Free application Valves PL (AutoCAD, IntelliCAD and BricsCAD application) in latest version containing libraries of CWK Sp. z o.o. company. VALVES aid drawing of 2D ventilation installations based on round sections/profiles and wires as well as molders with rectangular sections/profiles. It also contains libraries of molders and ventilation accessories produced by real manufacturers. Program allows comfortable building of installation as well as easy applying changes. In the end program creates automatically collation of elements used in the project. It is also possible to calculate in an automatic way declines in pressure at the finished installation or part of this installation.