In chemical, petroleum, air-conditioning and refrigeration engineering, the engineer often encounters systems where gases and condensing vapours co-exist. Key data describing the behaviour of such mixtures can be obtained by consulting an appropriate psychometric chart. This book brings together over 270 such charts, covering most of the systems likely to be encountered by chemical, petroleum, air-conditioning and refrigeration engineers. The condition of a mixture of a gas and a condensing vapour can be represented by a single point on an appropriate psychrometric chart. This point can usually be fixed using two pieces of data and, once defined, the chart can be used to determine other information concerning the gas mixture. For example, if a point is defined using the dry bulb temperature of a mixture and its relative humidity, a range of other properties, such as dew point, specific volume, specific enthalpy, absolute humidity and adiabatic saturation temperature can easily be found without recourse to lengthy calculation. In this book, following an introductory chapter on the construction and use of the charts, over 270 charts covering a wide range of systems at various temperatures and pressures are presented. These charts are based on a model characterizing the behaviour of the vapour phase using the Virial Equation of State and take into account the solubility of gas components in the condensed vapour. In use they offer the engineer rapid access to accurate, concise and otherwise difficult to obtain data. This book should be of interest to: chemical and environmental engineers in private consulting firms and government agencies; mechanical and petroleum engineers in similar firms; and lecturers in chemical engineering, environmental engineering, mechanical engineering and air conditioning engineering.