For ATCO’s Installation Instructions, click here. When hanging or supporting flexible duct, there are a number of different materials which are used regionally. ATCO doesn’t specify a particular material in our Installation Instructions, however ATCO and the Air Diffusion Council do make the following statement: “Hanger or saddle material in contact with the flexible duct shall be of sufficient width to prevent any restriction of the internal diameter of the duct when the weight of the supported section rests on the hanger or saddle material. In no case will the material contacting the flexible duct be less than 1 1/2″ (38 mm) wide”. As in all cases, local jurisdiction has final say in these matters.