Code Changes and Affect on Sustainable Ventilation System Design

Michael Walsh, R.G. Vanderweil Engineers, LLP

This presentation will outline changes to recent codes and standards that affect Laboratory HVAC system design. While many of the codes and standards applicable to laboratories were modified to allow safer and more energy efficient systems based on input from I2SL (formerly Labs for the 21st Century), recent changes are making design of code compliant and energy efficient systems more challenging. In addition complying with these new code requirements can create potentially hazardous conditions when authorities having jurisdiction or owners require continuous operation during multiple failure events. We will review modifications in the International Mechanical Code and standards such as NFPA 45, ASHRAE 62.1 and ASHRAE 90.1 that now require a more conservative approach to laboratory ventilation system designs. The presentation will also outline one example of a unique solution combining multiple energy recovery strategies to overcome some these new challenges.

Learning Objectives

  • Attendees will be made aware of recent changes to codes and standards including the International Mechanical Code, NFPA 45, ASHRAE 62.1 and ASHRAE 90.1.
  • Attendees will be made aware of how these changes vary from previous code changes that were intended to allow design of safer and more energy efficient mechanical systems.
  • Attendees will learn how code changes can create hazardous conditions during failure events and some examples of how these events can be mitigated.
  • Attendees will be presented an example of a system design that was developed to address these code changes while also meeting the energy efficiency goals of the project.


Michael is a Principal and HVAC Technical Director at Vanderweil promoting innovative and sustainable HVAC system design solutions. Mike has spent 30 years focusing on the design of HVAC systems to serve over 7,500,000 SF of space including animal facilities, BSL-2 and BSL-3 labs, biomedical research, public health, interdisciplinary science and forensic laboratories. Mr. Walsh is an ASHRAE, I2SL (formerly Labs 21) and an International Code Council member.


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