A bund or secondary containment is a structure that is designed to contain leaks or spills from a tank or vessel – the primary containment.  A bund lining is surface treatment designed to either protect the bund structure or improve the fluid tightness of the bund.

Why do bunds need lining?

Not all bunds need to be lined. Typically a bund will be lined if an aggressive chemical is to be stored in the bund that would attack the structure. A typical example would be a concrete bund that is containing a tank that stores a strong acid such as Hydrochloric acid. In the event of the tank leaking or rupturing the acid would quickly attack the concrete, compromising the ability of the bund to effectively contain the spill.

Another common reason for lining a bund would be that during periodic testing and inspection defects in the structure have been identified – typically cracking or fluid egress. By making repairs and applying a suitable lining the bund can be made compliant again and remove the risk of environmental damage from occurring in the evet of a leak or a spill.

Selecting the correct bund lining

There is no one size fits all bund lining system. Careful consideration needs to be given to issues such as the following;

  • The chemicals present and how they will be stored within the bund. Different bund linings have different chemical resistant properties that may make them unsuitable for different chemicals.  How the chemicals are stored can also affect the suitability of a given bund lining.
  • The condition of the bund – previous contamination of the surfaces to be coated, cracking or potential movement in the bund structure need to be considered to ensure fluid tightness is maintained.
  • Access – is the bund going to be trafficked by pedestrians or vehicles? If so a slip resistant finish may be required to allow safe access.
  • Clean Up /Response Time. A combination of factors above may mean that one type of bund lining has benefits that are required, however this may be at the cost of chemical resistance. Some clients are very proactive in their response to spills, however some sites are remote and clean up may be delayed.

As a typical rule a flexible bund lining is always desirable where possible when lining concrete and brick bunds as they offer some accommodation of future cracking or movement should it occur. However as a general rule flexible bund linings have lower levels of chemical resistance.


Types of Bund lining we apply?

Because there is no one bund lining that is suitable for all secondary containment applications, we are able to apply a wide range of bund linings depending on the application and recommendations from our trusted suppliers. These include but not exclusively;

  • Epoxy Bund Linings
  • Polyurea Bund Linings
  • Fibreglass bund linings
  • Highly chemical resistant bund linings, typically using a vinyl ester resin system

The Bund Lining Process

A typical bund lining project will often involve the following stages to ensure a successful application;

Often bunds which have been in use will be contaminated by the product contained within them. Materials like oils, greases and fats will prevent adhesion of the new bund lining, so these must be removed before bund relining works can commence. We have a variety of methods for cleaning including steam cleaning, pressure washing and in extreme cases our own ultra high pressure water jetting equipment. Waste streams produced from this stage of the bund lining process need to be contained and correctly disposed of in accordance with environmental regulations.

Both new and bunds which have been in service require the correct preparation to ensure adhesion of the new bund lining. New concrete structures have a layer of poorly adhered laitance that must be removed. Existing bunds may have old and poorly adhered linings that require removal. Any bund lining is only as good as the surface to which it is applied to – good preparation is essential if a bund lining is to last. Typical preparation techniques include the following;

  • Abrasive blasting
  • Water entrained abrasive blasting
  • Water Jetting and Ultra High Pressure Water Jetting
  • Vacuum controlled diamond grinding

Like the bund lining material itself the preparation methodology needs to be carefully matched to the requirements of the coating specification being applied and site requirements. For example abrasive blasting is an excellent method of surface preparation, however it creates large amounts of dust that can be harmful to health and disrupt site operations. Through our over 30 years of being in business we can help guide and select the best preparation methodology for the bund lining application.

Existing bunds often have cracks or areas of degradation that require repair. These repairs can be made using cementitious or epoxy repair materials depending on the repair requirements. Something that is often overlooked when applying linings to new bunds is that blow holes in the concrete need to be filled prior to the application of the bund lining. Blow holes cannot be filled with coatings alone, something many contractors overlook.

Different bund lining materials have different conditions that must be adhered to in order to ensure a successful lining application. These conditions specified by the manufacturer must be referenced from the technical data sheets and strictly adhered to. The moisture content of the substrate should be checked and recorded and the climatic conditions with regard to temperature, relative humidity and dew point checked and recorded as per best bund lining practice. Climatic monitoring must take place before and during the bund lining application to ensure compliance with the manufacturers recommendations.

The method of application of the bund lining can vary depending on the material specification and the size and type of application. Some lining materials such as fast set polyurea and polyurethane materials have to be spray applied using specialist plural spray equipment. Some bunds may be too small or cluttered with equipment to enable spray application. Much like the material selection and the preparation method we use our experience of applying bund linings to select the most appropriate application methodology for the specific bund lining application.

During application process the thickness of the lining material being applied is carefully monitored, typically using wet film thickness combs to achieve compliance with the lining manufacturers recommendations. Typically bund linings are applied in two or more coats/layers, however we have access to ultra high build materials that can be applied in a single coat/layer application.

To verify that a bund lining is fully sealed typically the new lining will be checked for porosity using a DC Holiday spark tester. This identifies any breaks in the coating using a high voltage and low current. This is essential where the bund will contain aggressive chemicals as a single pin hole is a point of lining failure.

On metallic substrates the final thickness can be checked using dry film thickness gauges against the lining manufacturers specification.

Nearly all bund lining materials have prescribed curing periods that must be observed at specified temperatures before the lining can be exposed to chemicals. This needs to be considered when planning the works in allotted programme time. Ultra fast curing polyurea bund linings and fast set epoxy coatings can be returned to service in less than 24 hours, however these may not be suitable for all chemicals and applications.

Why choose Corroless Eastern for your Bund Lining project?

  • Established – we have been applying bund linings since 1992, meaning you can benefit from our significant experience
  • Quality – We are UKAS ISO9001 accredited, employ 5 ICORR trained paint inspectors and have our own in house ICATS (Industrial Coating Applicator Training Scheme) trainer
  • Safety – We are Achilles UDVB, Constructionline Gold and Safe Contractor approved.
  • Capable – We own our own Ultra High Pressure water jetting, Blasting, Polyurea and plural spraying equipment. This means that we can prepare and apply almost any bund lining specification.