Federal Signal Model 5A and Federal Signal Model 5AT sirens in Oakmont, PA sounding for a call. https://www.youtube.com/watch?v=qA5JCTZcqZg

Here in Israel, sirens aren't used for calling, but only as air raid sirens (The "All clear" siren to declare a moment of silence, once at Holocaust Day and twice at Remembrance Day. Also, in haredi communities, the "All clear" siren are used when the Shabbat enters).

Beautiful. They have two sirens for fire calls? 

Here in Israel, sirens aren't used for calling, but only as air raid sirens (The "All clear" siren to declare a moment of silence, once at Holocaust Day and twice at Remembrance Day. Also, in haredi communities, the "All clear" siren are used when the Shabbat enters).

I hope they are used more for those purposes than war warning.

In Vicenza (near where i live), we have only flooding siren (we had an major flooding in 2010 and usually, during October, November, March, April, we have minor floodings).
They are mounted on tallest structures (bell towers) and i don't know why they costed us 15.000€/siren.
They play pre-recorded tones and, sometimes, also speech.
However, where i live, an mayor thought mobile walls in strategic points could prevent flooding, and they works fine, so we don't see floodings from years  .

Here you can see where mobile walls are placed when Tesina rise over guard levels.
https://goo.gl/maps/px07t

Here in Israel, sirens aren't used for calling, but only as air raid sirens (The "All clear" siren to declare a moment of silence, once at Holocaust Day and twice at Remembrance Day. Also, in haredi communities, the "All clear" siren are used when the Shabbat enters).

Sirens can have different meanings.  In the case of the video above, they are used by a volunteer fire department or ambulance service.  They were used to summon volunteers to the station when a call came in in the days before radio pagers, and some departments (particularly back east) still use them.  Most civil defense sirens in the US have been decommissioned or re-purposed.  In tornado-prone regions, they would be used used during tornado warnings.