The installation of a new Glass Reinforced Epoxy (GRE) saltwater system at a chemical processing site required comprehensive support layout planning and stress assessment. This system included several extended piping lines, both above ground and buried, as well as multiple compact manifolds situated between tanks and pumps. The Dynaflow Research Group (DRG) conducted the initial stress analyses and designed the support layout. Additionally, a field inspection was carried out during construction to evaluate the installation of supports and bellows, resulting in several recommendations for improving the setup.
Analysis
The initial stress analysis was performed according to the ISO 14692 standard for GRE piping. One significant challenge was the presence of compact manifolds combined with multiple nozzles. The support layout was designed based on the system routing provided, considering potential support locations and structures to create a realistic model and minimize unnecessary supports. The CAESAR II piping software was employed to calculate piping deformations, stresses, and loads.
The analysis included various load types: sustained, operational, occasional, and hydrotest loads. Data from the GRE piping supplier was used to establish the applicable stress envelope, ensuring that allowable loads were not exceeded and evaluating stress values accordingly. Additionally, flange loads were assessed using the conservative equivalent pressure method.
Field Inspection and Recommendations
A field inspection was conducted to review the installation of supports and bellows. This inspection led to several valuable recommendations:
Hydrotest Procedures: During hydrotesting, the closing of vertical lines resulted in excessive stresses due to the weight of the liquid column. It was recommended that vertical lines remain open during hydrotesting to mitigate these stresses.
Support Installation: Most supports were correctly installed as per the submitted drawings. However, further advice was provided regarding the impact of shock loads on supports and bellows. Proper installation of supports, including tie-rods, was emphasized to handle shock loads effectively.
General Recommendations: Additional suggestions were made to enhance the overall execution of the support installation and address any observed issues related to the support structures and bellows.
Conclusion
The combination of thorough stress assessment and field inspection ensured that the GRE piping system was installed with appropriate support layouts and stress management strategies. The recommendations provided during the field inspection contributed to optimizing the system’s performance and durability.
