How to store oil, design standards for tanks and containers, where to locate and how to protect them, and capacity of bunds and drip trays.
You must follow the rules on storing oil if you’ve got an oil storage container with a capacity of 201 litres or more at a:
- business, including marinas
- public sector building like a school, hospital or leisure centre
You must also follow these rules if you’ve got an oil storage container with a capacity of 3,501 litres or more at a home, including barges and houseboats.
Storage containers include:
- oil drums and fixed tanks
- intermediate bulk containers (IBCs)
- mobile bowsers - containers designed to store and dispense oil that can be moved between locations but not under their own power
- some types of generator and transformer
You could be fined or prosecuted if you do not follow the requirements in this guide. The Environment Agency can also serve an anti-pollution works notice to make you bring your oil store up to legal standards.
Storing oil on farms
There are separate requirements for storing agricultural fuel oil on a farm in England or Wales for agricultural purposes, for example as fuel for a tractor or to power a grain dryer.
But you must follow the rules for businesses in this guide if you store oil on a farm for non-agricultural business purposes, for example to fuel lorries or trucks.
You must follow the rules in this guide if you store any of these types of oil:
- vegetable oils, including any oil derived from a plant such as sunflower oil or plant-based oils used in aromatherapy
- synthetic oils, normally lubricating oils like motor oil
- oils used as solvents
- biodegradable oils, usually lubricating or hydraulic oils
- liquid bitumen-based products, for example waterproofing or damp proofing products, or coatings for a road surface
- cutting fluids, for example lubricants designed specifically for metalworking processes, that are made from or contain oil as oil-water emulsions
- insulating oils, used as electrical insulator and coolant
Grease is a mixture of oil and other substances, usually soap, and is viscous unless heated. We may ask for grease to be stored on a drip tray, but we expect that containers are either below 200 litres or stored indoors.
You do not need to follow the rules if you store any of the following substances, which are not classed as oil or are impractical to provide secondary containment for:
- liquid petroleum gas (LPG)
- hydrocarbon products that are solid unless they are heated, such as bitumen
- solvents that are not oil based such as trichloroethylene
- aromatic hydrocarbons like benzene and toluene
You must follow the rules in this guide if you store waste vegetable oil, waste cooking oil or waste synthetic oil.
You do not need to follow them if you store any of these types of waste oil but you should check if you need an environmental permit:
- mixtures of diesel and petrol which can no longer be used as vehicle fuel, for example fuel drained from a diesel car that’s been accidentally filled with petrol, creating a mixture
- any other oil drained from vehicle engines
- gearbox oil
- oil for turbines and hydraulic oil
Exempt oil storage containers
You do not need to follow these rules if your storage containers are:
- at a refinery
- at a premises for onward distribution of oil, rather than a premises which sells oil directly to end users
- stored in a building - a permanent or temporary structure with walls and a roof that would capture oil leaking from the container
If you store oil in a building, you may need to meet additional fire safety measures under the Building Regulations - contact your local council to discuss whether this is the case for your store.
If the building is on a farm in England or Wales, you must meet the requirements for storing agricultural fuel oil.
Oil depots at airports owned by oil companies are considered premises for onward distribution. These rules do not apply to them, but they do apply to oil depots at airports owned by airlines.
Marina ‘service boats’ are not considered premises for onward distribution, if they sell oil directly to boat owners. These rules apply to service boats.
Generators and transformers
These rules apply to any of the following generators or transformers that have a connected oil supply tank with a capacity of 201 litres or more:
- generators in daily use with a tank that supplies the generator where all of the oil from the tank is not used in 1 day
- ‘stand-by’ generators, which are generators kept for emergency use
- transformer headers tanks that are connected to the transformer by a one-way feed pipe
Design standards for containers
Your container must be strong enough not to burst or leak in ordinary use.
Fixed tanks that meet the design standard are any made to British Standard 5410, or:
- Oil Firing Technical Association (OFTEC) standard OST T100, if your container is plastic
- OFTEC standard OFS T200 or British Standard 799-5, if your container is metal
OFTEC is a trade association for the oil heating and cooking industry.
Drums and IBCs
If you get a drum or IBC marked with the letters ‘UN’ for United Nations it will meet the design standard.
Checking with the Environment Agency
Contact the Environment Agency if your container does not meet one of these standards or have a UN marking, and you want to discuss whether it’s strong enough and has enough structural integrity.
Where to position your container
You must position your container somewhere that minimises the risk of it being damaged by impact, for example away from driveways, tanker turning circles and fork lift truck routes.
Or you must make sure that any impact will not damage the container, for example by placing barriers or bollards around the tank.
If you fill your container via a remote fill pipe you must use a drip tray to catch any oil that may be spilled during the delivery.
A remote fill is when you fill your container at a fill point that’s outside the secondary containment (the bund or drip tray designed to capture leaks from the container). During a remote fill, the tank might not be visible from the fill point.
You must install secondary containment around your container to catch any oil that leaks.
Secondary containment is usually either:
- a drip tray beneath the container
- a bund - an outer case which holds the container
Fixed tanks must be bunded. Other containers can be bunded or use drip trays.
Secondary containment does not include:
- ‘double-skinned’ or ‘twin-walled tanks’, where the tank is surrounded by a second outer skin for extra strength
- oil separators
If you use a bund, it must hold 110% of the capacity of the container. If you do not have a bund, check your secondary containment has the required capacity, depending on what kind of container it’s holding.
Storage drums: secondary containment capacity
The secondary containment for a drum (usually a drip tray) must have a capacity equal to or more than one quarter of the drum it’s holding.
If the drip tray can hold more than one drum, it must be able to hold one quarter of the combined capacity of the drums it can hold. This applies even if you only use the tray to hold a single drum. For example, a drip tray which can hold 4 separate 205-litre drums must have a capacity of 205 litres, even if you’re only using it to hold a single 205 litre drum.
Single containers: secondary containment
For fixed tanks, mobile bowsers, IBCs and other single containers, the secondary containment must have capacity to hold 110% of the capacity of the container.
For example if your container has a capacity of 2,500 litres, your secondary containment must have capacity for 2,750 litres.
Multiple containers: secondary containment
Secondary containment that contains multiple fixed tanks, mobile bowsers or IBCs, must have a capacity that is equal to whichever is the greater of these 2 measurements:
- one quarter of the combined capacity of all the containers
- 110% of the capacity of the largest container
If the containers are hydraulically linked, they should be treated as a single container, so the secondary containment must have a capacity of 110% of the combined capacity.
If the containers are hydraulically linked, but have separate secondary containment, each separate secondary bund or drip tray must have a capacity of at least 110% of the combined capacity of all the containers.
If you hydraulically link the secondary drip trays or bunds together, you can count the combined capacity of the bunds or drip trays.
Design standards for bunds
Bunds can either be:
- manufactured as part of a tank system - tanks that are ‘pre-bunded’ by the manufacturer in this way are known as ‘integrally bunded’ tanks
- constructed from masonry or concrete
For bunds of either variety you must make sure:
- the bund is impermeable to oil and water - oil and water cannot pass through
- the base or walls of the bund does not have a pipe, valve or opening that allows the bund to be drained
- any fill pipe or draw off pipe that passes through the bund base or wall is sealed to stop oil getting out of the bund
- the bund contains every part of the container and its associated equipment (such as valves) unless the oil being stored has a flash point of less than 32℃ (such as ethanol), in which case filters, sight gauges, valves and other equipment can sit outside the bund
Bunds constructed from masonry and concrete are likely to need a rendering or coating on the internal surfaces of the base and walls to make them impermeable.
The Construction Research and Information Association has published advice on how to construct bunds that meet these requirements.
Fixed tanks: additional requirements
Fixed tanks must be bunded - you cannot use a drip tray for them.
Sight gauges must:
- have a bracket or brackets along the length of the sight gauge tube that fix the tube to the tank so the sight gauge tube cannot be knocked over
- be fitted with a valve that closes automatically when the gauge is not in use
Fill pipes, draw off pipes and overflow pipes must be positioned in a location that minimises the risk of damage by impact, for example away from driveways, tanker turning circles, and fork lift truck routes.
Or you must make sure they will not be damaged by any impact, for example placing barriers or bollards around them.
Any pipework above the ground must be properly supported, for example by a bracket connected to the nearest wall.
If your fixed tank has a flexible pipe permanently attached to it to dispense oil, the pipe must be in a secure cabinet that:
- is locked shut when not in use
- has a drip tray
Alternatively, all of the following must apply:
- the pipe must be kept within the bund
- there must be a lockable valve at the point where the pipe leaves the oil tank
- this valve must be locked shut when the pipe is not in use
Whether the pipe is in a secure cabinet or within the bund, it must also have a tap or valve at the delivery end that closes automatically when the pipe is not in use.
This tap or valve must not be able to be fixed open unless it also has an automatic cut off mechanism.
If your fixed tank has a pump, the pump must:
- have a valve in its feed line that prevents the tank contents emptying if there’s damage to the pump or feed line
- be positioned to minimise the risk of damage by impact, for example away from driveways, tanker turning circles, and fork lift truck routes, or protected by bollards or barriers
- be secured to prevent theft of the oil, for example by locking the pump shut when it’s not in use, or cutting the supply of electricity to the pump so it cannot function when not in use, or enclosing the pump in a lockable cage
Vent pipe, taps and valves
If your fixed tank has any permanently attached vent pipes, taps or valves that oil can leave the tank through, all pipes, taps and valves must:
- be within the bund
- be arranged so any oil coming out of them will go vertically down into the bund
- have a lock and be locked shut when not in use, this only applies to taps and valves, not vent pipes
If the vent pipe of a fixed tank, and the tank itself, cannot be seen from where the tank is filled you must fit an automatic overfill prevention device to the tank. This could be something that cuts off the flow of oil to the tank when it’s full or an alarm or fixed tank probe that sends a signal to alert the person filling the tank when the tank is full.
Screw fittings or fixed couplings
If the fill point of your fixed tank has a screw fitting or fixed coupling, it must be used when you’re having your tank filled.
Your screw fitting or fixed coupling must be kept in good working order.
Each time you get your tank filled, make sure the screw fitting or fixed coupling is not becoming corroded and that debris is not getting trapped in it.
Fixed tanks with underground pipework: additional requirements
If your tank has underground pipework, you must make sure the pipework is protected from physical damage, for example by:
- preventing vibration damage from lorries driving over ground that has pipework installed underneath
- placing a layer of specialist tape in the ground above the underground pipework, to alert anyone digging that pipework is laid beneath
If the pipework is made of a material that can be corroded such as steel or copper, you must also make sure it’s protected against corrosion, for example by:
- using plastic coated pipe
- laying the pipework in a trench filled with a material that will drain water, like compacted sand
Checking for leaks
You must check any underground pipes attached to your fixed tank for leaks.
You can fit a permanent leak detection device to the pipework that identifies leaks by, for example:
- detecting changes in the pressure in the pipe
- comparing flow into and out of the pipe
You must maintain any permanent leak checking device in working order and test it at appropriate intervals - check the manufacturer’s instructions.
If you do not fit a permanent leak detection device you must test your underground pipework for leaks when you install it and then:
- every 5 years if it contains mechanical joints
- every 10 years if it does not contain mechanical joints
A mechanical joint is a fitting used to connect 2 or more pieces of separate pipe, such as compression or threaded fittings.
Welded, braised or soldered joints and continuous pipework made from metal or plastic are not mechanical joints.
If your underground pipework contains mechanical joints, you must also be able to visually inspect each joint at any time.
Mobile bowsers: additional requirements
If your bowser has a permanently attached tap or valve through which oil can leave the bowser:
- the tap or valve must have a lock
- the lock must be locked shut when the tap or valve is not in use, to prevent oil flowing
Bowsers with permanently attached delivery pipes
Your bowser must have locks on appropriate pipes, pumps and valves so oil cannot flow when not in use. The lock should be on one or more of the following:
- any flexible delivery pipe permanently attached to the bowser - the lock should be at the point the pipe leaves the bowser
- any manually operated pump, like a hand pump
- the valve on the delivery end of the flexible pipe attached to any automatic pump, for example an electric pump - the valve must close automatically when the pump is not in use, like the nozzle on a pump at a petrol station