This book is a companion to the 2021 ASME Boiler and Pressure Vessel Code (BPVC). It explains only significant changes
to Code requirements that have been approved since 2019 and that will be published in the 2021 Edition. It covers the
following ASME BPVC Sections:
Section XI
Section II, Parts A, B, C, and D
Section V
Section IX

For each of the above Sections, an Introduction describes the historical background, scope of coverage, and commercial application of that Section by industry and government organizations. The list of changes follows the Introduction. The explanation for each change provides the reason for the action and the value to the Code user. The sequence of the changes follows the order of the Code requirements.