Industrial Utility Efficiency

Leak Detection Technology Transitions Toward Maintenance 4.0

Leak detection has developed significantly over the years. Interest in it first began to blossom with growing awareness of the energy saving potential it offers for a compressed air system and for obvious reason:  It has a direct impact on a company’s bottom line and also reduces their carbon footprint at the same time.

In our view, awareness and interest in leak detection only continues to grow thanks to a number of factors. What we have seen over the last 20 years is a more sustainable way of thinking, established international energy efficiency standards, reliable leak detection technology, and best practices to implement leak detection.

The transformation we experience now is driven by the needs of a digital society with the growing expectation that offline activities can be supported, eased or done by smart tools and software. In this article, we will delve into how leak detection has begun the transformation from an established, but individual, process into a fully integrated procedure for Maintenance 4.0, which describes the application of machine learning, automated processes and interconnectivity to maintenance activities.

Figure 1

Guided leak detection software allows users to quantify the size of a compressed air leak based on acoustic data.


Integrated Leak Detection Aligns with Maintenance 4.0

In the past, leak detection had quite a disjointed process. While there were major technological improvements, such as moving from bubble-testing to ultrasonic leak detectors, the entire process required separate micro-processes using multiple tools, such as clipboards, cameras, and leak tags. The leak auditor would need to find a leak, record it in his notes, (maybe) take a picture, and then fill out a leak tag. After the entire searching process was completed, the auditor would then need to write up a complete report with every leak detailed. This led to a cumbersome and time-consuming process.

By having a process with disconnected micro-processes, it is in turn, less automated. By connecting each step of the leak detection process, we can create a more integrated solution that is in-line with the goals of Maintenance 4.0.

Today, manufacturers have created new and improved leak detection tools that incorporate both hardware and software to make the leak detection process more efficient and automated. These improvements can be placed in five categories:

  • Technology Improvements
  • Simplified Application
  • Implementation of Data Collection Tools
  • Implementation of Reporting Tools
  • Implementation of Planning and Trending Tools

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Technology Improvements

Recently, there have been major improvements in the sensors that ultrasound instruments use. Companies have moved from analog probes, using piezo ceramic capsules centered at 38 to 40 kHz, to digital broadband ultrasonic sensors that use, for example, a Micro-electromechanical System (MEMS) microphone array.

This improvement can be compared to having an audio speaker that outputs only bass versus a speaker that outputs the whole range of sound. While also being more sensitive in the higher and lower ultrasound frequencies, these new sensors allow for significantly more powerful digital data processing, and much more signal information, in the form of ultrasound, being captured by the sensor. This paves the way for new features, such as a better  leak-rate estimation, being able to easily deal with extraneous ultrasound through viewing a large range of ultrasound simultaneously, and acoustic leak-detection cameras.


Simplified Application

New user guided leak detection software also helps to simplify the entire leak detection procedure. Software has been integrated into handheld leak detection tools to help walk the user through the leak detection processes. It prompts the user at each step of the process to input important pieces of information, such as taking a photo, typing in location information, adding text notes and what the pressure in the compressed air line is, and so forth.

This advancement leads to less training needed to operate the device and find leaks, as well as minimizing the number of mistakes that could be made by the operator. One example of a common mistake is the over or underestimation of the size of a leak. Some newer leak detection software now contains algorithms that automatically estimate the size of a leak based on the pressure in the compressed gas pipe and the acoustic characteristics.

Where an experienced leak tester may be able to provide an estimate of the size of a leak based off known variables, newer software eliminates the need for guessing and prior knowledge to develop this estimate.


Implementation of Data Collection Tools

Data collection plays a vital role during leak detection. Both software and hardware have been integrated into the leak detection procedure to help capture the most important parts of the inspection. This includes data points such as pictures, location of the leakage, leakage priority, when to fix the leak, etc. By incorporating data collection tools like a camera, notepad, and leak detector all in the same device, the user saves time, the process is further simplified, and the reporting is completed much faster.

With this integration, users do not have to switch from tool to tool in the process of reporting each leak. Rather, they can collect all the information with a single device and store it all in one place. This adds value as the total number of leaks is now linked and located to each machine, department or build in the plant, that helps to identify them easier than ever before.

Figure 2

Data collection tools, such as cameras, are often integrated into ultrasonic leak detectors.


Implementation of Reporting Tools

Everyone who has completed a leak audit will tell you the most tedious part of the entire leak detection process is the final report after the inspection is complete. Depending on the size of the facility, it can take hours, sometimes days to put together a report. Compiling all the gathered data, such as pictures, location, leak size, and other relevant information is time consuming, particularly if you have hundreds of leaks.

By implementing improved reporting tools, there is a significant amount of time saved. Today, there are phone applications, as well as software built directly into leak detecting devices, that allow users to output reports on collected data. These reporting tools allow the users to output a report from all the data they collected while in the field in an easy-to-read format, which can include graphs, photos, and even an estimated total cost for the power-draw from the air compressor(s). While most of these reports are in the form of a PDF or Excel file, some are even able to sync with their companies’ Computerized Maintenance Management system (CMMS) software for further trending and analysis.

Figure 3

Improved reporting tools can save users a significant amount of time as part of the leak detection process.  


Implementation of Planning and Trending Tools

The implementation of asset management tools helps streamline the planning phase of leak detection. By incorporating planning and trending tools similar to a CMMS system in the leak detection process, inspection routes can be easily planned and leaks and savings can be trended over time.

When it comes to inspection routes, someone such as a maintenance manager can plan when and where particular locations are inspected. This allows for better control over the entire process. Trending leaks can also be extremely valuable, as this can lead to finding important information such as incorrectly installed compressed air system parts, where the most leaks occur, and finally how much money the entire leak detection process has saved.

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Leak Detection Has Never Been Easier

With the new tools available today, the entire leak detection process has never been easier. New developments in both hardware and software have been integrated into existing leak detection solutions, saving time and giving users more, and higher quality, information for better decision making on maintenance issues.

While we are still in the early stages of incorporating leak detection into Maintenance 4.0, there have been significant improvements to the process. This includes new leak detection technology, simplifying certain aspects of the application, and the implementation of data collection, reporting and planning tools.


About the Authors

Brian Kavanagh is the Preventative Maintenance Sales Director for North and South America at SONOTEC USA, tel: 631-452-2805; email: Christian Schreiber is the Business Unit Director for the Preventative Maintenance Division of SONOTEC, based out of the company’s headquarters in Halle, Germany, tel: +49 (0)345/13317-829; email:


Founded in 1991, SONOTEC GmbH has developed into one of the world's leading product and solution specialist for innovative measurement technologies. With more than 180 employees and a modern corporate structure comprising three independent business units - Preventive Maintenance, Non-destructive Testing and Non-invasive Fluid Monitoring - the technology leader operates its global sales activities from the Halle (Saale) based German headquarters. The distributed portfolio includes customized ultrasonic transducers and sensors as well as testing devices and measurement solutions for a variety of different industries. For more information, visit

All photos courtesy of SONOTEC

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