Commissioning key to green Chicago high-rise

One of the biggest differences between ordinary buildings and "green" buildings may be that the green buildings actually operate the way they were designed. The U.S. Green Building Council awarded a Gold LEED certification last October to the 111 South Wacker building here, the first speculative high-rise office building with the designation. When developer

CHICAGO — One of the biggest differences between ordinary buildings and "green" buildings may be that the green buildings actually operate the way they were designed.

The U.S. Green Building Council awarded a Gold LEED certification last October to the 111 South Wacker building here, the first speculative high-rise office building with the designation. When developer The John Buck Co. got the keys, building commissioning had ensured that the building's systems worked as designed, said Jason Rahn, project engineer with Hill Mechanical Corp.

It's an old adage that whatever gets tracked gets done.

The mechanical contractor's crews worked with checklists throughout the project, Rahn said, to make sure that they were installing the equipment as required. Next, Hill Mechanical checked off tasks in a pre-function test — is all the electrical work done, is the control work done, has all the programming been completed?

The purpose of the pre-functional testing is to minimize "curveballs" at startup, Rahn said. Then the equipment was started and functional testing performed, including failure testing to see how the equipment and the building automation system reacted. Finally, Hill Mechanical adjusted the equipment as the air-and water-balancing contractor performed its work.

The U.S. Green Building Council wants to help develop a new generation of buildings "that deliver high performance inside and out." To do that, the USGBC developed the Leadership in Energy and Environmental Design Green Building Rating System, which is a voluntary, consensus-based national standard.

But how does LEED verify building performance?

"Through building commissioning," explained Mike Opitz, certification manager for LEED Existing Buildings for the USGBC. Building Commissioning is a prerequisite for a project to be LEED-certified, and LEED even allows for an extra commissioning credit for one LEED point.

The LEED process calls for a qualified, independent agent to be responsible for building commissioning, which is a " planned, systematic qualitycontrol process that involves all members of the design and construction team," Opitz said.

Commissioning involves systems testing to make sure that building systems perform the way they were designed. Hill Mechanical Service, a division of Hill Mechanical Group, was in charge of the commissioning.

When The John Buck Co. developed 111 South Wacker, "there were several pre-requisites on the HVAC side that we had to maintain," Rahn said. " Fundamental building system commissioning, minimum energy performance and reduction of chlorofluorocarbons in HVACR equipment were all part of the prerequisites."

Hill Mechanical Corp. designed and installed the HVAC systems as part of a design/build contract.

The Chicago office of consulting engineers Cosentini Associates developed the original mechanical scope and RFP for constructor Bovis Lend Lease, Rahn told CONTRACTOR. When the developer decided to pursue LEED certification, Hill Mechanical redesigned the systems and hired WMA Consulting Engineers, Chicago, to stamp the drawings as the engineer of record.

Hill was presented with three prerequisites, Rahn said: reduce CFC refrigerants; meet minimum energy performance requirements of ASHRAE Standard 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings; and conduct an independent energy analysis performed Chicago engineers Environmental Systems Design.

The original design specified chillers using HCFC-123, and Hill's designers changed that to three 1,200-ton Carrier 19XR Evergreen units using HFC-134A.

Hill Mechanical implemented an indoor environmental quality construction management plan, based on Sheet Metal and Air Conditioning Contractors' National Association guidelines on closing off the ends of duct and piping to keep them clean and not recirculating dust around the building through the ventilation system. Hill exceeded the requirements for outside air contained in ASHRAE Standard 62.1-2004 Ventilation for Acceptable Indoor Air Quality.

The chiller plant for the all-electric building is on the 11th floor. The main air-handling units are in a doubleheight space on the 29th and 30th floors. The built-up air handlers, 360,000 CFM each by Buffalo Air Handling, feed 40 tenant floors. They supply fan-powered boxes on the floors, which were left mostly unfinished for the tenants to fit out.

Nortek subsidiary Ventrol Air Handling Systems supplied chilled water coils inside the air-handling units. The building is electrically heated via coils in the air handlers.

Rahn noted that the building has 1,000 additional tons of cooling capacity available from the four Baltimore Air Coil cooling towers on the roof.

Controllability of the systems was an issue, Rahn said. The building automation system was modified and expanded to allow 50% of occupants to control their own spaces to achieve more thermal comfort, thereby minimizing overheating or overcooling.

To make sure that the calibrations on the air-flow monitoring stations were all proper, for example, the building commissioning team called on Fresh Aire Test & Balance of Lemont, Ill.

"We did the testing and balancing of the air and hydronic systems," said Fresh Aire's Bill Niehoff, president of the Chicagoland Sheet Metal Contractors Association.

CSMCA Executive Director Tony Adolfs said testing and balancing contractors such as Fresh Aire and others in the Testing, Adjusting and Balancing Bureau see tremendous business opportunities with LEED certification.

Aside from the environmental reasons, The John Buck Co. chose to develop 111 South Wacker as a LEED building because it made sense economically, said Buck's Dan Jenkins.

"A tenant's overhead costs include rent, taxes and utilities, and building operations and employee costs," Jenkins explained. "Generally, the cost of utilities is less than 1% of the total — so reducing building energy consumption becomes more important environmentally than it is monetarily."

The real savings, Jenkins said, comes in the form of employee productivity.

"Employees account for more than 80% of a tenant's total costs," Jenkins noted, "so the productivity benefits that result from measures taken under the LEED program become very important financially. Studies show that good lighting, natural light, increased ventilation and temperature comfort, as well as clean air, all contribute to higher productivity, reduced absenteeism and turnover. Even a 1% improvement in productivity is significant."

Jenkins added that nearly all Buck's potential anchor tenants appear interested in LEED certification, and some are currently specifying LEED certification as a requirement for the building that they will occupy.

"We believe that in the not too distant future, LEED certification will be a basic requirement of larger, sophisticated tenants," Jenkins said.

Opitz agreed. While about 400 buildings currently have LEED certification, another 3,000 are registered to go through the LEED process.

"In 2000, the dollar value of LEEDregistered buildings — meaning buildings which had registered to go through the LEED process — was $600 million," Opitz said. "Today, the dollar value is $8.3 billion."