Sirens in towns are usually perceived by ordinary people only during their tests at the beginning of each month. In fact, alarm systems consisting of sirens (whether modern electric and older electric motor ones) fulfil a vital function even when silent. Due to growing urbanisation trends, cities are becoming more populous and larger in area, so early warning is critical and should not be underestimated.

Risks, if not adequately assessed and managed, could endanger the city population and lead to potentially catastrophic consequences.  Although the probability of occurrence of some natural disasters in Europe is rather low, it is never zero either. These include fires, extreme storms, floods, earthquakes, and tornadoes. Sirens can also be used for warnings of the dangers of radiation leaks or military attacks.

A city warning system can have many different forms that depend on its population and area. What is the same for all the types, however, is the main control centre at the heart of every warning system, plus several smaller control centres in adjacent city districts or zones. The main control centre serves as the core or node for the activation of all strategically deployed sirens as well as loudspeaker systems inside buildings (such as sports arenas or shopping malls) that are connected within the alarm system. It is also possible to connect the software in the control centre to the emergency and rescue units for sharing current information. Such a system can provide a mass warning to the people living in the area within a few minutes.

Mobile sirens are recommended for use in remote areas. These can be connected to almost any vehicle and controlled remotely, even by emergency services.

Two recent examples from the USA can illustrate how much difference there is between using and not using sirens in an emergency.

In October 2017, 22 people died in one of the infamous California fires (the so-called Tubbs fire in the Santa Rosa area), where only SMS warning messages were used to alert the population. According to the LA Times, many people learned about the danger only when someone literally knocked on their doors. Neither general alarm was raised, nor mobile sirens were used to sound the alarms.

However, sirens sounded successfully in May 2019 in Jefferson City, the capital of Missouri. The city operates a system of 29 sirens in combination with an information reporting and software system that received the latest meteorological information, hence was able to warn the local population in due time of the impending tornado (with a power of EF-3 on the relevant scale). No single death was reported in the end.

Although different cities face different risks regarding the occurrence of disasters, the requirements for warning system parameters are more or less similar. Due to modern technological advancements, sirens and other safety features have changed, improved, and they can offer many benefits today.

Telegrafia´s products that easily find their applications in city warning systems include:

1. Stationary sirens, such as Pavian or Gibon, are modern devices with sound variability and volume level adjustability, low power consumption, backup batteries, and silent testing options. They are robust, weather-resistant, which is another essential factor in many cities.
2. Software applications interconnect all sirens and the infrastructure and automate all operations. They monitor, activate and deactivate the sirens, and diagnose their status and operability. The applications can send all kinds of messages to the pre-selected recipients, thus control the situation in the field. The Vektra® software remains continuously in operation as it is backed up for power supply in case of a power failure.
3. Additional components, such as the Screamer Car or Pavian Car mobile sirens, advised especially for warning remote areas, alongside other control modules or monitoring devices with weather sensors, for example, can make the warning system even more efficient and reliable.

Today´s warning systems are fully automated, fast and reliable. For illustration, a super-modern system in Europe is operated by the city of Dresden, where 204 sirens have been installed and wirelessly connected to the city control centre using the Vektra® software by Telegrafia.

As many cases have shown in the world, the importance of early warning in cities should never be underrated; otherwise, the negligence may result in far-reaching or even deadly consequences.

The article was written by

Zuzana Jacova

Zuzana works at Telegrafia at the marketing department. Her main responsibility is to keep an eye on Google Ads and Facebook. Online marketing is changing all the time, giving her the chance to expand her knowledge constantly and put it into real practice. After work, she relaxes best by going to the gym and watching good films.