Why are light taps with a hammer recommended during inspections of metallic linings?

Light taps with a hammer during inspections of metallic linings are recommended primarily to detect loose or cracked areas. This technique relies on the sound produced by the material when it is struck. If the metallic lining is intact and securely adhered, the resulting sound will be a solid, even tone. In contrast, loose or cracked areas will typically produce a dull sound or an echo, indicating that the material is not properly fastened or has developed structural issues such as cracking.

Using this method is an effective non-destructive testing technique that allows inspectors to identify potential problems without causing any further damage to the vessel. The focus on sound quality helps inspectors quickly assess the condition of the lining and identify locations that may require further investigation or repairs, facilitating early intervention to prevent larger issues down the line.

This technique is less effective for measuring thickness, evaluating corrosion levels, or assessing alignment, which require other specific instruments or methods to provide accurate and reliable results.