CPF99 is the basic calculation package of Arthermo. It performs thermodynamic and corporeal calculations such as enthalpy, entropy, density, and specific heat, for natural gas and gas mixtures, liquid hydrocarbons, and aqueous solutions, as well as combustion calculations for process equipment, heat exchangers, and combustion systems. It can be used to analyse the properties and behavior of vapor, liquid, and gas mixtures, analyze operating parameters, and size and design equipment. Additionally, CPF99 incorporates a number of calculations to assist in specific process problems and helps to verify, optimize, and troubleshoot existing systems.