HÖRMANN HLS

The **HÖRMANN HLS** (**H**och**l**eistungs**s**irene, and in English **H**igh **P**erformance **S**iren) is a series of large pneumatic electromechanical siren that was produced by HÖRMANN Warnsysteme during the mid to late Cold War. Designed to be far more powerful than a standard electromechanical siren, these sirens are some of the largest siren units ever built.

While they are rare today, they certainly left their mark on everybody who has heard them. They would be produced until 1985, when they would be replaced by the electronic ECL and later ECN series of sirens.

## History and Design

In the mid-to-late 1960s, in accordance with the West German government, HÖRMANN, alongside Pintsch Bamag and Rickmers Werft, would start developing a pneumatic siren intended to warn the public of air raids and nuclear attacks from the Eastern Bloc. After it was realized that a large number of civil defense systems in Germany did not have adequate warning in case of enemy attack, the government sought to introduce a siren which would be able to be heard from an extremely long distance to get the attention of citizens throughout the country. Releasing the HLS F71 in 1966, the siren used an air compressor that feeds through a pipe leading through the chopper, and thus supercharges the siren.

This siren saw much success, with several units being installed globally. The HLS F71 would be discontinued in late 1974 and was soon followed up with the HLS X73 series in early 1975, which used the same general design while improving on its predecessor. The series was more compact compared to the HLS F71, while also being more efficient. The siren's core was also slightly altered, with the disk rotor being replaced by a vaneless cylindrical rotor. The HLS X73 series would be sold until 1981, when it was replaced by the HLS 381. The HLS 381 would go on to be sold until 1985, when it phased out of HÖRMANN's lineup.

### HLS F71

The **HLS F71**, originally the HLS 167, was the first siren to be introduced of this lineup, debuting in 1967. Many of these would be installed across West Germany and had a decibel rating of 120 dB at 100ft. Units built between 1967 and 1971 would have the year they were built included in the name. For instance, an HLS F71 produced in 1967 would become an HLS 167. This practice ceased in late 1971 when the siren's name became the HLS F71.

The HLS F71 is similar to the sirens that were produced by Pintsch Bamag and Rickmers Werft, being cylindrical in shape with 4 holes on each side, with these essentially being horns for sound to pass through. The siren also has what looks to be a platform with railings on top of it. The HLS F71 was sold to many countries during its production, most notably Israel, who maintained a system of HLS F71s until they were replaced with ATI HPSS-32s.

The HLS F71 would be discontinued in 1973, when they were replaced with the HLS 381. Today, most HLS F71s have either been put out of service, or removed, and very few active units remain.

### HLS X73

The **HLS X73** series was introduced in 1973 as a successor to the HLS F71, and was more compact, possibly louder, and easier to install. These ranged from the HLS 273 to HLS 673, with each being a variant of the HLS 273. The HLS 273 is the standard option, essentially being a stripped-down HLS F71 with 4 large horns coupled to the siren. The much more compact design provided more mounting opportunities and took up less space, while also being louder.

The HLS 273 was also available with a compressor powered by an electric motor, with the variant being named the HLS 373. HÖRMANN also offered the siren head and controls by themselves, intended for areas that had their own compressed air supply. Units sold without the compressor or air tank are named HLS 473s. The HLS 573 was essentially a heavier duty HLS 273, utilizing several 200 bar bottles of compressed air, as opposed to the HLS 273's 16.5 bar compressed air tank. This made the unit much more compact and was generally easier to install. Finally, the HLS 673 is essentially an HLS 573 that lacks a compressor. This results in the siren's air bottles having to be replaced or filled externally.

The HLS X73 series would be discontinued in 1981, when they were replaced with the HLS 381.

### HLS 381

The **HLS 381** was introduced in 1981 as a successor to the HLS X73 series. There are very few differences between them and the HLS 381, with the only known ones being the size of the intake tube and the mount. The HLS 381 presumably also had several other variants, although no documentation confirming this is known to exist. The HLS 381 would be sold until 1985, when they phased out of HÖRMANN's lineup, with the ECL series taking its place. Due to the siren's short production run, not many units are known to exist today.

## References

1. ↑ Wiki der Interessengemeinschaft Warndienst und Sirenen - Hörmann F71 (Web Archive)
2. ↑ 2.0 2.1 Wiki der Interessengemeinschaft Warndienst und Sirenen - Hörmann HLS 273 (Web Archive)