Change in Class Location: Confirmation or Revision of Maximum Allowable Operating Pressure [49 CFR 192.611]

(A)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. [49 CFR 192.611(a)]#

(1)1. If the segment involved has been previously tested in place for a period of not less than 8 hours: [49 CFR 192.611(a)(1)]#

(a)a. 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 72 percent of the SMYS of the pipe in Class 2 locations, 60 percent of SMYS in Class 3 locations, or 50 percent of SMYS in Class 4 locations. [49 CFR 192.611(a)(1)(i)]#

(b)b. The alternative maximum allowable operating pressure is 0.8 times the test pressure in Class 2 locations and 0.667 times the test pressure in Class 3 locations. For pipelines operating at alternative maximum allowable pressure per §2720, the corresponding hoop stress may not exceed 80 percent of the SMYS of the pipe in Class 2 locations and 67 percent of SMYS in Class 3 locations. [49 CFR 192.611(a)(1)(ii)]#

(2)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 Subpart for new segments of pipelines in the existing class location. [49 CFR 192.611(a)(2)]#

(3)3. The segment involved must be tested in accordance with the applicable requirements of Chapter 23 of this Subpart, and its maximum allowable operating pressure must then be established according to the following criteria. [49 CFR 192.611(a)(3)]#

(a)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. [49 CFR 192.611(a)(3)(i)]#

(b)b. The corresponding hoop stress may not exceed 72 percent of the SMYS of the pipe in Class 2 locations, 60 percent of SMYS in Class 3 locations, or 50 percent of SMYS in Class 4 locations. [49 CFR 192.611(a)(3)(ii)]#

(c)c. For pipeline operating at an alternative maximum allowable operating pressure per §2720, the alternative maximum allowable operating pressure after the requalification test is 0.8 times the test pressure for Class 2 locations and 0.667 times the test pressure for Class 3 locations. The corresponding hoop stress may not exceed 80 percent of the SMYS of the pipe in Class 2 locations and 67 percent of SMYS in Class 3 locations. [49 CFR 192.611(a)(3)(iii)]#

(B)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. [49 CFR 192.611(b)]#

(C)C. 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 §§2503 and 2505. [49 CFR 192.611(c)]#

(D)D. Confirmation or revision of the maximum allowable operating pressure that is required as a result of a study under §2709 must be completed within 24 months of the change in class location. Pressure reduction under Subsections A.1 or A.2 of this Section within the 24-month period does not preclude establishing a maximum allowable operating pressure under Subsection A.3 of this Section at a later date. [49 CFR 192.611(d)]#

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:501 et seq.#

HISTORICAL NOTE: Promulgated by the Department of Natural Resources, Office of Conservation, LR 9:241 (April 1983), amended LR 10:533 (July 1984), LR 18:858 (August 1992), LR 30:1261 (June 2004), LR 31:684 (March 2005), LR 35:2806 (December 2009).#