RMS-LB 2018 with 12/20 Revisions

Building Investigations Prior to Design 9 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings Table 5.4.4 Operational Design of HVAC Systems Group 1 Basic Heating and Cooling A dedicated system for each room or unique area that does not provide seasonally variable outdoor air ventilation for added comfort or energy savings. • Forced-air heating and air conditioning (HAC) systems (such as normally seen in single-family residences). • Ductless Systems - Non-forced-air hot and cold water circulation (sometimes called radiator systems). - Window AC (w/fresh air closed). - Wall or baseboard heating/cooling. • Ductless Split Systems: One system for cooling and one for heat (i.e. window AC for cooling and Baseboard heat). Group 2 Multi-Zone Systems Independent systems and controls for different areas within the same room or unique sector. Group 3 Variable Outdoor Air Ventilation Systems that seasonally vary outdoor air ventilation for individual rooms, a unique area, or the whole building. Systems include: energy economizer systems, heart or energy recovery ventilators and evaporative cooling systems. Group 4 Variable Air Distribution Systems where airflow from a single air handler is distributed among multiple rooms with independent thermostat controls in each room or unique area that variably open and close dampers for heated or cooled supply air. Informative advisory —If it is unclear what type of system is present, consider consulting with the building representative, a mechanical engineer or a heating and air-conditioning contractor. Note—See Companion Guidance Section C for more information on HVAC systems. 5.4.6 Occupancy use For the purposes of this document: a) The term “Occupied” is defined as any area of the building that is occupied on a regular basis for more than 4 hours a day; b) The term “Significantly occupied” is defined as the time period where the building is typically occupied by the majority of the workers or students; and c) The term “Occupied work or school weeks” is defined as those weeks that do not include vacation days, winter breaks or similar weeks where test conditions do not represent normal occupied conditions. Informative advisory —Diagram(s) or documentation should identify the occupancy use for each unique area and the following details: a) the number of months per year that the building or individual portions of the building are significantly occupied; b) the hours of the day that each individual portion of the building is significantly occupied; c) other areas where occupants or workers may spend more than 4 hours per day; and d) areas that are not occupied yet can potentially become occupied. 5.4.7 Required evaluation of building operating conditions The following evaluation is required to estimate design capacity needs for effective mitigation across the seasonally changing operating conditions of the building: a) Normal occupied operating conditions Identify testing periods that reasonably represent the normal occupied operating condition for each unique sector of the building. For the purposes of this document, the “Normal Occupied Operating Condition” is defined as: The operational condition for the building or unique sector of the building that exists during the greatest amount of significantly occupied time. Figure 5.5.1.6