RMS-MF 2018 with 12/20 Addenda

Companion Guidance—Section E-4 AARST Informational CG 11 Companion Guidance RMS- MF 2018 economizers vary the amount of outdoor air based on outdoor temperature and humidity level. Confirm proper economizer settings are based on design specifications or local practices and in conformance with design criteria required for mitigation. Ensure that dampers operate properly (for outside air, return air, exhaust/relief air, and recirculated air), per the design specifications. FANS: Ensure that all fans (supply fans and associated return or relief fans) that move outside air indoors continuously operate during occupied hours (even when room thermostat is satisfied). 4. AIR DISTRIBUTION AIR DISTRIBUTION: Ensure that supply and return vents are open and unblocked. Ensure that supply and return air pathways in the existing ventilation system perform as required. This includes passive gravity relief ventilation systems and transfer grilles between rooms and corridors are functioning. If ventilation systems are closed or blocked to meet current fire codes, consult with a professional engineer for remedies. Ensure every occupied space has supply of outdoor air (mechanical system or operable windows). PRESSURIZATION IN BUILDINGS: Ensure that the system, including any exhaust fans, is operating on the “ occupied ” cycle when evaluating pressurization. Ensure that air flows out of the building through windows, doors, or other cracks and holes in exterior wall (for example, floor joints, pipe openings) . 5. EXHAUST SYSTEMS Exhaust systems are designed to keep certain rooms or areas under negative pressure (as compared to surrounding spaces). Exhaust systems are employed often to prevent migration of indoor contaminants from areas such as bathrooms, kitchens and labs to other areas of the building. EXHAUST FAN OPERATION: Ensure that air flows into exhaust fan grille(s) EXHAUST AIRFLOW: Ensure that air is drawn inwards into the room from adjacent spaces. Ensure that air is flowing toward the exhaust intake . EXHAUST DUCTWORK: Ensure ductwork downstream of the fan is sealed and in good condition 6. QUANTITY OF OUTDOOR AIR OUTDOOR AIR MEASUREMENTS AND CALCULATIONS: Measure the quantity of outdoor air supplied to each ventilation unit. •Calculate the number of occupants served by the ventilation unit under consideration. •Divide outdoor air supply by the number of occupants to determine the existing quantity of outdoor air supply per person. ACCEPTABLE LEVELS OF OUTDOOR AIR QUANTITIES: Compare the existing outdoor air per person to the recommended levels in ANSI/ASHRAE Standard 62.1-2010 “Ventilation for Acceptable Indoor Air Quality” for buildings that are more than three stories tall or ANSI/ASHRAE Standard 62.2-2010 “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings”. Correct problems with ventilation units that supplied inadequate quantities of outdoor air.