The friction coefficient of the DurkeeSox fabric duct is less than 0.024, similar to the GI duct system. In fact, the

actual resistance of DurkessSox fabric duct is much smaller than the traditional duct system, because the shape of most

DurkessSox fabric duct system is round, the average air-flow velocity especially the mid-end part are smaller than the

tradition duct system. For a simple straight fabric duct system, the resistance inside the fabric duct is much smaller than

the static pressure regain, so the resistance can be ignore. For a complicate fabric ductworks, the resistance is only 1/3

or 1/5 compare to the tradition metal ductworks. The airflow pressure are totally enough for the DurkeeSox fabric duct

system while designing. Also, the fabric   permeability and the orifices of the DurkeeSox fabric duct system can be

modified according to the airflow pressure, in order to secure the volume of the airflow supplied and no extra requirement

of the AC equipment.