§ Discipline · 03

Ultrasound — caught before vibration.

Acoustic detection of early-stage faults. Lubrication regime, leak detection, electrical partial discharge, and bearing pre-failure regimes — captured before vibration onset and before the spectrum has the signature.

Discipline
03 · Ultrasound
Methodology
Airborne · structure-borne · contact / non-contact
Frequency range
20–100 kHz audible-to-ultrasonic carrier
Primary signal
Earliest failure indicator on rotating equipment
Ultrasonic acoustic survey on rotating-equipment bearings
Field engagement · DZ-ENG-2026 · Acoustic detection across rotating, electrical, and utility assets DZ · 03
§ What it detects

Acoustic signatures we identify.

DETECTS · 03

Lubrication, leaks, partial discharge, bearings

  • Lubrication regime — starvation, over-lubrication, and contaminated grease detected acoustically before the bearing's vibration signature appears. The earliest, lowest-cost intervention in the program.
  • Pneumatic, gas, and steam leaks — compressed-air leakage is a multi-million-dollar energy loss at scale; ultrasound localizes leaks across plant utility lines and process piping under operating pressure.
  • Electrical partial discharge — corona, tracking, and arcing in MV/HV switchgear and transformers captured acoustically before thermal signature develops.
  • Early-stage bearing faults — high-frequency ultrasonic emissions from incipient bearing damage precede the FFT spectrum by weeks; the discipline's defining advantage.
§ Methodology

Three approaches, one acoustic surface.

METHOD · 01

Airborne
ultrasound

Non-contact probe captures airborne emissions — pneumatic and steam leaks, corona discharge, valve passing — at distances suited to safe stand-off from energized equipment.

Non-contactStand-offLeaksCorona
METHOD · 02

Structure-borne
(contact)

Contact probe on bearing housings and gearbox cases captures structure-borne high-frequency emissions — the earliest bearing-fault signal, well ahead of vibration onset.

Contact probeBearing housingHigh-frequencyEarly-warning
METHOD · 03

Lubrication
routing

Combined ultrasonic-listening and grease-replenishment route — operators hear the bearing accept the right quantity of grease, eliminating over- and under-lubrication.

Listen-while-greaseQuantitativeRoute-basedOperator-led

Methodology runs under the broader Predictive Maintenance engagement →

§ Standards applied

Anchored to ASNT & ISO 18436-8.

ASNT · UT

American Society for
Nondestructive Testing

Field engineers certified to ASNT Recommended Practice SNT-TC-1A Levels I–II for ultrasonic testing methodology where the program touches NDT-adjacent surfaces.

ISO 18436-8

Condition monitoring
& diagnostics — Ultrasound

Programs follow ISO 18436-8 categories for personnel qualification and assessment in airborne ultrasound condition monitoring.

ISO 9001

Quality management

Delivered under the firm's ISO 9001-aligned QMS — routes, reports, and recommendations under change control.

Full standards list →

§ Asset types

Rotating equipment, electrical, and utility piping.

DZ-A · Rotating equipment (subset)

Bearings & gear surfaces

Focus — lubrication, early bearing detection.

  • Electric motorsBearing surfaces
  • PumpsDrive-end & non-drive-end
  • CompressorsAir · gas · process
  • GearboxesBearing cases
  • Fans & blowersBearing housings
  • ConveyorsIdler & head pulleys
  • Mills & crushersTrunnion bearings
DZ-C · Electrical & controls (subset)

MV / HV electrical

Focus — partial discharge detection.

  • SwitchgearMV · HV
  • Motor control centersMCC enclosures
  • TransformersDistribution · power

Plant utilities and process piping — compressed-air systems, steam traps, gas distribution headers, and process-piping joints — surveyed for leakage under operating pressure.

Refineries · Oil & Gas →   Petrochemicals →   Power Generation →   Pulp & Paper →

§ Reporting cadence

Ultrasound routes typically piggyback the vibration route on rotating equipment — same cadence, same engineer, complementary signal. Lubrication-listening surveys run on a calibrated cadence per asset population (often monthly for production-critical assets). Compressed-air and steam-leak surveys run annually for utility cost recovery; partial-discharge surveys on MV/HV switchgear align with the thermography cadence.

§ Tools used

Specialist probes for every surface.

TOOL · 01

Panametrics

Panametrics (formerly GE Inspection) ultrasonic instruments for industrial inspection — thickness gauging, flaw detection, and condition-monitoring probes.

TOOL · 02

Krautkramer

Krautkramer ultrasonic equipment for NDT-adjacent surfaces of the discipline — wall-loss measurement on critical pressure piping and reactor components.

TOOL · 03

Specialist
airborne probes

Airborne / structure-borne probes (SDT, UE Systems, CTRL Systems class instruments) for compressed-air leak surveys, partial-discharge listening, and lubrication routing.

Full technology partner list →

§ Ultrasound
The earliest signal is acoustic. Hear the failure before the spectrum shows it.