LEO A DALY: Fort Riley Irwin Army Community Hospital
Automation, controls; electrical, power; energy, sustainability; HVAC, mechanical; lighting; and plumbing, piping.
Engineering firm: LEO A DALY
2017 MEP Giants rank: 28
Project: Fort Riley Irwin Army Community Hospital
Address: Fort Riley, Kan.
Building type: Hospital/health care facility
Project type: New construction
Engineering services: Automation, controls; electrical, power; energy, sustainability; HVAC, mechanical; lighting; and plumbing, piping
Project timeline: April 2009 to October 2016
MEP/FP budget: $129 million
LEO A DALY designed the Fort Riley Irwin Army Community Hospital in a joint venture with RLF. In addition to architecture and interior design, the team provided mechanical, electrical, structural and civil engineering for the replacement hospital, which opened in October 2016.
Sustainability was a major focus of the project, which sought LEED-NC Silver certification and needed to meet the Energy Policy Act (EPACT) 2005 mandate of 30% energy savings as well.
With 24-hour operation and complex energy needs, including specific airflow controls and specialized HVAC systems, hospitals are among the greatest consumers of energy in the United States. Balancing sustainable design principles with the needs of a new 44-bed, 263,000-sq-ft hospital on a 709,712-sq-ft campus required creative engineering solutions on the part of the LEO A DALY team.
Bi-weekly meetings were scheduled to discuss sustainable and energy-reduction methods. These meetings, coupled with the creativity of LEO A DALY’s engineers, led to many successful sustainable design solutions.
Energy efficiency was achieved through multiple avenues, including enhanced commissioning, heat recovery chillers, daylighting strategies, lighting design, and customized airflow and air-handling solutions.
Engineers focused on incorporating lighting that emphasized the project’s energy-reduction goals by selecting a combination of high-efficacy fluorescent lamps and LED sources. Lighting controls included occupancy sensors, lighting control relay panels, and daylight harvesting photo sensors. Daylight harvesting was used in public areas with access to abundant natural daylight. Photo sensors connected to dimmable luminaires to limit the perceptibility of changing light levels.
Additional energy-reduction strategies developed after unoccupied setbacks in operating rooms (ORs). ORs were designed to meet code-required air changes per hour during occupied periods, necessitating a significant amount of airflow and therefore a significant amount of energy. To reduce energy usage, airflow in the ORs was reset to a minimum during unoccupied modes. Venturi-type air valves were installed on each supply and return ductwork branch serving individual ORs. The air valves maintained a fixed airflow offset between the supply and return air to maintain required pressurizations in the spaces during occupied and unoccupied modes. When the OR was in unoccupied mode, air valves reduced the airflow into the space while maintaining its required positive pressurization.
Efficient air-handling was achieved with variable volume systems and internal control optimization, when possible. The hospital included 13 variable air volume air-handling units, each with multiple direct plenum fans. To optimize energy of the variable volume system, static pressure reset controls were implemented at each unit. The static pressure set point of the air-handling unit system was actively reset based on a controls sequence, which monitored all variable volume terminal unit damper positions. If all terminal unit dampers were monitored and in non-full open positions, the static pressure was reduced until a critical zone damper was monitored to be in a near full open condition.
Resetting static pressure set points provided significant fan energy savings within the mechanical system. A similar static reset controls sequence was implemented on the variable volume pumping systems within the system to reduce pump energy.
Additionally, LEED-NC Indoor Air Quality Credits were closely tracked with the goal of achieving each credit. The team had a multifaceted approach to achieving superior indoor air quality: ventilation rates exceeded minimum requirements and a specific Construction Indoor Air Quality plan was initiated during all phases.
The team’s diligence paid off. The facility achieved LEED Silver Certification, scoring 13 of 15 points for Indoor Air Quality, and four of five points for Water Efficiency and Innovation. The combined lighting source and control technology strategy allowed the project to obtain LEED SS credit 8 (Light Pollution Reduction) and LEED EQ credit 6.1 (Controllability of Systems).
The project realized energy savings of 32.5%, which is 2.5% greater than the EPACT 2005 requirement. The facility was one of the first, if not the first, Department of Defense hospitals to meet that requirement.