![](https://static.vecteezy.com/system/resources/previews/000/223/904/original/fire-alarm-icon-isolated-illustration-vector.jpg)
Fire Alarm Icon. Isolated illustration 223904 Vector Art at Vecteezy
The key concepts in choice of fire alarm symbols are uniqueness and recognition. If "V" in a box means fire alarm visual notification device, it must not be used for ceiling speaker volume control. "S" in a box usually means ceiling speaker, so this designer chose "S" in a hex box for ionization smoke detector.
![](https://www.gjplastics.co.uk/wp-content/uploads/2020/03/Fire-Alarm-Web-File-scaled.jpg)