Built in 1981, Des Moines’ Downtown Marriott needed to replace its cooling system’s chillers, pumps and controls. Baker Group was contracted to plan, design and orchestrate the project. 

According to Eric Johnson, Project Manager at Baker Group, this project presented significant challenges, including safely “flying” four 6,000-pound chiller barrels through an access opening on the hotel’s fourth floor – with only an inch of space to spare – without disrupting hotel operations and customer comfort. 

To deliver the pinpoint accuracy required by this project, Baker Group called upon its in-house, multi-trade expertise, technology and manpower. The solution was designed and executed collaboratively by the company’s Service, Building Automation, Sheet Metal and Electrical business units.

Project Essentials: BIM & Advanced Manufacturing
To determine how the 3-ton units could fit through the narrow opening, Baker Group’s Virtual Design team used a 3D scanner at the job site, which enabled it to reproduce the actual situation in a building information modeling (BIM) environment. 

“BIM enabled us to identify and plan for all the pinch points and issues on the project,” says Steve Brommel, Baker Group’s Virtual Design Construction Manager. “Among them, we determined that each section of the chiller had to be lifted by a crane and flown in at exactly a 21-degree angle.” 

With no room for error, Baker Group called upon its Advanced Manufacturing capabilities to enhance accuracy and safety. Load calculations were used to design and prefabricate a ramp with a 21-degree slope, which was bolted into place just inside the opening to guide the angle at which the crane operator and onsite labor maneuvered each piece into the room. Baker Group also prefabricated an overhead gantry system, which safely carried each piece into place without jeopardizing existing equipment and conduits. Both the ramp and gantry system were tested and retested prior to use.

“Making sure every angle, every movement, went exactly as planned on installation day required a lot of coordination, from the local utilities and signal person to the crane operator and the workers outside and inside,” Johnson says. 

Two days were allocated for the chiller upgrade. However, Johnson says, “All of that planning allowed us to complete the entire installation in just one, somewhat long day – without any chaos whatsoever. It’s just a lot less expensive to do it one time the right way.”

Meeting Our Client’s Needs
Johnson adds, “This project began with thoroughly understanding our client’s needs. The Marriott wanted to be sure we weren’t going to interrupt their daily business. They wanted to be sure their customers would be able to enjoy their stay in comfort and without lots of noise. We had everything it took under one roof to meet all of those needs.”

For a look inside this project see our video Inside the Project - Des Moines Marriott.