Pipeline reinforcement is performed to increase the pipe wall thickness in non-leaking pipe defects. These defects occur due to external corrosion or damage, dents, gouges, fretting or use at supports, internal corrosion and/ or erosion, manufacturing or fabrication defects. The Objective of pipeline reinforcement is to rebuild and increase the pipe wall thickness so that the resultant pipe mechanical strength is sufficient to resist operating conditions.
Especially in industries where hot works are not easily permitted, the implementation of pipeline reinforcement via cold repair works are useful in the repair and rehabilitation works of pipelines.
Pipeline Data & Operating Conditions
Before carrying out an effective pipeline rehabilitation and reinforcement work, pipeline data and operating conditions are gathered. These data are reviewed and evaluated under international standards and guidelines such as ASME PCC2 and ISO 24817 standards and requirements, to design an effective and appropriate pipeline repair and reinforcement solution.
Detailed Engineering Calculation and Application Method of Statement
Based on the pipeline data gathered, the manufacturer would design and provide a detailed engineering calculation and application technique for the pipeline repair and rehabilitation works. It is also necessary to ensure that the applicator is well-trained to apply the pipe repair wrapping products in addition as a site risk assessment has been performed prior to work commencement. Proper Personnel Protective Equipment should be worn and risk mitigating/ reducing steps employed to minimize or avoid all unnecessary risks.
Step 1 – Preparing, Cleaning and Roughening of Pipe Surface
Pipe surface should be cleaned and prepared to minimum standard of St2.5. This is to ensure good bonding between the repair resin with the substrate (pipe surface). The pipe surface profile is also roughed to meet the minimum of 60 microns roughness. Once the pipe surface has been cleaned and roughened, pipeline repair and rehabilitation works should commence closest.
Step 2 – Rebuilding to ensure Flushing of Pipe Surface
The first step in all rehabilitation works is to ensure that all pipe surfaces have been rebuilt so as to ensure surface being flush. The resin or metal putty compound is well-mixed in accordance to manufacturer’s instructions and applied onto the affected surfaces while ensuring there are no air entrapment. The repair compound is applied according to the required coating thickness and repair length stated in engineering calculation.
Step 3 – Pipeline Reinforcement via Pipe Wrapping
The final step is to pipe repair and reinforcement is wrapping of the reinforcement repair tape. Start wrapping the reinforcement repair tape over the pipe circumference just before the defect location. At each round of wrapping, wrap the pipe as firmly and uniformly as possible while pulling with sufficient strength. Ensure there is 50% overlap to the past wrapping inner. Repeat the wrapping based on the Engineering Calculation Report. The wrapping direction can be alternated between later layers of wrapping to increase its final mechanical strength.
Inspection of Pipeline Repair & Reinforcement Works
Inspect the strengthened pipeline for any visual defects. Check that the repair thickness and length complies with the requirements stated in the Engineering Calculation. Allow the repaired area to be cured for several hours and the reinforcement work is completed.