A single skin oil tank consists of a single container in which fuel is stored. Single skin oil tanks are not suitable for the storage of fuel at commercial, industrial or institutional premises, or at domestic installations with an installed capacity of over 2,500 litres – unless installed within a suitably bunded area. For all other installations, an Oil Tank Risk Assessment must be undertaken by a competent person prior to installation and in accordance with the requirements of OFTEC Technical Instruction Book 3. In anticipation of future possible regulations, serious consideration should be given to fitting a Bunded Tank, even where a single skin tank may currently suffice.

A Bunded Tank simply consists of an ‘oil tank within an oil tank’. In the event of a spillage, surplus liquid will collect in the outer tank, thus averting a pollution incident. Bunded Tanks are now required at commercial, industrial, institutional and most domestic premises.

All oil tanks must be installed on a flat, level and fire resistant base capable of supporting the weight of the tank when fully laden. If concrete slabs are used they should be a minimum of 50mm thick and are laid so that the tank weight is evenly supported. The base should extend at least 300mm beyond the widest points of the tank and fully support the base of the tank in its entirety. Piers or pillars are not suitable for this purpose and can cause irreparable damage to the tank.