Where most other types of ducting are formed from sheet metal, spiral duct pipe is formed from a coil of metal into a rigid steel tube with a 4-ply spiral lock seam. It has a relatively smooth interior for low friction loss with the grooved seam entirely on the outside. Typically, spiral duct is available in any length and although longer lengths of pipe do reduce the number of connections that need to be made during installation, the cost of shipping such long sections may make it more expensive to deliver. Pipe sections can be joined together by using inset-off-set with barrel clamp, standard spiral pipe connectors, sheet metal screws or special angle rings.
Most of the non-pipe components used in conjunction with spiral pipe are constructed using the same methods (sheet metal manufacturing) as those used with flanged duct, airtight tubing and clamp together duct. The connection ends of branches, elbows, gates, etc. are simply constructed to accommodate the spiral pipe.
i) Rolling Machine is function for restructure metal sheet by bending into cylinder shape.
ii) Metal sheet standard size rolling availability : 4ft x 8ft or 5ft x 10ft
iii) Metal sheet thickness rolling availability : 0.80mm to 16mm