ISO 8201:2017 specifies the requirements for an audible emergency evacuation signal intended to indicate without ambiguity, to all persons within the reception area of the signal, that an emergency situation (fire, gas leaks, explosion, nuclear radiation, etc.) requires immediate evacuation. Two acoustic parameters of the audible emergency evacuation signal are defined: the temporal pattern and the required sound pressure level at all places within the intended reception area of the signal. NOTE Recognition of the signal does not require the specification of its spectral content, which can be selected to satisfy specific site requirements. The signal specified in this document is intended to be used in buildings, including but not limited to schools, hotels, residential buildings, public institutions and work places (such as factories and offices) The signal can also be used in outside areas. ISO 8201:2017 is not applicable to warning signals, to signals for public disaster control or to alarm systems on board ships or in outdoor moving vehicles, such as police cars, fire engines and ambulances. The individual signalling-system components of the signal are also out of the scope of this document.