Most domestic oil tanks can be of single skin construction but in some circumstances to comply with current legislation they need to be bunded if:

• They are within 10 metres of a controlled water course i.e. Stream, river etc.
• Within 50 metres of a bore hole or spring.
• Where a spillage could run into a drain or loose fitting manhole cover.
• If the vent pipe is not visible from the fill point, as in an offset fill.
• Any other potential hazard to the individual site.

Building Regulations part 1. Single family dwellings where the heating system does not exceed 45 kW and storage does not exceed 3500 litres the tanks require:

• Fireproof base extending 300mm outside the tank on all sides except the side next to an approved type of building or boundary wall, or a fire screen wall. If located more than 1.8 metres from a building or 760mm from a boundary – no other protection.
• Any combustible eaves within 1.8 metres of the top of the tank, and for a further distance of 300mm on each side must be given 30 minutes fire resistance.
• Any part of the tank within 1.8 metres of an opening in a building wall must be protected by a 30 minute fire screen wall. Small openings such as airbricks do not count as openings requiring protection.
• Any part of the tank next to a wall with a resistance to internal fire of less than 30 minutes must be protected by a 30 minute fire screen wall.