This Subsection contains requirements for the material, design, fabrication, examination, testing and overpressure protection of items which are intended to conform to the requirements for Class 1 construction. The rules of Subsection NB cover the requirements for assuring the structural integrity of items. Careful application of this Section will help users to comply with applicable regulations within their jurisdictions, while achieving the operational, cost and safety benefits to be gained from the many industry best-practices detailed within these volumes.