Ultrasonic surveys are a form of non-destructive testing (NDT) that use vibrations of short wavelength and high frequency.

Ultrasonic technology can be used to penetrate most non-porous resilient materials used in structures, including steel, aluminium, concrete, wood, titanium, magnesium and ceramics.

Applications range from thickness measurements to internal testing of large turbine rotors. Even large cross-sections can be tested successfully for minute defects.

Hand-held units can be used for smaller inspections. Remote-controlled crawling robots can be used for the safe inspection of larger structures such as petroleum storage tanks.