This fourth edition of the ¿́¿Companion Guide¿́¿ of ASME Pressure Vessel & Piping Codes has been updated to the current (2010) Code Edition and (2011) Addenda. This edition has 38 chapters authored by 49 experts who have considerably updated and extensively re-written chapters, as well as provided entirely new chapters. Unlike the third edition, this fully updated and revised fourth edition is a classic reference work in a convenient two-volume format that focuses on all twelve sections of the ASME Boiler and Pressure Vessel Codes, as well as relevant Piping Codes and Standards. The first two volumes covering Code Sections I through XII consider the dramatic changes in the industry, state of the art of technology and regulatory practices. Organizational Changes of Boiler & Pressure Vessel Committees are included in the front matter of both volumes of this publication. A unique feature of this publication is the inclusion of all author biographies and an introduction that synthesizes every chapter, along with an extensive index including over 7500 individual terms.