One question I have been asked a fair bit recently as International Testing Services have invested heavily in the Advanced inspection field is can/will Phased Array (PAUT) ever replace Radiography. Clients often think that PAUT is too complicated and will never fully replace Radiography. This may well be the case as Radiography still certainly have major benefits. While many still opt for radiography over PAUT, it’s crucial to explore whether it’s the right choice for your project specific needs.

In this blog post, we’ll delve into the pros and cons of radiography and highlight the advantages that PAUT brings to the table.

Radiography: A Traditional Approach 

Radiography has a long history, dating back over half a century, as a prevalent method for weld inspection in field applications. Despite the safety implications and exclusion zones, radiography has several other limitations to consider.

Despite its popularity, there are considerations that might make you think twice before choosing it over PAUT.

Cost Considerations

At first glance, radiography seems cost-effective, with lower hourly or day rates. However, it’s essential to factor in production values, soft costs related to radiation exclusion zones, and the need for additional shots (reshoots, offsite development etc)

Practical Limitations

Radiography relies on film or computerised radiography plates, with the latter having limitations in harsh field environments. Exposure times vary based on pipe diameter, and panoramic techniques can be time-consuming and logistically challenging, involving confined space entry events.

Production Time and Feedback

Setting up radiographic exposures, especially panoramic shots, can take 20-50 minutes. The Processing stage adds another 30-45 minutes, resulting in a total time of 60-100 minutes per inspection. In contrast, PAUT can complete the scan in 10-15 minutes, providing instant feedback on process control and allowing continuous welding without significant interruptions.

As weld metal thicknesses increase and/or diameter the exposure time increases with radiography. This also increases the radiation exclusion zone required. This is the zone is where non radiation monitored personnel cannot be present during an exposure/inspection.

PAUT: A Faster and More Efficient Alternative

PAUT emerges as a compelling alternative to radiography, offering significant advantages in terms of speed, efficiency, and adaptability.

Production Values and Soft Costs

PAUT’s quicker scanning process results in higher production values, outweighing the minor cost differences in crew rates. It also eliminates the need for off-shift work and provides instant feedback on process control. A single PAUT crew can equal two crews performing radiography and this production advantage increases as the welds become thicker. Add in the indirect costs that have to be considered with a comparison between radiography and PAUT can save money even with a higher crew cost.

PAUT with ToFD

For thicker materials, combining PAUT with Time of Flight Diffraction (ToFD) enhances detection and sizing capabilities. ToFD, sensitive to various indications, can be seamlessly integrated into the scanning process without adding extra time.

Conclusion: Choose Wisely for Your Project

In conclusion, when deciding between radiography and PAUT/ToFD for your welding project, consider factors such as project volume, pipe diameter and schedule.

If you prioritise continuous welding, timely feedback, and overall cost savings, PAUT/ToFD emerges as the preferred option. especially if your project has a high volume of welds. If your project has larger diameter piping. If your pipe schedules are heavy, not to mention the safety complications with radiography. Make an informed decision to ensure a smooth and efficient inspection process for your project. For more information contact International Testing Services;