ASTM International Standard Practice for Measuring the Ultrasonic Velocity in Polyethylene Tank Walls Using Lateral Longitudinal (L CR ) Waves ASTM E2479-11

This practice covers a procedure for measuring the ultrasonic velocities in the outer wall of polyethylene storage tanks. The practice is intended for application to the outer surfaces of the wall of polyethylene tanks. An angle beam lateral longitudinal (LCR) wave is excited with wedges along a circumferential chord of the tank wall. A digital ultrasonic flaw detector is used with sending-receiving search units in through transmission mode. The observed velocity is temperature corrected and compared to the expected velocity for a new, unexposed sample of material, which is the same as the material being evaluated. The difference between the observed and temperature corrected velocities determines the degree of UV exposure of the tank.