Question

What is the purpose of the glass bulb in a fire sprinkler head?

Answer

The glass bulb in a fire sprinkler head contains a liquid that expands and breaks the bulb when it reaches a certain temperature. When the glass bulb breaks, water from the sprinkler system is allowed to flow through the head. The bulbs are available in sensitivities ranging from 155 to 355 degrees Fahrenheit (68 to 180 degrees Celsius).