In limited areas, you can use auxiliary means of warning: hand-operated sirens, electric megaphones, mobile sound amplifying stations. Their use allows for alerts at night when fixed assets — apartment loudspeakers, radios, and televisions — are turned off. At noisy industries and in medical institutions, light boards (banners) with texts of received signals and commands can be installed. As an auxiliary means, you can also use the beeps of industrial enterprises and the sound of vehicles.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.