Emergency signals are acoustic or visual danger signals. Primarily the following aspects have to be considered when such signals are used:
- Emergency signals must be clearly and unequivocally distinguishable from other signals,
- All persons concerned must at any time be able to hear and/or see the signals,
- All workers have to know the meaning of the signals and be familiar with the behaviour they have to show,
- Emergency signals have to be functional at any time.