The ventilation effect of many ventilation systems is not satisfactory because of the lack of permeability of traditional iron sheet air ducts in China. The fabric air duct is a new type of fiber duct, precise permeability to create first-class domestic duct. Today, I will introduce the permeability of fabric air duct.

First, what is the permeability of fabric air duct

Fabricair duct is made of special material fiber, permeability is equal to the permeability of ordinary textile, refers to the unit area under fixed pressure difference unit time permeability.

Internationally, the permeability of a fabric is defined as 1CFM /ft2 at an air permeation rate of 1CFM per square foot of surface area at 125Pa inside the tube. Unit conversion: 1CFM/FT2 =18m3/h/m2. In China, we usually simplify the unit m3/h/m2 into mm/s, so 1CFM/FT2 =18m3/h/m2=5mm/s.

Second, the importance of permeability selection of material used for fabric air duct

One of the characteristics of the fabric air duct is that the air volume of the equipment enters the working area through two ways. The first is through the penetration of fiber materials, and the second is through the jet holes evenly distributed around the duct (the main channel).

Generally, the air volume of infiltration is only used to eliminate condensation, accounting for 5%-10% or less of the total air volume of the system (except for pure infiltration mode air supply).

If too much heat exchange is carried out in the permeable air volume, certain waste will be caused at high altitude. Therefore, different permeability materials should be selected for different occasions. Even in the same project, in different areas or at different installation heights, we should choose different permeability materials.