255.609 Change in class location: required study.

At least once every five years or whenever an increase in population density indicates either a change in class location for a segment of an existing steel pipeline operating at a hoop stress that is more than 40 percent of SMYS, or 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 location, the operator shall immediately make a study to determine:#

(a)the present class location for the segment involved;#

(b)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;#

(c)the physical condition of the segment to the extent it can be ascertained from available records;#

(d)the operating and maintenance history of the segment;#

(e)the maximum actual operating pressure and the corresponding operating hoop stress, taking pressure gradient into account, for the segment of pipeline involved; and#

(f)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.#