 J’s Plumbing. “But it’s a doable project for us, just larger pumps and bigger pipe and fittings.”

The memorial had to be opened in time for the dedication ceremony to victims’ families on the 10-year anniversary of the attacks. It also had to be ready to receive visitors a day later on Sept. 12, 2011, when it opened to the public. Despite the years of planning and pre-construction, the contractors faced a tight deadline, and completing the project on time was a key initiative for the Port Authority and the National September 11 Memorial & Museum, the private nonprofit responsible for operating and maintaining the 9/11 Memorial.

 “I assured them it wouldn’t be a problem,” said Justus.

With multiple trades working on site at the same time, space in which to work was significantly limited. The pump rooms posed a particular challenge, especially the south pump room, which is about half the size of the north.

“The mechanical rooms are shared space,” said KSW CEO Floyd Warkol. “There were different companies working under different contracts for different entities all at the same time.”

Confined space issues also made it challenging. The heating and cooling system, which is used when necessary to keep the bronze parapets at a favorable surface temperature, was installed in a 4-foot-tall crawl space below the parapets.

A common solution

The team of contractors needed a pipe-joining system that would be quick and safe to install, while managing on-site space limitations. The solution was Victaulic grooved mechanical pipe-joining systems. Victaulic products were specified for a large portion of the piping for seven mechanical systems on each pool, including the stainless steel waterfall systems and filtration systems, stainless steel sump and galvanized ejector lines, and ductile iron plaza drainage system, as well as the name plaque heating and cooling system.

(Photo Credit: Amy Dreher, 9/11 Memorial)

“The use of Victaulic grooved products accelerated the installation process tremendously,” said Michael Russo, COO of Fresh Meadow Mechanical. “It’s a much easier system to install.”

Among the products specified were Victaulic Advanced Groove System (AGS) products and Victaulic QuickVic installation-ready grooved couplings. AGS couplings were used to join the 24-in. and 16-in. waterfall piping. These large-diameter grooved couplings feature enhanced pressure ratings and feature a two-piece housing design up to 60-in. in diameter. Victaulic installation-ready couplings were used on several systems.

The combination of Victaulic AGS and installation-ready grooved couplings offered much-needed time savings, according to Russo.

“With 3,000 to 4,000 connections, welding all the pipe on site before the completion date would have been impossible,” Russo stated.

Victaulic grooved couplings were also used to join the 4-in. steel mains of the heating and cooling system. The flame-free joining method, which does not require heat or produce fumes during installation, proved advantageous in such a confined space.

“Victaulic was definitely a problem solver,” said Warkol. “This was an absolute perfect application.”

Piping and equipment installation for the fountains began in early 2010. In June, the contractors received notice that the north pool needed to be filled and operational for a demonstration in November. Using the Victaulic grooved products was a tremendous help in getting the project ready for the demonstration. With a union at every joint, grooved mechanical systems provide easy access for system alteration, as well as maintenance and expansion. To access the system, a worker simply loosens two bolts and removes the coupling housings and gasket. There is no need for a torch, saw or welding machine.

“With grooved pipe, if you have to take something apart, you take off the coupling and you extend it or alter it; it’s easy to work with,” explained Justus. “If you have welded pipe, you have to cut into the pipe and you have to weld another fitting. Doing that in the field versus the grooved system, it’s night and day.”

Maintainability of the piping systems was an important consideration for the waterfall piping. The chemical treatment of the water necessitates periodic inspections to detect microbiological growth within the systems.

“The access capabilities of the Victaulic connections [allows maintenance personnel to] take systems out of service, open up the piping, and do a visual internal inspection very easily,” Russo explained.

Another consideration was the accommodation of thermal movement. The design of a flexible grooved piping system accommodates expansion and contraction by permitting linear movement and deflection of the pipe within the coupling. This minimized the need for expansion joints or large expansion loops, which given the space constraints, would have been nearly impossible.

A majority of the larger pipe was fabricated offsite and delivery was coordinated so that it arrived at the memorial when the pipe fitters were ready for it. Relocation of some of the labor to the controlled environment of the fabrication shop made assembly of the systems efficient, minimized the amount of material handling on site, and saved space in the cramped pump rooms.

A proud moment

On Nov. 3, 2010, the contractors turned over the north pool to the Port Authority and the Memorial and Museum. By January 2011, installation of the piping systems for the south pool was substantially complete — more than three months ahead of schedule.

“Victaulic was a key player in being able to meet the required timelines for the project,” Russo said.

“The Port Authority and the Memorial and Museum foundation were really happy with what we did,” Justus said proudly. “They praised us for our workmanship and for completing the job in the timeframe we did.”

Helping build the 9/11 Memorial took on a special meaning for 4 J’s, Fresh Meadow and KSW.

“Being a part of the rebirth of the World Trade Center area was a remarkable experience,” said Russo. “It meant a lot to us as a contractor in the New York metropolitan area and our employees to be involved in the project.”

Warkol added, “It’s exciting to be a part of what’s taking place down there. It’s a major piece of American history.”

To learn more about the 9/11 Memorial and to reserve a free visitor pass visit: www.911memorial.org.

 

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