ABSTRACT
This chapter provides the procedures for balancing low pressure constant volume systems and the low pressure side of any system, constant air volume, or variable air volume. An electronic digital rotating anemometer measures air velocity in feet per minute. Capture airflow hoods are used at the face of ceiling diffusers, grilles, registers, coils, or filters. They are also used to measure openings in ducts, walls, doors, etc. and to measure face velocity of fume hoods. The air balancing technicians have measured and recorded static pressure in the air handling unit. The alternate test and balance procedure starts at the supply outlets then the takeoffs, branches and fan. DD or double duct systems are dual path systems usually having a cooling coil and heating coil. Commercial and industrial heating, ventilating, and air conditioning system are designed to have a certain amount of airflow into each room to keep the room at design temperature and humidity.
