Three computer programs for slzlng ductwork and calculating duct pressure are described and input and ouput examples are shown. One of the programs is a single trunk static regain duct sizing program which provides rectangular duct sizes. The second program is a duct pressure program which, given either rectangular or round duct sizes, calculates duct pressures. The third program is a network duct program which, usin~ the static regain method, sizes a duct network.