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Unsafe Site Notification - oil tank not fully supported

The need to provide suitable bases and supports for oil storage tanks both of steel and plastic construction is of paramount importance for reasons of both safety and environmental protectionIf an oil storage tank is inadequately supported, it can be weakened leading to the eventual failure of the oil storage tank and escape of the stored fuelThe homeowner, end user, fuel delivery driver, installer and service engineer can all be at risk from an inadequately supported oil tank. 

An inadequately supported fuel tank, especially when raised above ground poses a very serious safety hazard and threat of injury as a result of a collapse.  

When a 1,500-litre delivery of oil weights over 1 tonne it is easy to understand why fuel delivery drivers must be very careful when assessing the risks involved in filling a tank that may not be supported correctly. 

Suitable oil tank bases include concrete of at least 100mm thickness, paving stones of at least 50mm thickness or stonework or other non-combustible load bearing material of at least 50mm thickness. Materials must be laid on a level prepared surface and provide an imperforate base. 

The overall size of the base should be larger than the oil storage tank including any integral oil storage bund, so that when the tank is in position the base has a clear projection of 300mm minimum all the way around the tank.   For barrel shaped tanks the 300mm must project past the widest point of the tank itself. 


Plastic tanks must be fully supported along the whole underside of the storage tank however steel tanks due to their construction may be supported by several piers with a maximum span of typically 600mm depending on the bottom plate thickness. 

Some tanks may also need to be strapped if there is risk of high winds or flooding if no other suitable location can be found. 

Learn more about unsafe tanks and how you can check your heating oil tank before delivery.