Chapter 2

2.5.3 Circular ducts of mineral wool Material quality

The ducts are made of compressed glass wool with a reinforced foil on the inside and outside of the duct. The water vapour resistance > 140m2h Pa/mg Material thickness

The average insulation thickness is 30mm. Connections in duct

There are no longitudinal connections in the ducts. The manufacturing process results in a completely closed inner, middle and outer layer. Connections in fittings

Fittings are manufactured from half-pressed layer parts, which are glued together. The outer and inner layer of the fitting are entirely covered with reinforced foil. This construction gives the fitting sufficient stiffness and strength. Dimensions

The ducts are executed in standard diameters indicated in the table below.
It is possible to make the duct rectangular by using a suitable rectangular deformer. The dimensions and shape for this are in the table below. Pipe length

The pipes are manufactured with a standard length of 2350 mm. The duct can be easily shortened to the desired length. Sealing of end pipes

A special end seal is used to cover the duct end (insulation) to make a proper airtight connection with the fitting. Made of plastic. For assembly see manufacturer's assembly guide. Bends

As regards form, bends are manufactured as standard with a radius measured across the centre of the bend and equal to the diameter. (inside diameter) The bends are executed in an angle of 90° or 45° with a tolerance of ± 2°. The bends consist of 1 segment. For dimensions see table below. Adapters

Adapters are carried out symmetrically. Adapters are made to connect two different sizes of pipes.
The adapters are made of Sendzimir galvanized steel. The part of the adapter which does not fall within the duct must be insulated with a material which has the same properties as the base material of the pipes. Branches / T-pieces

Branching/splitting is carried out with a preformed T-piece. The T-pieces are manufactured in the same way as the bends. Dimensions according to the table below. Connectors

Connectors are made of Sendzimir galvanized steel, fitting into the pipes. There are two types of connection pieces;

  • Connection between pipes
  • Connecting the pipe with a standard spiral flanged pipe

The dimensions and insertion length of these connectors are fully matched to the pipe system.
The connectors are fixed with reinforced tape (tape according to supplier's recommendation) and go around the outer layer of the insulated duct. Erosion resistance

In order to guarantee erosion resistance, the ducts are internally finished with a reinforced aluminium foil layer. Fire resistance

The ducts are classified according to EN 13501-1:2007 - A2-S1, d0 (non-flammable) System pressure/air density

The maximum permissible system pressure is 1000Pa (internal overpressure) The maximum negative pressure is -400Pa.
The duct is tested according to EN1507:2006 , airtightness class D. Operating temperature

The maximum operating temperature is -40°C - +60°C Transition from mineral wool to steel

The transition to steel circular ducts is made by means of the appropriate transition piece, type adapter. Tolerances

Tolerances for circular ducts are +/- 1 mm

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