Silencer for reducing the noise on the suction side of roof fans. With sound insulation baffles made of abrasion-resistant and non-flammable mineral fiber boards. Recommended accessories: intermediate socket SZ for connecting pipes. Article: SD 22, Max. flow velocity: 20 m/s, Housing material: galvanized sheet steel, Weight: 27.5 kg, Weight with packaging: 29 kg, Suitable for nominal width: 225 mm, Width: 805 mm, Height: 850 mm, Depth: 805 mm, Width with packaging: 806 mm, Height with packaging: 875 mm, Depth with packaging: 806 mm, Insertion loss at 125 Hz: 3 dB, Insertion loss at 250 Hz: 6 dB, Insertion loss at 500 Hz: 20 dB, Insertion loss at 1 kHz: 21 dB, Insertion loss at 2 kHz: 23 dB, Insertion loss at 4 kHz: 30 dB, Total insertion loss: 9 dB