IKM was requested to assist with a Secondary Containment Study at a petrochemical storage facility to provide the client with information to help the re-endorsement of tanks within a COMAH Upper Tier site.
The client needed to understand the compliance risk associated with the bund and what engineering works would be required to achieve this.
The tank bunds were adjacent, and both required engineering works to achieve best practice.
A containment study was completed on each bund and included:
• Defect inspections
• Volumetric modelling
• Bund strength assessments
• Reporting against COMAH requirements
Defect reports were produced, and engineering solutions were proposed. The bund strength assessment demonstrated that the bunds had the capacity for resisting hydrostatic load in both short term and long-term load conditions.
It was identified that each bund contained insufficient storage capacity to achieve compliance with the 110% rule.
The initial proposal was to hydraulically link the bunds. As this would have required crossing an existing site road, IKM developed an innovative solution to avoid this.
The engineering team developed a manhole and culvert solution that would contain small spills to a single bund but would supply sufficient capacity to utilize both bunds in the event of a serious break in containment.
This solution avoided the requirement for significant works to individual bunds.
To verify the proposed solution, IKM carried out Computational Fluid Dynamic (CFD) modelling of various tank rupture models, to advise on credible flow rates for the culvert, overtopping volumes and subsequent tertiary impacts.
A report was developed to assist the client in making an action plan for re-inventorying and improving compliance against the COMAH Containment Policy and associated guidance documents.