Silencers reduce noise in ventilation, exhaust, generator-outlet and industrial process air ducts while keeping pressure drop low. Absorptive, dissipative, reactive or combined types give insertion loss of 15–50 dB. Types include mineral-wool absorptive, cellular resonance, hybrid, splitter/lamella, round (tube) and high-temperature stainless exhaust silencers. Insertion loss 15–50 dB; pressure drop 30–150 Pa; flow 5–25 m/s; temperature −20 °C / +500 °C (exhaust); materials galvanized, stainless steel, aluminium; fill mineral wool 80–120 kg/m³. Uses: genset intake and exhaust, HVAC ducts, cooling-tower fans, blowers, compressors, vacuum and dust collection.