The ducts that circulate air for heating and cooling are usually connected to HVAC machinery by flexible duct connectors made of durable fabric. For many decades, textiles woven from asbestos fibers were the primary material for this application.
Metal air ducts connect all the rooms in a home or building to HVAC equipment. When ducts are attached to heaters, air handlers and air conditioners directly, the noise and vibrations produced by the equipment may rattle throughout the entire ventilation system
