^ Pipeline valves
Article by Mohanned W. Tarabzouni
Valves are the main components of a pipeline that control and regulate product flow. They are essential equipment for any pipeline or piping section intended for fluid control or isolation purposes, and need to be properly functioning, maintained, and operated. During the valve’s life span, it shall experience controlled processes to achieve maximum product quality.
Maintaining and preserving valves before installation contributes greatly to the life span of the valve, and ensures the valves continue to perform safely and as intended.
This highlights the importance and relevance of pre-commissioning, which includes design selection, manufacturing, testing and inspection, transportation, and storage. Each stage requires a set of check items to go through and verify.
Proper body design and trim selection shall be identified to ensure full service and chemical compatibility of the pipeline product. This also includes all types of seals and non-metallic components that are embedded within the valve body, along with further consideration for corrosive and erosive services for pressure containing and controlling parts.
Alongside this, assembly is a very crucial stage during which the valve parts should be put the valve parts shall be put together carefully and without damaging any seals, gaskets, and other parts. Documented and well-developed procedures should be implemented and logged to prevent any future failures.
Testing and inspection
Several aspects of T&I shall be addressed, including hydro testing medium quality and sufficient drying/draining post-testing. The hydro test medium shall be periodically monitored to prevent any corrosion related risks.
All hydro test mediums must be fully drained and dried after testing activities from all valve internals and ports as well as drain passages. Several corrosion issues have been reported due to the residual hydro test medium left inside the valve with insufficient corrosion inhibitor application.
Quality control and inspection prior to shipping include packaging, quality checks, and other activities as per manufacturer recommendations or as per end-user requirements or internal guidelines.
Serialization, heat numbers, MTRs, and all related documentation shall be availed, verified, and prepared during this stage along with inspecting the valve of any defects, dents, or damage. The manufacturer shall fully comply and ensure industry standard regulations and end-user recommendations are being adhered to.
Transportation, storage & startup
After the valve is properly packed and approved for quality, it is ready to be shipped to the customer. Care should be taken for valves with extensions, high heads, or mounted actuators.
There shall be no damage reported on components. Handwheels and other parts are permitted during the whole period of shipping, loading, and unloading. Ensure lifting legs and designated eyes are utilized for their purpose efficiently and at all times.
In some projects, valves shipped may not be scheduled for immediate installation as other construction activities may take place such as pipe blasting, welding, and so forth. In such conditions, the valve must be preserved in a safe and approved location to prevent any debris, splatters, or flakes from impacting the valve and causing damage.
When the valve is due for installation, proper preparation activities shall be implemented, including correct orientation, proper positioning, and bolting torques for ends and bonnets.
Prevent potential damage
It is essential to prevent improper practices from causing damages to the valve. This includes welding splatter and debris from contacting the valve trim during all construction and welding events.
Other activities to consider during pre-startup are pigging runs and associated tasks, during which valves must be set at full open flushed and drained from residual particles to prevent any potential damage after and before each run. Valves shall also be seat-lubricated to ensure debris-free internals.
Once the valve passes all the precommissioning-related activities and gets the proper attention, it is now ready for commissioning and operations. The valve then shall also be properly monitored and maintained to ensure safe and functioning conditions across its life span.
To conclude, maintaining the valves before pipeline startup will significantly improve their performance and prolong the design life. Furthermore, it will prevent unplanned project delays and process upsets, which may severely impact the energy supply to end-users. We will utilize future contribution opportunities to discuss best practices in the post-commissioning stage.