Bund integrity testing is fundamental because the purpose of a bund is to provide containment for tanks or drums in the case of a leak. It is therefore important that bund integrity testing be carried out before a bund enters service and then assessed for integrity on a regular basis thereafter.
Integrity assessment of newly built bunds
Bund integrity testing by means of a hydrostatic test should always be carried out on new bunds before they enter service.
Integrity assessment of in service bunds
For in-service bund, the method of bund integrity testing depends on the regulator. In Ireland, the EPA’s preference is for hydrostatic testing unless there are valid safety or practicality issues in which case a visual inspection may be carried out by a Chartered Engineer.
In the UK, the COMAH-Containment-Policy states that hydrostatic testing of in-service bunds is not best practice due to dangers in tank stability and also because water can be forced under the base of the tank which will lead to corrosion problems. Visual inspections are therefore preferred in the UK for bund integrity testing.
Assessment by Hydrostatic tests
The procedure for hydrostatic bund integrity testing requires the bund to be filled with water and the drop in water level to be measured over a defined period. There are two standards for hydrostatic testing, BS8007 and CIRIA 163 with the latter standard being a much shorter test.
Bund integrity testing by visual inspection entails the examination of the bund for cracks, holes, and other defects which may cause a loss of integrity. Examples of defects include exposed rebar, unsealed pipes passing through bund walls and unplugged shuttering bolt holes. In both Ireland and the UK the inspection must be by a competent person such as a Chartered Engineer.
Environmental Efficiency carries hundreds of bund visual assessments every year across the UK and Ireland. Where necessary Environmental Efficiency can fill bunds with water and dispose of afterwards.
In addition to bund integrity assessments, Environmental Efficiency can advise on bund design, pipeline testing and Firewater Retention Assessments
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.