1. Air duct size determination. Based on design requirements and review minutes of drawings, combine with on-site measured data to draw an air duct processing sketch, and indicate the location of system air volume and pressure measurement holes.

2.

Duct Unrolling. Lay out the surface shape of the duct according to the duct construction drawing (or layout drawing) in actual size on the sheet material; there are three methods of unrolling, namely the parallel line unrolling method, the radial line unrolling method, and the triangular line unrolling method.