Bolted or sectional tanks have been used extensively in the water, waste water and biogas industries due to their cost effectiveness and speed of erection when compared to other tanks. Most commonly the steel panels are protected using glass enamel, epoxy or galvanizing. All of these treatments have a finite lifespan, which when reached or when the surface protection leads to corrosion and in aggressive environments perforations.
In terms of preparation these tanks are very similar to Steel Tanks, however there are some important differences that must be taken into account.
One important difference when preparing these tanks is that there is often an excess of sealant/mastic between panel joints and around bolt heads. This must be removed as this is often compromised hiding corrosion beneath which if left unchecked will continue and lead to perforations.
Where perforations exist these can be repaired prior to the tank lining being applied by bonding or mechanically fixing plates of the same thickness and material.
When selecting a tank lining material for bolted/sectional tanks it is important to consider that due to their sectional nature movement is possible in their structure. Therefore we would always recommend that a flexible tank lining material is specified which can accommodate such movement. This would usually be in the form of a polyurea, polyurethane or flexible epoxy tank lining.
As with all of our tank relining projects the same quality assurance steps would be taken and implemented by our own in house ICORR accredited paint inspector. Once cured our tank linings are tested for pin holing and porosity using a DC holiday spark tester as a pin hole is a point of failure where moisture and chemicals can reach the steel substrate.