The Barenbrug psychrometric charts are well-known to South African mine ventilation practitioners. Notwithstanding the common use of computers and formulae to automate psychrometric calculations, many situations are more easily visualised using charts. Students in particular find it much easier to grasp psychrometric processes when presented in graphical form. These charts are easy to use and provide a clear and concise view of heating, cooling, and humidification processes. This complete set of psychrometric charts (for barometric pressures of 80-130 kPa) is accompanied by theory and worked examples of psychrometric calculations as well as psychrometric formulae, and special charts for quick determination of sigma heat, enthalpy, humidity, water-air processes, and compressed air. Each chart is provided with a plastic overlay to simplify graphical representation of processes.