High standards for labs, research buildings: HVAC systems
- Bryan Laginess, PE, LEED AP, Senior associate, Peter Basso Associates, Troy, Mich.
- Jeremy Lebowitz, PE, Vertical market leader, Rolf Jensen & Associates Inc., Framingham, Mass.
- Brian Rener, PE, LEED AP, Associate, SmithGroupJJR, Chicago
- Joshua Yacknowitz, PE, LEED AP, Associate principal, Arup, New York City
CSE: What unique HVAC requirements do laboratory/research facility structures have that you wouldn’t encounter on other structures?
Laginess: Laboratories usually require a high air change rate, and usually require 100% outside air. From an energy standpoint, it is a very costly operation. Although not always required, energy recovery systems are commonly used to reduce the operating cost.
Yacknowitz: Once-through air requirements in many lab types; control zone fire separation and need to segregate exhaust risers in shafts; specialized exhaust systems such as radioisotope and perchloric acid, which require dedicated exhaust systems and special controls; fast-acting terminal air valves for control of airflows in labs; and minimum air change rates in lab spaces, to name a few.
CSE: What changes in fans, variable frequency drives, and other related equipment have you experienced?
Yacknowitz: Variable frequency drives (VFDs) are quite common nowadays because the cost of these controllers is quite low compared to years ago. In labs, however, depending on the science, there may be a need to provide 12- or 18-pulse VFDs in order to control harmonic distortion in the building power grid. These VFDs are more expensive and often require significantly more space to install. We have also seen more dc motors for small systems such as clean room fan filter units, as these motors are infinitely adjustable in terms of speed and run at high efficiency.
CSE: In your experience, have alternative HVAC systems become more relevant?
Laginess: We are seeing an increased use of chilled beams in laboratory projects. The design approach is very different from the standard air systems. This system can reduce energy costs and require less space for installation. I think that as we see energy costs continue to rise, alternative methods will become standard.
Yacknowitz: Chilled beams are becoming more acceptable, particularly in nonchemistry labs where recirculation of air within the lab is not as much of a health or safety risk.
CSE: Do you find it more challenging to retrofit HVAC systems on older buildings than installing on new?
Laginess: It is more challenging to retrofit HVAC systems on older buildings than to install them on a new building. The design team has much more control over the systems used and how they fit into the facility when they can start with a clean slate.
Yacknowitz: Generally, it is easier in new buildings since the current code requirements for control zoning, shaft segregation, and other factors can be planned into the structural and floor plan arrangement of the building. Older buildings are often built to older codes, which makes it difficult to meet current control zone, shaft space, and floor-to-floor height requirements that result from current codes and standards. However, there is generally a huge opportunity to dramatically increase energy efficiency in older labs.