The dynamic behaviour of an atmospheric liquid storage tank upon sudden change of meteorological conditions is analysed with the aim of establishing criteria for the safe and effective design of thermal breathing devices. A simulation model is presented based on a lumped-parameter multiple-zone representation of the tank. Simplified design criteria based on reasonable and conservative approximations of the governing equations are derived. Application of the simulation procedure and of design criteria is exemplified. Results are discussed and critically compared with prescriptions of existing codes.