[Tank Cleaning & Decommissioning]

Bund Integrity Testing

      

A Bund containing 1 No. vessel should have a nominal capacity of 110% of the vessel's maximum capacity.  A Bund containing more than 1 No. vessel should have a nominal capacity of 110% of the largest vessel or 25% of the total capacity of all the vessels - whichever is the greater.  Sumps built with double skins (ie an inner and an outer layer) should have no water in between the two layers.

EPA Guidance Document states that Bunds should be designed in accordance with CIRIA Report 163 (1997), The Construction of Bunds for Oil Storage Tanks, which incorporates BS 8007: 1987 Code of Practice for Design of Concrete Structures for Retaining Aqueous Liquids.

Bunds require testing at regular intervals to ensure continued protection of the tanks, drums and other vessels in the bund.  In general, the EPA and local authorities require testing every three years.  Bund Integrity tests will check the water tightness of floor slabs, floor joints and of wall kicker joints.

Lehane Environmental conduct Bund Integrity Testing by means of a water retention test.  This involves filling the bund to a known level and measuring the drop in level over a given time period taking account of a permissable dip in level to allow for evaporation (ie 1/500th of the average water depth of the full bund).

CIRIA 163 is a bund test protocol specifically intended for bunds and is a six hour test.  As the test can be carried out in one working day this reduces the cost and environmental risks compared to longer tests and in situations where longer tests are not viable.

BS8007:1987 (Code of practice for design of concrete structures for retaining aqueous liquids) Section 9 sets out the protocol for bund integrity testing which is a 7 day test.  The bunds are filled with water to the fill level, marked and allowed to stabilise for 24 hours.  After stabilisation, the level of the liquid surface is recorded by means of a photograph at 24-hour intervals for the test period of 7 days.  A daily log for the area is also reported.