Health & Safety

IAQ Image Page: Evaluation Methods

New and used air filters A visual inspection is normally the first step when evaluating a building's heating, ventilation and air conditioning (HVAC) system. For example, the filters and duct work in this HVAC unit were inspected. The filter on the left is a new, clean filter. On the right is a used filter.

Air filters are necessary to filter dust and debris from the outside air (OA) before it is distributed throughout the building.

Tracer gas decay and VOC analysis
Tracer gas concentration-decay testing to determine the room air-exchange rate in a laboratory specimen room. We also evaluated formaldehyde, phenol, and alcohol levels in this IAQ survey. Report for tracer gas decay and VOC analysis
Using the balometer to measure supply air (Q, cfm) The skilled industrial hygienist measures the amount of supply air (SA) delivered to this room from the ceiling air diffuser. This data will be compared to the building's design specifications and HVAC "test and balance report". Any deficiencies noted during this evaluation will be reported to Physical Plant Services for corrective action.


Commonly Used Physical Parameters for IAQ:

Temperature: Summer 72.5-80 F depending on %RH; Winter 68-76 F, depending on %RH (Source: ASHRAE 55)

Relative Humidity: 30% to 60%

Air Movement: 0.8 ft/s (Source: WHO)

Ventilation (Carbon Dioxide): 650 ppm over ambient (Source: ASHRAE 62)