Phased Array Ultrasonic TestingInspection Solutions for Today and Tomorrow

PAUT Training and Certification Requirements

•ASNT added PAUT in 4th quarter of 2011

•Prerequisite to PAUT is UT level II Certification

•Minimum 80 hours classroom training• Training course outline is specified in CP-105

•Minimum 160 hours on the job (hands on) training

• Specific examination consisting of a minimum 30 questions on PAUT

Levels of Responsibility

• ASNT does not address PAUT level I’s. It’s assumed that a PAUT inspector will be an experienced UT level II.

• General Industry Level II PAUT under ASNT

• Additional Performance Demonstration Qualification (PDQ) certs under• EPRI

• API

• Per Contract Documents

• No certified Level III PAUT per ASNT, only in house or contractor designation as Subject Matter Experts (SME).

Codes and Standards Accepting PAUT

• ASME

• First through Code cases 181 and 2235

• Now as direct acceptance through article 4 and mandatory appendices

• ASTM E2700 – Standard Practice for Contact Ultrasonic Testing of Welds using Phased Array

• ASTM 2491 – Standard Guide for Evaluating Performance Characteristics of Phased Array Test Systems

• API 1104 – Welding of Pipelines and Related Facilities

• AWS D1.1 – Structural Welding Code – Steel

• AWS D1.5 – Bridge Welding Code

History of PAUT• 1801 – Constructive/Destructive

interaction demonstrated

• In phase combination = reinforcement

• Out of phase combination = cancellation

• 1960’s – Researchers begin to develop systems using pulsed multi-point transducers to direct mechanical waves

• 1970’s – Medical imaging diagnostics appear

• Beam steer offers cross sectional image views

What is PAUT

• Phased Array Ultrasonic Testing is an advanced ultrasonic technique used for flaw detection, sizing, and imaging

• Uses multi-element (array) probes for increased beam steering and focusing compared to conventional UT

• Like having many small conventional UT probes in one pulsed at predetermined intervals

How Phased Array Works

Each individual wave generated within the scan goes through the pulse/receive cycle as shown below

How Phased Array Works

• Each received analog A-Scan is digitized and rendered into 2D display formats

• Signals from the entire sequence are compiled into various image formats for evaluation

PAUT Views

• A data view is a 2D graphic rendering of the ultrasonic data

• Data views • A-Scan• B-Scan• C-Scan• S-Scan• ToFD• Ray Tracing• Strip Charts

A-Scan View

• Source by which all other views are created

• Amplitude vs time• An A-Scan exists for every

sound beam• One for each segment

of a linear scan• One for each angle of

an S-Scan• Rulers allow presentation

of information in time, sound path, or true depth

• Amplitude is linked to color pallet

B-Scan View

• A side view looking from the back side of the probe• Represents data collected through the entire scan length for one A-Scan• View changes dynamically as angle or VPA is scrolled

C-Scan View

• C-Scan is a plan view/top view• View is generated based on gate positioning and mode (may be configured for

gate A and B independently)• Data can be presented in amplitude or position (thickness) formats

S-Scan View

• Presents all A-Scans within the group in an angular sector or sweep range

• A-Scans are converted to color coded lines representing amplitude

• May be corrected for delay and true depth relative to the ultrasonic axis as shown here

Time of Flight Diffraction (ToFD)

• The ToFD display offers a B-Scan representation of the diffracted signals detected in “pitch catch” conventional UT probes

• As with all other image views ToFD is built off individual A-Scans

Ray Tracing View

• Provides 2D representation of the weld, showing rebounds of the beam path and A gate position for the first, last and active focal law

• Should only be used as a reporting tool

Master Thoughts

• It’s still UT• Anything UT can do PAUT can do better

• Technology enabled• UT is not new, neither is PAUT

• Computer assistance of proven technology

• Advancements in transducer material/design

• Medical use and capability perfected• Adapted for use in industrial sector

• Key elements• Multi-dimension sizing offers more accurate assessment of integrity

• Weld images provided in multiple 2D orientations, giving 3D of views

• Raises production while reducing costs

PAUT for Pipelines

API 1104 21st Edition

API 1104 21st Edition Appendix A Option 1 Engineers

Critical Assessment (ECA)

• PAUT has been accepted since 19th

Edition of API 1104• Approved by PHMSA• Approved by The Ohio Gas Association• Multi dimension sizing allows for use of

ECA• ECA/Fracture Mechanics acceptance

criteria used and can reduce reject and repair rates.

Why PAUT? Why Now?

• No dangerous ionizing radiation• Reduced safety factor• Increased production• Possible reduction in reject rate• No expensive regulatory fees

• Accurate permanent records• Equipment generated reports with detailed

indication tables• Physical and cloud storage of data with no

degradation• Multiple weld images included with data• Results auditable onsite or remotely every day• Setup and equipment data/configuration

automatically included in report

Why PAUT? Why Now?Pipeline NDT PAUT RT

Mainline crew $120/hr $175/hr

Data/Film$5/per weld

$35/weld

Equipment fees $600/day$800-

$1200/day

Tie-in/HDD NDT crew $95/hr $175/hr

Project lead

N/A (combined with other

service position)

$1200/day

Licensing N/A$1000-

$10,000 per project

Auditing $5/weld $1000/day

• Tremendous cost savings• Lower hourly fees• Less manpower• No regulatory costs• Lower data vs film cost• Remote auditing offering lower costs• No production interruption• Lower liability consideration due to

safety• Safety

• No ionizing radiation• Less manpower• Only seasoned personnel are certified• ECA criteria more accurately reflect

likelihood of failure

•Benefits Recap

• Increased production• Increased usefulness of data• Increase in job safety• Decreased costs of inspection/NDT• Decreased repair/rejection rate

An investment in innovation is an investment in a safe profitable future!