IAQ Issues LEED Building San Francisco – Part Two

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IAQ Issues LEED Building – Part Two

As a healthy building inspector and industrial hygienist, I have performed several pre-occupancy IEQ tests to the LEED standard and specifically for LEED certification. I am familiar with both the testing and flush out options and IAQ issues related LEED Building certification. The flush out option is most often used as it usually saves costs and is more straightforward; there is no pass-fail, if you do the flush out you get the credit. Testing can cost more, but can save time (as flush out can take 2 weeks or more). The advantage of the testing option is hard data that speaks to the actual air quality of the building, whereas the flush out option is more of a “do the procedure and hope” type, but it is possible to fail the testing, which requires additional flush out and then re-testing. If 75 Hawthorne had undergone the testing option rather than the flush out, that testing data could have been used and compared to testing data from the time of occupant complaints to see if any of the VOC’s found in the recent testing were present during the pre-occupancy testing, and if so, what levels of these VOC’s were measured.

The USGBC (US Green Building Council) is aware of the shortcomings of the LEED v3 method and has addressed them in v4. Air testing is now mandatory and they have added several additional air quality measurements to the testing regime as well as looking for a group of specific hazardous VOC’s in additional to measuring Total VOC (TVOC). This new testing standard for LEED v4 should improve the air quality of new buildings built to this standard and assure that flush out is complete and proper.

As for the EPA Building at 75 Hawthorne, several theories abound. Time and additional testing may help clarify the root cause of the air quality problems.

I have seen some of the publicly available data and have read reports about the building.

DISCLAIMER: I have not personally inspected or conducted any testing at 75 Hawthorne. My hypotheses below are merely conjecture and my opinion based on the limited information available at this time. These hypotheses MAY indicate SOME the possible causes resulting in poor air quality at a building like 75 Hawthorne. Further investigation, inspections and testing are required to find the root causes and solutions for the IAQ issues at 75 Hawthorne.          


IAQ Issues LEED Building Hypothesis 1 – Improper or Incomplete Flush Out


One possibility concerning IAQ issues in a LEED building is that even with best efforts, in the real world, procedures are not always exactly followed. Fans may have been placed in areas that were not ideal or even ineffective. Windows or doors may have been left closed that would impede airflow. Fans might not have run as long as they were supposed to. The shape of the building and idiosyncrasies of the floor plan may not allow for a complete and thorough flush out even if standard LEED procedures are followed. It is possible to follow the LEED IEQ flush out procedure to the letter and STILL not effectively flush out a building, meaning that testing would fail when performed. One of the benefits of testing is that an experienced inspector can help locate and determine sampling locations that might indicate “worse case” scenario locations, such as dead ends and other areas that might be prone to incomplete flush out. An incomplete or improper flush out could lead to increased VOC’s in breathable air due to off gassing of materials and furniture.


IAQ issues LEED Building Hypothesis 2 – Inadequate Regular Air Circulation


Even if the flush out was effective, materials and furniture continue to off gas VOC’s for months and even years. We count on dilution via the regular HVAC system to help reduce interior VOC’s to acceptable levels. If the flush out was not effective at reducing initial VOC’s prior to move in, the regular HVAC system may not be able to keep up with the material and furniture off gassing, allowing a build up of interior VOC’s.

Commercial buildings often do not have operable windows, so the HVAC system is the only method of bringing in fresh outside air for occupants. Outside air flushes out and dilutes interior contaminants including VOC’s. ASHRAE Standard 62.1 calls for AT LEAST 15 CFM (cubic feet per minute) of fresh, outside air per occupant or 0.35 ACH (Air Changes per Hour). This is a balance between recirculating air for energy efficiency and providing fresh air and oxygen for occupants.

It is possible that the HVAC system was designed to this standard but in the real world not all areas of the building are being provided fresh air equally. There are many reasons this could be the case. Some areas of the building may not have been receiving ANY fresh air, allowing build up of CO2, VOC’s and other interior airborne contaminants. At 75 Hawthorne, more occupant complaints were from the 10th floor, while the 9th and 11th floors registered fewer complaints. This evidence supports the hypothesis that the 10th floor was not receiving enough make up air, not providing enough fresh oxygen, and not diluting VOC’s and other contaminants. Further investigation may support this hypothesis.

In conclusion, I believe that IAQ issues such as the one that had occurred at 75 Hawthorne may have been avoided if these procedures had been instituted:


  • LEED IEQ testing in addition to the flush out would have provided empirical evidence of VOC’s in the air prior to occupancy and would have verified the effectiveness of the flush out.
  • Verification and monitoring of the HVAC system to assure ALL areas of the building are being supplied adequate fresh make up air and oxygen to facilitate dilution of VOC’s and other interior contaminants. ALL occupied areas of the building should be tested to assure that they comply with ASHRAE 62.2.
  • Air quality testing post occupancy at the 6th month and/or 1st year after initial occupancy may indicate potential problems prior to occupant complaints or possible illness.


I am personally curious as to the root cause(s) of the LEED Building IAQ issues at 75 Hawthorne and hope the issues are resolved so all occupants can work in a healthy building with good air quality. We want all buildings, including the buildings housing the EPA, to be healthy buildings.