All galvanized round spiral duct & fittings shall be manufactured from G-90 galvanized steel, with a RL-1 spiral duct lock seam, and conforming to ASTM and SMACNA standards.
All galvannealed round spiral duct & fittings shall be manufactured steel with a galvanized coating then subjected to an annealing process to enhance the surface properties of the material for paint adhesion, with a RL-1 spiral duct lock seam, and conforming to ASTM and SMACNA standards. Our standard coating minimum thickness is A40 rated and chem-treat dry.
All stainless steel round spiral duct shall be manufactured from 304SS, with a RL-1 spiral duct lock steam, and conforming to ASTM and SMACNA standards.
Galvanized Spiral Duct can theoretically withstand 400F, past this point the zinc-based coating begins to degrade and flake. Manufacturer’s recommendation is that sustained temperature should not exceed 200F for long periods of time.
Galvannealed Spiral Duct can theoretically withstand 750F, past this point the material properties and coating strength degrade. Galvannealed Spiral Duct has an annealed coating surface that is better suited to receive paint products. All painted products must be cleaned, regardless of finish, to remove surface contaminants and oils from manufacturing. Manufacturer’s recommendation is that sustained temperature should not exceed 300F for long periods of time.
Stainless Spiral Duct can theoretically withstand well above 1000F, past this point the material strength decreases drastically and moving towards 1500F corrosion resistance begins to degrade. Manufacturer’s recommendation is that sustained temperature should not exceed 900F for long periods of time.
With all stated temperature ratings, the appropriate engineering and specifications must be followed and properly gaged to ensure mechanical strength properties are sufficient in each pressure application.