AUSTIN, TX — According to one IAQ expert, there are several types of IAQ investigations and several ways to approach them, if a business is considering adding investigation to its stable of services.

Francis J. (Bud) Offerman, P.E., C.I.H., of Indoor Environment Engineering, San Francisco, CA, told HIE attendees that “The main essential tool is a rational investigative plan,” and not to “get shackled by the client who is paying for the investigation.”

Offerman said there are different types of investigations:

Reactive — responding to occupant complaints (described below);

Post mitigation — clearance testing;

Proactive — healthy building management and real estate transactions;

Forensic — legal determinations of causality.


Offerman said there is a logical progression of processes during a reactive investigation. These processes begin with a description of the problem and then lead to the following:

  • Venting the building;

  • Taking system measurements (air contaminants and potential source inspections);

  • Interpreting the data;

  • Mitigating the problem; and

  • Finding a healthy resolution.

    “The first thing to do is to interview building occupants and perform a source inspection, including the outdoors and underground areas,” Offerman said. “Next, take ventilation system measurements and inspect. This step involves checking the outside air, air filtration, and air pressure.

    “Take air contamination measurements, which are useful for documenting contaminant exposures but are not real useful in diagnosing IAQ problems. Lastly, interpret the data.”

    Offerman added that investigative tools should include ASHRAE ventilation standards and local building codes.

    He concluded that it is important to encourage building owners and managers to form an IAQ management plan. That way, “When an investigator comes in, a lot of the work is already done (i.e., complaint logs, ventilation records, etc.).”

    Publication date: 06/03/2002