Josh Kahn, vice-president of Kahn Mechanical Contractors, Dallas, TX, knows that Design/Build doesn’t end with a delivered system to a customer, no matter how good that system may be. When the company takes on a Design/Build project, it strives to build a client relationship that will withstand the test of time: from identifying the customer’s requirements, to design, delivery, and then continuing on through the entire life cycle of the executed solution.

That philosophy has helped make for a busy year for Kahn and his team at Kahn Mechanical Contractors. In March, the company was selected as Contracting Business’ 2008 Commercial Contractor of the Year. Obviously not content to rest on its laurels, the company has been honored with a 2008 Design/Build Award for its work on phase three of a four-phase HVAC system renovation at a business that also knows a little bit about long-hauling: the corporate facility of Stevens Transport.

Stevens Transport is based just east of Dallas in Mesquite, TX. Since its founding in 1980, it has become one of the country’s leading refrigerated truckload carriers, servicing the 48 contiguous states, Mexico, and Canada. In a sure sign of the company’s wisdom, even from its inception, Stevens Transport’s management selected Kahn Mechanical Contractors for their facility’s HVAC service needs from day one.

In 1989, Stevens Transport moved into its current 50-acre, 80,000 sq.ft. corporate headquarters. At the time, the business needed only about one-half of the conditioned space. But growth was continuous, and as early as 2002 the company was in discussions with Kahn about the need to upgrade its facility’s infrastructure.

“It was obvious that the dynamic growth of Stevens Transport was going to push the facility’s aging mechanical plant to the brink,” says Kahn. “From the initial meetings in 2002, an ambitious four-phase plan was devised to replace the HVAC systems serving this 24/7/365 active facility with only three scheduled shutdowns over a three-year time frame.”

All told, this project required the replacement of more than 1,000 ft. of underground condenser water piping, 800 ft. of welded steel chilled water piping above occupied interior ceilings, two cooling towers, two water-cooled centrifugal chillers, six circulation pumps, four central station variable volume air handling units, five fan coil units, one dedicated outside air unit, and a new central building management system.

Delivery of this large project was broken down into four phases: central station air handling units and interior building piping in 2006; underground piping to the cooling tower and driver’s building, cooling tower replacement, and driver’s building renovations in 2007; the current phase, the central chiller plant renovation in 2008; and a still-proposed installation of new VAV controls throughout the facility in 2009. Kahn was selected for this Design/Build Award based on its performance in phase three, the central chiller plant renovation.

Identifying the Customer’s Goals
As with any Design/Build project, the customer came first when Kahn Mechanical tackled the Stevens Transport project.

“We worked directly with Gary Lyde, Stevens Transport’s facilities manager, to fully understand the client’s needs and goals,” Kahn says. “The client understood what they wanted, and it was our job to design systems to meet those goals.”

Kahn also worked closely with the equipment manufacturers, to ensure that each component that was selected would work well with the other elements of the design. Equipment efficiency, ease of maintenance, and sustainability were always at the forefront of equipment selection, according to Kahn. “Throughout this project, we made decisions to blend different manufacturers’ equipment together to best satisfy the customer’s goals,” Kahn says. “In doing so, we’ve obtained optimal airflow, water flow, and cooling outputs, and created a system that operates at the highest possible efficiency while operating within the required footprints.”

Kahn also made sure to communicate with the customer the potential benefits of stepping up to higher quality designs at each of the project’s crossroads. “Although they didn’t purchase every upgraded offering we suggested, they did consider every suggestion we made,” Kahn says. “The final design choices of this project were a true contractorclient partnership. The finished design was a result of our design experience, and the client’s consideration of the merits of our presentation of their choices.”

Five Steps to a Chiller Plant Renovation
For the chiller plant renovation, Kahn’s proposal consisted of five major components:
• replace the 31-year-old, 262-ton centrifugal dual chiller plant with a new, 400-ton dual chiller plant
• replace and redesign all existing piping for more efficient operation and fluid flow
• replace all pumps with new high-efficiency pumps
• control secondary water flow with variable speed drives to best match water flow with the building load
• modernize all controls that interface with the chiller plan to a web-based system that communicates faults via e-mail.

Kahn explained to Stevens Transport’s management that the benefits of this proactive renovation would include prevention of unplanned outages caused by mechanical failure, reduced utility consumption, improved comfort thanks to better control of the chilled water capacity and water flow, and better information from the controls system to help reduce equipment downtime.

Keeping the facility operational during the work was of paramount importance to Stevens Transport. “We’ve designed this chiller project to execute in a fashion that will continually improve the dependability of your operation, from the moment we begin the work to the final completion,” Kahn promised Stevens’ management. And he made sure his company kept this commitment.

Kahn’s experienced team of craftsmen (see “The Project Team” in the “Winner at a Glance” sidebar that accompanies this article) made sure each component was installed to the highest standards, and also managed subcontractors handling steel pipefitting, underground C900 piping, insulation, concrete, electrical installation, and the building control systems.

The team’s skills were put to the test when the controls subcontractor landed another large project during the completion phase of the Stevens Transport project and required replacement with another skilled subcontractor. However, Kahn’s team took the challenge in stride. As Kahn says: “The best team, with the most comprehensive training, using the best possible equipment, is destined to resolve any challenges it faces. We just sensed that delivering quality and customer focus were no longer the primary goals of this subcontractor, so we terminated the relationship and hired a new subcontractor to complete the project.”

The new chilled water plant at Stevens Transport is energy efficient (the chillers are rated at 0.538 kW/ ton) and can be maintained without the need for a complete shutdown. Two fully independent primary chilled water and condenser water loops with full cross-flow capability allow for service and maintenance of each section of the plant at any time.

The newly configured controls systems operate all the staging of the chillers and pumps, as well as the fresh air systems from previous phases of the projects, to provide optimal comfort. It also provides control for lead/lag rotation and the zoned variable speed secondary pumping to the facility. All of this control is operated via an easy-tonavigate graphical interface.

A Commitment to Commissioning
No design of this magnitude would succeed without attention to commissioning.

“We take the approach that a project of this type is minimally a twoyear commitment,” Kahn says. “We believe it takes two complete cycles of the seasons to adequately adjust a mechanical plant.”

Kahn’s commissioning takes several steps to complete. It begins with an assumption of how the systems are going to work, based on the company’s careful design and installation practices. The equipment is then commissioned following the manufacturers’ recommendations.

“Next, we discover all the improper assumptions we made during each seasonal change, and adjust the equipment and controls systems accordingly to account for these changes,” Kahn says. “This is also the appropriate time to discuss any operational changes at the facility, and to investigate further opportunities to serve the client.”

Finally, the company observes the effects of its commissioning throughout the first year of seasonal changes, and makes additional adjustments as necessary.

This attention to commissioning is just another example of how Kahn Mechanical uses the Design/ Build approach to meet customers’ needs not only during a project, but throughout the life of their facility.

“The ongoing relationships we build with our clients allow us the opportunity to provide retrocommissioning on the equipment and control sequences,” Kahn says. “We’re also able to ensure proper operation of the equipment through comprehensive mechanical maintenance. This lifecycle relationship ensures that our commitments to our clients’ requirements will endure for the entire life of their investment.”

Bob Nelson, senior vice president, Stevens Transport, is impressed with his company’s long-haul relationship with Kahn Mechanical Contractors.

“We highly recommend Kahn,” Stevens told Contracting Business. “They’ve been great over the years for us, very dependable and if we’ve got a problem they’re Johnny-on-the-spot. They were on schedule with everything on this project, very professional, and very efficient.”

Is there a secret to success for 2008 Commercial Contractor of the Year and Design/Build Award winner Kahn Mechanical Contractors? There is indeed. It’s a simple one, and Josh Kahn is willing to share it: “We do what we say, when we say we will do it. Nothing less.”