ETD is pleased to announce the successful recent completion of an inspection, fitness for service and life assessment project for a European based plant.

In October 2017, microcracks were observed on a welded T-piece of main steam balancing pipe connections. Defect/ crack assessment was performed by the plant engineers and the results showed that the component will be fit for service for another 4 years with the repair of cracks by burring techniques. However, these results were not acceptable by the owners and insisted further analysis would be performed. The results of the second assessment showed that the component should be replaced as early as possible. Due to the disagreement between the owners and plant management, a decision was made that further analysis would be performed by an independent third party and then make appropriate decision for run/repair/replacement of the component. Therefore, ETD were asked to submit a proposal to perform further inspection and analysis to assess fitness for service and predict remaining life and of the component.

ETD proposed to carry out the project in the following two phases. The objectives and scope of work for each phase are:

Phase 1:
(i) Review two previous reports – defect assessment and life assessment reports completed by the client.

(ii) Perform onsite inspection. This will include the followings:

  • On-site replication at 4 clock positions for the affected T-piece of the balancing pipe connection;
  • On-site hardness testing at the same locations as the replication spots;

(iii) Review design and operating parameters, previous failure and maintenance history;

(iv) Perform condition assessment and fitness for service assessment based on the damage classification.

(v) Report covering the results of the investigations & provide recommendations on whether the component is fit for service.

Phase 2:
(i) Perform pipeline stress analysis of the piping system to obtain line loads and bending stresses which will be used in Finite Element (FE) analysis. This will include the following Tasks:

  • Review of design/ isometric drawings clearly showing all dimensions and piping connections of the piping system.
  • Review and analysis of inspection data/ information of hangers and supports collected during hot and cold condition inspection.
  • Perform pipeline stress analysis of the piping system using CAESAR II software.

(ii) Perform Finite Element (FE) analysis to obtain accurate stress levels at the affected T-piece location of the balancing pipe.

(iii) Perform remaining life assessment using the stress values obtained from FE analysis.

A report was then issued detailing the findings with photographic records including results of stress analysis & life assessment and highlighting any possible causes for concern regarding the pipe integrity. Furthermore, the report included recommendations for possible remedial actions that may improve component integrity.

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