Introduction: Why correlation is crucial for leak detection.
When a leak occurs somewhere in an underground drinking water network, water engineers and service providers often have to embark on a challenging detective mission. This is where correlation comes into play—a proven method for pinpointing the exact location of leaks. But what exactly does correlation mean, how does it work, and how can modern technologies such as the HL 7000 or SmartEAR® from SebaKMT® make this process efficient and reliable?
What does correlation mean?
In leak detection, correlation refers to the evaluation of differences in the travel time of sound waves emanating from a leak. A leak generates characteristic noises that propagate through the pipe system. Sensors—known as correlators —are used to record the sound at two points along the pipe.
The basic idea
- The sensors measure when the leak noise pulse arrives in each case.
- The exact leak location can be determined from the time difference and the known speed of sound in the pipe material.
- The result: precise leak detection without unnecessary digging.
Important factors influencing accuracy
The quality of the correlation depends on various factors:
- Pipe material and diameter: Sound propagates differently in plastic pipes than in cast iron pipes.
- Distance between sensors: The greater the distance, the more accurate the calculation – up to a certain limit.
- Leak noise quality: If the leak noise is very quiet or masked, the probability of detection decreases.
Tip: This is where smart devices such as SmartEAR®, which reliably detect even quiet leak noises using modern sensor technology and intelligent algorithms, has proven its worth here.
When should correlation be used?
Correlation is particularly suitable for:
- Buried pipes where acoustic location using a ground microphone is difficult.
- Long distances where listening carefully to every spot would be inefficient.
- Nighttime operations where ambient noise is low.
In combination with pre-location using noise loggers such as SmartEAR® or acoustic monitoring via POSEYEDON®, correlation can be used in a targeted and efficient manner.
Products that support you in correlation
🔍 SmartEAR®
Ideal for continuous noise monitoring in drinking water networks. Works with NB-IoT/LTE-M and sends encrypted data to the POSEYEDON® cloud.
Advantage: Early detection of leaks and targeted correlation operations thanks to location focus.
🎯 HL 7000 Correlator
The premium device for precise leak detection using correlation—with touchscreen operation, GPS, automatic data analysis, and optional extension for ground microphony.
Practical tips
- Avoid vibrations: Position sensors stably to prevent interference noise.
- Enter pipe data correctly: Material, length, and diameter have a significant impact on the calculation.
- Perform comparisons: Repeat measurements from a different direction if necessary for confirmation.
Conclusion: Correlation – precise, efficient, indispensable
SmartEAR® – IoT noise/frequency logger Forwater managers and service providers , correlation offers a scientifically sound yet practical method for quickly and accurately locating leaks in the drinking water network. With modern devices such as the HL 7000 and SmartEAR® in combination with the POSEYEDON® cloud solution, leaks can not only be found, but also proactively prevented.
💬 Would you like to learn more or receive personalized advice?
Feel free to contact us—we will help you find the right solution for your challenge.
FAQ on correlation
What is the difference between correlation and ground microphony?
Ground microphony actively listens to the noise above the ground, while correlation passively calculates the leak from signals in the pipe system.
How long can the distance between the sensors be?
In practice, correlators work at distances of up to 600 m, depending on the pipe material and leak noise.
Can I also use correlation at night?
Yes, conditions are often optimal at night—there is less noise and signals are clearer.