IEC 61709:2011 gives guidance on how failure rate data can be employed for reliability prediction of electric components in equipment. Reference conditions are numerical values of stresses that are typically observed by components in the majority of applications. Reference conditions are useful since they are the basis of the calculation of failure rate under any conditions by the application of stress models that take into account the actual operating conditions. This standard also gives guidance on how a database of component failure data can be constructed to provide failure rates that can be used with the included stress models. This edition includes the following significant technical changes with respect to the previous edition: - the addition of a number of component types and the updating of models for a large number of component types; - the addition of annexes on reliability prediction, sources of failure rate data and component classification information.