Kohler Ronan LLC: Marist College Natural Science & Applied Health B

Commissioning, retro-commissioning; electrical, power; fire, life safety; HVAC, mechanical; plumbing, piping; IT/security; construction administration.

By Kohler Ronan LLC August 11, 2016

Engineering firm: Kohler Ronan LLC

2016 MEP Giants rank: 98

Project: Marist College Natural Science & Applied Health Building

Location: Poughkeepsie, N.Y.

Building type: Educational facility; research facility/laboratory

Project type: New construction

Engineering services: Commissioning, retro-commissioning; electrical, power; fire, life safety; HVAC, mechanical; plumbing, piping; IT/security; construction administration

Project timeline: June 2014 to March 2015

MEP/FP budget: $323,000


The recently completed Natural Science and Allied Health Building at Marist College in Poughkeepsie, N.Y., is evidence of the college’s dedication to natural and health sciences. The state-of-the-art facility will be an integral part of the School of Science and to its health-related graduate programs. Housed across 3 floors of this attractive, 55,000-sq-ft. gray stone building are existing programs including athletic training, biology, biomedical sciences, medical technology, and environmental science as well as newer programs, such as the physician’s assistant program. Several simulation rooms, laboratory spaces, a vivarium, and a gross anatomy suite are incorporated.

From a mechanical engineering standpoint, all of these space types require specific airflow rates, pressure relationships, and temperature setpoints. To meet all of these stringent requirements, many different pieces of equipment had to be integrated into the facility. These included 100% outside air (OA) units with fixed-plate heat exchangers, high-plume exhaust fans, Venturi-type air-valves, and constant- and variable-flow terminal boxes.

The real challenge in a science and health building of this type is not so much in sizing the equipment, as is often the case in other building types, but rather in the interaction between individual mechanical systems. It was critical that systems not be in conflict with one another. As such, to achieve the necessary conditions for the specific room type as well as to provide occupant comfort throughout the space, Kohler Ronan’s team of professionals needed to design sophisticated mechanical systems. Air temperature, pressure, ventilation, and air quality were key factors. Motivated by the challenges inherent in this project, Kohler Ronan viewed the Natural Science and Allied Health Building as an opportunity to implement distinctive, impactful engineering design.


Kohler Ronan designed systems for the Marist College Natural Science and Allied Health Building with great care to address the challenges posed by the specific building type and its numerous requirements. Regarding temperature controls, the 100% OA units serving the lab spaces included fixed-plate heat exchangers to recover energy from the general exhaust air streams. The exhaust air from the fume hoods was not passed through the units, but instead had to be pulled directly out of the building through dedicated exhaust ductwork and high-plume exhaust fans. This led to an unbalanced airflow relationship at the heat exchangers, where consideration had to be given to selecting equipment that would eliminate the possibility of freezing. The face and bypass dampers at the plate heat exchanger then had to be sequenced properly to allow for both maximum energy recovery and frost prevention. Outside ventilation air was either directed through the plate or bypassed around it, depending on the incoming air temperatures. The preheat or cooling coils were then sequenced to provide a uniform discharge air temperature from the unit year-round. Due to the simultaneous heating and cooling loads year-round, and the many different space setpoints that need to be maintained, the remainder of the heating was handled locally through reheat coils at terminal boxes or mounted remotely in the ductwork.

As to the challenge posed by pressure relationships, Venturi-type air-valves were used whenever possible to maintain constant pressure relationships in lab spaces. Two basic setups were used: 1) single-supply valve groups and single-exhaust valve groups modulating to maintain airflow offset, either negative or positive depending on the space; or 2) supply, general exhaust, and fume hood exhaust valves, allowing for varying degrees of exhaust airflow from the hood while maintaining constant room airflow offset. In the gross anatomy suite, space limitations required the design team to use a combination of constant-volume terminal boxes on the supply side and multiple banks of Venturi valves on the exhaust side. This required another layer of sophisticated controls integration beyond the standard lab setup. To ensure the room-pressure relationships were maintained, the base building management system had to communicate with the Venturi air-valve controls. The air valves were then staged to ensure that supply air was setback fully before the exhaust valves went to their setback positions (unoccupied airflows) and that the exhaust valves opened to their full-flow positions before the supply air was reset upward (occupied airflows).

While the engineering design process was certainly challenging, the end result was just as successful. Mechanical systems are housed in a rooftop penthouse, providing easy access and maximum space. More importantly, these systems provide the conditions necessary for the optimal operation of the building and the optimal functioning of its occupants. The stunning, new facility will serve the Marist community, faculty, and students well for the foreseeable future. Kohler Ronan was pleased to have been part of the design team for this unique science/health facility.