Retrofit and Renewal Exhaust-tion: Exhaust and Intake Considerations for Converting Offices to Labs

Mike Craig, RWDI

Many buildings designed for life at the office are being converted to lab spaces in the hopes of attracting future, long-term tenants. These buildings are often located in mixed-use, urban areas and require significant changes to mechanical systems to accommodate lab ventilation requirements. Designers need to provide flexibility in the core design to accommodate various types of lab tenants while also considering possible future tenant needs.

A key challenge to the design process is locating lab exhausts and AHU equipment within the physical constraints of the building, while maintaining safe air quality in, and outside, the lab. Re-entrainment of exhaust contaminants can affect air quality within the building and at neighboring mixed-use buildings. Prudent planning during early design stages using typical parameters can help to properly locate core building exhaust and HVAC equipment, and future tenant exhausts, resulting in a final design that is both safer and more energy-efficient. The I2SL Exhaust Design Guide provides several concepts that can be especially beneficial. However, detailed evaluation is often necessary to confirm exhaust dispersion performance and maximize long-term energy savings.

This presentation will outline design planning strategies using specific examples that can be used early in the design process to reduce air quality impacts of the new lab exhausts on the renovated building and its neighbors.

Learning Objectives

  • Have an understanding of air quality concerns associated with converting office buildings to labs;
  • Identify design planning strategies that can be used in early design stages to minimize re-entrainment issues and maximize lab tenant flexibility;
  • Outline a method for developing emissions estimates for a wide range of exhaust contaminants; and
  • Summarize the best practice tools used to evaluated exhaust and intake designs including developing applicable design criteria and mitigation strategies for reducing exhaust re-entrainment impacts.


Michael is an air quality specialist in the Exhaust Dispersion and Design practice at RWDI Inc. He has nearly 20 years of air quality dispersion modeling and exhaust re-entrainment experience, and delivering engineering support for laboratory, healthcare and commercial building projects. Michael is a registered professional engineer in Ontario and a participating member of ASHRAE.


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