Underground Fuel Tank Shot Blast & Repair

Our engineers successfully executed specialised surface preparation works on two tanks and manways at a strategic MOD operating base in the South of England.

PROJECT SCOPE

The job included internal and external tank work. Internal work consisted of shot blasting and repair to the coating inside both tanks and three plates cold bonded to Tank 2 due to an identified wall thickness issue. The external work included spot blasting and painting of all external pipework relating to Tanks 1 and 2. REDS engineers blasted back to bare metal where required.

FIRST TANK REPAIRS

Internal Paint

The areas of visible coating failure were blasted back to bare metal (SA 3 spec), with an approx. area of 150mm around the cleaned area. Blasted lightly to feather into the existing coating to allow for better adhesion.

Sherwin Williams Dura-plate UHS was selected for the tank internals due to its edge adhesion for patching.

Manway

Identified areas were blasted back to bare metal (SA 3), the hatch lid was stripped and tested for true, no repairs were required. After observing the water ingress into the chamber, the original paint spec was swapped to the same paint as the tank lining (Dura-Plate UHS) due to better performance underwater.

SECOND TANK REPAIRS

Internal Paint

Areas of visible coating failure were carefully blasted to bare metal, with a 150mm surrounding region feathered for optimal adhesion. Sherwin Williams Dura-plate UHS was selected for tank internals due to its superior edge adhesion. Three areas of the tank shell were below the recommended thickness, this was addressed with a cold weld solution for effective repair.

Internal Repair

The client prohibited hot works repairs due to fuel storage in a third underground tank, with this in mind a petrochemical resistant epoxy bonding solution was chosen. This involved bonding specially prepared steel plates to the shell wall, creating a 98% surface bond.

Areas with shell loss were identified, blasted to bare steel, and repaired with plates fabricated off-site. An emergency repair was conducted for a hole discovered during blasting. After edge bonding and resin injection, grub screws sealed the plates. The repairs were then painted with Dura-Plate UHS.

PAINTWORK REPAIRS

External Paintwork

Any loose areas of paint were rubbed back, and where required, were blasted to bare metal.

Following the spot blasting procedure, the exposed bare metal areas received an application of two coats of Sherwin Williams Macropoxy M902 primer. For all pipework involved, a systematic application of two coats of Sherwin Williams Macropoxy M905 mid/undercoat was carried out, followed by an additional two topcoats of Sherwin Williams Acrolon in Signal Grey.

Project Result

As a result of the internal and external tank work carried out by REDS engineers, the tanks have been refurbished to meet the required standards.

Internally, shot blasting and coating repairs were executed, ensuring structural integrity. Additionally, three plates were cold bonded to address a wall thickness issue in Tank 2.

Externally, spot blasting and painting of all pipework have rejuvenated the tanks’ appearance and durability. With surfaces blasted back to bare metal where necessary.

Assets have now been handed over to the client.

Date Posted: 25/04/2024