Are Your Isolation Valves Ready for Your Major Shutdown?

Are you ready for your annual shutdowns?

The season of major shutdowns is fast approaching. Are your isolation valves leak-tight? Will lockout/tagout be completed on time—or will internal leakage impact the progress of your work and the safety of your workers? Do your valves need refurbishment or replacement? Will supply chain slowdowns affect your planned projects?

All these questions must be asked—and the solution is simple:
Ultrasonic inspection of isolation valves.

Why Ultrasonic Inspection Matters

Leak testing of isolation valves is crucial in many industries, such as petrochemicals, food processing, pharmaceuticals, and more. Defective or leaking valves can cause product losses, production interruptions, delays during planned shutdowns, and even safety and environmental risks. That’s why regular valve monitoring is essential to maintaining safe and efficient operations.

How Is the Inspection Performed?

During the inspection of a valve, the technician uses an ultrasonic tool to measure decibel levels upstream and downstream of the valve. This method, commonly known as the A-B-C-D technique, requires a pressure differential across the valve.

Ultrasonic tools provide a non-destructive method of inspection, meaning valves do not need to be dismantled, damaged, or taken out of service during testing. This allows companies to maintain continuous production while ensuring safety and quality.

The Ultrasonic Phenomenon

By maintaining higher pressure on one side of the valve, turbulence is created that generates ultrasonic waves. These sounds are outside the audible range of the human ear but can be detected and measured with ultrasonic equipment.

When a valve is closed, if the valve seat or element (disc, knife, ball, etc.) is worn, the resulting flow will not be smooth and laminar. This turbulence is what makes it possible to diagnose problematic valves.

Client case study

At a fuel transfer terminal receiving diesel and different grades of gasoline by rail, tank cars are unloaded via a pump. The pump’s output supplies several buffer tanks, from which tanker trucks are filled for regional distribution.

The pump has two suction lines—one for gasoline and one for diesel—each isolated by a set of valves and actuators. The discharge is equipped with the same type of valve and actuator assemblies.

During routine quality control tests, operators detected traces of diesel in the gasoline. To continue operations, the backup pump was put into service. However, this pump had its own valve and actuator network with lower capacity, which caused operational delays.

The initial strategy was to replace all four valve/actuator assemblies. Each assembly costs $85,000, but only three were available for the scheduled July shutdown. The fourth had a 16-week delivery lead time. Given the situation, a “Plan B” was needed.

The client contacted us to explore alternatives, and an ultrasonic inspection was carried out.

Results: Only two valves showed symptoms of internal leakage. This allowed the client to prioritize the work, saving $170,000 from their budget forecast. Additionally, since the faulty valves were identified, the main pump could continue to operate on gasoline only (the diesel valves were leak-tight, eliminating contamination risk), and operations were far less impacted.

Pascal Morel
Reliability Services Supervisor
[email protected]