|emergency = siren|
|A loud noise maker, such as an air raid siren or a tornado siren.|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
An outdoor warning siren (also known as a civil defense siren, air-raid siren, or tornado siren) is a loud noise maker used to deliver emergency alerts to the public, especially for fast-developing weather events such as tornados. Other common uses of sirens include summoning firefighters to a fire station or alerting the public about a tsunami, chemical spill, earthquake, or impending airborne attack.
There are two general types of outdoor warning sirens, based on the mechanism used to generate the warning tones. A pneumatic siren is powered by either a hand crank (mechanical) or an electric motor (electromechanical). An electronic siren uses electric circuitry to emulate the sounds of a pneumatic siren or to deliver voice messages, similar to a public address loudspeaker.
A siren may be mounted on a pole (similar to a power=pole) or on the roof of a building. A rotating siren produces sound in one direction at a time, relying on a motor to rotate a single horn in a circle, while an omnidirectional siren produces sound in every direction simultaneously through the use of multiple horns.
How to map
Depending on the region, outdoor warning sirens are typically found near parks, schools, fire stations, factories, power plants, substations, or water towers. In aerial imagery, pole-mounted sirens are easy to confuse with power transformers (power=transformer) at all but the highest zoom levels, so confirm the siren in street-level imagery if possible.
- siren:purpose=* - add here the specific use case, if valid, e.g. tornado/storm/air_raid/civil_defense, optional
- siren:type=* - pneumatic, electronic, or electromechanical, optional
- siren:range=* - range of audibility, e.g. 1000, like usual Units format, optional
- siren:model=* – manufacturer name and model number
- manufacturer=* and manufacturer:wikidata=*
- height=* – height of mounted siren
- operator=* – name of the entity that maintains or is responsible for sounding the siren
- location=roof – the siren is mounted on a rooftop
OSM Emergency Map renders sirens with icons at zoom level 11 and above (example).
- Air Raid Sirens Wiki – useful for identifying the model from aerial or street-level imagery