Bunds are secondary containment vessels that prevent chemicals and other liquids from escaping in the event that primary containment fails. Bunds are used in tanks and pipes to bolster containment and assure health and safety.
A bund lining lines the bund to make it impermeable, fabricated from a material that is inert to the chemicals or liquid it stores.
The two most common materials are GRP (glass-reinforced plastic) linings and 2-part epoxy linings, with GRP favoured overall for its longer lifespan.
When specifying a bund lining, we must consider the type of chemicals and liquid stored, volume, pressure and temperature. The same criteria apply with bund lining repairs and when refurbishing a bund lining to ensure optimal performance.
Signs your bund lining needs repairing
Bund linings can be damaged by various things including impacts, weathering, prolonged exposure to chemicals, and extreme temperatures.
Here are some of the signs your bund lining needs repairing:
- Unsealed joints and gaps: Insufficient waterproofing around pipes entering the bund can create leakage.
- Cracked walls: Cracks in the bund are a sign the bund is compromised. Cracks should be inspected immediately.
- Vegetative growth: Vegetative growth, including mould and fungus, is a sign that the bund is improperly sealed.
- Contaminated walls and floors: A damaged bund will leak liquid, or if the liquid is too large to escape, it will leak vapour.
When to repair
Bund linings should be inspected when damage is first detected. It is good practice to deactivate the vessel when damage is suspected, using procedures to safely drain the vessel so that an inspection can be performed.
When a bund lining is compromised, there is a direct risk to the containment vessel, operational uptime and health and safety. Repairs should be performed swiftly. Sometimes, it is possible to patch a lining but not always.
Any repair should return the bund lining to previous performance. For example, if a crack has formed in epoxy, the epoxy will need resealing to the same standard as it was installed.
Sometimes, bund linings are beyond repair. After 10-20 years, epoxy breaks down and needs replacing. GRP offers a longer lifespan, which is why we recommend GRP whenever it is suitable for the chemicals/liquids stored.
How to repair a bund lining
Bund linings are repaired onsite. The first step is cleaning the vessel with water or grit blasting to inspect the damage. If the lining can be repaired, the repair area is thoroughly cleansed to ensure it’s ready for repair.
- With GRP bund repair, we cut out the old GRP and install new glass fibre mat. It is then saturated in polyester resin. Once cured, a resin topcoat is applied. When dry, the repair is functional and the bund is ready to use again.
- With GRP bund refurbishment, we remove the old bund lining and install new timber decking. GRP trims are then installed along the edges on a solid substrate. Glass fibre mat is installed, the mat is saturated in resin, and a topcoat is applied.
Bund lining repairs should be carried out by trained professionals specialising in bund linings. Bund linings are specialised structures that require engineered substrates with a defined specification for the intended application.
To comply with health and safety guidelines, bund linings should be chemically inert and impervious to liquids. GRP is the best choice for most applications, but a 2-part epoxy resin can be used in applications that demand more flexibility.