The Need for Nitrogen Testing
A midstream operator was looking to pneumatically test its gas processing line. Due to the structure of the line, the line was classified as non-piggable. This meant it would be difficult to conduct a hydrostatic test as there was no guarantee that all the water could be removed. Knowing the drying requirements for this line could not be met and to prevent any gas processing issues, the client requested a nitrogen test to be conducted.
Nitrogen testing can be riskier than hydrostatic testing due to the stored energy in the line. PL Testing took a comprehensive approach to address client needs and ensure safety throughout the testing process. This included developing a full risk assessment and test plan, addressing leakage concerns.
Risk Assessment and Planning
PL Testing developed a full risk assessment document with requirements to conduct an integrity test on connections. Additionally, the client was required to undergo ASME PCC-2 certification for stored energy and blast radius. This assessment also included a materials review.
Address Leakage Concerns
Any failure of the line during the testing can lead to significant consequences. It was crucial to ensure flange and seam integrity to prevent leakages. If anything in the system leaked, it would lead to days of repair work for the client. Prior to the nitrogen testing, butt welds were examined through radiography testing to make sure they were sound. The flange integrity was inspected during nitrogen testing to ensure they were bubble-tight with no leaks.
Successfully Testing the Line
Through proactive risk management and planning, the client’s line was successfully tested and verified while remaining dehydrated. The client received the following benefits:
- Successful nitrogen testing of its line
- Fulfillment of strength test requirements
- Verification of all connections to be bubble-tight
- Confirmation of all butt welds through radiography testing
