U.S. District Courthouse for the Northern District of Iowa

New construction; U.S. District Courthouse for the Northern District of Iowa; KJWW Engineering Consultants

08/15/2013


This image shows the entrance to the U.S. District Courthouse for the Northern District of Iowa in Cedar Rapids. Courtesy: KJWW Engineering ConsultantsEngineering firm: KJWW Engineering Consultants
2013 MEP Giants rank:
29
Project:
U.S. District Courthouse for the Northern District of Iowa
Address:
Cedar Rapids, Iowa, United States
Building type:
Office
Project type:
New construction
Engineering services:
Code Compliance, Electrical/Power, HVAC
Project timeline:
April 2009 to July 2012
Engineering services budget:
N/A
MEP budget:
$1.48 million

Challenges

The new 287,600-sq-ft LEED Gold federal courthouse in Cedar Rapids presented many challenges due to the often-competing security and sustainability requirements of the General Services Administration (GSA). At the same time, KJWW needed to make sure the systems designed to address these challenges did not undermine the architect’s “Big ideas of the building,” which included a 59,675-sq-ft glass curtain wall facing north and a spacious atrium in the center which splits the building into two distinct sides. The GSA mandated that the building be extremely energy efficient, using no more than 55 kBtu/sq ft each year. The GSA’s security criteria, meanwhile, included such items as enhanced steel reinforcements and systems with greater-than-normal energy use, such as security-based lighting and continuously-running dedicated ventilation for holding cells and mail room.

The most overlap between security, HVAC design, and sustainability occurred in the air distribution design. The GSA’s Facilities Standards for the Public Buildings Service (PBS P100) requires that no air handling unit (AHU) can be larger than 25,000 cfm and no unit can serve more than one floor. With 287,600 sq ft over eight floors, split in two sides (courtroom side and tenant side), there had to be an AHU for each floor on each side (16 total AHUs). In addition, code required each AHU to bring in outside ventilation air, but the GSA’s anti-terrorism standards do not allow for any air intake below the 4th floor, and the architect did not want any air intake or relief on any exterior walls. Traditional mixed air AHUs normally would have air economizers, which bring in air from the outside to condition the building when outside air conditions are right. For the courthouse, this would have required each floor’s AHU to be ducted to the roof. With all the required AHUs, such a system would have a far greater need for mechanical room space, something that was not cost effective where floor space was at a premium and being built at $300 to $400 per sq ft.

Solutions

To meet the GSA’s energy efficiency goals and security requirements and not compromise key architectural features, KJWW developed two key solutions which were supported through energy modeling evaluations by The Weidt Group:

  1. Elimination of the outside air capability for all AHUs and installation of a completely decoupled dedicated outside air system. Two units on the ground floor have the sole purpose of providing outside air for the building. They draw in air from the roof, condition it, and send it through the building for ventilation air. They also take all the air that they put into the building, bring it back to the units, and exhaust the air at grade level. The outside air coming in and the exhaust air going out exchange energy through enthalpy wheels (another energy-saving measure).

  2. The use of water economizers instead of air economizers for the AHUs. Water economizers create chilled water by routing the chiller system condenser water outdoors to be cooled by the cold ambient air, and then use that cold water to cool the indoor system chilled water via a heat exchanger. The system creates chilled water in the winter without having to run mechanical cooling. Water economizers have their own challenges, however. Ice can form on the cooling tower in the colder months. During transitional months when days are warm but nights are still cold, the mechanical chillers, needed during the day, often don’t start up easily when there is still cold water coming to them from the water economizer that may have operated overnight. The engineers developed a control sequence for going from one system to the other during these periods to ensure the system ran reliably.

Commissioning played a critical role in verifying the systems operated as designed. Although the water economizers added a degree of operation complexity, KJWW and the GSA determined that the water economizers would cost far less on a lifecycle basis than air economizers, which would have required larger air handling rooms throughout the building. In addition, the chases and chase space required by air economizers for intake and relief would have been impractical for the building, where floor space was at a premium. Another key energy-saving feature was the use of electric “point-of-use” water heaters instead of a central hot water system, since there is not much need for hot water in the building.

While gas is less expensive for heating water, installing small point-of-use electric heaters where the water is needed—at each sink or bathroom group—eliminated the need for central storage of hot water, distribution and recirculation piping, saving all the cost involved and eliminating “parasitic” heat loss. As for the glass curtain wall, members of the core design team traveled to Washington, DC, where the GSA’s HVAC Peer Review panel accepted the engineers’ solution that flushing air along the wall would prevent condensation. 



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Your leaks start here: Take a disciplined approach with your hydraulic system; U.S. presence at Hannover Messe a rousing success
Hannover Messe 2016: Taking hold of the future - Partner Country status spotlights U.S. manufacturing; Honoring manufacturing excellence: The 2015 Product of the Year Winners
Inside IIoT: How technology, strategy can improve your operation; Dry media or web scrubber?; Six steps to design a PM program
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Warehouse winter comfort: The HTHV solution; Cooling with natural gas; Plastics industry booming
Managing automation upgrades, retrofits; Making technical, business sense; Ensuring network cyber security
Designing generator systems; Using online commissioning tools; Selective coordination best practices

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me