E57 sirens should be replaced urgently with modern electronic sirens.
E57 sirens are neither low-maintenance nor blackout-proof.
The E57 motor siren was a central element of civil defence in the 20th century and served as the primary warning system (Haack, 2009; Secty-Electronics, 2005; BBK, 2022). Although it is still in use in Austria and, in isolated cases, in Germany, it is now considered obsolete from a technical, safety and organisational point of view (BMI Austria, 2021; BBK, 2023; FH Burgenland, 2023; BBK, 2024a).
Technical classification of the E57 siren
The E57 motor siren is an electromechanical device that operates with a three-phase motor and generates air pulses via a rotating slotted cylinder (Haack, 2009; DIN, 2017). A fixed stator modulates these pulses to generate a continuous wailing sound (Haack, 2009; ResearchGate, 2015). The emitted sound is directed vertically downwards through a protective roof, resulting in high sound pressure levels in the immediate vicinity (<30 m). The maximum sound pressure level at a distance of 30 m is approximately 101 dB(A) (Honeywell, 2024). In combination with the lack of optimisation of sound propagation and focusing, this technology proves to be inefficient compared to modern systems (Expert‑Security, 2023). The widespread assumption that motor sirens are low-maintenance is proving to be misleading (Haack, 2009; DIN, 2017). The E57 has many maintenance-intensive assemblies and components, which lead to significant operational risks.
Weaknesses of the E57 siren
Dependence on the power grid
The E57 requires three-phase current (3 × 380–400 V) to start up. In the event of a power failure, this leads to a fundamental operational failure unless a separate emergency power supply is available (BBK, 2022; DIN, 2017). Only a small number of locations have their own emergency power generator (BMI Austria, 2021; Secty-Electronics, 2005), which significantly limits failure protection (BBK, 2023b). The economic and technical integration of an uninterruptible power supply is hardly feasible in practice (Aumüller, 2023). Electronic sirens, such as the Delta 8, can be operated for several days in the event of a power failure, independently of the mains supply, via the built-in batteries or a solar panel, and can be used to raise the alarm.
Low range
The effective range of the E57 is usually less than 500 m in built-up areas, which leads to inadequate warning of the population, especially in densely populated urban areas (BMI Austria, 2021; BBK, 2022). Modern electronic sirens, such as the Delta series, achieve ranges of up to 1,200 m at a sound pressure level of 118 dB(A) thanks to precisely aligned high-performance sound transducers (Expert Security, 2023).
No voice alarm and system integration
A major technical disadvantage of the E57 is the lack of voice alarm capability, which makes it impossible to address the population in a targeted manner in critical situations (Schmidbauer & Lauer, 2020; BBK, 2024b). In addition, without retrofitting, there is no connection to digital warning systems such as MoWaS or TETRA BOS, which means that remote control and system monitoring are not possible (BBK, 2023; SWP, 2024). As a result, neither flexible alerting strategies nor adaptive system adjustments are possible in crisis situations (Bertelsmann Stiftung, 2022).
Risks associated with the E57 siren
Mechanical risks
Bearing and seal wear, material fatigue and corrosion impair the long-term functionality of the E57 motor siren. Longer downtimes promote resin build-up, which causes blockages and mechanical overload (Haack, 2009; FH Burgenland, 2023; DIN, 2017; ResearchGate, 2015).
Electrical risks
The outdated relay controls of the E57 are prone to malfunctioning in the event of temperature fluctuations and voltage drops. The lack of diagnostic and remote maintenance functions makes fault diagnosis and preventive maintenance difficult (BBK, 2023; Secty-Electronics, 2005; Schmidbauer & Lauer, 2020; Aumüller, 2023).
Legal maintenance requirements
According to DIN 14685-1, regular visual and functional checks of sirens must be carried out on site by qualified personnel. However, electronic sirens require less maintenance as they have no mechanical components and often offer remote maintenance and diagnostic functions, which reduces the use of resources (DIN, 2017; BMI Austria, 2021; BBK, 2023b).
E57 sirens in Germany and Austria
The D-A-CH region has a dense network of sirens, some of which are outdated. In Austria, there are around 8,300 sirens in use (as of 2021), many of which are E57 motor sirens that are over 40 years old, not self-sufficient and not integrated into the system (BMI Austria, 2021; Haack, 2009; Secty-Electronics, 2005; BBK, 2024a). In Germany, there are just under 40,000 sirens registered, only a small proportion of which are motor sirens (BBK, 2022; Bertelsmann Stiftung, 2022, Schmidbauer & Lauer, 2020). Historically, there were up to 86,000–100,000 sirens in Germany, but many were decommissioned at the end of the Cold War or replaced by electronic systems. Since the flood disaster in 2021, the BBK has been promoting the replacement and installation of modern, low-maintenance electronic sirens.
Conclusion E57 siren
The E57 motor siren was once a robust and reliable warning device (Haack, 2009; Secty-Electronics, 2005). However, it no longer meets today’s requirements for disaster control because it:
- has no blackout capability (BBK, 2022; DIN, 2017),
- requires high maintenance and power consumption (DIN, 2017; FH Burgenland, 2023),
- does not enable voice alarms (Schmidbauer & Lauer, 2020; BBK, 2023),
- requires retrofitting for integration into modern digital warning systems (SWP, 2024).
Modern electronic sirens, on the other hand, offer considerable advantages, including:
- significantly greater range and sound focusing capability (Honeywell, 2024),
- integrated voice alarm and emergency power supply (BBK, 2023; Expert‑Security, 2023),
- comprehensive digital system integration (BBK, 2024b)
From today’s perspective, the E57 motor siren is not a viable component of a modern disaster control system. Its nostalgic robustness cannot replace the resilient alarm systems provided by current systems (Haack, 2009; BBK, 2023; FH Burgenland, 2023).
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Sources Information
BBK. (2022). Special funding programme for sirens – Implementation report. Federal Office for Civil Protection and Disaster Assistance. https://www.bbk.bund.deBBK.
BBK (2023). Guidelines for warning the population. Federal Office for Civil Protection and Disaster Assistance. https://www.bbk.bund.deBBK.
BBK (2024a). Social science aspects of warning the population (FiB‑29). Federal Office for Civil Protection and Disaster Assistance.
BMI Austria. (2021). Siren network in Austria – status and strategy. Federal Ministry of the Interior. https://www.bmi.gv.atDIN.
DIN (2017). DIN 14685‑1: Fire service sirens – Part 1: Requirements, testing. German Institute for Standardisation.
Haack, H. (2009). Sirens: Technology, History, Significance. Berlin: Verlag für Technikgeschichte.
Schmidbauer, R., & Lauer, T. (2020). Public warning in Germany: Challenges and future prospects. Journal of Civil Protection, 6(2), 45–54.