In the last several years, evidence-based design, wellness objectives, and a focus on the occupant experience have enabled a pronounced shift in workplace acoustics to increase productivity and satisfaction. Laboratory building owners tend to accept areas with elevated levels of noise and vibration as beyond designer control within reasonable construction budgets. However, laboratories are workplaces too! Occupants deserve attention to acoustical design, which can indeed be made cost-effective by involving the acoustical engineer early to establish appropriate noise and vibration targets and prioritize workplace enhancements.
These are exciting times in the field of life sciences, with synthetic biology and genomic sequencing offering opportunities to radically advance outcomes in healthcare and associated fields. In addition to biotech expansion and upgrades, we are seeing a trend in “spec” laboratory workplace buildings, both ground-up and adaptive re-use, promising future tenants the best of both worlds for Class A workspace amid research laboratory environments. The acoustical design for these projects starts with an understanding or assumption of the range of intended uses to devise a suitable project plan that addresses noise- and vibration-sensitive activities or equipment.
Here are some of the key elements we consider for workplace design in life-science environments.
Vibration Assessment of Site or Building
When evaluating an existing building or site for use as a life science laboratory and workplace building, it can be crucial to quantify the exposure to vibration, which may impact optical microscope use, vivarium environments, nano-scale research, and more. Human sensitivity for workplace comfort can also be factored into the design analysis.
Environmental vibration sources are site-dependent and typically outside the control of the design team (e.g. proximity to highways, rail, airports). The results of the vibration assessment can be used to optimize the location of the equipment and determine where structural upgrades (e.g. stiffening, breaks, isolation) can significantly reduce risk of impact on operations. In some cases, results can be used to determine a site not suitable for the proposed program.
When evaluating vibration exposure, Mechanical, Electrical, and Plumbing (MEP) equipment and occupant activity within the building are also vibration sources to consider. Vibration criteria will typically reference the Vibration Criteria (VC) curves adopted by the IEST for general categories of sensitive equipment or specific equipment that may have manufacturer’s requirements (e.g. an electron microscope). Additionally, the AISC steel design guide and ANSI S2.71 provide criteria guidance in evaluating the human response to building vibration.
Interior Acoustical Design
Noisy equipment control
Research on sustained exposure to elevated noise levels demonstrates associated fatigue, irritability, and overall decrease in well-being due to raised cortisol levels. Additionally, OSHA and EU “noise at work” have enforceable requirements for extended noise exposure, typically applied for regular work in central plants and data servers.
To the greatest degree possible, high-noise equipment should be contained in separate enclosed areas. For environments where occupants are expected to share a space with the equipment for extended duration, buffer zones and enclosures (similar to pod/cell offices) are strategies worth considering and are being used on current projects. Portable acoustic screens on casters can provide flexible noise attenuation for labs (e.g. maker space) when it is unknown where equipment will be located or how often it will be used.
Similar to a recent shift in design strategy for the open office, space planning efforts should encourage accessible quiet places, such as enclosed phone and huddle rooms, to perform focused work. Enclosed rooms with door frame seals should be expected for meeting rooms to enable teleconferencing technology to function well for participants on both ends of the call.
An effective technique for noise control in a teaching or workplace laboratory environment is the incorporation of sound-absorbing treatments, typically applied to the ceiling for distributed benefit. Durability, cleanability, accessibility, and maintenance are all aspects to be addressed in the selection of appropriate products or materials. For performance, NRC 0.70 is a good starting minimum value to control excess noise in occupied work areas, though spectral sound absorption analysis may be needed on a case-by-case basis.
Acoustical treatments can be efficiently incorporated into the structural or architectural design, such as by selecting a perforated metal deck, large-format flat panels, acoustical spray-applied finish, or spaced baffles, to be coordinated with other suspended ceiling items.
Sound-absorbing elements that are advertised as sound-isolating, such as free-standing or hanging felt panels or screens, can improve acoustical separation between shared work areas but are not to be compared with enclosed room partitions.
HVAC noise and vibration
Laboratory needs for increased air turnover and exhaust require elevated attention to noise and vibration control measures. ASHRAE provides guidance on appropriate Noise Criteria (NC) to use, differentiating labs where regular voice communication can be expected, such as a teaching lab, from research labs with limited speech.
Common noise control measures (such as fiberglass lining) may not be acceptable in facilities with cleanliness requirements. Elements commonly used to achieve NC ratings include packless (fiber-free) silencers for exhaust fans, fan-wall air-handlers, protected or non-fiberglass duct-liner downstream of supply-air valves, and maximum allowable noise limits specified for the fume hoods. Although systems are typically sized for equipment-specific analysis with available sound data late in the design process, it is best to set expectations for feasibility evaluation as soon as the system types are defined. For design-build projects, engaging the mechanical designer early in the effort helps to set expectations, improve ongoing coordination, and prevent re-work.
Vibration isolation of equipment should be provided per ASHRAE within reason. Thickened slabs, raised isolation platforms, and aligning equipment with column lines can be effective risk-reduction measures. Projects with critical requirements may require finite element analysis to define appropriate vibration isolation, in coordination with input from the structural engineer.
Projects that include a vivarium, if built to NIH or NSF or other standards, would have specific requirements for noise and vibration. Detailed acoustical input is necessary to address noise from cage-wash and wheeled-cart equipment, transfer between loud and quiet animal areas, and behavioral sensitivity. Consider the range of species that will be housed and particular frequency-sensitivity hearing profile in the design of MEPT systems, in particular HVAC and motion detectors that can have harmful physiological responses. To address vibration, isolation slab joints, similar to a seismic joint, can be used to mitigate the concern for structure-borne transfer, especially if located in close proximity to MEP equipment areas.
For the growing technology needs in life-science buildings, rightsizing technology distribution rooms (e.g. MDFs and IDFs) is critical for space planning. Sufficient server rack space, proximity to potential video walls or other immersive AV elements, and identification of energy-saving systems are early design decisions helpful to serve potential tenant needs.
TEECOM Can Help
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