Lab Design for Sustainable Construction
The design of labs for sustainable construction and operation has become a major driver in the A/E/C industry over the past 10 to 15 years. Most large academic, government and corporate lab clients are looking for sustainable design approaches at a minimum, and third-party certification, such as LEED, in many cases. This sustainable trend is driven heavily by the high construction and operating costs of laboratories and the quick payback potential sustainable design approaches provide for end users.
LEED serves as the most common third-party certification in the U.S. for sustainable design, with other systems such as BREEAM applied in other countries. Many new academic, government and corporate laboratories are required to meet LEED Silver requirements at least. Sustainable laboratories are also a driving force to attract some of the world’s most talented researchers and professors, leading to noted scientific discoveries.
The LEED credit choices related to sustainable sites, water usage and materials are driven less by lab programs and more by typical site/project/owner-specific influences. However, the approach to addressing energy and indoor environmental quality credits is more directly impacted by laboratory operational constraints and regulatory requirements. According to Josh Yacknowitz, PE, LEED AP, Arup, some examples include challenges in getting a high number of energy-conservation credits due to the high fresh air rates and process loads in labs, the utility of doing enhanced commissioning to ensure more robust and better-calibrated MEP systems and difficulty in providing individual thermal and lighting controllability within certain types of open laboratories.
However, to create a sustainable building, the A/E/C firm must consider all aspects–from MEP systems, to lighting, to materials and even the orientation of the building.
Energy-efficient technologies are focusing on many significant components. There’s an active discussion about appropriate air change rates in wet labs in occupied and unoccupied modes. While safety remains the critical factor, there’s significant data that indicates labs can reduce air change rates and maintain safe environments. Many institutions actively monitor air quality in labs to control air change rates, which has a positive end result on lab energy use.
Demand-controlled ventilation is a common sustainable solution becoming more prevalent in certain lab types where pollutants of concern are well understood. This ventilation strategy uses sensors to monitor spaces for a range of pollutants, allowing minimum air change rates during unoccupied periods to be reduced when pollutant levels are below some threshold value, saving thermal and fan energy related to once-through air. “The use of fast-acting lab-grade airflow control devices and systems has also become more standardized, and has provided the designer with greater latitude to develop tight environmental control schemes and centralized HVAC systems which are right-sized for the peak anticipated loads,” says Yacknowitz.
In addition, heat recovery on both general and lab exhaust is becoming a more common energy-saving technique. “Ways to minimize the air volumes with strategies like setbacks in unoccupied times or sensors that can monitor the air to adjust the flow allows us to have higher air change rates only when needed, rather than ubiquitously as was done in the past,” says Andrea Love, AIA, LEEP AP, Director of Building Science, Payette.
Five years ago, it was revolutionary to put chilled beam heating and cooling in a lab; the concern was that air wasn’t moving through at the necessary exchange rates. Humidity was also a problem with this type of hydronic heating and cooling system early on. Europeans have used chilled beams for over 10 years, but they don’t have the humidity extremes seen in the U.S. However, today, chilled beam technology has become viable in laboratories, as they are a more efficient use of space than air ducts. And active chilled beams are more widely accepted in laboratory spaces where air recirculation is considered safe. Chilled beams save energy in that they reduce the overall fan energy associated with moving air for cooling. And, when compared to typical all-air systems, they enable greater flexibility, reduce energy and increase comfort, all with a rapid ROI, according to Blake Jackson, AIA, LEED AP, Tsoi/Kobus & Associates Inc.
Labs are also shifting towards decoupling ventilation and space-conditioning air because using air for both is expensive, energy intensive and inefficient. “Filtered fume hoods are gaining traction, as they filter room air of contaminants, releasing the clean air directly back into the space,” says Jackson. This significantly reduces exhaust demand, need for dedicated fume hood exhaust and further reduces concern of cross-contamination should enthalpy wheels be utilized.
Heat pumps are also becoming more commercially viable, according Jackson, as they come in an array of shapes and sizes–from small air-source variable-refrigerant flow (VRF) systems up to large-scale ground-coupled heat-recovery chiller plants. “These are more effective than boilers, because instead of turning fuel into heat, they simply transfer heat from one space to another,” says Jackson.
Other HVAC strategies such as enthalpy wheels for high-efficiency thermal transfer rom exhaust air stream to supply air stream; heat-shift chillers for redistribution of waste heat output from high-energy-load zones to other zones in the building; solar energy and geothermal solutions where land area is available to eliminate carbon fuel-based chillers and boilers are also common in today’s labs.
In addition to HVAC items, low-flow and flow-limiting devices on water fixtures are more widely used in laboratories today. Also, various technologies for managing airflow through fume hoods have become more widely accepted, including such measures as zone presence sensors to reduce face velocity when an operator isn’t present, automatic sash closers and constant face velocity flow control, according to Yacknowitz.
Emerging as an important trend is also a focus on integrating utilities and building technologies into adaptive, reusable and flexible spaces for science. “The concept of adaptive labs is of interest to clients who can remain flexible in their programming over time while lowering replacement costs,” says Bill Harris, Practice Leader, Principal, Perkins+Will.
Systemized utility racks allow laboratory personnel to quickly rearrange laboratory benches to address pressing research needs, instead of engaging in costly and wasteful renovations that would have been the only solution a few years ago. “The programming requirements of our clients can change very quickly, and ultimately, the most sustainable solution for addressing evolutions in the workplace is one that doesn’t require new construction, but instead focuses on adaptability to most efficiently meet their goals,” says Harris.
A/E/C firms are also seeing building management systems (BMS) and related controls becoming more sophisticated as they offer technological solutions to reducing energy consumption, both initially and long term, with significant results.
As energy costs rise and laboratories become more air-tight, Building Envelope Commissioning (BECx) is also becoming more typical, as the envelope will play a greater role in driving energy consumption. “Several products are available to minimize thermal bridging, and greater QA/QC collaboration on projects yields a better product,” says Jackson.
Let the light shine
As lab designers want to make lab spaces more comfortable, they’re addressing features which have historically made laboratories difficult places to work: overly bright light levels and excessive noise. Going back beyond three years, scientists claimed to need 100 footcandles (fc) of light on the bench. The need for energy efficiency has forced the question: Do researchers really need that much light?
The answer, of course, varies from lab to lab, depending on the research conducted. But overall, instead of blanketing a lab with fc, designers use a more targeted design. The new focus is on finding the most efficient combination of task lighting and overhead lighting.
In order to provide an effective and efficient solution, most lab design firms provide ambient (direct/indirect) lighting combined with task lighting at the bench. This approach is a logical means of balancing energy efficiency and visual acuity, as well as the increased emphasis on effective daylighting and the control systems necessary to realize these efficiencies.
Firms have seen an increase in LED light usage. Whereas in the past LEDs were only reserved for “feature lighting due to the high costs, according to Jackson, as their costs continue to fall, LEDs are increasingly being used for ambient lighting, back-of-house lighting and task lighting.
Overall, labs are searching for ways to customize their spaces without driving up costs. Many vendors are now able to accommodate these needs by working with designers and researchers to create benches and casework that’s mobile, light, adaptable and highly functional at a reasonable cost. Comfort and safety are important in the laboratory environment as well. “Flooring that meets safety standards and is ergonomically supportive is key,” says Jackson. “We specify finishes that will stand up to the intensity of use, are sustainable (VOC free, recycled content) and are going to perform over the life of the building.”
As with most sustainable construction, materials which have low volatile organic compound (VOC) content are becoming preferred. “This mostly impacts adhesive, paint and finish materials specifications,” says Yacknowitz. The use of low ozone-depleting and global warming potential refrigerants in equipment such as chillers, direct-expansion air conditioners, cold rooms, freezers and ice makers are also quite common in laboratory settings.
A/E/C firms have also observed an increased focus on the materials that go into a building’s facade and how they may impact the overall performance. “Things such as thermal breaks to improve the thermal performance, which were hardly considered three years ago, are now becoming more conventional,” says Love. “There has also been an increasing emphasis on how the facade design may impact the building performance, looking at things like how much glass and where should it be to balance between performance, aesthetics, daylight and the connections between occupants and the exterior,” continues Love.
What’s next for sustainable labs?
Beyond high-efficiency equipment, sustainable materials and improved technologies, the most important contributor to healthier environment is the end user. “Engaging scientists and staff to be more aware of the material and energy consumption of their own spaces encourages the type of efficient operations that are at the center of sustainable projects and performance,” says Harris. Implementing direct feedback and local control, whether at the lab bench, fume hood or office, helps the individual recognize the importance of their personal behavior in defining sustainable outcomes for their workplaces.
Some standard approaches and benchmarks in determining minimum air change rates in laboratory spaces and within fume hood have led to very energy-intensive HVAC systems. “These rates are often prescriptive, typically set by owner safety management in response to a range of values commonly used in the industry,” says Yacknowitz. “There is an opportunity to employ a risk-based approach to determine these minimum rates on a space-by-space basis, which could lead to a significant downsizing of central HVAC systems and resulting energy use.” A risk-based approach will require rigorous methodologies, and direct involvement by safety, facilities and user groups to be effective. The potential capital and operational savings, as well as overall carbon generation, are potentially huge, according to Yacknowitz.
Resiliency is also an increasingly important consideration in sustainable laboratory design. “Today, the conversation considers ‘one-off’ events: natural disasters, power disruption and more,” says Jackson. “In the future, I project needing to consider how a building adapts to these challenges and to climate change over time.”