API RP 1117:2008 pdf download

API RP 1117:2008 pdf download.Recommended Practice for Movement in In-service Pipelines.
Conclusion: The minmium trench length required to achieve the desired 5-ft vertical deflection of the pipe is 510 It. The pipeline must be supported every 51.3 ft.
5 Procedure Considerations
5.1 General
A pipeline-moving protect has three steps, which are to be performed in the following order a) project planning:
b) the actual work of ditching, moving, backfilling, and cleanup: and
c) documentation to meet pipeline-operator and regulatory requirements.
Each of the consideration discussed in this section should be taken into account in at least one of these steps.
5.2 Safety Precautions
Caution—For safety, the cautions and recommendations described in 5.2.2 through 5.2.7 should be considered and followed.
5.2.1 General
5.2.2 Internal Operating Pressure
Prior to the pipe movement, the Internal operating pressure of the pipeline should be reduced in accordance with the pipeline operators procedures and appkcable regulations.
5.2.3 Pipeline Location
Prior to planning and excavation, the location of the pipeline, including its depth, should be determined.
5.2.4 Other Underground Facilities
Prior to planning and excavation, efforts should be made to determine whether underground facilities may be encountered and, it so, where the facilities are located. The construction area should be checked for utility markers and other evidence of underground facilities. If available, state or local One Call” systems should be accessed. Otherwise, operators of such underground facilities should be contacted directly so they may locate and mark their facilities. All contacts should be documented.
5.2.5 Girth Weld Inspection
It available, pipe mill test reports and welding Inspection records should be reviewed. In addition, consideration should be given to (he visual and nondestructive inspection of girth welds once the pipeline is exposed and prior to movement should be considered.
5.2.6 Attached Appurtenances
Attachments to the pipeline such as fittings or valves may affect the pipeline movement. Their effect on the movement should be considered. The movement of pipelines with attached appurtenances is beyond the scope of this recommended practice (see 1.2).
5.2.7 Excavation Safety
Excavation presents some unique safety considerations. It should be performed in accordance with the pipeline operators procedures and applicable safety regulations. Refer to OSHA trend’iing and excavation regiiations.
5.3 Terrain
Terrain refers primarily to the profile of the ground where the pipeline is located. Terrain affects a pipeline movement primanly by influencing the length of the trench required to move the pipeline.
In flat or gently rolling terrain, a pipeline is often laid by elastically conforming it tO the terrain profile. In this case, the movement should be executed to ninimize additional stress in the pipeline.
Caution—In flat or gently rolling terrain, to limit additional stress and ensure the safe movement of the pipeline, it may be necessary to excavate a longer trench than that required by the trench length equation.
In mountainous or hilly terrain, the pipeline may have permanent overbonds or sag bends. In such cases, the physical profile for the moved pipeline should incorporate these bends. Movement operations on the pipeline should be executed to prevent the alteration of these bends.
Caution—To maintain safe conditions in difficult terrain such as that found in mountains and hills, movement operations should be treated as special cases and may require a detailed engineering analysis and the use of specialized construction techniques.
5.4 Soil
The soil type may determine the cross-sectional shape of the excavation and how the pipeline will be handled over the ditch.
5.5 Other Considerations
Caution—All pipeline movement projects should be executed with caution. If the pipeline is in tension and little or no slack is available, the movement will subject the pipe to additional stress due to the weight of the pipe, the weight of the fluid In It, and to seasonal temperature changes. Particular care should be taken in older pipelines in which the pipe connections may be mechanically weak.