Compressed air is one of the most expensive utilities in manufacturing — yet it’s also one of the most overlooked when it comes to efficiency. In many facilities, between 20% and 30% of compressed air is lost to leaks. This hidden waste drives up energy costs, increases a facility’s carbon footprint, and can put ISO 50001 compliance at risk.
Locating leaks is an important first step, but for energy managers under pressure to reduce costs and prove return on investment, detection alone isn’t enough. Leak rate quantification (LRQ) transforms a simple list of “found leaks” into a set of prioritized, measurable action items. By putting a number on the cost of each leak, energy managers can direct maintenance teams to fix the most impactful problems first, verify savings after repairs, and demonstrate continuous improvement to both leadership and auditors.
Modern broadband acoustic imaging cameras, equipped with LRQ capabilities, are changing how energy managers tackle one of their largest hidden costs.
Quantifying Leaks for Smarter Energy Decisions
In many plants, leak repair decisions are made based on what a technician sees or hears during an inspection. While this may uncover obvious leaks, it often means that smaller but high-cost leaks go unaddressed, while minor leaks consume maintenance time and resources. Leak rate quantification changes this dynamic by providing a numerical estimate of leak severity.
With LRQ, each detected leak is assigned an estimated flow rate or an index value that reflects its cost impact. This data empowers energy managers to set repair priorities based on actual loss, not guesswork. It also makes it easier to secure budget for repairs by translating leaks into annualized cost and energy loss — and to track how those numbers improve over time.
How Acoustic Imaging Powers LRQ
Modern acoustic imaging cameras, like the Fluke ii905 Acoustic Camera or Fluke ii915 Acoustic Camera, make it possible to locate and quantify leaks quickly, even in noisy industrial environments. These handheld devices use an array of microphones paired with a visible-light camera to generate a sound map of the inspection area.
When pressurized gas escapes from a system, whether through a worn quick-connect or a loose threaded coupling, the resulting turbulence creates broadband noise across audible and ultrasonic frequencies. Narrowband ultrasonic detectors, which listen only at a specific frequency (often around 40 kHz), can be effective in controlled environments but struggle in real-world conditions where distance, background noise, and measurement angle vary.
Broadband acoustic imagers overcome these limitations by capturing a wide range of frequencies, making them more reliable when detecting leaks from farther away or in areas with competing background noise. This ability to “hear” more of the sound spectrum directly supports the accuracy of leak rate quantification.
The Variables That Shape Accuracy
Accurate leak rate quantification depends on understanding the conditions around the leak. The size, shape, and material of the opening influence the sound it produces. System pressure and flow rate also play a role, with higher values generally creating stronger acoustic signatures. A cut hose will behave differently from an open drain, and a faulty quick-connect fitting will produce a different sound than a loose threaded cap.
The properties of the gas itself matter as well.
- Less dense gases, such as helium, produce weaker acoustic signals than air, making them harder to detect. Ambient temperature and pressure affect gas density and viscosity, which in turn influence the sound generated.
- Environmental conditions, such as distance to the leak, air temperature, humidity, and even nearby equipment, can all impact the way sound travels from the leak to the detection device.
- Doubling the distance between the leak and the camera, for example, can reduce sound intensity by about 5 dB. (See graphic below.)
Understanding these factors helps energy managers interpret LRQ results accurately, ensuring repair decisions are based on sound data.
From Detection to Decision
LRQ in acoustic imaging follows a two-step process. First, the camera classifies the leak into a common category such as hose, open-end/orifice, quick-connect fitting, or threaded coupling. This classification matters because each type has distinct acoustic characteristics, which influence the accuracy of flow rate estimation.
Once the leak is classified, algorithms match its acoustic signature to laboratory-tested data, producing an estimated flow rate. This is converted into a Leak Rate Quantification index, typically on a scale from 0 to 10. The higher the number, the greater the urgency for repair. For energy managers, the LRQ index becomes a common language across departments, helping maintenance teams understand the repair priorities and giving leadership a clear view of cost impact.
Real-World Benefits for Energy Management
Facilities that integrate LRQ into their compressed air management programs often see faster and more measurable results. In one large manufacturing site, just four leaks accounted for more than 40% of annual compressed air loss. By repairing those leaks first, the plant achieved a noticeable drop in energy consumption and utility costs, with results that were easy to validate during the next ISO 50001 audit.
The benefits go beyond cost savings. Having quantified leak data improves communication between maintenance teams, energy managers, and executives. It also simplifies compliance reporting by providing clear, documented evidence of leak identification, prioritization, and repair.
Why LRQ Is Now Essential
In an environment where energy costs are volatile, sustainability targets are increasingly strict, and compliance requirements are growing, energy managers can’t afford to treat compressed air leaks as a background issue. Leak rate quantification, powered by modern acoustic imaging, provides the insight needed to make confident, cost-effective decisions.
By turning sound into actionable data, LRQ makes it possible to identify leaks with visual precision, quantify their true impact, prioritize repairs for maximum ROI, and prove results to stakeholders. For today’s energy manager, that combination of technical accuracy and business relevance isn’t just helpful, it’s essential.