Where are impact testing exemption curves found?

• A. UCS-66
• B. UG-99
• C. ASME Section VIII
• D. IEEE Standard

Answer: (A)

Impact testing exemptions are defined by curves that show when Charpy impact testing can be waived based on material thickness and service temperature. These exemption curves specify the boundary: if a given material thickness at a certain temperature lies below the curve, impact testing is not required; if it lies above, testing is still needed. The curves used for this purpose are published in UCS-66, which is the place in the code where these exemption provisions are laid out. ASME Section VIII provides the broader vessel requirements, but the specific exemption curves come from UCS-66. IEEE standards are not related to this aspect of pressure-vessel toughness testing.