What Activates Fire Sprinklers?

Movies really make fire sprinklers dramatic but we will explore how fire sprinklers actually work. We will explain how fire sprinklers function, what activates them, and movement between heads.

Fire sprinklers cannot be activated by smoke like in the movies but solely by heat. In the movies you see the fire sprinkler being activated and triggering all the rest of the sprinkler heads but that is not true. The fire sprinkler head nearest the heat will be triggered, unless you had a deluge system but what is a deluge system?

Deluge systems are most commonly found in high hazard areas such as aircraft hangers, power plants, or chemical plants. They have open sprinkler heads, which means every sprinkler head is activate (just like the movies). There are heat or smoke sensors throughout the building that will trigger the main valve to activate water or foam running through the system extinguishing the fire throughout the building.

The most common type of fire sprinklers have a thermal element. This thermal element is the link between the pressurized sprinkler piping and the seal holding the sprinkler head together. Due to the various residential, commercial, and industrial environments, engineers have manufactured many different temperatures of activation depending on the ambient temperature of operation. Color codes make the fire sprinkler temperature rating readily apparent. Here is a list of color codes.

Temperature rating

• 135F-170F

• 175F-225F

• 250F-300F

• 325F-375F

• 400F-475F

• 500F-650F

Mechanical Link Color

• Uncolored or Black

• White

• Blue

• Red

• Green

• Orange

Glass Bulb

• Orange of Red

• Yellow or Green

• Blue

• Purple

• Black

• Black