ASTM E 797 - 95. Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact Method

American Society for Testing and Materials (ASTM). 1995, 7 pages.
This practice2 provides guidelines for measuring the thickness of materials using the contact pulse-echo method at temperatures not to exceed 200°F (93°C).
This practice is applicable to any material in which ultrasonic waves will propagate at a constant velocity throughout the part, and from which back reflections can be obtained and resolved.