GLUMAC - Engineers for a sustainable future

David Summers, P.E., LEED^® AP 
Los Angeles Associate Principal

"The collaborative relationship between the GSA, designers, contractors, and local utilities delivers an innovative design and the latest building technology for the Wayne L. Morse Federal Courthouse"

A Focus on "Design Collaboration"

Many of the successes of the Wayne L. Morse Federal Courthouse project have been "design collaboration." GSA's unique initiative to bring the general contractor and key sub-contractors on early during the design process and utilizing competitive pricing has allowed the team to work together in a collaborative process.

"The contracting strategy and approach was designed to optimize value for the US taxpayer. The strategy was based on several axioms. First that there are never enough resources to do everything that needs to be done. Second that teamwork creates synergy or manufactures additional resources. And third, teams succeed as teams, not as individuals. Contract placement and administration focused on assigning scope based on proven strengths and skills then deference was provided to those tasked with executing that scope. If desired outcomes weren't achieved the whole team contributed to analyzing root cause and formulating potential corrective action, not fault finding. In the end the strategy tried to create relationships that ensured decision making consistently focused on what was best for the project."

The new 262,000 sf Wayne L. Morse Federal Courthouse will be a spectacular architectural, engineering and construction achievement when complete in August 2006. The "team collaboration" has been a hallmark of the design and construction process. The significant challenges facing the project, including a $267/sf budget, is amongst the lowest, on a square foot basis for a recent Federal courthouse. Additionally, a goal to achieve LEED^® certification after the design had begun and the budget had been fixed, and the need to meet these goals, while not compromising on the bold design created by design architect Morphosis and executive architect DLR Group, required a unique approach unlike previously constructed courthouses.
The Wayne L. Morse Federal Courthouse is part of the General Services Administration (GSA) Design Excellence program, which aims to raise the design quality of federally procured buildings. DLR Group and Morphosis, along with engineers Glumac, mechanical and KPFF, structural/civil, sought to create a building that would set a new benchmark of architectural and engineering excellence for the city of Eugene, Oregon and for the GSA. The lower floors are a two-story glass podium containing the administrative departments. Three sweeping curved metal and glass fa€ade pods, housing six courtrooms and Judges Chambers, are connected by a central atrium.

Contractors Control Costs

To assist in keeping the project on budget, the general contractor, J.E. Dunn, was selected during the design development phase. Additionally, the subcontractors Total Mechanical and Cherry City Electric bid the design development drawings and were also selected to participate in the design process. The selections were made through an interview process in which the "best value" contractors were chosen based on many factors including price and ability to collaborate.

Cost controls were implemented early in the design, major pieces of equipment were pre-purchased, and specific routing of the mechanical, electrical and plumbing (MEP) systems was coordinated with the contractors. This allowed the final documents to be designed around these early selections and was crucial due to the limited space the building allowed for mechanical and electrical systems. This collaboration generated a design that saved money through improved coordination.

"Through our collaboration with the design team, we were able to save significant dollars on the HVAC budget, which allowed that money to be returned to the overall project budget to pay for mechanical upgrades and enhancements to other parts of the building," said Chuck Foreman, vice president for Total Mechanical.

Some of the mechanical upgrades included using "fan-wall" technology for the large air handlers, which are smaller in size and acoustically superior to other types of air handlers, and adding features to the DDC controls to accommodate the requests of the GSA facilities group that will maintain the building.

Following the LEED^®

Although attaining Leadership in Energy and Environmental Design (LEED^®) certification was not part of the original intent of the project, the design team did not need to adjust the design significantly when LEED^® became a project requirement. The HVAC system had already been designed to minimize energy use, and the energy modeling results confirmed that the building energy use was more than 38% below ASHRAE Standard 90.1, earning six LEED^® credits. The project is now expected to achieve LEED^® Silver certification.

The HVAC design includes an underfloor air distribution system serving the majority of the spaces, including the six courtrooms. Lobbies and public spaces are served by radiant slabs for heating and cooling coupled with displacement ventilation. The HVAC central plant utilizes a heat recovery chiller to reject heat from the 24/7 server room loads into the heating water system. Condensing boilers maximize the efficiency of the heating water system while keeping water loop temperatures low so that the heat rejection chiller works efficiently.

Radiating Comfort

Below the floors of the atrium, public corridors, and jury assembly room will be a radiant heating and cooling system designed to save energy, increase comfort, and seamlessly integrate with the architecture of the building. These spaces are some of the most visible and architecturally important spaces in the building. With their high ceilings (up to 70 ft in the atrium) and large glazing areas, they are also amongst the most difficult spaces to condition.

The radiant system consists of PEX tubes encased in a concrete floor slab. The tubing distributes heating water or chilled water from the central boiler and chiller plants through the floor slab. A radiant system was the logical choice to condition these spaces. Radiant systems are excellent at offsetting large radiation loads from glazing, which allows for comfort to be achieved within a more lenient air temperature range. The radiant floor handles 100% of the heating load in the winter, which solves the issue of how to heat tall spaces while minimizing stratification. Typical air systems struggle to keep the heat at floor level where the occupants are, thereby wasting a lot of energy and achieving less than satisfactory comfort. Radiant floor heating is inherently more energy efficient and comfortable for these types of spaces. In the summer, the radiant floor is used to provide partial cooling. The supplementary air system meets the remainder of the cooling load as well as providing ventilation in both summer and winter.

In order to calculate the floor cooling capacity, Glumac collaborated with the radiant floor manufacturer to perform a finite-element analysis of the floor at various conditions. The historical concern with radiant floor cooling has been condensation on the floor. Space humidity sensors and floor slab temperature sensors are employed to prevent condensation and ensure comfortable operation. The system design and control sequences incorporate the current state-of-the-art thinking on radiant floor cooling and lessons learned from previous radiant cooling projects.

Architectural Integration: HVAC Systems

When designing a radiant floor system, care must be taken to ensure that the heat transfer is directed up, to the conditioned space, rather than down, wasted to the space below. This is achieved by insulating underneath the radiant floor and by not insulating on top of the floor.

In the Wayne L. Morse Federal Courthouse, the insulation under the floor was already part of the architectural design to maintain the floor level with adjacent spaces. An underfloor air distribution system is used throughout the building, except in the public spaces in which the architect desired a tile floor. The tile floor is raised on a rigid foam and concrete topping slab construction in order to maintain a consistent finished floor level throughout the building. The tile floor covering provides very little thermal resistance to the heat transfer between the tubing and space, and the foam underneath prevents energy waste below. The arrangement is ideal for the radiant floor, at no added cost to the project.

A supplemental air system provides ventilation air and a portion of the cooling capacity for these public spaces. The air system is also integrated into the architectural design. The air is delivered down through the wall stud cavities to hidden grilles at the bottom of the walls. The air is supplied at a low level and low velocity, a classic displacement ventilation system. The air distribution capabilities and noise level produced by the system were tested during the design phase with a mock-up built by the contractor.

The air system with a radiant floor is smaller than that without the radiant floor. The resulting reduced shaft sizes and duct distribution are another benefit to the architecture of the building.

Drawing in Three Dimensions

With the mechanical sub-contractors, Total Mechanical taking the lead, all of the sub-contractors created shop drawings in three dimensions using Autodesk Building Systems. With this software, all MEP systems were brought into a cohesive, functioning, and controllable 3-D virtual building model that can easily be edited. This level of coordination, at the sub-contractor level, allowed the team to really see what was in the tight spaces before it was built.

For example, the administrative levels had less than two feet of space between the ceiling and post-tensioned slab. In this narrow space there are perimeter VAV boxes and ducts, heating and chilled water piping, plumbing, conduits, cable trays, lighting and security control devices. In many areas, several systems were stacked on top of each other with a fraction of an inch clearance between them. With post-tension construction, the layout of these systems and insertion of hanger supports is best done before concrete placement to eliminate the potential of drilling hangers into a tensioned cable later. This required the stakeholders in the MEP disciplines to provide accurate shop drawings early in the process.

Sub-contractor coordination meetings consisted of a high-performance laptop, a projector, laser pointers, and a real discussion of where the conflicts were and what needed to move to make everything fit. The computer did the calculations, identified the conflicts, and automatically generated sections and isometric views, so that the team could spend time on solving problems. Real time changes to the shop drawings were made and printed so each member could carry the latest information back to their crews.

The additional cost of the shop drawings and coordination was more than made up by avoided conflicts and changes in the field. The contractors have estimated that the 3-D shop drawing process identified 95% of potential conflicts, as compared to 80% for a standard 2-D process on a project of this complexity.

Let There be Daylight

With the large amount of glazing on the Courthouse, including floor-to-floor curtainwall glass on the lower two levels, the potential for energy savings through daylighting control was enormous. Despite this potential, budget constraints initially kept daylighting out of the building design. The project team continued to search for ways to add daylighting into the project while the building was under construction. Obtaining incentives from the local electric utility, Eugene Water and Electric Board (EWEB), and tax breaks from the State of Oregon proved to be the answer.

Working with Rod Olsen, Energy Management Specialist for EWEB and Kit Meith, Region 10 Energy Coordinator for the GSA, Glumac performed energy modeling of the building and determined that daylighting would save an estimated 160,000 kilowatt-hours per year. EWEB provided energy incentives to offset 75% of the initial cost of the daylighting system, with the GSA picking up the remainder of the cost. As Rod Olsen put it, "Daylighting was just too good an energy-savings opportunity to let go."

As a federal entity, the GSA is not taxed by the State of Oregon. However, the GSA still qualifies for the Business Energy Tax Credit (BETC) program through the Oregon Department of Energy, using a 3^rd-party pass-through organization to capture the credit. After the BETC rebate is realized, the GSA's net cost for the daylighting system will be minimal. Kit Meith and Richard Broderick, project manager for the GSA, understood that a daylighting system was clearly in the best interest of the project and of the GSA, and they were able to find the initial funding to make sure that it happened.

Cherry City Electric incorporated dimmable electronic ballasts and sensing controls in all perimeter offices, public spaces, and Judge's Chambers where Glumac's analysis had indicated daylighting was cost effective. Although the final decision on daylighting control came late in the construction, Cherry City was part of the process throughout and ensured that it was incorporated without delay to the schedule.

Collaborative Commissioning

To minimize cost and maintain design integrity, Glumac was also retained to provide commissioning services for the project. The success of the commissioning process depends on the buy-in of all stakeholders including the GSA, general contractor, sub-contractors, and the design team. The GSA laid the groundwork for commissioning early in the project with all involved parties, and the commissioning tasks are incorporated into the overall construction schedule. All building components to be commissioned are scheduled for completion with adequate time for pre-functional and functional testing before the expected building occupancy date.

An important component of the commissioning process is ensuring the integrity of the raised access floor plenums. Working together the GSA and Glumac developed a procedure for testing the air tightness of the raised access floor plenums. An initial test was conducted on a 4,000 sf mock-up area. The initial test for the mock-up area indicated in excess of 70% leakage. Utilizing smoke machines, the leaks were located and repaired. A goal of less than 10% leakage for all floor plenums has been established for the project. This plenum leakage testing will become a new standard for raised access floor commissioning.