Guso drop band9/18/2023 ![]() ![]() Flexible hoses can break if duct connection is too "sharp". If hoses are installed in a sharp bend immediately after connection to the duct or fixture, a supporting bracket must be installed. The connection of flexible hoses to ducts and components must be made with due care. ![]() Manufacturers recommend a minimum bending radius of two times the diameter (d). For flexible hoses a minimum bending radius of R = d + 2 x insulation thickness must be observed. Therefore, the aim should be to have the largest possible bend. However, this minimum bending radius results in a large pressure drop. Also support the hose at least over half its circumference.Īccording to NEN-EN 13180 the bending radius of a flexible duct must comply with R = d. by perforated band) make sure that the hose is not reduced in diameter. Deformation reduces the internal diameter and increases the pressure loss. This size depends on the type of hose that is used.Ī hose is generally very flexible and can be deformed quite easily. The distance between two suspension points can vary between 1.5 and 3 metres.The maximum permissible sagging the hose, between two fixing points, shallnot exceed 50 mm (measured at the centre).This must bedone according to the installation instructions of the suppliers. The hose may also be mounted using a so-called "guso" ring.Use aluminium tape for pure aluminium and aluminium foil hoses and use plastic tape for plastic hoses.Clamp the outer casing with the inner hose on to the connection usinga sturdy hose clamp or by using a tie-rap which must be tightened with the appropriate pliers and the prescribed preload.Preferably use tape with a width of at least 50 mm.Push the hose at least 40 mm over the connection.Push back the insulating material and the outer casing a little and tape theouter casing, including the insulating material, firmly and airtight to the inner hose.This shouldbe done according to the installation instructions of the suppliers. Then secure the hose with a sturdy hose clamp or by using a tie wrapwhich should be tightened with the appropriate pliers and preload.Push the hose at least 40 millimetres over the connection.Using scissors, remove any excess insulation material.Cut the hose along its full circumference and use a pair of cutters to remove the cut the spiral of the inner hose.Using a sharp knife, cut through the outer layer, insulating material andinner hose.Use a pair of cutters to cut the spiral of the hose.Between the spiral windings, cut the material along its full circumference.Measure the correct length and mark this point with a felt-tip pen never use more hose than absolutely necessary.Stretch out the hose properly an incomplete stretch leads to unnecessarypressure loss.If a longer length has to be used, the hose must be properly clamped. ![]() The aim should be to use a minimum of 0.5 to a maximum of 1.5 metres of hose. When compressed, the lengths are 0.4 to 3 metres, depending on the type and manufacture of the hose. The lengths available vary by manufacturer and are available from 1 to 10 metres when extended. After stretching, the hose should be no more than 3% shorter than the nominal length specified by the supplier. The hose must be stretched out before use. The flexible hoses are usually supplied in a compressed version. The dimensions depend on the manufacturer. The nominal sizes available for intermediate flexible hoses are standardized to NEN-EN 13180 and can be selected as shown in the table (see right). If required, the fire resistance must be specified in accordance with the fire classifications in the NEN-EN 13501-1. The spiral wire is made of steel concealed or non-concealed, if necessary with a coating. ![]() The thickness of thematerial depends on the type of hose and on the supplier. The hose is manufactured from a fibre-reinforced synthetic cloth or from avinyl-coated fabric cloth incorporating a spiral wire. Thethickness of the material depends on the type of hose and on the supplier The hose is composed of layers of aluminium and polyester foil oraluminium polyester laminate in which a spiral wire is incorporated. The thickness of the material depends on the typeof hose and on the supplier. A flexible hose is used in an air transport system to connect a vent, valve or vent plenum to an air duct.įor normal comfort ventilation, flexible hoses are manufactured from the following materials:Īluminium straps according to NEN-EN 573 are used for manufacturingaluminium flexible ducts. ![]()
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