Visual Inspection
Cannot access hidden contact areas beneath supports.
Advanced NDT Inspections
Phased Array Technique for Corrosion Under Support Inspection
Advanced ultrasonic inspection technology designed to detect and evaluate hidden corrosion beneath pipe supports, clamps and contact points — without removing the support.
Accurate Detection
Identify hidden corrosion
Non-Invasive
No support removal required
Reliable Data
Encoded inspection results
PA-CUS Technology
Corrosion Under Support Inspection
Advanced phased-array ultrasonic inspection for concealed areas that are difficult or impossible to inspect visually.
Introduction to PA-CUS
What is PA-CUS?
Phased Array Corrosion Under Support (PA-CUS) is an advanced ultrasonic inspection technique developed to detect and assess hidden corrosion occurring beneath pipe supports, clamps, and contact points.
These areas are highly susceptible to corrosion due to moisture entrapment and coating degradation, yet remain inaccessible to visual inspection. PA-CUS enables reliable inspection without removing supports or interrupting operations.
The Inspection Challenge
Corrosion Under Support (CUS)
A concealed corrosion mechanism that can progress unnoticed beneath piping support structures.
Why CUS is difficult to detect
Corrosion Under Support (CUS) is a localized corrosion mechanism that develops at the interface between piping and its support structures. Water ingress, trapped contaminants, and damaged coatings accelerate metal loss in these concealed areas.
Since corrosion progresses unseen, CUS can lead to unexpected wall thinning, leaks, or structural failure if it is not detected early through advanced inspection techniques.
Inspection Comparison
Why Conventional Methods Fall Short
Traditional inspection methods can have significant limitations when the affected area is concealed beneath a support.
Radiography
Radiation safety concerns and limited coverage can complicate inspection.
Point Thickness
Conventional UT provides point thickness measurements rather than a broader scan.
High Impact
Support removal can increase cost, downtime, and safety risk.
Technology
How PA-CUS Works
The PA-CUS technique is based on analyzing ultrasonic signal attenuation between two phased array probes positioned on non-corroded areas of the pipe.
In areas without corrosion, ultrasonic reflections remain undisturbed and form a consistent vertical pattern known as the nominal signature.
Any deviation from this signature indicates the presence of corrosion or wall loss beneath the support. This approach allows detection and characterization without direct access to the affected area.
Inspection Setup
Equipment & Technique
PA-CUS inspection combines phased-array ultrasonic equipment, optimized probes and repeatable encoded scanning.
- Phased Array UT unit (32:128 PR or higher)
- Phased Array probes with frequency range 2.25 MHz to 5.0 MHz
- Optimized wedges (COD / AOD) for axial and circumferential scanning
- Encoded scanning capability for repeatable inspection
Inspection Data
Inspection Results & Data Presentation
PA-CUS inspection results are generated using C-scan data acquired from multiple phased array probes, along with continuous coupling monitoring.
The data is processed to generate a two-dimensional representation of corrosion depth versus scan length, providing clear visualization of corrosion severity, extent, and remaining wall thickness.
AITT NDT Services
Why Choose Us?
Experienced inspection professionals combining advanced and conventional NDT expertise with a strong safety and quality culture.
Advanced NDT Expertise
Advanced and conventional NDT expertise supported by forward-thinking inspection methodologies.
Safety & Quality
Strong safety and quality practices designed to deliver reliable and code-compliant inspection solutions.
Minimal Operational Disruption
PA-CUS can inspect concealed areas without requiring support removal, helping reduce operational impact.
Clear Inspection Reporting
Structured inspection data and reporting provide clear, auditable information for engineering decisions.
Need PA-CUS Inspection?
Discuss your inspection requirements with AITT NDT Services.