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The technical characteristics of MatHellas venti-ducts meet the special requirements of each project. The quality of the fabric, the diameter of the duct, the section length, the coupling and the suspension system, are capable of being adapted to the needs of any underground work.

Selection of Diameter
For the standard types, MatHellas flexible ducting is available in the following sizes :

  • Diameters ranging from O200 to O3500 mm
  • Section lengths of 10, 15, 20, 50, 100 and 200 m.

mathellasWe can also manufacture other sizes of diameter and section length upon request.

The diameter of the venti-duct and the power of the fan are proportional to the demands of the face of the gallery for fresh air.
The demands for fresh air depend on factors like the cross-section of the gallery, the length of the tunnel, the kind and the weight of the explosives that may be used, the number of workers as well as the number and the kind of the mechanical equipment that is used.
The diameter on the ventilation duct must always be computed to be as large as possible. A duct with a large diameter provides more air than a smaller duct with significantly lower energy costs.


Suitable Fabric

mathellasMatHellas venti-ducts consist of a knitted textile made from polyester yarn coated on both sides with softened PVC (polyvinyl chloride), normally yellow colour.

The polyester textile gives the ventilation ducts their mechanical strength. Different textile thicknesses are used in the different duct qualities. The specially developed knitted textile gives the material a high tear resistance and thus prevents small holes and cracks from growing and causing the entire duct to tear.
The coating on the textile makes the ventilation duct air and water tight, protects the yarn against UV radiation and chemical effects of light, plus it makes it possible to weld the individual sheets together into a circular duct. Thicker coatings provide better wear resistance.

There are 2 available qualities: PVC650 and PVC750. Both are quality-certified with ISO 9001 & ISO 14001, anti-static and flame resistant in accordance with international standards. The technical specifications are available upon request.
Our fabrics are distinguished by the fact that they are relatively low weight while at the same time, very strong which results in a very pliable and easy to handle duct.