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LDN December Feature 1 Image 1

Strategic placement of ventilated enclosures and point exhaust capture devices will increase personnel safety and IAQ at DOE’s Energy Systems Integration Facility, to be built on the campus of the National Renewable Energy Laboratory. All photos: SmithGroup

Is laboratory safety at odds with sustainable building practices? This is a fair question—one so central to lab design it has even spurred a conference on the topic alone. In his morning keynote for the "Safe Labs Can Be Green Labs" conference in Seattle last June, James Kaufman, president of the Laboratory Safety Institute (LSI), focused on the topic of lab ventilation and the OSHA standard 1910.1450 for occupational exposure to hazardous chemicals. He concluded that what lab occupants don’t know may, in fact, hurt them.

"Life is filled with choices and, unfortunately, hazards too," said Kaufman, a former chemist. "The persons best prepared to choose will know the likely outcomes. In many cases, the people in labs are not free to choose because they know neither the choices nor the consequences."

Our firm's experience in laboratory building projects and operations lends evidence to this statement. While we see widespread interest in smarter laboratory practices—efforts to reduce the amounts of toxic materials and dangerous chemicals present, for example—improving the safety performance of sustainably designed lab buildings requires knowledge of both design alternatives and equipment capabilities. When done right, high-performance research facilities improve not only occupant safety but also energy efficiency and return on investment (ROI).

A systems approach
Today, there are a few givens that challenge design teams and owners striving to create state-of-the-art laboratory facilities. First and most obvious, the work environment must be safe. Second, the largest consumer of energy in labs is the ventilation system. (Not surprisingly, LSI's conference was sponsored by a maker of molecular-adsorption fume hoods and detection systems.) Third, the next generation of laboratories is striving for record reductions in energy use. Some new facilities, in fact, aim for net-zero energy operations, with super-efficient systems such as heat recovery and renewable energy installations that actually generate enough power to stand alone.

To address this triple challenge—safe, well-ventilated and green—requires more than just a few high-quality fume hoods. Building teams in the laboratory world must tackle the problem from a systems perspective, working on every system and material choice available. Key goals include not only fine-tuning the optimal ventilation rate but also reducing overall facility heat loads and maintaining a continuous and well-insulated building enclosure.

These are first-level systems, which include the heating, ventilation and air-conditioning (HVAC) plant. When first-level systems are optimized, the lab designer can consider second-level systems, including laboratory equipment and services. These process loads are too often overlooked in the design of green buildings, even by sustainability certification and advocacy groups such as LEED.

At the end of the day, if it isn't a safe laboratory, it doesn’t matter how efficient or green the facility is. The real goal is to create a reliable, secure and hazard-free workspace within the framework of high performance and energy efficiency.

Novel ventilation strategies
The solution to the puzzle of safe green labs is largely dependent on applying the appropriate technologies, although scientific practices are also a factor. Lab designers and owners are seeking appropriate devices and systems tailored to local venting needs. Examples include point exhausts and ventilated enclosures: targeted technologies that serve specific research purposes and yield a significant impact on the building's environmental and energy footprint.

The process of selecting suitable ventilation strategies starts by assessing need. Equipment-intensive research takes place in a load-driven lab. Controlling heat in these instrumentation-heavy environments is the top priority, handled by local extraction, fan-coil units and, increasingly, novel chilled-beam technology. Contrast this with ventilation-driven labs, where air quality is paramount: for these labs, engineers and architects must focus on the number of air changes per hour (ACH), selection of suitable ventilation devices, and source control of toxic hazards.

For the ventilation-driven space, tradition has dictated bringing more fresh outside air indoors. Through the early 1970s, the ratio of supply air to exhaust air in U.S. facilities was typically 70:30. As recently as a decade ago, biomedical labs would average 10+ ACH—even more for chemistry labs—meaning 100% exhaust of the lab air. While labs in Europe often use filtered, recirculated air, today's lab designers in the U.S. still embrace 100% exhaust, using the National Institutes of Health (NIH) guidelines that allow six ACH as a minimum for occupied spaces.

Six ACH is good, but when labs are unoccupied even less is possible using HVAC system setbacks—and proper supplementing technologies. At these rates, it's critical to monitor for indoor air-quality (IAQ) incidents using air-sampling systems and to carefully specify appropriate localized venting technologies.

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The Clinical and Transformational Research Building at the Univ. of Louisville uses an IAQ monitoring system maximizing ventilation and safety during an IAQ incident and saving $116,000 per year in utility costs.

Comparing ways to keep air safe
To create greener ventilation-driven environments, our instincts say reduce ACH. As a result we become more cautious, and rightly focus on the selection of air-control devices. Does the application or lab activity need a point exhaust or a fume hood? Could a ventilated bench work, or is a biosafety cabinet required? To make the call, begin by weighing the application, benefits, and costs.

  • Point exhausts. Small point-extraction arms—also known colorfully as snorkels and elephant trunks—are ideal for low-toxicity applications and the removal of local heat. High-temperature versions in stainless steel or aluminum are effective up to 480 F. Outsize versions are also available for large work areas, vehicle exhaust and the like. For specific applications, portable extractors can be employed that filter exhaust before recirculating it to the room, minimizing energy use. Though their efficacy in maintaining air quality is limited, point exhausts are highly effective support for smallarea capture.
  • Ventilated enclosures. Devices in this group are designed to exhaust air but don't meet the requirements to be classified as fume hoods. Available in a range of sizes, materials and configurations to support lower ACH rates, ventilated enclosures are ideally suited for stations dedicated to nano-particles, weighing, powders, and the like.
  • Ventilated benches. Similar to a ventilated enclosure, these benches are dedicated to enhancing IAQ for a specific work area. The benches offer a more open construction, allowing direct access to the work area. Downdraft tables and rear exhaust benches both allow for some removal of noxious substances while providing effective work support.
  • Fume hoods. These are not to be confused with ventilated enclosures. Laboratory fume hoods are specifically designed to carry undesirable effluents—generated within the hood during a laboratory procedure—away from lab personnel and out of the building, connected to a properly designed laboratory ventilation system. Configurations include bench top, distillation and walk-in hoods, with specific equipment types made to accommodate radioisotope, perchloric acid and acid digestion workflows. Explosion-proof versions are also available.

High-performance fume hoods are a good product for a green lab. Teamed with variable-air-volume (VAV) mechanical systems and auto sash closure, a good-quality fume hood can reduce energy use by up to 40% in some laboratories. The novel "GreenFumeHood" technology, a ductless system, actually cleans the air it intakes rather than exhausting outside the building. These hoods recirculate room air through a series of specially designed filters mounted above the enclosure, eliminating the need to exhaust and makeup room air, and reportedly saving significant amounts of energy for lab areas using a long list of approved chemicals, compared with other ductless hood systems.

  • Laminar flow hoods (LFHs). These hoods are specifically designed to create clean bench environments. Supply air passes through filtration media and moves horizontally across or vertically down onto the work surface, depending on the device type and need, then exhausting through a face opening. An LFH is specified with attention to the desired level of cleanliness and proper filtration media, which are the dominant drivers of energy usage. Bear in mind, these hoods are intended to protect the product only, not the personnel or the environment.
  • Biosafety cabinets. Contrast these devices with biosafety cabinets, which can protect the product, personnel and the process environment. They are selected based on application, with selection factors including risk level, the need to protect the lab products and specimens, and the possibility of using chemicals. In certain configurations, they help reduce energy use and are very effective for safety when appropriately selected. Today’s greenest option is the Class II, Type A2 cabinet, which exhausts air back into the room; this configuration is appropriate for a number of biological applications where odors or chemical fumes are not involved.
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High-efficiency fume hoods with horizontal sliding sash panes help limit peak ventilation demand at the Institute for Critical Technology and Applied Science II at Virginia Tech.

In fact, specifying the equipment is vital to making a ventilation-driven lab a truly sustainable facility. Comparing Type A2 and B2 cabinets in the Class II spectrum reveals dramatic differences in performance. While Type A2 cabinets recirculate a percentage of air within the cabinet and can be exhausted to the room, Type B2 cabinets have no internal recirculation and must be hard-connected to a laboratory exhaust system. This configuration makes the Type B2 cabinet appropriate for use with biologicals and certain quantities of chemicals.

Even seemingly minor choices make a difference in facility energy use. One rarely discussed example is motor selection for these types of equipment. Single-phase AC motors have been the standard until now, yet today’s manufacturers are turning to DC and three-phase AC motor technologies to drive down energy use and increase efficiency.

Operations matter
One last consideration when it comes to safety and green building: It’s not just how the HVAC system is sized or what types of equipment are used that make a lab sustainable. People and processes make them green, too.

For biosafety cabinets and laminar flow hoods, for example, there are a multitude of ways to conserve energy without impacting effectiveness or lab productivity. Turning off fan blowers when the devices are not in use is one way; another is using night mode for fans. Lab personnel should be trained to fully close equipment sashes when devices are not in use. Ultraviolet lights, which are commonly used for specific types of decontamination, shouldn't be left on constantly unless an absolute necessity. Last, consider the filtration media (see sidebar, page 4). High-efficiency particle arrestors, better known as HEPA filters, use much less energy than their ultra-low penetration air (ULPA) cousins.

With better operations, better equipment choices, and the reduction of controllable hazards, labs can indeed become a green and safe place for people to help people and make tomorrow’s great scientific discoveries. With these three steps, the building itself can be made far more efficient, with downsized HVAC systems and more productive, inspiring places to work together. That means greater ROI and fewer resources consumed.

Behind this promising trend are smart research practices and new ideas in renewable energy and high-performance building design. Perhaps in only a few years from now we’ll consider the net-zero energy lab building less a wonder than a reasonable expectation.

Victor Cardona is VP/director of laboratory planning and Adam Denmark is a laboratory programmer and planner at SmithGroup (www.smithgroup.com), an 800-person architecture and engineering firm that specializes in the science and technology market. SmithGroup designed the U.S. Department of Energy's new Energy Systems Integration Facility, now under construction at the National Renewable Energy Laboratory in Golden, Colo.

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