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 31, Max. flow velocity: 20 m/s, Housing material: galvanized sheet steel, Weight: 33.2 kg, Weight with packaging: 35 kg, Suitable for nominal width: 315 mm, Width: 915 mm, Height: 850 mm, Depth: 915 mm, Width with packaging: 930 mm, Height with packaging: 880 mm, Depth with packaging: 930 mm, Insertion loss at 250 Hz: 5 dB, Insertion loss at 500 Hz: 16 dB, Insertion loss at 1 kHz: 14 dB, Insertion loss at 2 kHz: 17 dB, Insertion loss at 4 kHz: 15 dB, Total insertion loss: 6 dB