What Do Dampers Mean In Construction?
What Do Dampers Mean In Construction?
Dampers are devices used in construction to reduce vibrations and building displacement, as well as to provide comfort for occupants. There are several types of dampers, including visco-elastic dampers, viscous dampers, and viscoelastic dampers.
Visco-elastic dampers are typically used in buildings in seismic areas, while viscous dampers are used to absorb seismic energy and reduce harmful deflections, forces, and accelerations.
Viscoelastic dampers convert mechanical energy into heat energy and have been successfully incorporated into a number of tall buildings.
In bridge applications, direct-acting damping can be used with fluid viscous dampers to absorb wind, seismic, and pedestrian energy. Tuned Mass Dampers (TMDs) are also used in structures to reduce the effects of human-induced vibrations such as the axial shortening of columns in tall buildings.
What Is The Purpose Of A Damper?
The purpose of a damper is to regulate ventilation, prevent warm or cold air from entering a home through the chimney when it’s not in use, and help control how quickly warm air, waste gases, and smoke are released from the fireplace during a fire.
Dampers also help to reduce the inflow of outside air into the flue, which helps to keep a home warm in winter and cool in summer. Additionally, dampers can help prevent animals, birds, and debris from entering the chimney.
What Are The Types Of Dampers?
There are several types of dampers used in HVAC systems, including multi-blade control dampers, single-blade dampers, backdraft and pressure-relief dampers, face and bypass dampers, and inlet vane dampers.
Multi-blade control dampers, also known as rectangular or multi-blade louver dampers, are typically found in two varieties based on the blade action – the direction of airflow.
Parallel blade dampers may be used in gas turbine inlets and outlets, fan inlets, atmospheric exhaust, scrubbers/oxidizers, and precipitators.
Single-blade dampers, also known as butterfly or wafer dampers, can be supplied in round, square, or rectangular varieties.
The blades can be of a single-thickness or double-skin airfoil design Backdraft and pressure-relief dampers are used to control the relationship of the flow/pressure of a fan or blower from the inlet side.
Face and bypass dampers are normally referred to as tee dampers or diverter dampers that have a tee-pipe configuration to divert the airflow in different directions.
Inlet vane damper is also referred to as variable inlet vanes or inlet vane controls. It is used to regulate the airflow from the inlet side and is suitable for manipulating the flow rate of air into an HVAC system.
How Do Dampers Work In Buildings?
Seismic dampers, also known as shock absorbers, are materials or devices used to reduce the amplitude of vibrations during an earthquake.
They work by lagging behind the motion of the building and eventually moving in the opposite direction, which reduces the overall sway. There are several types of seismic dampers, including friction dampers, metallic dampers, and tuned mass dampers.
Friction dampers are designed to slip before the building loses any structural integrity or experiences significant damage. Metallic dampers are usually made from steel or lead and designed to deform during an earthquake.
Tuned mass dampers are large masses mounted with flexible components that absorb energy by converting it into heat.
These dampers have been successfully incorporated in a number of tall buildings as a viable energy-dissipating system to suppress wind and earthquake-induced motion of building structures.
Where Dampers Should Be Placed?
Smoke dampers must be installed at or adjacent to the point where the duct passes through the smoke barrier in accordance with NFPA 90A. The maximum installation distance is 24″ (609mm) from the smoke barrier.
Duct air outlets, inlets, or branches shall not be located between the smoke damper and the smoke barrier.
All moving parts of the damper must be inspected and cycled at intervals not greater than every twelve (12) months or in accordance with the latest edition of NFPA 80, 90A, 92A, local codes, and the manufacturer’s instructions.
Smoke dampers must also be installed square and free from racking to ensure proper operation and performance. Additionally, they must not be installed in fiberglass-lined ducts in a manner that will damage the lining material or interfere with damper blade operation.