![[logo] US EPA](https://webarchive.library.unt.edu/eot2008/20090514162416im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
IAQ TfS Action Kit
IAQ Reference Guide: Section 5 - Diagnosing IAQ Problems
IAQ Reference Guide
Why IAQ is Important to Your School
Hiring Professional Assistance
Emissions from Motor Vehicles and Equipment
Contents
The goal of diagnosing an IAQ problem is to identify the cause of the problem and implement an appropriate solution. Often, more than one problem can exist, requiring more than one solution. For this reason, EPA created the Problem Solving Checklist (Appendix A: "IAQ Coordinator’s Forms" in the IAQ Coordinator’s Guide) and the IAQ Problem Solving Wheel (a separate tab of the Action Kit). For best results, it is also important to have good background knowledge of the basics of IAQ as outlined in Sections 1 and 2.
The IAQ diagnostic process begins when a complaint is registered or an IAQ problem is discovered. Many problems can be simple to diagnose, requiring a basic knowledge of IAQ and some common sense. If the cause (or causes) of the IAQ problem has already been identified, proceed to the solution phase outlined in Section 6: "Solving IAQ problems."
Not all occupant complaints about IAQ are caused by poor indoor air. Other factors such as noise, lighting, and job-, family-, or peer-related stress can -- individually and in combination -- contribute to a perception that IAQ is poor.
How to Diagnose Problems
The Problem Solving Checklist and the IAQ Problem Solving Wheel are your primary tools for finding solutions to problems. They will help simplify the process and lead the investigation in the right direction.
Start with the Problem Solving Checklist and encourage school staff to answer questions or perform activities posed by the checklist and the wheel. Pollutant sources and the ventilation system may act in combination to create an IAQ problem. Resolve as many problems as possible and note any problems that you intend to fix later.
Once you identify the likely cause of the IAQ problem, or the solution is readily apparent, refer to Section 6: "Solving IAQ Problems," for potential courses of action.
Spatial and Timing Patterns
As a first step, use the spatial pattern (locations) of complaints to define the complaint area. Focus on areas in the school where symptoms or discomfort have been reported. The complaint area may need to be revised as the investigation progresses. Pollutant pathways can cause complaints in parts of the school that are located far away from the source of the problems. See the "Spatial Patterns of Complaints" table.
After defining a location (or group of locations), look for patterns in the timing of complaints. The timing of symptoms and complaints can indicate potential causes and provide directions for further investigation. Review the data for cyclic patterns of symptoms (e.g., worst during periods of minimum ventilation or when specific sources are most active) that may be related to the HVAC system or to other activities affecting IAQ in or near the school.
Timing Patterns of Complaints
|
SPATIAL PATTERNS OF COMPLAINTS |
SUGGESTIONS |
| Widespread, no apparent spatial pattern |
Check ventilation and temperature control for entire
building. Check outdoor air quality. Review sources that are spread throughout the building (e.g., cleaning materials or microbiological growth inside the ventilation system). Check for distribution of a source to multiple locations through the ventilation system. |
| Localized (e.g., affecting individual rooms, zones, or air handling systems) |
Consider explanations other than air contaminants. Check ventilation and temperature control within the complaint area. Review pollutant sources affecting the complaint area. Check local HVAC system components that may be acting as sources or distributors of pollutants. |
| Individual(s) |
Check for drafts, radiant heat (gain or loss), and
other localized temperature control or ventilation
problems near the affected individual(s). Consider that common background sources may affect only susceptible individuals. Consider the possibility that individual complaints may have different causes that are not necessarily related to the building (particularly if the symptoms differ among the individuals). |
|
TIMING PATTERNS OF COMPLAINTS |
SUGGESTIONS |
| Symptoms begin and/or are worst at the start of the occupied period | Review HVAC operating cycles. Pollutants from building materials, or from HVAC system itself, may build up during unoccupied periods. |
| Symptoms worsen over course of occupied period. | Consider that ventilation may not be adequate to handle routine activities or equipment operation within the building, or that temperature is not properly controlled. |
| Intermittent symptoms | Consider spills, other unrepeated events as sources. |
| Single event of symptoms | Look for daily, weekly, or seasonal cycles or weather-related patterns, and check linkage to other events in and around the school. |
| Symptoms disappear when the individual(s) leaves the school, either immediately, overnight, or (in some cases) after extended periods away from the building | Consider that the problem may be building-associated, though not necessarily due to air quality. Other stressors (e.g., lighting, noise) may be involved. |
| Symptoms never disappear, even after extended absence from school (e.g., vacations) | Consider that the problem may not be building-related. |