Engineered Systems - February 2009 - (Page 33) Uniform Success The training facility is heated hydronically with 11 water-to-air heat exchangers that range in capacity from 3,500 to 18,500 cfm. project manager for Messer Construction Co., the commercial and industrial general contracting firm chosen by the city of Columbus to build the new facility. Messer Construction Co. is a regional general contractor and commercial construction firm specializing in complex building construction projects throughout the Ohio, Kentucky, Indiana, and Tennessee. “There definitely were some unique aspects to the mechanical systems at the Police Academy,” added Hann. “We chose Fox and Aggressive because of their experience with jobs on this scale, and because they were eager to take on the uniqueness of the project. Fox tapped Martina Metals to handle the airside work, and Stotts Insulation. Both are Columbus-based firms. “The geometry of the building created the need for a lot of offset piping” said Hann. “To complete the heating loop system, we’d make five-degree angle welds in the black pipe to accommodate the curvature of the building,” explained Joe Fox, president of Fox Mechanical. “To say the least, this was very time-consuming. We had three [two person] welding crews working non-stop on the primary loop for four months.” According to Fox, the primary loop’s large-diameter piping network — in the 2-1/2 to 8-in. sizes — was black pipe. Anything 2-in. or less was run in copper. “The building is heated hydronically, entirely by hydro-air,” added Fox. “We built the heating system around 11 primary water-to-air heat exchangers that ranged in capacity from 3,500 to 18,500 cfm per unit.” But there are an additional 170 VAV boxes, one per zone, and 14 fancoil units that serve some of the hallways and stairways where ducting of the hydro-air isn’t feasible. “All of these devices permit fine-tuning of zoned temperatures,” continued Fox. “Each of the remote units is separately piped with supply and return lines.” The mechanical room is spacious and intelligently designed. At its center, set like crown jewels, are four, 2-million Btuh Pennant boilers by Laars Heating Systems — two sets, two high — that provide 16 stages of firing, all controlled by a Honeywell BAS installed by Columbus-based Commercial Control Services. One hundred and seventy VAV boxes, one per zone, and 15 fancoil units allow for the fine tuning of zone temperatures. EXTENSIVE SYSTEMS The building’s complex mechanical systems, though less visible than its many architectural amenities, are no less important to the success of the facility. When the general contractor and planners for the building settled on the mechanical installations firms, they chose two Columbus-based firms. Fox Mechanical, Inc., was tapped to do the substantial heating job, and Aggressive Mechanical was chosen to handle the domestic water system. Both companies are union shops and specialize in commercial and industrial work. The contract for Fox encompassed an extensive heating system, HVAC, controls, and system insulation, exceeded $2.5 million, putting them on the jobsite for 11 months. Aggressive stayed on the job a few more months to complete the domestic water system for the new building. “This was about an 18-month project, overall,” said Michael Hann, In the mechanical room, four 2-million Btuh boilers, controlled by a BAS and stacked one pair on top of another, provide 16 stages of firing. w w w. esmag a zin e. c o m 33 http://www.esmagazine.com
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