FAQs on oil storage tanks
What types of oil storage tanks are available?
There are three generic types of oil storage tanks available for use in different applications such as single skin (which may be installed in a reinforced concrete or masonry bund), double skin (predominantly commercial underground applications (USTs)) and integrally bunded (above ground and within buildings). Oil storage tanks are constructed of steel or polyethylene and can be supplied in a range of shapes and sizes to suit the site requirements.
What is a bund?
A bund (or catchpit) is a secondary containment system designed to prevent fuel loss from the tank escaping to the environment. Bunds may be constructed from masonry or concrete to contain a single skin oil storage tank and must be able to hold at least 110% of the tank’s contents in the event that a leak or overspill occurs. Integrally bunded oil storage tank systems are available and provide a practical solution to satisfying environmental protection requirements.
Does a domestic oil storage tank require secondary containment (bunding)?
Building Regulations for England and Wales requires all domestic oil storage tanks exceeding 2500 litres capacity to be provided with secondary containment (bunding). The bunding of oil tanks not exceeding 2500 litres capacity is dictated by the outcome of an individual site pollution risk assessment. Only when there is no risk of oil reaching for example, a watercourse, water extraction point or aquifer following a release of oil from the tank may a single skin tank be considered.
We will be able to perform a fire and pollution risk assessment and advise on the type of tank most suitable for an installation.
What is controlled water?
Controlled Waters can be defined as the following: Rivers, streams, lakes, canals, coastal waters, estuaries and groundwater. This means all water which is below the surface of the ground in the saturation zone and in direct contact with the ground or subsoil.
For the purposes of an oil tank pollution risk assessment, consideration should also be given to any ditches, Soakaway, septic tanks and gullies which could pollute groundwater or reach controlled waters. Environment Agency defined Special Protection Zones (water abstraction points and aquifers) should be equally protected.
What fire separation distances apply to domestic oil storage tanks?
For details surround fire separation requirements for domestic oil storage tanks serving fixed combustion appliances, please see the OFTEC Easy Guide to Domestic Oil Storage.
What fire separation distances apply to non-domestic oil storage tanks?For details surround fire separation requirements for non-domestic oil storage tanks serving fixed combustion appliances, please see the OFTEC Easy Guide to Non-Domestic Oil Storage.
Can screening be erected to disguise an oil storage tank from view?
Yes, screening of domestic oil storage tanks is permitted. However, consideration should be given to providing service access for inspection of the tank and filter maintenance, etc. British Standard 5410: Part 1: 1997 requires that a minimum of 600 mm separation be provided between a tank and screening. If the screening forms part of the property boundary a 760 mm separation should be provided unless a fire barrier is erected.
Can a domestic oil storage tank be installed internally?
Yes, British Standard 5410: Part 1: 1997 does permit a domestic oil storage tank up to 3500 litres capacity to be installed within a building so long as the tank is provided with secondary containment, such as an integrally bunded oil storage tank, contained within a 60 minute fire resistant chamber and is located at the lowest possible level. The chamber should contain nothing but the tank and be ventilated to outside.
Can a domestic oil storage tank be installed underground?
Yes, however the installation of domestic underground oil storage tanks (UST’s) do not fall within scope of Building Regulations. If a UST is to be directly buried below ground it should be specifically constructed for underground use and should be installed strictly to the manufacturer’s instructions. In addition, the recommendations in Pollution Prevention Guidance note PPG 27 should be followed and planning permission may also be required.
If an oil storage tank is removed from its base temporarily, for example to repair the base and piers, would I be allowed to reinstall the original oil storage tank as it was before or would I have to treat this as a new installation?
Yes, but OFTEC would recommend that all oil storage tank installations should be compliant with regulatory requirements and industry guidance. However, the installation of a ‘new’ or ‘replacement’ oil storage tank would fall within the scope of the Building Regulations.
Is the support offered by the oil storage tank base really that important?
Yes, the need to provide stable bases and supports for domestic oil storage tanks both of steel and plastic construction is of paramount importance for reasons of both safety and environmental protection. If an oil storage tank is inadequately supported the oil storage tank itself can be weakened leading to the eventual failure of the oil storage tank and escape of the stored fuel. During the life of an installation an oil storage tank base will need to provide continual structural support even though ground conditions may alter from season to season and year to year.
What material should the oil storage tank base be constructed of and what dimensions does it need to be?
Types of base materials, as listed in British Standard 5410: Part 1: 1997 to achieve this protection, include concrete of at least 100mm thickness, paving stones of at least 42mm thickness or stonework of at least 42mm thickness (all laid on a hardcore base to give an imperforate base). The overall size of the base should be larger than the oil storage tank and any integral oil storage tank bund, so that when the oil storage tank is installed, the base has a clear projection of a minimum of 300mm around all sides of the oil storage tank.
Why is the tank base required to extend 300mm around the perimeter of the oil storage tank?
The fire protection provided by the base, is to help prevent the installation itself from becoming overgrown and to help protect against fire spreading across the ground to the contained fuel, from another source. If the tank is raised on piers, the platform supporting the tank should be sized to sufficiently support the tank. Reference should be made to the tank manufacturer’s installation instructions.
What is the purpose of a remote fill pipe?
Remote fill pipes are provided for oil storage tanks sited in excess of 30m from a road, or where there is restricted access generally. For domestic installations this would generally take the form of a 50mm steel pipe connected to the tank and routed to an accessible position. The pipe should incorporate a screw cap at the fill point, a gate valve, a non-return valve and be adequately supported. Due to increased risk of spillage during filling process, the tank it serves should have secondary containment, such as an integrally bunded oil storage tank, and should be fitted with and overfill prevention device. An audible overfill alarm is also recommended.
FAQs on oil fired boilers
Does a new or replacement oil fired boiler installed within a domestic property need to be of the condensing type?
Oil fired boilers need to be of the condensing type unless formally exempt by the completion of an OFTEC CD/30 form which would be completed by the installer,
What condensate drain options are available?
Suitable condensate drain points are, Internal stack pipeWaste pipeExternal drain or gullyRainwater hopper that is part of a combined systemPurpose made Soakaway
Is it possible to replace an oil fired appliance but keep the existing oil storage tank?
Yes, there is no legal requirement, on appliance change, to upgrade an existing oil storage tank to meet current legislation providing that the appliance installation works does not make the oil tank any less compliant than it might be already. However, if you were unfortunate enough to suffer a fire or pollution incident, non compliance may bring about complications with an insurance claim. Our best advice would be for you to also consider upgrading your oil storage tank at the time of appliance replacement.
FAQs on Oil Supply Pipes
Is it likely for kerosene oil to freeze during the winter months?
No, the Cloud Point of Class C2 Kerosene to BS 2869 is minus 39 degrees C. Therefore, unless the location of an oil pipe is extremely exposed to wind chill, it is very unlikely for temperatures to plummet low enough within the British Isles to cause Class C2 Kerosene to freeze.
If a blocked oil supply pipe is encountered during the winter months, a more likely cause is that the oil line contains beads of water that have frozen, expanded and blocked the pipe.
Our best advice would be for an OFTEC Registered Technician to inspect the oil storage tank for the presence of water. If water is found, methods of extracting the water to prevent a reoccurrence can be looked into.
Can oil supply pipes be buried?
Yes, oil supply pipes can be buried with caution,
Can plastic oil supply pipe be used above ground at my home?
No, approved types of plastic oil supply pipe should only be installed below ground.
Can galvanised pipe be used as an oil supply pipe material?
No, because this increases the risk of electrolytic corrosion of dissimilar metals.
Are soft soldered joints permitted on copper oil supply pipes?
No, joints in copper oil supply pipes should be made with compression fittings, either Type A nut and olive with inserts or Type B flared as required by British Standard EN 1254: Part 2.
Can PTFE tape be used for joints in oil supply pipes?
Yes, however PTFE tape should only be used to ‘pack’ the thread out to ensure a firm joint is made.
PTFE tape should always be used in conjunction with an oil resistant soft setting jointing compound.
Is it ok to have flexible oil pipes exposed outside of the appliance casing?
No, British Standard 5410: Part 1: 1997 requires oil supply pipes within a building or above ground externally to be constructed of steel or copper. Unless the flexible oil pipes have an equal degree of fire rated resistance to that of steel or copper (to be declared by the manufacturer) it should remain concealed within the appliance casing where it is protected by a remote fire valve.
Is there a maximum length that the oil supply pipe must not exceed?
Generally, there is no limitation as to the maximum length of oil supply pipe between an oil storage tank and an appliance as long as the supply pipe is correctly sized and designed for the application. Limitations may be encountered during the design process.
Are de-aerators of Perspex construction permitted to be installed internally?
No, oil de-aerators of Perspex construction should be installed externally to a property as they are not deemed fire rated. Furthermore, they may vent vapours to atmosphere and can promote an explosive environment if sited within a confined space.
Oil de-aerators are available for internal installation. These are manufactured from fire resistant material and should be provided with a means of taking vented air to the outside via a fireproof vent pipe or releasing vapours via the burner.
Where and how should a remote acting fire valve be installed?
A remote acting fire valve should be installed with the sensor inside the appliance casing and the valve body external to the building as per British Standard 5410: Part 1: 1997 so that in the event of a fire or an over heat situation at the appliance, the oil is isolated external to the building.
For externally installed appliances, the fire valve cut off point should be located a minimum of 1m from the appliance.
Is an additional fire valve required for an oil fired vaporising range cooker?
Yes, two fire valves are generally required for an oil fired vaporising range cooker installations. One for the protection of the cooker and one for the protection of the oil float control valve. Cooker installations that also incorporate an oil lifter would require a third remote acting fire valve.