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Frequently Asked Questions (FAQs)

1 / What does the fabric duct look like when the blower is off?














2 / Can the fabric duct be used for exhaust?

AD Industry PRIHODA, specializing in fabric ducts, is the first manufacturer in the global suction duct market. The suction duct is square or triangular in shape. The main principle is to apply sufficient stretching (tension control) to the four horizontal/vertical sides of the fabric duct. This tensioning system is easy to disassemble or reinstall, and a laser hole (normal hole) is used for the air intake port of the duct.


3 / How long is the service life of the fabric duct?

fabric ducts are not used for a short period of time. PRIHODA's high-quality fabric material can be used for more than 15 years, and the lightweight fabric (approx. 100g/m²) can be washed up to 50 times and is lightweight. Durability may be limited (as polyurethane foil may tear).  


4 / What is the pressure loss rate of the fabric duct?

A basic diffuser that does not use a special shape maintains a constant static pressure. The laser hole is calculated by the average value of the static pressure. In other words, the diffuser is designed according to the external static pressure (external pressure) of the fan while it is attached to the fan outlet. Connections and turbulence equalization components (EQs) have additional pressure losses and must be considered when designing. Loss due to friction is usually negligible, and that loss is due to the decreasing air velocity inside the diffuser. The minimum usable pressure is at least 50 Pa (20 Pa for light materials).


5 / What if the vents are blocked by contaminants?

Laser holes (fine/normal holes) are rarely clogged with contaminants (the effect of using a pre-filter of at least EU-3). For hygiene and aesthetic reasons, maintenance (washing in a washing machine) is required, and each part that can be separated with a zipper has a tag with detailed washing instructions attached. From experience, the interior of ducts made of endless fibers remained clean even after many years of operation.


6 / Does the diffuser get mold?

  Mold can form on any material if it is damp and not ventilated. Certain materials undergo antibacterial treatment. Only one material NMF can prevent white mold. Do not store damp fabric diffusers or leave them unused for long periods of time in humid air. This can also lead to mold problems.


7 / Is it possible to use a square or rectangular diffuser?

Frihoda has developed a special structure for the use of square ducts. Rectangular ducts are built on the basis of stretching (pulling) fibers in the transverse/longitudinal direction by means of a tensioning system. Rectangular duct is simple to dismantle and can be reassembled. Square fabric ducts can be installed directly on the ceiling or suspended in a specific location.


8 / Does the fabric diffuser have a filter function?

If a permeable material is used, the fabric duct functions as a filter for the air passing through the fibers. As textile contamination gradually increases, pressure loss increases and airflow decreases. Therefore, the fabric duct needs washing. I think the best way is to use a material with a laser hole (fine hole, general hole). The fabric material with laser holes does not function as a filter, but does not increase pressure loss and does not increase the number of washes. PRIHODA is an air conditioning company, not a filter company.


9 / Why doesn't PRIHODA use plastic nozzles or slots?

In the past, plastic nozzles or slots were used to control the wind direction and had the ability to stiffen the holes. It was processed to produce precise specifications using laser technology, but it was not meaningful in terms of efficiency. The same purpose could be achieved with uniformly processed laser holes (fine holes, general holes), and it is superior in price and appearance. That's why we use fabric nozzles, not plastic, for long-distance airflows or vertical outlets. Fabric nozzles are light in weight and are sonic welded, so friction won't damage or disassemble the duct during cleaning.  


10 / Why doesn't PRIHODA use more permeable materials?

When dispensing air at a temperature below the dew point of the surrounding environment, permeable fabric is used to prevent condensation. The materials we own apply only a single transmittance coefficient. This is a very low value and is suitable to prevent condensation. Air distribution uses special laser holes (microholes, regular holes, a combination of both) and calibrated holes (nozzle, counterflow pocket holes). Our fabric types also include impermeable materials, which can be used in other situations as well.


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