Download the latest free standalone installation of Chasm Consulting VentSim Premium Design 5.1 for Windows 64-bit. Chasm Consulting VentSim Premium Design 5.1 is a professional application for visual work with ventilation and simulation of underground ventilation systems. Chasm Consulting VentSim Premium Design 5.1 Overview Chasm Consulting VentSim Premium Design 5.1 is a professional application for