Design Solutions For Greening Hospital Labs
We know that hospitals are energy and water intensive, and when looking inside, laboratory space emerges as one of the worst offenders. As with all conservation measures, best practices start with downsizing wherever practical.
Fume hoods may provide one of the biggest opportunities for energy conservation within a lab environment, since they demand high air flow that may drive the overall HVAC sizing and energy requirements of the building.
Improper use of fume hoods or overuse of fume hoods means constant air exchange, which can dramatically increase energy use. An assessment of work practices and material use helps inform hood needs and air exchange needs. Frequently, laboratories are exchanging air at a more frequent rate than necessary.
Each standard 6-foot hood’s energy costs range from $4,600 per year for moderate climates such as Los Angeles to $9,300 per year for extreme cooling climates such as Singapore. As designers and engineers optimize low-risk laboratories with air flow below six air exchanges per hour, a hood sash management system becomes more critical, as it educates users on how to properly use the hoods to reduce energy waste. Shutting the hood sash helps the fume hood run efficiently.
As an alternative to ducted fume hoods, some laboratories consider a ductless or advanced filtering fume hood with an advanced molecular carbon filter. The carbon filter traps and adsorbs chemicals, rather than exhausting the chemicals outside into the air. Considerations of whether a lab could benefit from a ductless or advanced filtering hood include the quantity of experimentation, chemical handling, and the types and amounts of chemicals in use. Under the right conditions, a carbon filtered hood can improve energy performance and indoor air quality. But if the filter needs to be changed more than once a year, it’s probably not worth the switch because the cost is too high and return on investment isn’t there.
By using advanced filtering fume hoods to achieve energy conservation goals, not only is there reduced energy use but the duct work to vent outside is eliminated and the make-up air system size is reduced. The hood can also be moved so it creates a flexible operation that can help with lab reconfiguration down the road.
Cooling systems and airflow
According to a UC Irvine study, it’s also important to size cooling systems for heat generation from equipment and lighting. Some design standards are vastly exaggerated to about 10 W/sq. ft., while actual plug load measurements show about 0.5 W/sq. ft. in gallery labs, 4W/sq. ft. in mixed-use labs, and 10 W/sq. ft. in equipment rooms, and the overall floor averages under 2 W/sq. ft. This demonstrates that laboratory systems are sometimes over designed to provide support for a much higher plug load than needed.
With a perception of more ventilation is better, laboratories can have a tough time meeting conservation goals. As with operating rooms, laboratories can be scheduled for reduced airflow or “setbacks” so that the unoccupied space (after hours, on weekends) can have reduced air flow when not in use. Some labs have 30 air exchanges per hour and can be reduced to less than 10 in off hours or when not in use.
Laboratory buildings should always have separate air handlers for offices and conference rooms versus laboratories. Re-circulated air for office zones is much easier to condition than 100 percent outside air needed for laboratories.
Overhead lighting can be reduced by using LED task lighting at the bench. Flooring choices should be selected for cleanability, and tile may be optimal over sheets to reduce the need more easily replace sections in the event of a spill. There are numerous technologies available for recirculation of waste water which is used for equipment cooling. For example, low-flow equipment and washer specification can dramatically reduce water use in the laboratory setting.
While staffers value natural day lighting and a connection to nature, some equipment requires a dark space for best performance, such as microscopes, or a cool environment, such as lasers. Knowing what equipment will be housed in which room is important for natural lighting, ventilation, and cooling needs. These details require input from technicians and managers to best site equipment in a way to provide engineering controls for each need rather than trying to meet individual needs in one space.
Finally, most hospital pathology labs use both xylene and alcohol for tissue processing. Through on-site distillation, the waste solvents are heated to remove waste contaminants, resulting in a pure product available for reuse. The on-site distillation reduces costs on both purchase and hazardous removal of the used solvents. While there’s no need to have this equipment in a separate room, efficiency dictates a close proximity to solvent use.
Eighty-two percent of Practice Greenhealth’s top awarded facilities have an on-site laboratory, and 61 percent of those facilities have a program to distill solvents on-site. The average savings per facility is $18,000 or $84 per staffed bed.
Laboratories that don’t take advantage of on-site distillation speak of space constraints, so ensuring space for the distillation equipment in proximity to its use is critical for success on an ongoing basis once the space is opened and occupied.
Walking the talk
The J Craig Venter Institute, a genomic research center, is constructing a 45,000-square-foot sustainable lab located on land leased in San Diego, California by UC San Diego and will house 125 scientists. The facility is seeking LEED Platinum certification and will be “net zero” for energy, which means that it will produce on-site through solar power as much energy as it consumes.
Water will be collected for irrigation, washing PV (or solar) panels and for cooling towers. A green roof and window placement provide natural lighting and cooling. Regional and recycled materials will be purchased for construction materials and finishes.
Its net zero certification is from the International Living Future Institute, which requires proof that the project has met the intended goal of harnessing enough energy from earth, wind, or sun to meet its energy demands. The building is slated for completion by the end of the year.
Laboratories benefit from an energy audit and retro-commissioning to identify opportunities for reducing plug load and addressing lighting, equipment, ventilation needs, and setback opportunities, freezer sizing and maintenance, fume hood use, and maintenance.
With the variety of equipment, heating and cooling needs, and high regulatory framework, the laboratory is ripe for a closer look when it comes to helping a facility achieve its sustainability goals and including staff experts in laboratory renovation and new design.
Additional guidance can be found from Labs21, a voluntary partnership program and resource for sustainable lab design and operations. Previously sponsored by the U.S. Environmental Protection Agency and the U.S. Department of Energy, Labs21 is currently being phased out and replaced by the International Institute for Sustainable Laboratories, though its resources are still available. Learn more at http://www.labs21century.gov/.
Janet Brown is a contributing editor for Healthcare Design. She’s the director of facility engagement for Practice Greenhealth and the director of content and outreach for the Healthier Hospitals Initiative. She can be reached at firstname.lastname@example.org.