(a) Change is class location—required study. When an increase in population density indicates a change in class location for a segment of an existing steel pipeline operating at a hoop stress that is greater than 40 percent of SMYS, or indicates that the hoop stress corresponding to the established maximum allowable operating pressure for a segment of existing pipeline is not commensurate with the present class, the operator shall make a study to determine:
(1) The present class location for the segment involved;
(2) The design, construction, and testing procedures followed in the original construction, and a comparison of these procedures with those required for the present class location by the applicable provisions of this part;
(3) The physical condition of the segment to the extent it can be ascertained from available records;
(4) The operating and maintenance history of the segment;
(5) The maximum actual operating pressure and the corresponding hoop stress, taking pressure gradient into account for the segment of pipeline involved;
(6) The actual area affected by the population density increase, and physical barriers or other factors which may limit further expansion of the more densely populated area.
(b) Change in class location—Confirmation or revision of maximum allowable operating pressure. If the hoop stress 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 the requirements set forth in section 49 CFR 192.611, which is hereby incorporated by reference.History: Rule 02-01, eff 30 Aug 01.