Wendes HVAC estimating software allows the estimator  to define duct  construction standards for rectangular, round and oval ductwork for positive or negative pressure classes up to 10" water gage. Ductwork construction standards to unlimited widths in gages 28 to 1/2" and diameters to 96" in gages 28 to 1/2" plate. HVAC duct construction standards are used in the software to accurately calculate material and labor for an estimate by specifying the various aspects of duct construction. SMACNA duct construction standards can be defined. Duct construction standards allow an estimator to specify what gages, connections, reinforcing and tie rods are to be used for rectangular, round and oval duct.