Valve disassembly is a costly and time-consuming prospect that requires the system to be placed in an at-risk condition. IIA’s Phased Array Sectorial Scanning (PASS®) allows for highly accurate valve testing — without disassembly.

Our team developed the patented PASS® inspection technique in 2012 as a way to leverage proven phased array ultrasonic testing (PAUT) on components not typically considered ideal configurations.

Today, IIA’s game-changing innovation offers non-intrusive valve scans that provide an unmatched level of detail regarding performance aspects of valve integrity and how the valve reacts during operation.

Offering a superior technique to radiography, conventional ultrasonic testing, and acoustic emissions, PASS makes valve inspections faster, easier, more accurate and less costly.


Using our PASS technique, IIA provides inspection and diagnostic services for a variety of valve configurations. PASS has the ability to detect and measure some of the following trend-able attributes:

  • Flow Rate
  • Total Disc Travel
  • Disc Fluttering
  • Disc Back Tapping
  • Stuck Disc
  • Disc Velocity
  • Stroke Time
  • Angular Disc Movement Exceeding Design Values

Phased array ultrasonic is a method of generating and receiving ultrasound. Sweeping beams are generated by the use of multiple element probes and electronic time delays, thus creating constructive and destructive interferences. The delays are programmed to generate beams at a given angle in relation to a target.

The PASS technique uses phased array probes to capture the interaction of the sound waves with the valve component’s assemblies and/or body structure. Sound waves are propagated through the valve bonnet and body at strategic locations to target key components of the valve. The resulting sound beam interactions are in turn captured as a function of time and cataloged by site unit number, system, and valve serial number. The time-captured data is then post processed and analyzed. In terms of ultrasonic signature, a given valve condition in static or dynamic operation can now be captured and a signature database developed for each valve in each system.


Once valve testing is complete, our user-friendly PASS® Visualization Software translates the raw PAUT data into a dynamic valve simulation. We then provide a visual representation of the valve as a 3-D model. Our patented software allows technicians and plant personnel to quickly and easily analyze and interpret valve conditions and performance characteristics and move forward with any necessary maintenance.

In addition, our PASS database collects and stores detailed attributes, which can be used to track valve performance over multiple inspections. This historical data helps owners make well-informed decisions regarding repairs and predictive maintenance.

Our proprietary PASS inspection technique offers a number of benefits:
  • Uses proven Phased Array Ultrasonic Testing (PAUT), which is a superior technique to radiography testing, conventional ultrasonic testing, or acoustic emissions.
  • Delivers highly accurate and detailed data regarding valve operability and supports the customer’s decision to eliminate or defer valve disassemblies.
  • PASS valve data can help plant owners plan assessments and generate valve work lists to assist in outage planning.
  • Minimizes outage impact when used in lieu of radiography.
  • PASS Visualization Software provides a complete and easy-to-use solution for PAUT data analysis and field interpretation.
  • Reduces operating costs compared to other testing methods by eliminating the need for valve and piping disassembly.
  • Helps plant owners make informed decisions regarding valve operability and predictive maintenance.
  • Makes valve inspection faster, easier, more accurate and less costly.


Brochures & Summary Sheets

IIA’s PASS inspection procedure uses proven Phased Array Ultrasonic Technique (PAUT), which is a superior technique to RT, Conventional UT, or Acoustic Emissions. PASS offers complete and accurate scans of valves without the need to disassemble pipes and valves.
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Blog Posts & Articles

December 28, 2023
IIA Lab Services Brochure
With roots that date back nearly a century, IIA has grown to become one of North America’s largest and most trusted providers of industrial and commercial laboratory services. Our capabilities include metrology, metallurgical testing, non-destructive testing, dimensional inspection, mechanical testing, EMC/EMI, consumer goods testing, calibration, environmental testing and chemical analysis — to name a few.
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Two recent, well-publicized events have brought home the life-saving importance of non-destructive testing. Recently, the Carowinds amusement park in North Carolina shut down its Fury 325 roller coaster after frightening video circulated of a visibly detached crack in a key support beam as unsuspecting passengers zoomed over it at high speeds.
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Inspection Newsletter – Q2 2023
At the end of the day, a proactive approach to inspections can help you avoid costly repairs and compliance issues down the road — and IIA can help.

Other IIA Technology

Simple & Advanced Manual Encoded Ultrasonic Testing

IIA’s ARMUT® technology is the most cutting-edge PAUT examination available today. It’s an alternative to conventional manual and encoded track phased array examinations.

Advanced Inspection of Reactor Vessel & Internals

We understand that time is money. IIA’s advanced AIRIS™ inspection method delivers more reliable data while saving plant owners time, trouble and cost.