This NORDTEST method primarily specifies the way in which the acoustic properties of sound signalling devices are to be tested.
The main purpose of the test is to determine acoustic parameters relevant for the design of indoor and outdoor warning systems. Another purpose of the present NORDTEST method is to provide results which may form a common basis for evaluating the acoustic characteristics of sound signaling devices in general.
Data on the sound emitted by the signalling device are obtained when measurements are made in accordance with this NORDTEST method. These data are relevant to the sound pressure levels generated by the device at remote points. This NORDTEST method does not, however, include procedures for the measurement of sound pressure levels at such remote points.
The method should be considered as a supplement - in the field of acoustics - to other standards and methods, see clause 11.
In addition to the test described in this NORDTEST method further tests may be relevant, e.g. tests for the influence of and resistance to cold, heat, humidity, electromagnetic fields, shock and vibration. Test methods for these phenomena are not included in the present method. Reference is made to other related standards.
Furthermore tests under extreme conditions and endurance tests may be relevant. It may also be relevant to use specified methods for the selection (sampling) of test specimens and for handling the deviations between test specimens. Methods and requirements for this may be found in other related methods or may be defined by authorities or users of the test results for specific purposes.