Читать книгу Installation, starting and adjustment of ventilation and air conditioning systems A Guide - - Страница 20

Most often, metal ducts are used in air conditioning systems, which have great strength and resistance to fire.

They are made of galvanized or stainless steel.

Spiral-lock round (with a folding connection). They are made of steel tape with an anti-corrosion coating 0.5–1 mm thick, about 130 mm wide. They have increased rigidity compared to straight-seam ducts, there is no length restriction, aesthetic appearance, high seam density. The disadvantages include the fact that the seam takes about 15% of the metal from which the duct is made.

Spiral-welded round. They are made of steel tape with an anti-corrosion coating 0.8–2.2 mm thick, about 400–750 mm wide. The joints are welded overlap. Spiral-wound air ducts have less metal consumption compared to spiral-lock air ducts, there is no length restriction, high seam density. However, they cannot be made from steel thinner than 0.8 mm.

Rectangular straight-folding air ducts. They are made of steel sheet, it is desirable to place the seam on the bend so that it serves as an additional stiffener. Such ducts are easier than round ones to place in a space with a limited height, they fit better into the interior of the building. Rectangular ducts have greater aerodynamic drag than circular ducts with similar performance.

Round straight-folding air ducts. According to the manufacturing method and material, they are similar to rectangular air ducts, they differ only in a circular cross section.