Manual

10. Technical Information
% Outside Air - HVAC systems use a combination of outside air, supply air, and
return air to maintain consistent and comfortable air quality. The 1010 can calcu-
late outside air either by measuring temperature or by measuring CO2. The for-
mula for % Outside Air is:
Dew Point Temperature - This is the temperature at which condensation begins
Wet Bulb Temperature - This is the lowest temperature evaporating water can
reach
Recommended Levels by Agency
Notes:
If too little outdoor air enters a home, pollutants can accumulate to levels that can
pose health and comfort concerns. Unless they are built with special mechanical
means of ventilation, homes that are designed and constructed to minimize the
amount of outdoor air that can 'leak' into and out of the home may have higher pol-
lutant levels than other homes. However, because some weather conditions can
drastically reduce the amount of outdoor air that enters a home pollutants can build
up even in homes that are normally considered 'leaky'.
Parameter
IDPH
1
ASHRAE
2
OSHA PEL
3
ACGIH TLV
4
Humidity 20% - 60% 30% - 60% N/A N/A
Temperature 68 - 75 (winter)
73 - 79 (summer)
68 - 75 (winter)
73 - 79 (summer)
N/A N/A
Carbon Dioxide 1,000ppm
(<800ppm preferred)
1,000ppm 5,000ppm 5,000ppm
Carbon Monoxide 9ppm 9ppm 50ppm 25ppm
N/A-Not Applicable or Not Established
1
Illinois Department of Public Health (2009)
2
American Society of Heating, Refrigerating and Air Conditioning Engineers
3
Occupational Safety and Health Administration Permissible Exposure Limit -- this level
is a time-weighted average and is an enforceable standard that must not be exceeded
during any eight-hour work shift of a 40-hour work week.
4
American Conference of Governmental Industrial Hygienist Threshold Limit Value -- this
level is a recommended time-weighted average upper limit exposure concentration for a
normal eight to 10-hour workday and a 40-hour work week.