Basic characteristics


1/ Cross section

Fabric ducting - Flexible duct shapes

We also make fabric transitions to adapt and join different shapes together.


2/ Sizes and Diameters

We manufacture fabric ducting and diffusers of all dimensions from 100mm to 2000 mm, each designed to specific requirements. The duct inlets and connection spigots are always manufactured 10-15 mm larger than the specified size/diameter for ease of connection.

The ducts have dimensions (A) or (B) depending upon shape, please see the chart above or the table below.

Fabric ducting - Hvac duct dimensions

3/ Length

Determining the length of Fabric Ducting & Diffusers depends primarily on the availability of space. We can manufacture a fabric diffuser to deliver the same air volume whether the duct is short or long, the precise design depends on the material type, perforation designs and system pressure.


Fabric ducting - Hvac duct lenght

A – Beginning (edge /zip) – length  100mm – 200 mm

– Continuous part (zip/zip) – length 5000mm –10000 mm, these are multiplied to create the correct duct length

C – Blind part (zip/end) – length from 100mm to 11000 mm

– Individual parts are connecting with zippers; the number of zippers (or the distance between them) is flexible and can be specified by the customer

– Only the overall length in mm (A + B + C) is provided in the specification, the ducting and diffusers are separated into segments during production.


4/ Pressure

Pressure losses of Fabric Ducting & Diffusers are very similar to those in the traditional ducting. Calculating a more complex fabric distribution system is achieved using similar methods to those for sheet metal ducting. The minimum static pressure necessary to keep the correct shape of a Fabric Duct or Diffuser depends upon the weight of the fabric used. A minimum of 20 Pa is sufficient for light materials and 50 Pa necessary for medium and heavy ones. The pressure distribution along Fabric Diffusers is different from traditional sheet metal ducting because with declining airflow longitudinal velocity decreases. To verify the design of your fabric distribution system, please contact us.

Fabric ducting - Hvac system pressure


5/ Types of Ending

Fabric ducting - Hvac system types of ending