This is a companion guide to the ASME Bioprocessing Piping and Equipment (BPE) Standard and explains what lies behind many of the requirements and recommendations within that industry standard. Following an introductory narrative to the Standard's early history, industry related codes and standards are explained; the design and engineering aspects cover construction materials, both metallic and nonmetallic; then components, fabrication, assembly and installation of piping systems are explored. Examination, Inspection and Testing then precede the ASME BPE certification process, concluding with a discussion on system design. The author draws on many years experience and insights from first-hand involvement in the field of industrial piping design, engineering, construction, and management, which includes the bioprocessing industry. The reader will learn why dimensions and tolerances, process instrumentation, and material selection play such an integral part in the manufacture of components and instrumentation. This easy to understand and navigate guide will assist engineers (design, piping, chemical, etc.) who need to understand the basis for much of the Standard's content, as do the contractors and inspectors who have to meet and validate compliance with the BPE Standard.