Checklist for Pipeline Pre-Commissioning Procedures
Once the construction of a new pipeline is complete, the next critical phase is pre-commissioning. This set of procedures bridges the transition from pipeline construction to full operation, ensuring that the system is clean, safe, and ready to carry fluids or gases under pressure.
If pre commissioning activities are skipped or done incorrectly, the pipeline risks failure, reduced efficiency, and costly downtime. By following a structured pre-commissioning procedure, operators can guarantee compliance, maximize pipeline integrity, and extend the service life of their infrastructure.
Below, we’ve outlined the pipeline pre commissioning checklist that American Pipeline Solutions (APS) follows. Each step highlights its purpose, tools used, and its importance for oil and gas pipelines as well as other industries.
What is Pre Commissioning?
Pre commissioning refers to the series of activities conducted after pipeline construction but before final commissioning. These steps prepare the line for operation by cleaning, testing, drying, and verifying its readiness.
In oil and gas, pre commissioning activities help ensure that pipelines meet safety standards, function at peak performance, and comply with PHMSA regulations. It is different from commissioning, which focuses on introducing the actual fluid or gas into the system and beginning operations.
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Pre Commissioning vs Commissioning
Many operators ask: what is the difference between pre commissioning and commissioning?
Pre commissioning: Involves preparation activities such as pigging, cleaning, testing, and drying. Its goal is to verify that the pipeline is ready and safe.
Commissioning: Follows pre commissioning and includes introducing the pipeline’s intended medium (oil, gas, or water) into service and monitoring its performance.
Both stages are essential, but without thorough pre commissioning, commissioning cannot be successful.
Checklist for Pipeline Pre-Commissioning Procedures
Pig the Line
The first step in any pre commissioning procedure is pigging the pipeline to remove construction debris, weld slag, dirt, and other contaminants.
Pigging improves flow efficiency.
Ensures tests like hydrostatic testing or nitrogen testing deliver accurate results.
Reduces risk of internal damage once the line enters service.
APS uses advanced pigging tools designed for different pipe diameters, ensuring thorough cleaning before the next step.
Gauge the Internal Diameter With a Caliper Tool
After cleaning, APS measures the internal diameter of the pipeline. This step helps:
Compare actual construction against piping and instrumentation diagrams (P&IDs).
Detect dents, ovality, or restrictions that could impair flow.
A caliper pig equipped with mechanical sensors records the pipeline’s internal structure, ensuring it aligns with design standards.
Perform Pipeline Integrity Tests
Integrity testing is one of the most important pre commissioning activities in oil and gas. APS conducts proactive tests to detect weaknesses before they cause downtime or environmental hazards.
Hydrostatic testing: The most common test, verifying that the pipeline can maintain specified pressure levels for a given duration.
Nitrogen testing: An alternative for smaller pipelines or when weather conditions make hydrotesting impractical.
APS uses certified and calibrated digital gauges, recorders, and deadweights to ensure precise results. These pipeline inspection and pressure pipe inspection methods confirm that the pipeline is leak-free and safe for commissioning.
Fill and Stabilize the Line
Before testing, the line is filled with water using a specialized fill pig. The pig removes air pockets that could cause inaccurate test results.
Once filled, the line is pressurized slightly (around 200 psi) and allowed to stabilize for several hours. Equalized pressure and temperature confirm pipeline stability, preparing it for full-scale integrity testing.
Dewater and Dry the Line
Following hydrostatic testing, APS carefully dewaters the pipeline. The same pig used for filling is propelled back through the line with compressed air.
Dewatering is closely monitored to prevent dangerous air pocket formation.
Once water is removed, soft foam swabs and cleaning pigs eliminate any remaining moisture.
The line is dried to the required dew point, often specified as -40°C, using oil-free compressors and desiccant dryers.
This ensures that the pipeline is free of moisture, preventing corrosion and contamination before commissioning.
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Why Pre Commissioning Services Matter
Skipping or rushing pre commissioning services can lead to serious issues such as leaks, blockages, reduced capacity, or environmental risks. By thoroughly cleaning, testing, and drying a pipeline, operators:
Reduce unplanned downtime.
Extend pipeline service life.
Comply with PHMSA and industry regulations.
Ensure smooth and efficient commissioning.
APS specializes in complete pipeline pre commissioning services, providing operators with confidence that their infrastructure is safe, reliable, and ready for operation.
Pre Commissioning Checklist Summary
Pigging: Clean out debris and construction residue.
Caliper tool inspection: Measure and verify pipe diameter.
Integrity testing: Hydrostatic or nitrogen pressure testing.
Fill and stabilize: Remove air pockets and prepare for testing.
Dewater and dry: Eliminate moisture and prevent corrosion.
By following this pre commissioning checklist, pipeline operators can transition from construction to commissioning safely and effectively.
Partner with American Pipeline Solutions
At APS, our team of experts delivers tailored pre commissioning services for oil, gas, and water pipelines. From pigging and cleaning to integrity testing and drying, we ensure your pipeline is fully prepared for commissioning and long-term operation.
Looking for an experienced partner for pipeline pre commissioning? Contact American Pipeline Solutions today for expert solutions that maximize safety, efficiency, and reliability.
FAQs:
What is pipeline pre-commissioning?
Pipeline pre-commissioning is the series of activities completed after construction but before a pipeline enters service. It includes cleaning, gauging, integrity testing, dewatering, and drying to verify that the system is safe, leak-free, and ready for commissioning. APS performs complete pre-commissioning programs that meet PHMSA and industry standards for oil, gas, and water pipelines.
How does pre-commissioning differ from commissioning?
Pre-commissioning focuses on preparing and verifying the pipeline—removing debris, testing pressure integrity, and drying the line. Commissioning begins after those steps, when the intended product (oil, gas, or water) is introduced and monitored under operating conditions. Both stages are essential, but commissioning cannot succeed without proper pre-commissioning.
Why is pigging an important step in pre-commissioning?
Pigging removes construction debris, weld slag, and contaminants that can restrict flow or damage the internal surface. APS uses purpose-built cleaning and gauging pigs sized to each line diameter. Effective pigging ensures that hydrostatic or nitrogen tests yield accurate results and prevents internal corrosion once the pipeline begins service.
What integrity tests are performed during pipeline pre-commissioning?
APS performs hydrostatic or nitrogen pressure tests to verify pipeline strength and leak-free performance. Hydrotesting fills the line with water to a specified pressure for a set duration; nitrogen testing is used when hydrotesting isn’t practical. Certified digital gauges and recorders document results to confirm compliance and readiness for commissioning.
How are pipelines dewatered and dried after testing?
After hydrotesting, APS propels a fill pig back through the line using compressed air to remove water. Foam swabs and cleaning pigs follow to eliminate residual moisture. The pipeline is then dried to the required dew point—often around -40 °C—using oil-free compressors and desiccant dryers to prevent corrosion and contamination.
What happens if pre-commissioning is skipped or rushed?
Omitting or rushing pre-commissioning can lead to leaks, corrosion, poor flow, or inspection failures. Contaminants left in the line may damage equipment or shorten pipeline life. APS’s structured procedures reduce downtime, ensure regulatory compliance, and confirm that each system is fully prepared for safe commissioning and long-term operation.
How does APS ensure accuracy and safety during pre-commissioning?
APS technicians use calibrated instruments, documented procedures, and safety controls such as differential-pressure monitoring and confined-space protocols. Every step—from pigging to drying—is verified against acceptance criteria and recorded in a closeout package that supports PHMSA compliance and client integrity programs.
What types of pipelines can benefit from APS pre-commissioning services?
APS supports oil, gas, refined-product, water, and industrial pipelines ranging from small-bore facility lines to large-diameter transmission systems. Whether it’s a new build or rehabilitation project, APS tailors cleaning, testing, and drying procedures to the pipeline’s material, length, and service conditions.
Looking for an expert in pipeline pre-commissioning services?
Contact American Pipeline Solutions and receive a timely and affordable solution today.
