It listens for the high-frequency sound pressurised gas makes escaping through a small opening.

That sound is generated at the leak itself rather than where gas accumulates.

So the detector responds to the release rather than to a concentration.

Wind direction and dilution become irrelevant.

Response is within seconds of a release starting.

It is detecting the event rather than its consequence.

Because wind can disperse a substantial release before it reaches any conventional detector.

Point detectors need gas to drift to them; open-path needs it to cross a beam.

Offshore platforms, compressor stations and open process areas are where this happens.

A large release can occur with no detector ever seeing a concentration.

Ultrasonic detection removes that dependency entirely.

It is one of the few technologies whose performance improves in open, windy conditions.

What is leaking, how much has accumulated, or whether an atmosphere is safe to enter.

It detects a release, not a concentration.

It cannot distinguish one gas from another by sound alone.

It gives no information about accumulation in enclosed spaces.

For entry decisions, conventional concentration measurement is required.

That is why it is used alongside point or open-path detection rather than instead of it.

No - the leak must be energetic enough to generate ultrasound.

Low-pressure releases produce little or no detectable sound.

Liquid leaks and slow seepage are generally not detected.

Manufacturers state minimum pressures and leak rates for their instruments.

Those figures define what the detector can genuinely be relied on for.

A site with predominantly low-pressure systems is a poor fit for the technology.

Background ultrasound from steam venting, air tools, pressure relief, machinery and some electrical discharges.

Industrial sites are acoustically noisy in the ultrasonic band as well as the audible one.

Instruments learn the background level and alarm on deviation from it.

Directional sensitivity is used to reduce response to known sources.

A site acoustic survey before installation is what prevents the problem.

Changes to plant that introduce new ultrasound sources can require reconfiguration.

A radius rather than a point or a line, and it depends on leak rate and background noise.

Manufacturers publish coverage radii for stated leak rates and background levels.

A noisy background reduces effective range because the alarm threshold sits higher.

Obstructions attenuate ultrasound, so line of sight to the potential leak source matters.

Coverage mapping is normally done as part of the detector layout study.

Fewer detectors are usually needed than for equivalent point detection coverage.

Functional testing with an ultrasonic test source, and periodic review of the background acoustic environment.

There is no sensor to calibrate in the conventional sense.

That is a genuine operating advantage over electrochemical and catalytic technologies.

Test sources generate a known ultrasonic signal at a stated distance.

Microphone condition and any protective grille are checked for contamination.

Background review matters after plant changes that add or remove noise sources.