An ultrasonic pig (UT pig) is an inline inspection tool that uses high-frequency sound waves to measure pipeline wall thickness and detect internal/external defects with high precision.

An ultrasonic pig (UT pig) is an inline inspection tool that uses high-frequency sound waves to measure pipeline wall thickness and detect internal/external defects with high precision. UT pigs are the gold standard for accurate wall loss measurement and crack detection in liquid-filled pipelines.

UT pig types include:
• Standard UT pigs — wall thickness measurement using pulse-echo technology.
• Phased Array UT pigs — multi-angle inspection for crack detection and sizing.
• Dual-sensor pigs — combining UT with MFL for comprehensive assessment.

UT pigs require liquid coupling between transducers and pipe wall, making them primarily used in liquid pipelines. Gas pipelines typically use MFL technology or specialized gas-coupled UT tools.

For unpiggable pipelines where UT pigs cannot be deployed, EMPIT’s CMI technology provides aboveground corrosion detection and wall condition assessment without internal tools — filling the inspection gap for pipelines with design, flow, or access limitations.