Leak Detection

Pressure-based leak detection monitors sealed systems for unplanned pressure loss. It is used across oil and gas pipelines, chemical processing facilities, nuclear power plants, manufacturing process lines, and industrial utility distribution systems where containment integrity is a safety, environmental, and operational requirement. Large leaks announce themselves quickly through rapid pressure loss or visible release. The dangerous and costly leaks are the slow ones that produce small, gradual pressure drops indistinguishable from normal system variation. By the time a slow leak becomes apparent through other means, it has typically been releasing product, contaminating the environment, or weakening containment long enough to require expensive remediation.

Pressure decay testing works by sealing a system at a known pressure and monitoring for loss that exceeds what normal operational variation would produce. The challenge is distinguishing real decay from the noise inherent in industrial systems. Pump start/stop cycles, temperature-driven pressure variations, compressor cycling, and mechanical vibration all create pressure fluctuations that can mask or mimic a leak signal. A sensor that cannot separate this noise from actual pressure decay either triggers false alarms that erode confidence in the monitoring system or misses genuine leaks entirely. This page covers applications ranging from low-pressure gas distribution systems to high-pressure industrial process lines, requiring sensors capable of accurate detection across that full range.

Superior Sensor’s HV Series and ND Series sensors deliver the sensitivity, noise rejection, and fast response that leak detection applications require. Multi-Range technology covers the full range of leak detection applications without requiring separate sensor configurations for each pressure range. The integrated pressure switch provides a direct output when pressure falls below a defined threshold, enabling automated alarm and shutdown responses at the sensor level, eliminating the need to wait for the signal to reach a remote controller. Long-term stability ensures that continuous monitoring systems maintain the sensitivity needed to distinguish genuine pressure decay from normal baseline variation throughout the monitoring cycle.

Why Choose Superior Sensor for Leak Detection

Detecting a slow leak requires a sensor that is sensitive enough to detect small pressure changes, fast enough to trigger a response before the situation worsens, and stable enough that its own drift cannot be mistaken for a real signal. Superior Sensor’s NimbleSense architecture delivers each of these properties in a single sensor platform that spans the pressure ranges required for leak detection applications.

Recommended Sensors

Common Device Features: 3.3V supply
Long-Term Stability is measured after first 12 months
Short-Term Error Band (STEB) is measured over 24 hours, after auto-zero

Common Specifications

Leak Detection FAQ

How does pressure decay testing detect leaks?

Pressure decay testing detects leaks by sealing a system or component at a known pressure and monitoring pressure loss over a defined period. If the system is leak-free, the pressure remains at the initial value, with only minor variations due to temperature changes or system noise. If a leak is present, the pressure drops at a rate proportional to the leak rate and the system volume. The drop is compared against a pass/fail threshold based on the application’s acceptable leak rate. Larger leaks produce faster decay and are detected quickly. Smaller leaks produce slower decay and require a more sensitive sensor, a longer test duration, or both to distinguish the signal from normal baseline variation. Any system noise adds uncertainty that must be accounted for in the test specification, which is why low-noise measurement is the foundation of reliable pressure decay testing.

What pressure ranges are used in leak detection?

Leak detection applications span a wide range of operating pressures, depending on the industry and the system being monitored. Low-pressure gas distribution and HVAC duct leak testing typically operate between a few hundred and a few thousand pascals. Industrial gas lines, chemical process piping, and pneumatic systems operate at pressures from tens to hundreds of kilopascals. High-pressure hydraulic systems, fuel systems, and pressure vessels operate at pressures reaching thousands of kilopascals. The sensor for each application must be accurate at the system’s operating pressure and sensitive enough to detect the minimum acceptable leak rate at that pressure. The HV Series addresses the low end of this range, while the ND Series Low- and Mid-Pressure variants cover the broader industrial range.

Why do leak detection systems produce false alarms, and how are they eliminated?

False alarms in pressure-based leak detection typically arise from three sources: system noise that creates apparent pressure variations, temperature-driven pressure changes in sealed volumes, and mechanical vibration from pumps and compressors that appears as pressure fluctuations. When a sensor cannot distinguish these sources from actual pressure decay, any of them can trigger a leak alarm. System noise is addressed through digital filtering that removes high-frequency variations before they reach the sensing element. Temperature effects are addressed through temperature compensation and by allowing adequate stabilization time before monitoring begins. Mechanical vibration is addressed through notch filtering and digital signal processing that separate vibration-induced pressure variations from genuine pressure trends. Reducing false alarms is not just about convenience. A monitoring system that produces frequent false alarms is bypassed or ignored, which defeats its purpose entirely.

What is the minimum leak size a pressure sensor can detect?

The minimum detectable leak size depends on the sensor’s resolution and noise floor, the volume of the system under test, the test duration, and the working pressure. For a given system volume, a smaller leak produces a slower pressure decay, which requires a lower-noise sensor and a longer test window to detect reliably. For example, a leak rate of 0.1 standard cubic centimeters per minute in a one-liter system at 100 kPa produces a pressure drop of roughly 10 Pa per minute. A sensor with a noise floor at or below this level can detect it within a one-minute test; a noisier sensor requires a longer test or cannot detect the leak at all. The ND Series Low Pressure sensor addresses the sensitivity requirements of applications where small leaks at low differential pressures must be reliably detected within practical test cycle times.

How does the integrated pressure switch improve leak detection response time?

In a standard leak detection architecture, a sensor detects a pressure drop, transmits it to a controller, processes it, compares it against a threshold, and then activates an output. This sequence introduces a delay at each step. In applications where a leak means hazardous material is being released, a gas line is losing pressure in an occupied space, or a product line is contaminating a batch, that delay has consequences. The integrated pressure switch eliminates the controller loop by producing a direct output the moment pressure crosses a programmed threshold. The response is triggered at sensor speed rather than at the control loop’s speed. This provides a fast, reliable first response that activates before the full control loop has completed its cycle.