MALB_2014 with 1-21 Revisions

Conducting Measurements of Radon and Radon ANSI/AARST MALB-2014 with 1/21 Revisions Decay Products in Schools and Large Buildings 47 HVAC GROUP DESCRIPTIONS Page 3 of 3 Group 3: VARIABLE OUTDOOR AIR VENTILATION Variable Outdoor Air Ventilation (HVAC) systems are those that add outdoor air ventilation for seasonal comfort or energy savings. Such systems may service a whole building, multiple dwellings or a single dwelling or unit ventilator. Radon concentrations can vary widely from test to test based the volume of outdoor air supplied to a dwelling or room at any given time. Group 4: VARIABLE AIR DISTRIBUTION Variable Air Distribution systems are those where airflow from a single air handler is distributed to multiple dwellings, rooms or common use areas with independent controls within each area that open and close duct dampers. The normal operation of these systems can cause changes in distribution of radon or ventilation air and can also affect pressure relationships that can enhance or diminish radon entry. HRV or ERV