This is the sixteenth post in a series by J. David Odom (ASHRAE), Richard Scott (AIA/NCARB/LEED AP), and George H. DuBose (CGC). It was first published as a mini-monograph for NCARB (National Council of Architectural Registration Boards).

Indoor Chemical & Pollutant Source Control Intent: Minimize exposure of the building occupants to potentially hazardous particulates and chemical pollutants.

Depending on the climate where the building is located, it may be important to utilize different types of ventilation approaches to control indoor air quality degradation and indoor chemical and pollutant source control. In climates with outdoor air conditions that carry large summer moisture loads (which includes much of the Eastern portion of the country), ventilation approaches should include a combination of exhaust and make-up air to achieve the pressure differentials required by the credit.

This credit requires a pressure differential of 5 Pascals (Pa) between the area with the chemical or pollutant source and adjacent areas. The recommended approach is to exhaust the space with the chemical or pollutant source to a point that is at least 5 Pa negative when compared to adjacent areas and a minimum of .50 cfm per SF. If this recommendation is incorrectly applied, its result can create depressurization of the entire building (or portions of the building).

To be continued…

J. David Odom is a Vice President and Senior Building Forensics Consultant with Liberty Building Forensics Group. He has managed some of the largest and most complex mold and moisture problems in the country, including the $60M construction defect claim at the Hilton Hawaiian Village in Honolulu and the $20M claim at the Martin County courthouse. He has also managed over 500 projects for the Walt Disney Corporation dating back to 1982 that have included technical issues related to corrosion, moisture, and design & construction defect-related problems. He has published numerous manuals and technical articles, including a monograph on moisture and mold for the National Council of Architectural Registration Boards (NCARB). For more information, contact J. David Odom at

With over 35 years of experience, Richard S. Scott is an expert in the areas of architecture, interior design, and building forensics, with a focus on moisture-related building problems. He is certified by both the American Institute of Architects/AIA Florida and the National Council of Architectural Registration Boards (NCARB). He has published over 30 articles, and has lectured or presented at nearly 40 seminars or events. Mr. Scott has developed various training courses, including a 16-hour IAQ training course for NASA and an 8-hour water intrusion prevention training course for the Naval Facilities Engineering Command (NAVFAC). He can be reached at

George H. DuBose, CGC is a certified Florida General Contractor and Vice President with Liberty Building Forensics Group, a firm specializing in moisture intrusion, mold problems, litigation support/buildings forensics, problem-avoidance peer reviews, commissioning, and implementation of green buildings. He has authored numerous articles and co-authored three manuals on moisture-related indoor air quality (IAQ) problems and building commissioning. He has diagnosed and solved hundreds of moisture and mold related building problems worldwide. DuBose can be contacted at