Environmental Efficiency has many years experience in Bund Wall Design & Construction. The purpose of a bund wall is to provide containment for oil tanks or drums in the case of a leak. Bunds therefore need to be correctly designed to provide adequate containment.
Bund Wall Design & Construction
The video below explains some of the rules for bund wall design & construction such as determination of the correct bund capacity, bund wall height, rainwater removal and how to deal with jetting failure. These rules are summarised below site operators should be aware that some regulators may have different requirements.
In general, the required bund capacity is the greater of
- 110% of the largest tank and
- 25% of the total tank capacity
Compact bund designs can be achieved using high walls, however, for firefighting and ease of access the wall height should be limited to 1500 mm. It should be noted that for ease of maintenance the minimum tank to wall distance should be 750 mm. Some regulators will require that jetting failure be also taken into consideration.
Most authorities state that bunds should be constructed of reinforced mass concrete (RMC). These bunds have the lowest failure rate. Bunds built of hollow core block built can leak water between and through the blocks and this is a common failure mode. For drums and small tanks, prefabricated bunds made of plastic or steel can be used.
The accepted design standards for masonry bunds include BS8007 and CIRIA163 but some regulators may prefer one standard over the other.
Newly constructed bunds should always be tested hydrostatically before tanks and other equipment are placed in the bund. Once in service, the integrity of bunds should be assessed regularly. This is either by hydrostatic testing or visual inspection, the preferred method depends on the regulator and the jurisdiction.
What guidance is available?
For sites in England, Wales, Scotland and Northern Ireland the legal requirements are listed in PPG2. For sites with licences issued by the Irish EPA, the requirements are listed in the Agency’s document IPPC Guidance Note on Storage and Transfer of Materials for Scheduled Activities. Design guidance can be found in CIRIA 163 and BS8007.