This part of ISO 13475 specifies the test conditions under which the acoustic emission levels of stationary audible warning devices may be obtained. It is applicable to sirens for use in outdoor public warning systems and sound signalling devices for use outdoors.The purpose of this test code is to be able to produce reliable sound emission level measurements for stationary sirens to be used outdoors.This part of ISO 13475 does not cover spoken messages and contains no recommendations for specific warning signals.