Plant Expansion & HVAC Replacement

Nike AirMI – St. Charles, Missouri

Project Background

As part of a major plant expansion project initiated in 2017, McClure Engineering replaced the HVAC and constructed a central chiller plant at a confidential facility. The overall plant expansion project added approximately 52,000 sq. ft. of manufacturing space and a 15,000 sq. ft. community center to the existing 230,000 sq. ft. facility. This included expanding the existing heating, ventilation, and air conditioning (HVAC) system in the facility to meet the increased loads in the space and improve occupant comfort while also pursuing the conversion from DX to a more efficient chilled water system.

Project Deliverables

As manufacturing operations in the facility run 24 hours a day, nearly 365 days a year, the project was designed to be built in phases to minimize the impact on the operations of the existing facility.

The HVAC replacement portion of the project included installing new chilled water AHUs to serve the entirety of the manufacturing space, and replacing rooftop packaged DX units that were original to the building. HVAC chilled water is provided by the new chiller plant, constructed as a stand-alone building immediately adjacent to the existing plant. The new chiller plant also includes a new process chilled water system, which supplies 65°F chilled water year-round to process equipment throughout the plant. These loads were previously served by an open tower water system.

As with many projects, changes occurred throughout the process and McClure adapted to each new challenge to deliver a project that meets the requirements and expectations of the client. The manufacturing operations and loads within the facility are constantly changing, requiring flexibility in the design and implementation of mechanical and electrical infrastructure.

Energy Efficiency
While there are four phases of construction, for the purposes of the Ameren Incentive Program Application (which was approved in May 2017), we broke the project into two parts to track the energy efficiency. To satisfy the energy efficiency requirements, an air-side economizer was included on all new AHUs and a water-side economizer on the process chilled water system.

The first part has been completed, and our calculations show an energy savings of 3,984,759 kWh electricity due to the increased efficiency of the HVAC system and 1,863,372 kWh electricity due to the increased efficiency of the processing system, totaling 5,848,131 kWh of electricity saved each year. The second part has not yet been completed, but we expect to save an additional 1,370,715 kWh of energy each year, all of which is due to HVAC improvements.

Indoor Air Quality
The new HVAC chilled water system and associated air handling units allow the Owner to maintain the desired temperatures in the plant, improving occupant comfort for the employees. Although normal plant operations do not produce unpleasant odors, new relief/exhaust fans installed throughout the plant will allow the Owner to effectively exhaust the space in isolated cases when process equipment cleaning does create an undesirable condition.

Operation & Maintenance
There were packaged rooftop units spread across the plant. Existing controls were minimal and not very reliable. The existing tower water system had self-contained controls that were not well documented and contained some quirks, leading to interruptions in production at times.

The new chilled water plant and AHUs were installed with full BAS controls. A new head-end BAS system was included with a main operator interface workstation installed in the chiller plant. Full sequences of operation were provided for all new systems and equipment.

The chiller plant was designed with multiple layers of redundancy and contingencies in the event a chiller or pump is down for maintenance. The systems are designed so the HVAC chilled water system can provide backup capacity to the process chilled water system, providing redundancy for that system — critical to production in the plant.

Percent of Occupancy
The chiller plant is complete and fully operational (or “occupied”). Two of the four plant expansion construction phases are complete and the third is nearing completion. The fourth and final phase is in the early stages of construction. The existing plant has remained 100% occupied throughout the project.

Architect Of Record

Fox Architects

Construction Cost




Market Sector

Industrial Infrastructure

Year Completed




Our Services
McClure Mechanical services
McClure Electrical services
McClure Plumbing services

Erik Eaves, P.E.