What are the base requirements for Storage Tanks?

As a minimum, all plastic oil tanks should be installed on a flat, level, fire resistant surface, capable of supporting the weight of the tank when fully laden. Where concrete slabs are used, they should be at least 42mm* (recommended 50mm) thick.

The base should extend at least 300mm beyond the widest points of the oil tank and fully support the base of the oil tank in its entirety. On plastic tanks, piers are not suitable for this purpose and will cause irreparable damage to the oil tank, possibly resulting in premature failure and catstrophic product loss.

Detailed oil tank base requirements can be found within OFTEC Technical Instruction Book 3.

The relevant Oil Storage Regulations should be observed in all instances. For more information visit www.oilstorageregs.org


Section J of the Building Regs

It is unlikely that a fire could be started by a fuel storage tank and it’s contents, However it does need to be protected from a fire that may originate nearby.

For example, tanks should be sited:

  • On a solid non-combustible base, level and at least 42mm thick*, that extends a mimimum of 300mm around the footprint of the tank and is able to support the tanks weight when full.
  • 1800mm away from non-fire rated eves of a building
  • 1800mm away from openings (such as doors or windows)
  • 1800mm away from any appliance flue terminals
  • 1800mm away from a non-fire rated building or structure (ie: garden shed)
  • 760mm away from non fire rated boundaries (ie: wooden fence)

If it is not possible to meet these requirements, a fire rated barrier with at least 30 minutes protection should be provided, extending 300mm higher and wider than each applicable face of the tank.

Download a copy of Section J of the building regulations.

Commercial Requirements

OFTEC recommend that non domestic tanks equal to or below 3500L capacity should be located a minimum of 2m away from any buildings or boundaries. (6m for tanks above 3500L capacity).

If this is not possible, walls or barriers of at least 60 minutes resistance which extend 900mm beyond each applicable face of the tank should be used. (120 minutes rating for tanks above 3500L capacity).

All commercial tanks over 200L capacity should be bunded if stored outdoors. Steps should be taken to help minimise the risk of accidental impact. Please refer to the Oil Storage Regulations for more information

Planning Permission

Domestic users will need to apply for planning permission to install a heating oil tank when:

  • Greater than 3500L capacity
  • Higher than 3m above ground level
  • Nearer to the public highway than the closest applicable corner of the property**

Planning permission is also required for any domestic storage tank for fuels other than for oil fired heating applications (ie: LPG).

If you are installing an oil tank and/or connecting pipe work and you employ an installer registered with one of the related competent person schemes, you will not need to involve a Building Control Service

Further Reading

OFTEC T19 - Domestic Oil Tank Bases (Construction & Design)
Covers Class 1 installations, (domestic tanks up to 3500L capacity), details information on: Location, Safety aspects & Environmental considerations. Includes information on Concrete, Lintel & Paving Slab base construction.
T19 oil tank base construction

* 50mm thick if using slabs. Tanks over 3500L capacity should be placed on a re-enforced concrete base a minimum of 100mm thickness. If in doubt contact our technical team on +44 2380 231 007

** does not apply if proposed site is greater than 20m from the nearest public highway

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