Have you ever wondered how fire sprinklers work? Believe it or not, real-life sprinkler systems don’t work like they do in the movies, where an indoor cigarette activates all sprinkler heads at once, flooding the entire building. At Fire Safety Solutions, we know exactly how, why, and for how long fire sprinkler systems get activated, and we are ready to answer some of the questions we get asked daily.

How Do Fire Water Sprinklers Work?

In a nutshell, a fire sprinkler is just a plug that holds back the water in a pipe that is similar to other plumbing pipes, – this plug can look like a small glass tube or a piece of solder. An increasing air temperature due to fire eventually breaks this glass tube or melts the piece of solder, releasing the water from the pipes. When this happens, water comes out as a spray that covers the area right below and around the sprinkler. 

While a system of multiple sprinklers around the building is installed as a precaution, only one sprinkler immediately above the fire goes off. In 90% of fires, this is enough to effectively stop the fire.

Different Types of Fire Sprinklers

There are three main types of fire sprinkler systems:

• Wet pipe systems. In this type of system, sprinkler piping is constantly filled with water. The water is immediately released when the sprinkler goes off.

• Dry pipe systems. In dry pipe systems, the water is held behind a valve some distance away from the sprinkler head. When the sprinkler goes off, the air is released from the sprinkler head, which opens the valve and fills the system with water.

• Pre-action systems. Pre-action sprinklers have the most complex systems, – here, a combination of a specific event (or events) must occur before water is released. This may mean that heat detection devices are activated, the sprinkler plug is broken, or both.

What Triggers Fire Sprinklers to Go Off?

Simpler wet pipe and dry pipe systems are triggered by the heat in the air, – when the air reaches a certain temperature, the sprinkler plug breaks, and the water is released. Pre-action sprinkler systems are more complex and may require the heat/smoke detection device to be activated as well.

Are Fire Sprinklers Activated by Smoke?

Contrary to popular belief, fire sprinklers are activated by heat, not by smoke. On the other hand, certain types of pre-action or deluge systems can be activated by smoke.

Will a Vape Set Off a Fire Sprinkler?

While you may trigger a fire alarm by smoking or vaping, it is impossible to set off a fire sprinkler with a vape. Sprinkler heads are triggered by heat and are completely unaffected by smoke or vapour.

At What Temperature Does a Fire Sprinkler Activate?

Different sprinklers activate at different temperatures, depending on the sprinkler system type. In most cases, fire sprinklers will activate at 155 degrees F (or 74 degrees C).

How Sensitive Are Fire Sprinklers?

Fire sprinklers are sensitive to fires but are not overly sensitive to normal day-to-day activities. Because the air around a fire sprinkler head must reach a specific temperature for the fire sprinkler to go off, manual activation will require some deliberate efforts. If you hold a candle directly under the fire sprinkler head for long enough for the sprinkler head to reach the activation temperature, the sprinkler will eventually go off. Other than that, you have nothing to worry about.

Can a Fire Sprinkler Go Off Accidentally?

Accidental activation is possible, but it is incredibly rare. Only one in 16,000,000 sprinkler systems may activate for no apparent reason, and modern sprinkler heads are becoming less and less likely to go off without just cause.

Can Hitting a Fire Sprinkler Set It Off?

To activate a fire sprinkler, you would have to hit and break the glass plug holding the water back. However, this plug is located deep within the sprinkler head and is difficult to reach and break accidentally.

How to Prevent Fire Sprinklers from Going Off?

To minimize the risk of sprinklers going off accidentally, we often recommend high-temperature-rated sprinklers for areas near heaters, skylights, and other high-heat places.

Do Fire Sprinklers Shut Off Automatically?

Once the glass plug is broken, the sprinkler will continue to release water until the water flow to the sprinkler pipe is shut off completely. Once this is done, the activated sprinkler head must be replaced, – most in-code facilities will have a box of spare heads within the building.

Curious to learn more about fire sprinkler systems or related services? Give us a call now.