Collectively, the labs served over 1500 students per year out of the JHU undergraduate student body of 5000. Lab vacuum for organic and physical chemistry labs was being provided by 72 water jet aspirators, with a comparable number in the intro chemistry labs. Water jet aspirators create lab vacuum by relying on a stream of cold water rushing through a faucet-mounted device at a rate of up to 2 gpm. Over the course of a year, each aspirator was consuming thousands of gallons of domestic water.
A Problem of Flooding and Inferior Vacuum Supply
The organic and physical chemistry labs were housed in the ground floor of the old building, and on the floor above. The “rain” in the basement labs was coming from overflowing cup sinks in the labs on the floor above. Any blockage of the sinks – say, from a paper towel in the sink – caused the shallow sinks to overflow. “The rain happened at least 5 times per semester, sometimes leading to wet lab benches in the lab, other times leading to wet and slippery floors,” reports Louise Pasternack, Teaching Professor at JHU.
Furthermore, when all of the aspirators were in use at one time, building drains were unable to handle the capacity of all of that water. “The problem in teaching labs is that when you size plumbing for lots of sinks, you don’t assume that all the sinks will be turned on at full blast at the same time,” notes Associate Teaching Professor Jane Greco, “but when we do an experiment using vacuum that tends to be what happens.” Drains would back up, flooding the lab floors.
Besides the flooding problems, the heavy utilization was degrading the vacuum supply. “The system was not built for 60 aspirators being used at the same time,” notes Dr. Greco. “The more students who used the aspirators at once, the lower the water pressure in the building and hence the lower the vacuum would become.” With enrollments in the chemistry courses increasing, vacuum availability was declining, water usage was increasing, and the problem was getting worse.
On top of the flooding and vacuum performance problems, there was concern about the environmental impact of using water aspirators for vacuum production in the chemistry labs. “We used dichloromethane and ether,” notes Greco. “When students would filter these solutions, the organic solvent vapors would be pulled into the water.” It was clear that something had to be done.
Looking for a Viable, Water-Efficient Alternative
As it turns out, at the time the university was looking into how it could “consolidate the undergraduate teaching laboratories for biology, chemistry, biophysics and neuroscience into a single, modern facility that would foster an interdisciplinary approach to science education, share core facilities, and create highly flexible and interchangeable teaching labs,” according to Travers Nelson (AIA LEED AP), Program Manager for Design and Construction at JHU. Award-winning architecture and engineering firm, Ballinger, based in Philadelphia, was selected to design the new Undergraduate Teaching Laboratories (UTL) building.
Online, Drs. Greco and Pasternack identified an approach to lab vacuum supply being used by the University of Colorado Chemistry Department. “We were concerned about the capacity and the pressure from the house vacuum and looked for other options,” noted Greco. The technology involved generating vacuum in the labs, an approach referred to as “local vacuum networks.” Instead of utilizing a central vacuum system, with a single pump in the basement of the building to supply all vacuum to every lab, small pumps are installed in each lab to support several workstations each (at lab benches and fume hoods).
Special turrets control flow within the vacuum networks, ensuring that the small pumps can support several users each. “The goal was to provide vacuum service for all of the labs simultaneously. The local vacuum network approach was seen as a viable, water-efficient alternative,” observed Brian Smiley (AIA LEED AP), Director of Sustainability for Ballinger. Besides the water-free operation, the pumps operate oil-free with exceptionally low maintenance demands, and produce vacuum on demand – an energy-saving alternative to central vacuum systems which typically operate 24/7. The local installation also support the University’s objective of flexible labs that can be easily modified over time as science evolves.
To review JHU’s vacuum needs, Ballinger scheduled a conference call in early 2012 and included the architects, Drs. Pasternack and Greco, and an engineering team from VACUUBRAND, INC., whose parent company in Germany devised the local vacuum network approach some 20 years ago. The discussion focused on JHU’s need for simultaneous vacuum in many labs, and the actual depth of vacuum needed to support the intended academic program.
Local vacuum networks can be designed to provide vacuum comparable to central vacuum supply, or with the much deeper vacuum needed for evaporative applications (2 Torr or 29.86 in. Hg). Following confirmation that filtration-depth vacuum (55 Torr or 28 in. Hg) would be sufficient to meet JHU’s needs in the teaching labs, representatives of the company visited Johns Hopkins to conduct filtration demonstration tests. University staff were in attendance to assess the adequacy of the technology, along with the construction contractor (Whiting Turner) and the installation contractor (Southern Mechanical). Shortly after demonstration tests, the local vacuum network technology approach was selected for the general and intro chemistry labs, organic chemistry and intermediate and advanced inorganic labs.
Dry, High-Performance Labs
The new, 105,000 GSF Undergraduate Teaching Laboratories (UTL) building opened in August 2013. The labs were designed with an open, flexible layout with a long, thin lab configuration that maximized space for fume hoods, sinks and equipment. Each lab ends at a sweeping glass façade overlooking trees and a sculpture garden. For students and faculty, this was a dramatic departure from the windowless basement labs in Mergenthaler. Twenty teaching labs occupied three floors, with an additional upper floor for biological research, and a ground floor lab for undergraduate research.
By incorporating numerous energy savings systems into the UTL, the design is achieving 50% less energy use than a similar code compliant lab building relying on conventional technology. Besides the energy efficient local vacuum network, the project incorporated chilled beams, occupancy sensors that control lights and HVAC, high performance fume hoods, daylight sensors, and energy wheels that recover heat and moisture from exhaust air. For their work on the building, Ballinger has received design awards from the Maryland, Pennsylvania and Philadelphia chapters of American Institute of Architects. The project is also listed as a finalist for the Maryland US Green Building Council annual Wintergreen Award.
The local vacuum networks have proven a welcome alternative to the aspirator-based vacuum in the old building. “It allowed us have the strength of the vacuum that we need for our experiments in the chemistry labs,” reports Greco. The vacuum is “much more reliable” and “keeps organic solvents out of the water,” in contrast to the aspirators which tend to pull a lot of organic solvent vapors into the wastewater as they create vacuum.
In addition to the improved vacuum performance, Dr. Pasternack appreciates the “definitely greener approach” of vacuum supply without the massive water usage and contamination, to say nothing of labs without periodic rain and floods. Drs. Pasternack and Greco report only minor operating concerns since the installation two and a half years ago. One pump was damaged by a power surge from a lightning storm shortly after installation, and was replaced by the supplier. The other pumps have been “trouble-free,” according to Pasternack. A few of the vacuum turrets, which are made of a special chemical-resistant plastic, have been damaged in use by the thousands of students who have used them since 2013, but the modular fittings were readily repaired or replaced without tools. No other maintenance issues have been encountered with the local vacuum networks.
The pumps are designed for service intervals of many years in the type of use typical of college labs such as those at Johns Hopkins. Replacing water aspirators with an innovative approach to vacuum supply provides reliable lab vacuum while saving Johns Hopkins tens of thousands of gallons of water per year. This not only helps significantly improve the university’s water use efficiency but would also contribute if the project elected to pursue a LEED 2009 Process Water Innovation Credit. The university is currently seeking a LEED (Leadership in Energy and Environmental Design) Gold or Platinum certification for the building.
© Halkin/Mason Architectural Photography LLC