How Do Fire Sprinklers Detect Fire? And How Do I Know They’re Working?

  • October 18, 2023
Fire Prevention Plan and Your Workplace

Sprinklers for fires are among the most effective fire protection methods available today. According to the NFPA, they are 96 percent effective at controlling fires when properly installed and maintained. But how do fire sprinklers know when to put out a fire?

Traditional Activation Methods

When it comes time for fire sprinkler installation in your building, traditional automatic sprinklers have long relied on a clever solution. They don’t require any electronics or complex sensors but instead use a few simple physical properties.

Traditional sprinklers for fires contain piping filled with water, with individual sprinkler heads spread throughout the building. Sprinkler heads are blocked by small glass bulbs that have a glycerin liquid. When heated, the glycerin expands rapidly and breaks the bulb, letting water flow freely.

This simple system is incredibly reliable, only requiring the application of heat to open the sprinkler heads. When a fire starts, smoke and hot air quickly reach the ceiling, allowing the traditional sprinklers to activate within moments of a fire occurring. Each sprinkler head is activated independently and only covers areas that meet the heat threshold. 

However, this traditional system isn’t without its downsides; false activations aren’t impossible. Accidentally striking a sprinkler head can break the glass bulb, and any vandal who can reach a sprinkler head could activate it with a simple pocket lighter.

Additional Detection Methods

Thanks to advancements in sprinkler design, a wide range of sensors can detect smoke particles, sense heat, or identify other signs of fire. You can also always pull manual fire alarms that send information to a central control system to turn on the sprinklers.

Understanding your sprinkler system and knowing where sprinklers activate can help you maintain your system and allow for effective evacuation during an emergency response.

Interlock Sprinklers for Fires

In many cases, the combination of both modern detection methods and traditional sprinklers can provide the best results. These are called interlock systems, and they address the need to respond to fires quickly and avoid false activations.

The pipes in an interlock system don’t necessarily remain filled with water. Instead, they have a valve linked to sensors or a central control system. Electronic heat sensors, smoke detectors, or alarms will trigger the valve, filling the pipes with water.

However, this process hasn’t technically activated the sprinklers yet. They still have the glass bulbs holding them closed. In the area affected by the fire, bulbs will quickly heat up and break, allowing the water in the system to control the fire.

If a sprinkler head is damaged or activated without a fire present, there’s no need to worry about flooding the building. The valve for the overall system stays closed until activated by other sensors. Similarly, someone pulling a fire alarm won’t start sprinklers unless the heat of a fire is present.

Routine Inspections for Your Fire Sprinklers

How can you know that these systems will work if an emergency arises? Traditional sprinkler heads themselves are incredibly reliable due to their simple mechanism. However, other parts of the system may only succeed if adequately maintained. That’s why routine inspections are beneficial and required by law.

Depending on the size of your facility and the type of fire protection system in place, you’ll require a fire sprinkler inspection from time to time. The assessment will verify that sensors correctly trigger control systems and valves and identify other potential issues.

Most sensors will also have a dedicated test function that will allow you to check if they’re working without actually triggering the system. However, this isn’t a substitute for a professional inspection.

Find the Right Fire Prevention Solution for Your Facilities

If you’re unsure which type of sprinkler system is right for your building, the team at A&A Fire Protection can help. We install a wide range of custom fire protection solutions and provide ongoing maintenance and routine inspections. Contact us today to get started!