International Monetary Fund
Washington, DC
General Contractor:  Shapiro & Duncan, Inc.
Architect/Engineer:  Setty Associates, Inc.
Contract Amount:$3,150,200
Contract Start Date:  11/3/2010
Contract Completion Date:  4/15/2011
Actual Completion Date:  3/30/2011

Challenge
The International Monetary Fund (IMF) HQ 1 Cooling Tower Replacement (HQ1CTR) project was a design-bid-build delivery with Shapiro & Duncan as the prime contractor. This complex phased replacement of the complete condenser water cooling tower system, while the building was occupied, was completed from December 2010 thru March 2011 during the building’s lightest cooling load period. We were tasked with maintaining adequate cooling capacity (1000 tons) to support the IMF food services complex and the data center that tracks and maintains critical information on international finance and the world economy.

Solution
To complete this large scale rooftop project (6000 tons of cooling), we closed H Street N.W., three blocks from the White House in the heart of downtown Washington, D.C. and erected a tower crane on pads with a cross base. This allowed us to disassemble and remove in phases the existing cooling tower cells and bring in:

  • New 24" and 18" prefabricated condenser water piping assemblies
  • Prefabricated structural steel; conduit and cable
  • New cooling towers in phases; and
  • Pipe insulation and jacketing.

The majority of the work was completed during nights and over weekends to avoid disrupting the IMF executive directors whose offices and board room are immediately below the cooling tower well.

Using drawings verified and adjusted with field measurements, we created 3D mechanical CAD documents for fabrication. In addition, Capital Welding and J.E. Richards Electric produced 3D structural and electrical CAD documents for fabrication. All of the file sets were then integrated using Navis to create a BIM model where clash detection exposed all conflicts between the existing conditions and the trades.

Once the conflicts were resolved digitally, the work was released for prefabrication.

Once replacement began, the first task was to isolate one cooling tower cell from the other three so they could be removed while the remaining tower would maintain cooling capacity. This was completed over New Year’s Eve weekend after installing a temporary cooling tower and generator assembly on the loading dock. The temporary tower was tied in with six inch hoses, through the parking garage to the building condenser water loop, to maintain the data center.

Next, the first three cells of existing cooling towers were disassembled piece by piece and loaded into skip boxes lifted out and lowered into recycling dumpsters on the street. The piping was cut up in the largest safely removable sizes and lifted out of the well and into recycling dumpsters. At project completion, more than 105 tons of debris had been removed from the project of which over 89% was recycled.

With the first three cells out of the way, we began lifting prefabricated assemblies of 24" and 18" steel pipe (in up to 30 foot sections) and roughing in below the existing steel for new Cooling Tower 1. Then the prefabricated steel dunnage and isolation was hoisted and set, and electrical and controls conduit roughed in place. The first cooling tower arrived on site on four wide load trailers containing two stainless steel basin sections, each 12’W x 30’L x 8’H, and four fan sections (each 12’W x 15’L x 8’H). When the first cooling tower was in place and in operation following pre-functional testing and factory start-up, we were able to take the final existing tower cell off line and disassemble that section.

The second cooling tower was set in place following the same step-by-step process. After the second tower was brought on line, the tower crane came down and H Street was cleared, cleaned, inspected and reopened.

Result
Our crews worked seven days a week in multiple shifts from December 31 through March 20, when the cooling towers were in place and running and the tower crane removal was complete. The stellar performance by the Shapiro & Duncan team provided the IMF, in a very abbreviated time frame, with a new state of the art cooling tower assembly for the HQ building’s condenser water system with no negative impact to the IMF's mission.