Smoke, trigger a fire sprinkler. Most fire sprinkler heads appear equipped with a glycerin-crammed glass bulb. Since the glycerin heats up because of the heat from the fire below, it expands, shatters the glass bulb, and triggers the sprinkler head. The fire sprinkler swap senses this movement of drinking water https://andresewlyn.goabroadblog.com/34367782/fire-alarm-systems-no-further-a-mystery