Ultrasound Inspection Uncovers Hidden Vacuum Leaks, Saving Facility $280k

How an ultrasound inspection saved hundreds of thousands of dollars by finding vacuum leaks hidden beneath thick pipe insulation.

A major industrial facility faced a critical need to locate a vacuum leak in a pipe insulated with 1.5‑inch thick rock wool wrapped in aluminum. Downtime was estimated at $35,000 per hour, and the maintenance crew had only one full shift (8 hours) to pinpoint the leak.

An Enercheck Systems inspector was brought in. He pressurized the system with compressed air at 25–30 psi and used an ultrasonic detection device that converts high‑frequency emissions from a leak into audible sound.

Through the instrument’s headphones and on‑screen display, the inspector could hear low‑frequency leak sounds and see intensity spikes. While scanning, a nearby 250‑lb steam line produced louder ultrasounds. Because the leak sound would be much quieter after passing through insulation, the inspector temporarily shut off the steam line to reduce background noise.

Using an airborne‑ultrasound scanning module, the inspector identified three leaks, which were sealed by welding within hours. A subsequent pressure drop revealed additional leaks that the ultrasonic scanner could not detect.

Time was critical. The plant needed all leaks found before the evening shift. The inspector requested permission to create test points in the insulation by perforating the aluminum skin with a screwdriver. The request was granted, and he drilled strategic holes along the 8‑inch piping.

He then switched to a contact (stethoscope) module, which uses a metal rod to transmit structure‑borne ultrasounds from the leak to the sensor. Inserting the rod into the holes, he listened for sound increases. At an elbow, he finally heard the culprit: a leak in the non‑316 stainless‑steel elbow.

The leak was temporarily sealed with a quick‑hardening putty that bonds in under 10 minutes, taking advantage of the vacuum to draw the putty into the opening.

After switching the system from positive to negative pressure, the inspector performed a final scan. All leaks were located and repaired, allowing the plant to resume operations.

Follow‑up inspections confirmed the facility ran continuously for the two weeks needed to fabricate the production part, keeping order fulfillment on track and potentially saving hundreds of thousands of dollars in downtime.

Bruce Gorelick, Vice‑President, Enercheck Systems, Charlotte, NC; Alan Bandes, Vice‑President Marketing, UE Systems Inc., Elmshird, NY. For more information, visit enerchecksystems.com and uesystems.com.