Underground Tank Lining: Belfast Case Study
The Task
One of our forecourt clients sought our expertise to extend the lifespan of their ageing tank storages. Five underground vessels, used for storing both petrol and diesel, were successfully relined over a five-week period by four of our highly skilled teams.
Stage 1. Pipework Removal and Preparation
- Upon arrival, our team discovered the tanks were nearly empty, allowing us to expedite the process.
- The Industrial specialist team, in conjunction with our Forecourt specialists, safely removed the remaining fuel and stored it off-site.
- All lids and pipework were removed from the tanks, rendering them offline.
- Subsequently, the confined space and rescue team performed a thorough man-entry cleaning of all five vessels, ensuring they were completely gas-free.
Figure 1. All tanks were rendered offline and thoroughly cleaned out.
Stage 2. Man, Entry Cleaning, Shot Blasting, and Lining Preparation
Once the tanks were thoroughly cleaned and dried, our Coatings & Linings team commenced work.
Over the following four weeks, they meticulously removed the old, worn-out lining from two of the tanks and then all five tanks were shot-blasted and prime to prepare the surfaces for relining.
Figure 2-4. Storage tanks are media blasted and prepared for lining.
Stage 3. Lining & Leak Detection System
Taking every precaution required for the task and ensuring the environments are tested for dew point, the LCM lining team applied a double walled lining system in line with the TUV international standards. The lining was applied on a dry and clean surface, according to the adhesion criteria of ISO EN 18479 for epoxy-based materials.
At first, the LCM team applied the EPOFLEX® first layer by spraying. Once it was cured, the tank was Holiday, Thickness and Hardness- tested; any pinholes repaired upon discovery.
Figure 5. EPOFLEX layer is applied by spraying.
The tank was then drilled, and the team fitted the in interstice monitoring lines.
Figure 6 – 8. Aluminium sheets application.
The application of the knotted aluminium sheets followed – the sheets overlapped approximately 10-15mm and were fixed in place with bio-adhesive tapes. They were then partially laminated, with a woven double layer of fibreglass (450 g/m2) layered on top.
Figure 9-10. The entire surface was sandpapered to even it out and all dust was removed afterwards.
A second layer of EPOFLEX® was sprayed on and left to cure.
Figure 11-13. Second layer applied and pinhole tests complete.
Then the vacuum of the interstice was pulled and a thorough inspection for pinholes was performed. If any pinholes were located, they were swiftly reworked, and the inspection was repeated.
12-hours later, a tightness test was performed on the storage vessels.
Then the conductive coating was applied.
Figure 14-15. Conductive coating applied.
Then the vacuum of the interstice was pulled and a thorough inspection for pinholes was performed. If any pinholes were located, they were swiftly reworked, and the inspection was repeated.
12-hours later, a tightness test was performed on the storage vessels.
Then the conductive coating was applied.
A class 1 vacuum monitoring system was installed at the interstice layer, according to EN13160-2, to ensure ongoing leak detection
Stage 4. Testing, Commissioning, and Client Handover
The leak detection system was thoroughly tested upon completion of the relining process. Our forecourt pipefitting team then reinstalled all lids and pipework.
A series of comprehensive tests were conducted to verify the safety and compliance of the newly relined tank storages. Once our team leaders were satisfied with the results, the site was recommissioned and handed over to the delighted client.
Outcomes:
Relining tank storages offers a more sustainable and cost-effective alternative to complete replacement. By investing in a double-walled lining system, our client was able to significantly extend the lifespan of their tanks, avoid the disruption and expense of excavation, and ensure their continued compliance with safety regulations.
We are proud of our successful collaboration with the Forecourt sector. This project demonstrates LCM’s expertise in linings and coatings and our commitment to delivering exceptional client service.