Section 6-77-161 - Change in class location: confirmation or revision of maximum allowable operating pressure(a) If the hoop stress corresponding to the established maximum allowable operating pressure of a segment of pipeline is not commensurate with the present class location, and the segment is in satisfactory physical condition, the maximum allowable operating pressure of that segment of pipeline must be confirmed or revised according to one of the following requirements: (1) If the segment involved has been previously tested in place for a period of not less than eight hours, the maximum allowable operating pressure is 0.8 times the test pressure in Class 2 locations, 0.667 times the test pressure in Class 3 locations, or 0.555 times the test pressure in Class 4 locations. The corresponding hoop stress may not exceed seventy-two percent of the SMYS of the pipe in Class 2 locations, sixty percent of SMYS in Class 3 locations, or fifty percent of SMYS in Class 4 locations;(2) The maximum allowable operating pressure of the segment involved must be reduced so that the corresponding hoop stress is not more than that allowed by this chapter for new segments of pipelines in the existing class location;(3) The segment involved must be tested in accordance with the applicable requirements of subchapter 12, and its maximum allowable operating pressure must then be established according to the following criteria: (A) The maximum allowable operating pressure after the requalification test is 0.8 times the test pressure for Class 2 locations, 0.667 times the test pressure for Class 3 locations, and 0.555 times the test pressure for Class 4 locations;(B) The maximum allowable operating pressure confirmed or revised in accordance with this section, may not exceed the maximum allowable operating pressure established before the confirmation or revision; and(C) The corresponding hoop stress may not exceed seventy-two percent of the SMYS of the pipe in Class 2 locations, sixty percent of SMYS in Class 3 locations, or fifty percent of SMYS in Class 4 locations.(b) Confirmation or revision of the maximum allowable operating pressure of a segment of pipeline in accordance with this section does not preclude the application of sections 6-77-153 and 6-77-154.(c) Confirmation or revision of the maximum allowable operating pressure that is required as a result of a study under section 6-77-160 must be completed within eighteen months of the change in class location. Pressure reduction under subsections (a)(1) or (2) within the eighteen-month period does not preclude establishing a maximum allowable operating pressure under subsection (a)(3) at a later date.[Eff ] (Auth: HRS § 269-6) (Imp: 49C.F.R. §192.611, OCT 1, 1990)