ASTM E2906/E2906M-18(2022)

1.1 This practice describes use of Acoustic Pulse Reflectometry (APR) technology for examination of the internal surface of typical tube bundles found in heat exchangers, boilers, tubular air heaters and reactors, during shutdown periods.

1.2 The purpose of APR examination is to detect, locate and identify flaws such as through-wall holes, ID wall loss due to pitting and/or erosion as well as full or partial tube blockages. APR may not be effective in detecting cracks with tight boundaries.

1.3 APR technology utilizes generation of sound waves through the air in the examined tube, then detecting reflections created by discontinuities and/or blockages. Analysis of the initial phase (positive or negative) and the shape of the reflected acoustic wave are used to identify the type of flaw causing the reflection.

1.4 When proper methods of signal and data analysis are developed, APR technology can be applied for sizing of flaw/blockage indications.

1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standards.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.