Air duct type

The air duct can be rectangular or circular. Any type of materials used in pipeline construction must have the characteristics of not transmitting fire, not releasing toxic gas in case of fire, and must be able to bear its weight, stress generated by handling, and vibration and erosion generated by air passing through its interior mechanically.

As for the type of materials used to construct them, pipes can be:

Galvanized steel duct

They are conduits made of sheet metal, mainly galvanized steel, but also stainless steel, copper and aluminum. They are usually prefabricated and shaped in different forms according to their use. There are round, rectangular or even oval pipes. Its constructive features, such as; The European standards UNE-EN 1505-1507 and UNE-EN 12236 and 12237 standardize the thickness of plates, reinforcement, joints, dimensions and even supports. The insulation and sealing characteristics of HVAC facilities are usually reflected in specific regulations. In Spain, the latest version of RITE, 1, was released in 2007.

In order to select the characteristics, it must be considered that the air pressure in the pipeline must determine the structural strength and leak tightness, while the noise, vibration and friction loss mainly depend on the air velocity.

The circular pipe is made of smooth flange plate with a diameter of about 900 mm. More common in the factory is the spiral tube made of galvanized sheet tape, which is spirally coiled and made into a pluggable module with an internal diameter of 80 to 2000 mm.

Rectangular pipes are also widely used because they are easy to adapt to low height spaces such as false ceilings, although it is recommended to respect the relationship between their two sides, R ≤ 4. They are widely used for ventilation facilities such as garages and ventilation facilities requiring large pipes.

Fiberglass air duct

They are pipes, and their main advantage is that they are made of high-density glass wool rigid panels during construction, and must comply with the European standard UNE-EN 13403 on thermal insulation products for building equipment and industrial facilities. The panel manufacturer provides a solution with an external reinforcement, which acts as a vapor barrier and an internal reinforcement to increase its mechanical strength.

In addition, these conduits also have the outstanding characteristics of light weight, good fire resistance, 2 as absorbent and acoustic attenuator. Of course, no additional insulation is required, because glass fiber itself plays this role. Its greatest disadvantage is aesthetics. They are not very suitable for landscape facilities, but they are widely used in air-conditioning facilities because they simulate beams or building components through false roofs or plaster coverings.

With regard to the health problems sometimes attributed to such pipelines, it is worth recalling that the above UNE standards require that the materials used in their construction must be classified as noncarcinogenic materials and should not promote microbial proliferation.

Flexible conduit

The most commonly used is composed of two pieces of PVC or aluminum plates with intermediate insulators and spiral steel wire armouring to maintain a circular cross-section. Their characteristics must comply with the European standard UNE-EN 13180. They are used as the connection part from the main pipe to the terminal or outlet, and the maximum length is not more than 1.5 meters, because they have the problems of load loss and noise generation.

More Recommendations:

Duct Fabrication Machines

Duct Board Cutting Machine

Insulation Cutting Machine

Pre Insulated Ductwork

Phenolic Ductwork

Duct Fabrication Procedure

Duct Board Fabrication

How to Fabricate Ductwork

Types of Duct

HVAC Industry Trends