The Hazardous Liquid pipeline regulations in §195.424 allow for the movement of pipelines, subject to the conditions in the regulation. But this not a projec undertaken lightly, and some thought and planning must go into it.
The following from the PHMSA Enforcement Guidance provides some insight as to what steps an operator must take to comply with this rule.
Operations and Maintenance Guidance (Subpart F)
The operator must have a written site specific plan for the lowering or relocating in service pipeline.
This plan should include at a minimum an analysis of the following factors prior to considering the lowering of an in service pipeline: the required deflection, the diameter, wall thickness, grade of the steel, characteristics of the pipeline, the terrain, the soil, safety, the cumulative stresses on the pipe while moving and after lowering, and the toughness of the of the steel.
The plan should include sufficient details such as the calculations concerning the length of pipe that can span (unsupported) an excavation prior to lowering the pipe. There should be information regarding the maximum vertical and horizontal movement (should be in steps) allowed at each stage of the lowering process.
Additional precautions are necessary when moving pipelines that contain HVLs.
Detailed plans should include notification and possible evacuation of nearby public when moving HVL pipelines, evacuating the medium in the pipe, excavation of the pipeline and checking for coating damage during the moving process.
Emphasis must be placed on protecting the public, the operator’s employees, property, and the environment while accomplishing this task.
Examples of aProbable Violation
1. The lack of a procedure is a violation of 195.402.
2. The lack of records is a violation of 195.404.
3. Operator did not follow written plan, document deviations from written plan, or show that removal of HVLs was impractical.
4. The written plan does not effectively address the requirements of the code section.
5. Operating pressure was not reduced to less than 50% of MOP prior to moving a pipe segment, except for HVL which must be kept at a pressure which maintains them as a liquid.
6. There was no documentation to indicate that it was impractical to evacuate the HVL from a pipeline segment prior to lowering the segment.
7. The operator did not notify residents near the pipeline prior to moving an HVL pipeline.
Examples of Evidence
1. Site specific line pipe movement plan for the project and other pertinent information concerning the line lowering project.
2. Completed site specific line pipe movement plan implementation record including OQ qualified personnel responsible for the project.
3. Photos of the site before, during and after the project.
4. Line pipe movement procedures.
5. Records of pipeline pressures during the movement process.
6. Lack of procedures or records.
All this for you in WinDOT, The Pipeline Safety Encyclopedia.