(a) General. An operator may use direct assessment either as a primary assessment method or as a supplement to the other assessment methods allowed under sections 255.901 through 255.951 of this Part. An operator may only use direct assessment as the primary assessment method to address the identified threats of external corrosion (EC), internal corrosion (IC), and stress corrosion cracking (SCC).
(b) Primary method. An operator using direct assessment as a primary assessment method must have a plan that complies with the requirements in:
(1) ASME/ANSI B31.8S (as described in section 10.3 of this Title), section 6.4; NACE SP 0502 (as described in section 10.3 of this Title); and section 255.925 of this Part if addressing external corrosion (EC).
(2) ASME/ANSI B31.8S, section 6.4 and appendix B2, and section 255.927 of this Part if addressing internal corrosion (IC).
(3) ASME/ANSI B31.8S, appendix A3, and section 255.929 if addressing stress corrosion cracking (SCC).
(c) Supplemental method. An operator using direct assessment as a supplemental assessment method for any applicable threat must have a plan that follows the requirements for confirmatory direct assessment in section 255.931 of this Part.