Caleffi insulation for degasser - dirt separator 546 DiscaldirtCaleffi insulation for degasser dirt separator 546 Discaldirt Code: CBN5460002 The Caleffi insulation for the 546 Discaldirt deaerators dirt separators consists of an expanded polystyrene shell , one centimeter thick, which thermally insulates the Discaldirts from both heat and cold. The insulating shell also blocks the passage of water vapor inside the deaerator when operating with chilled water. It therefore also prevents the formation of condensate