The following Australian Standards are to be considered when decommissioning, abandoning or removing tanks:
- AS1940–2004: Storage and handling of flammable and combustible liquids (AS 2004)
- AS4976–2008: Removal and disposal of underground petroleum storage tank (AS 2008).
These standards identify industry best practice procedures and OH&S considerations when a tank is decommissioned, abandoned or removed.
In general, tank removal when they are no longer in use is preferred industry best practice. However, where tanks are to remain in situ, the disused UPSS should be emptied and decommissioned and records kept of the methods used and the size, description and location of the tanks. Reports must be provided to WorkCover and the relevant local authorities.
An industry-recognised specialist and licensed contractor with knowledge and experience in the field of tank removal (a ‘duly qualified person’ under the UPSS Regulation) should be engaged to remove UPSS. They should be able to provide a comprehensive range of works and appropriately document the removal of tanks and supporting infrastructure.
Tank removal should include the recording of any evidence that a leak has occurred, whether contamination is present within the excavation and all containment and mitigation measures undertaken at the time of the removal. A photographic and/or video log of the event is strongly recommended, as well as field screening of materials to assist in sample assessment during and immediately after tank removal.
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Some of the more common observations during removal include:
- evidence of tank or pipe failure via holes or corrosion
- evidence of odours, staining or sheen within the excavation pit or the collection of water in the pit
- the use of incompatible UPSS materials for the product being stored
- incompatible geotechnical conditions, such as reactive or collapsing soils
- evidence of human error, such as inadequate system management, poor installation, damage, tank filling activities, loose fittings and spills
- bent, damaged or unsuitable tank dipping or gauging equipment, such as perforations of the lining of the tank by dip sticks.
- The procedure to be followed should be planned and documented before tank removal gets under way. This should include contingencies to deal with any contaminated soil or groundwater which may be encountered and any other related site-specific issues, such as shallow groundwater in the area.
Consideration should also be given to the requirements of the relevant dangerous goods legislation when transporting disused tanks.
Source: State of NSW and Department of Environment, Climate Change and Water NSW
UPSS Technical Note:Decommissioning, Abandonmentand Removal of UPSS
ISBN 978 1 74232 518 7 DECCW 2010/36 January 2010
If you need removal of an underground storage tank, contact Australian Enviro Services.