Details of duct insulation including fastened ,anchor , insulator ,supporting member , angle fastened side of angle , duct size mentioned
457mm x300mm of angle 3.81 x 1.61 mm , also 610mm x 508mm of angle 25x 3.2 mm insulations are put on the external surface of ducts to prevent condensation and energy loss. However, insulations are sometimes pasted on the internal surface of ducts to suppress noise especially for the ducts of air handling units (AHUs). ductwork needs to be insulated to maintain the optimum temperature, as air makes its way from the HVAC unit to living or working areas. and suggested size also mention in this drawing with details for more details of Details of duct insulation download this file .