Fire sprinkler systems are essential for fire safety in homes, businesses, and industrial buildings. However, many people wonder what can accidentally trigger them. Unlike what movies often portray, fire sprinklers work based on heat activation, not just smoke. Instead, specific factors set them off, sometimes unexpectedly.
In this guide, we’ll break down seven common causes that can trigger fire sprinklers, how they work, and ways to prevent accidental activation.
How Do Fire Sprinkler Systems Work?
Before diving into the causes of sprinkler activation, let’s take a moment to answer the question, “how do fire sprinklers work?”.
Fire sprinklers are designed to activate only under specific conditions, primarily when heat reaches a certain threshold. Here’s a simple breakdown of how they function:
- Each sprinkler head contains a heat-sensitive element (glass bulb or fusible link) that reacts when exposed to a specific temperature threshold.
- When the temperature reaches around 155°F to 165°F, the element breaks, releasing water directly onto the fire.
- Unlike the Hollywood version, only the sprinkler closest to the heat source activates, preventing unnecessary water damage.
- They are not triggered by smoke detectors or a fire alarm system, as those devices serve different roles in fire suppression.
However, accidental discharges can still happen. Below are the most common reasons fire sprinklers might go off unintentionally and repairs might be needed.
7 Common Causes of Accidental Fire Sprinkler Activation
1. Excessive Heat (Not From a Fire)
Sprinklers are heat-activated, so exposure to high temperatures from non-fire sources can trigger them. Some common causes include:
- Proximity to heaters, furnaces, or heat lamps
- Direct sunlight through skylights, heating the area beyond the activation threshold
- High-temperature industrial equipment placed near sprinkler heads
In environments with high ambient temperatures, installing the wrong type of sprinkler (one with too low of an activation temperature) increases the risk of unintended discharge.
2. Freezing and Pipe Bursts
Sprinkler systems that use wet pipes (pipes filled with water at all times) are vulnerable to freezing in cold temperatures. When the water inside a pipe freezes, it expands, exerting pressure on the pipe walls. Eventually, the pipe can burst or crack. Once temperatures rise again and the ice melts, water can begin flowing unexpectedly from the damaged pipe or sprinkler head.
This is a common problem in unheated buildings, exterior walls, or areas with poor insulation. It becomes highly susceptible to freezing damage if the system lacks proper safeguards, such as dry-pipe sprinklers or antifreeze solutions.
3. Mechanical Damage
Fire sprinkler heads are sensitive components, and any physical impact can result in accidental activation. This is particularly common in areas where sprinklers are exposed to regular movement or activity.
Some common scenarios that lead to mechanical damage include:
- Workers accidentally striking a sprinkler head with tools, ladders, or equipment
- Forklifts, carts, or machinery bumping into exposed sprinkler pipes in warehouses
- People hanging objects from sprinkler heads, causing them to break or loosen
- Intentional tampering or vandalism, where individuals tamper with the system
Even minor force can be enough to trigger a sprinkler, leading to unnecessary flooding and damage.
4. Corrosion and Deterioration
Fire sprinkler systems are exposed to water and air, both of which can contribute to corrosion over time. Corroded sprinkler heads or pipes may fail, leading to leaks or sudden activation.
Factors that accelerate corrosion include:
- High humidity levels, which can cause rust to form inside pipes
- Poorly maintained or aging sprinkler systems that haven’t been inspected regularly
- Chemical exposure, particularly in industrial settings where airborne particles can weaken metal components
Corrosion doesn’t just increase the risk of accidental activation—it can also reduce the system’s effectiveness when needed most. If a sprinkler head is blocked by corrosion buildup, it may not function properly in a fire emergency, increasing the potential for fire damage.
5. Manufacturing Defects or Poor Installation
Although rare, manufacturing flaws or improper installation can cause fire sprinklers to activate unexpectedly. Defects may include:
- Weak or overly sensitive heat sensors that respond to lower temperatures than intended
- Leaks or cracks in sprinkler heads leading to unintentional discharge
- Faulty seals or connections cause pressure imbalances that release water prematurely
Installation mistakes can also contribute to accidental activation. If a sprinkler head is positioned too close to a heat source, such as HVAC ducts or lighting fixtures, it may trigger under normal operating conditions. Additionally, incorrect water pressure settings within the system can lead to performance failures.
6. High-Pressure Water Surges
Fire sprinkler systems rely on a stable water supply, but sudden pressure fluctuations can sometimes cause unintended activation. If there is a sharp increase in water pressure, it can force open a sprinkler valve, leading to unexpected water discharge.
Pressure surges may occur due to:
- Municipal water supply changes, especially during repairs or maintenance
- Fire hydrant usage nearby, which can temporarily alter water pressure
- Pump malfunctions within the building’s sprinkler system
If a sprinkler system isn’t equipped with pressure-regulating valves, these fluctuations can lead to costly water damage.
7. Vibration and Physical Disturbance
Even without direct impact, fire sprinkler systems can be affected by vibrations from nearby movement. This is particularly an issue in:
- Construction zones, where heavy equipment causes the building structure to shake
- Industrial settings with large machinery, which can create continuous vibrations
- Earthquake-prone areas, where seismic activity weakens pipe connections
Prolonged vibrations can loosen sprinkler fittings, damage heat-sensitive elements, or even break pipes, all of which can result in unintended activation. Over time, continuous exposure to movement increases the risk of failure in fire sprinkler components.
How to Prevent Accidental Fire Sprinkler Activation
To avoid unnecessary sprinkler discharges and the associated water damage, here are a few preventative steps to consider:
- Regular Inspections: Schedule a fire sprinkler inspection to identify any signs of corrosion, mechanical damage, or wear in your sprinkler system. This includes inspecting sprinkler heads, pipes, and fittings to ensure they’re in good condition.
- Avoid Tampering and Obstruction: Do not place objects too close to sprinkler heads or tamper with the system. If the system is in an area with high traffic or machinery, install protective covers around the heads to prevent accidental impacts.
- Insulate Pipes in Cold Environments: If your property is in a region where temperatures drop below freezing, make sure your sprinkler pipes are properly insulated to prevent freezing. For additional protection, consider installing a dry pipe system.
- Use Pressure Regulators: To prevent surges in water pressure from triggering the system, install pressure regulators to control fluctuations and maintain consistent pressure.
- Hire Certified Professionals: Ensure that your sprinkler system is installed and regularly maintained to ensure the system meets NFPA (National Fire Protection Association) standards. Proper sprinkler system installation by trained experts ensures that your system is effective and compliant with safety regulations. Routine maintenance by certified technicians will also keep your system functioning efficiently and reduce the risk of malfunction.
Final Thoughts
Understanding what sets off fire sprinklers is crucial for property owners looking to protect their homes and businesses from unnecessary property damage while ensuring the system operates effectively when needed. By maintaining your fire sprinkler system and being aware of common causes for activation, you can significantly reduce the risk of accidental sprinkler discharge.
For expert fire sprinkler maintenance, inspection, or installation, contact All About Sprinklers today! Our professional technicians can ensure that your system is running smoothly and ready to protect your property in the event of a fire.