255.619 Maximum allowable operating pressure: steel or plastic pipelines.

(a)Except as provided in subdivision (c) of this section, no person may operate a segment of steel or plastic pipeline at a pressure that exceeds the lowest of the following:#

(1)the design pressure of the weakest element in the segment, determined in accordance with this Part;#

(2)the pressure obtained by dividing the pressure to which the segment was tested after construction as follows:#

(i)for plastic pipe in all locations, the test pressure is divided by a factor of 1.5;#

(ii)for steel pipe operated at 100 psig (689 kPa) or more, the test pressure is divided by a factor determined in accordance with the following table:#

Factors Class Location | Installed before (Nov. 12, 1970) | Installed after (Nov. 11, 1970) | Converted under § 255.14 1 | 1.1 | 1.1 | 1.25 2 | 1.25 | 1.25 | 1.25 3 | 1.4 | 1.5 | 1.5 4 | 1.4 | 1.5 | 1.5#

(3)the highest actual operating pressure to which the segment was subjected during the five years preceding July 1, 1970, unless the segment was tested in accordance with section 255.505 or 255.507 of this Part during the five-year period or the segment was upgraded in accordance with section 255.555 or 255.557 of this Part. The MAOP must not exceed the MAOP on August 30, 2011 if the MAOP is determined using this method.#

(4)for furnace butt welded steel pipe, a pressure equal to 60 percent of the mill test pressure to which the pipe was subjected;#

(5)for steel pipe other than furnace butt welded pipe, a pressure equal to 85 percent of the highest test pressure to which the pipe has been subjected, whether by mill test or by post installation test; or#

(6)the pressure determined by the operator to be the maximum safe pressure after considering the history of the segment, particularly known corrosion and the actual operating pressure.#

(b)No person may operate a segment to which paragraph (a)(6) of this section is applicable, unless overpressure protective devices are installed on the segment in a manner that will prevent the maximum allowable operating pressure from being exceeded, in accordance with section 255.195 of this Part.#

(c)Notwithstanding the other requirements of this section, an operator may operate a segment of pipeline found to be in satisfactory condition, considering its operating and maintenance history, at the highest actual operating pressure to which the segment was subjected during the five years preceding July 1, 1970, subject to the requirements of section 255.611 of this Part.#

(d)Notwithstanding the limitation of paragraph (a)(3) of this section, an operator may maintain a previously established maximum allowable operating pressure for a cathodically protected steel or plastic pipeline provided that, when the pressure is increased above the highest pressure to which it has been subjected during the last five years, it is leakage surveyed and all leaks found are repaired in accordance with this Part.#