Sprinkler head (closed)

NFPA 15 / NFPA 13 / NFPA 20 / ISO 13702 (fire protection) / company legend practice (NFPA 13)

Drawn as

A small drop from the pipe ending in a closed head: a small filled circle (the glass bulb) with a short deflector bar.

Meaning

Automatic sprinkler: opens on its own when its bulb bursts. Used in quarters, workshops and stores. Becomes deluge-nozzle, which also covers sprinkler heads.

Variants

Building legends draw a small circle with a cross, or a filled dot
Upright vs pendent is written beside it