This part of ISO 16732 provides the conceptual basis for fire risk assessment by stating the principles underlying the quantification and interpretation of fire-related risk. These fire risk principles apply to all fire-related phenomena and all end-use configurations, which means these principles can be applied to all types of fire scenarios. The principles and concepts in this part of ISO 16732 can be applied to any fire safety objectives, including the five typical objectives listed as examples in Clause 1 of ISO 23932:2009: — safety of life, — conservation of property, — continuity of business and safety operations, — protection of the environment, — preservation of heritage. This part of ISO 16732 is designed as a guide for future standards that provide formal procedures for the implementation of the risk assessment principles for specific applications, e.g. situations in which only certain types of fire scenarios are possible. Those future standards will complete the process of full standardization begun by this part of ISO 16732, which not only specifies the steps to be followed in fire risk assessment but also provides guidance for use in determining whether the specific approach used for quantification falls within an acceptable range. Principles underlying the quantification of risk are presented in this part of ISO 16732 in terms of the steps to be taken in conducting a fire risk assessment. These quantification steps are initially placed in the context of the overall management of fire risk and then explained within the context of fire safety engineering, as discussed in ISO/TR 13387. The use of scenarios and the characterization of probability (or the closely related measure of frequency) and consequence are then described as steps in fire risk estimation, leading to the quantification of combined fire risk. Guidance is also provided on the use of the information generated, i.e. on the interpretation of fire risk. Finally, there is guidance on methods of uncertainty analysis, in which the uncertainty associated with the fire risk estimates is estimated and the implications of that uncertainty are interpreted and assessed. This part of ISO 16732 is not structured to conform with any national regulation or other requirement regarding the use of fire risk assessment or the type of analysis that is to be performed under the name of fire risk assessment.