Indoor Air Quality Guide to Acceptable Conditions
INDOOR AIR QUALITY ACCEPTABLE CONDITIONS TABLE 1. TYPICAL AND TRIGGER IAQ PARAMETERS HUMAN MARKERS TRIGGER CONDITIONS ** TYPICAL CONDITIONS * CONDITIONS* Comfort Issues 10% or less complaining of any one thermal condition Greater percentages than these listed 20% or less complaining of general thermal conditions Health Issues Infectious diseases: 100% protected Any less than listed Asthma/allergies/MCS: 95-99% satisfied PHYSICAL MARKERS TYPICAL CONDITIONS* TRIGGER CONDITIONS** Temperature 68 degrees to 76 degrees Farenheit Temperatures outside this range. Temperature range in a space. 1-3 degrees Farenheit More than 3 degrees Farenheit Relative Humidity 40-60% RH <30% or >60% RH Building Under positive pressure; air delivered to occupied spaces Different conditions than listed Air movement on people Air velocities > 20fpm but x delivered to occupied spaces Different conditions than listed (80% satisfaction) Air velocities <100-200 fpm when warm Outdoor air delivery 20 cfm/person: offices Less than 15-20 15-20 cfm/person 15 cfm/person: classrooms Total air delivery to space 1 cfm/sq. ft; 6 air changes per hour (offices) Different conditions than listed CHEMICAL MARKERS TYPICAL CONDITIONS* TRIGGER CONDITIONS** Carbon dioxide 400 to 1100 ppm 700+bkgrnd (ASHRAE 62-1999) TVOC 300 m g/m 3 ( 1-2 ppm) (approximately 1-2 ppm) Depends on compound; 300 m g/m 3 to 3000 m g/m 3 Formaldehyde 0.005 - 0.05 ppm >0.05 ppm (60 ug/m 3) 60 m g/m 3 Carbon monoxide 1 - 3 ppm > 3 ppm NO2 0.01 - 0.05 ppm 0.05 ppm Ozone 0.01 - 0.02 ppm > 0.02 ppm Particles up to 50 m g/m 3 (total) any visible aerosols (e.g., dust smoke); high quantities up to 15 m g/m 3 (PM 2.5) of settled dust on flat surfaces; visible particles emitted from supply registers Bioaerosols varies widely with site/locate Counts 2-3X greater than other spaces or outdoors Asbestos < 0.01 fb/cc > 0.01 fb/cc < 2 g/m 3 Radon < 0.5 pCi/lit > 4 pCi/lit (EPA recommended standard) Odors "none" Any detectable for extended periods of time * Non-industrial environments, e.g., office space, classroom, conference room. **Trigger means "take note," "investigate." Caution: Do not use the Table for compliance or design; always obtain competent professional assistance. Source: IAQ and HVAC Workbook, 2002, D. Jeff Burton.
