Air Flow Equipment, Air Flow components, Air system terminals

Air flow equipment speaks to air flow components and air system terminals which are used to direct and adjust air volumes in ducts are:


  • Louvres are multi-bladed sections of aluminum or steel construction to architecturally affect openings in the outside walls of buildings or in doors within the building. These openings are generally used for intake or exhaust of air within the the air distribution system. Dampers
  • A balance damper are adjustable bladed air flow equipment which are used to restrict or decrease the flow of air through a duct or an outlet.
  • Grill

  • A grill is an opening with slots which supplies or exhausts air to or from a zone.


  • A grill with a damper added to it makes it a register. Registers with adjustable volume dampers are found on supply, return and exhaust duct systems and are necessary for proper balancing of the system.

    Fire damper

  • A loosely hinged damper which is held open by a fusible link and which is made of a heavy gauge steel is called a fire damper. When the temperature in the duct melts the fusible link, the damper slams shut since the blades are installed to close with the flow of air rather than against the flow of air.

    Mixing damper

  • This air flow equipment are sets of dampers which are installed in the return air duct and the outside air intake duct which are usually linked together and are often motorized.

  • The purpose is to be able to adjust the mixture of outside and return air by closing one and opening the other simultaneously to any desired setting.


  • Dampers may be of a multi-shutter type or opposed blade type. The multi-shutter variety have a series of gang operated blades which rotate in the same direction. The opposed blade variety have adjacent blades which rotate in opposite directions. Opposed blade dampers are more desirable since they do not have a tendency to turn or deflect air in any direction as do the multi-shutter type.

    Air Flow Equipment Dampers

    Locking quadrants

  • Most dampers in ducts or registers are operated by removable keys, fixed or removable levers or locking quadrant hardware which allow locking in one position. Splitter dampers.
  • These dampers are used to help proportion the static pressure equally between two ducts at a transition in the duct. Turning vanes
  • Turning vanes are devices with adjustable or fixed curved parallel blades, the purpose of which is to turn the flow of air in a different direction. They are installed at 90 degree elbows to assist in turning the air with a minimum build up of static pressure. Straightening grids
  • Straightening grids are simply devices made up of straight parallel blades used to straighten out the flow of air in duct work. Usually installed just upstream from a diffuser or register so that the air will flow evenly across the deflecting blades to achieve proper throw patterns. Diffusers
  • Ceiling diffusers are terminal air distribution devices which are used for supply purposes. They are connected to the branch ducts of air distributions systems at the ceiling. They are available with or without volume control dampers and in round, square or rectangular configurations.
  • Professional Air Balance

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