Frequently asked questions on the Water Environment (Oil Storage) (Scotland) Regulations 2006

These questions and answers are in relation to the Water Environment (Oil Storage) (Scotland) Regulations 2006 only[1]. There are British Standards and other regulations that may apply to oil storage, containers, ancillary equipment and pipe work. It is the responsibility of the person with custody or control of oil in storage to ensure they are compliant with all relevant legislation.

Questions and answers are divided into the following headings:

When the regulations come into effect

Where the regulations apply

Exemptions from the regulations

Oil containers

Secondary containment

Ancillary equipment, pipe work and pumps

Enforcement

When the regulations come into effect

Timescale for compliance with regulations

The regulations came into force in three 3 stages:

  1. New tanks (ie facilities commenced after 1 April 2006) had to comply by 1 October 2006.

  2. Previously existing tanks at significant risk (ie facilities that are located within 10 metres of any surface water or 50 metres of a borehole or well) had to comply by 1 April 2008.

  3. All remaining existing tanks will have to comply by 1 April 2010.

SEPA may also serve an enforcement notice under the Water Environment (Controlled Activities) (Scotland) Regulations 2005 on existing oil storage facilities, where it is considered that there is significant risk of pollution of the water environment, requiring compliance with all or part of the regulations before the required date.

How do I know if a drum should be bunded or not between now and 2010?

The regulations allow for a container that was used to store oil before April 2006 to have until 2010 to comply with the regulations. Between now and 2010 it will be difficult to judge if the drum was used for that purpose before 2006 or not, so the safest option is to store drums within a drip tray capable of containing at least 25% of the drum capacity as soon as possible.

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Where the regulations apply

Do the regulations apply in England, Wales and Northern Ireland?

The Water Environment (Oil Storage) (Scotland) Regulations 2006 only apply in Scotland. There are similar regulations in England, namely the Control of Pollution (Oil Storage) (England) Regulations 2001. There are currently no similar regulations in Wales or Northern Ireland.

Are there differences between the Scottish and English regulations?

The requirements of the regulations in Scotland differ slightly from those in England. Key differences include:

  • Regulations in Scotland apply to domestic oil storage above 2500 litres. The English regulations apply to domestic oil storage with over 3500 litre capacity.

  • Regulations in Scotland apply to storage of waste oil. The storage of waste mineral oils is exempt under the English regulations because it is covered by The Waste Management Licensing Regulations 1994.

  • Regulations in Scotland apply to storage of oil in buildings while the English regulations exempt the storage of oil within a building.

  • Regulations in Scotland exempt oil stored in accordance with a Part A permit under the Pollution Prevention and Control (PPC) Regulations 2000, or the Environmental Protection (Prescribed Processes and Substances) Regulations 1991. Premises used as an oil distribution depot for the onward distribution of oil to other places are also exempt under Scottish regulations. The English regulations exempt storage of oil at premises used for refining oil or for the onward distribution of oil to other places.

  • Storing oil for agricultural use on a farm in Scotland is covered by the new oil storage regulations, but there are separate regulations governing how agricultural fuel oil, above a certain volume, must be stored in England, Wales or Northern Ireland, specifically The Silage, Slurry and Agricultural Fuel Oil Regulations in England and Wales, and The Silage, Slurry and Agricultural Fuel Oil Storage Regulations in Northern Ireland.

  • The Scottish regulations require that if oil is stored in a portable container of <200 litres, the container must be of sufficient strength and structural integrity that it doesn't leak in ordinary use. There is no similar requirement in the English regulations.

Which types of oil are covered?

The Water Environment (Oil Storage) (Scotland) Regulations 2006 apply to any kind of oil including petrol, diesel, kerosene, mineral oil, heating oil, lubricating oil, waste oil, vegetable and plant oil but does not include uncut bitumen because the material is likely to solidify in the vicinity of any spillage. The storage of agricultural fuel oil is now controlled by these regulations because Regulation 8 therein removes such oil storage from the Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) (Scotland) Regulations 2003.

Uncut bitumen is specifically excluded from the definition of oil within the regulations and is therefore exempt. Bitumen based products which are liquid at normal ambient temperatures (eg bitumen emulsion) should be stored in accordance with the regulations however.

The relevant provisions of The Waste Management Licensing Regulations 1994 (as amended) also apply to handling and storage of waste oil.

It is important to note that in the case of flammable liquids such as petrol, additional health and safety requirements may also apply.

Are drums, Intermediate Bulk Containers (IBC's) and mobile bowsers included?

Yes. The regulations apply to drums greater than 200 litres, IBCs and to mobile bowsers.

All containers must comply with the general requirements of the regulations (Regulation 6). In addition there are specific requirements for mobile bowsers [Regulation 6(8)]. Many self-bunded bowsers are now available. Bowsers that are not bunded will need to be kept in a bunded area with 110% capacity when in use. Drums [Regulation 6(6)] with a drip tray are subject to special requirements: the tray must have a capacity of at least 25% of the total storage capacity.

If an IBC is being used for permanent oil storage then we would regard it as fixed storage and therefore the requirements for fixed tanks [Regulation 6(7)] will apply.

What isn't oil for the purpose of the regulations?

The regulations are wide enough to include any kind of oil. However there are some hydrocarbon based products which we would not expect to be covered by the oil storage regulations such as LPG, which is a gas and therefore impractical to bund. Solid hydrocarbon products which are solid at normal ambient temperatures are also impractical to bund and have minimal impact on the water environment.

Is oil stored at marinas, on banks or on pontoons covered by the regulations?

The definition of a premise includes land and mobile plant but does not include vehicles or vessels. Storage at all marinas (inland and coastal), on banks or on pontoons must therefore comply within the appropriate specified timescale. Tanks in these locations should also be secured to prevent them lifting or floating away in the event of unusually high tides or floods.

Oil storage on barges at coastal marinas comes under the jurisdiction of the harbour master and as such is not covered by these regulations. The storage of petroleum is additionally controlled by the Petroleum Consolidation Act and a license is required from the petroleum licensing authority, usually the Fire Service or Local Authority Trading Standards Department. There may also be local bye-laws in place for inland waterways.

Is storage within buildings covered by the regulations?

Oil storage within buildings must comply with the regulations. Whilst we prefer use of 'traditional' tank secondary containment systems, the 110% secondary containment requirements of the regulations may be met within the building itself eg 110% secondary containment may be provided within the building by forming a 'lip' on doorways and calculating the floor area capacity. All other requirements of the regulations must still be met, such as additional requirements of the secondary containment system relating to impermeability, no drains etc. 

Is oil storage at sites regulated under Integrated Pollution Control (IPC) or Pollution Prevention & Control (PPC) regimes covered by the regulations?

The Water Environment (Oil Storage) (Scotland) Regulations 2006 exempt storage of oil in any installation which is a Schedule 1 Part A Activity of the Pollution Prevention and Control (Scotland) Regulations 2000, or a Schedule 1 Part A process of the Environment Protection (Prescribed Processes and Substances) Regulations 1991 and where oil is stored in accordance with the authorisation or permit. However Best Available Techniques not Entailing Excessive Cost (BATNEEC) and Best Available Techniques (BAT) must be applied at these sites. The regulations may be considered the reference point for BAT or BATNEEC for where no Best Available Techniques Reference Document (BREF) note is available to identify BAT, or no Guidance Note to identify BATNEEC.

Do the regulations cover mobile bowsers used at licensed waste sites?

Mobile bowsers used at all licensed waste sites must comply with the regulations.

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Exemptions from the regulations

Is grease exempt?

Not necessarily: where grease is stored in a container with a storage capacity of 200 litres or greater we would ask for the grease to be stored on a drip tray to ensure that any leaking or spilt oil cannot enter the water environment. 

Do heat transfer fluids like those within transformers or fluid filled cables come under the regulations?

No. The oil within transformers is being used rather than stored.

However, bulk tanks for storing these oils are regarded as oil in storage and will come under the requirements of the regulations unless otherwise exempt. Some transformer header tanks may come into this category if they are connected directly to the transformer by means of a 'one way - tank to transformer' feed pipe. If the transformer has an expansion tank (where oil leaves the tank and enters the transformer and on expansion leaves the transformer and re-enters the tank), the container is regarded as being part of the transformer with oil in use and is therefore not stored and does not come under the regulations. However, in order to minimise the risk of polluting the water environment we recommend following the requirements of the regulations where possible.

Transformers in storage awaiting installation or disposal are not generally regarded as oil storage containers for the purposes of these regulations but it is good practice to provide secondary containment where there is a risk of oil spillage.

Are bitumen and bitumen products exempt?

Uncut bitumen is specifically excluded from the definition of oil within the regulations and is therefore exempt. 

Bitumen based products which are liquid at normal ambient temperatures (eg bitumen emulsion) should be stored in accordance with the regulations.

Does oil stored within a generator come under the regulations?

It depends on whether the oil is being stored or used.

The regulations apply to generators where the oil is being stored rather than used, and where no exemptions apply. They will therefore apply to stand-by generators which are storing oil for later use.

Sets containing more than 200 litres of oil would require secondary containment of the day tank. Bulk storage tanks greater than 200 litres that supply a standby generator or its day tank fall under the regulations because the oil is being stored but not used.

Where a generator is in regular or constant use and its day tank is of a capacity such that the oil will be used during an operating day – even if the volume of oil is greater than 200 litres – the oil will be regarded as 'in use' and the regulations will not apply. But if oil is not all used up in the operating day it will be regarded as being stored and the regulations will apply if the tank holds over 200 litres.

Even if the regulations do not apply the potential for environmental harm from an oil spill remains and we therefore recommend that all generator tanks and pipe work are provided with secondary containment as good practice.

Is all oil at a distribution depot exempt from the regulations?

Yes. An exemption applies to any premises used as an oil distribution depot for the onward distribution of oil. Onward distribution should be the primary business of the site. The exemption applies to the premises and therefore includes any oil that is part of the onward distribution chain and also oil that is stored such as heating oil or oil for refuelling vehicles. However we would consider compliance with the regulations as good practice.

A guidance note Model Code of Safe Practice Part 2: Design, construction and operation of petroleum distribution installations (3rd edition) by the Energy Institute http://www.energyinst.org.uk/ is specifically directed at these installations.

Is oil used for domestic premises exempt?

Tanks with a capacity greater than 2500 litres must comply with these regulations.

New and replacement single domestic oil storage tanks are covered by The Building Regulations (Scotland) 2004, which require a risk assessment to determine the need for secondary containment.

For the purposes of these regulations:

  • Holiday homes and bed & breakfast establishments where the owner lives on the property are regarded as domestic premises.

  • An office within a house would still be exempt providing the building is used wholly or mainly as a private dwelling.

  • Residential care homes are not exempt from the regulations because they are not used wholly or mainly as a private dwelling.

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Oil containers

Do the regulations cover the volume of oil stored or the size of the container?

The regulations cover the size of the container. For example, sites with an oil tank of 1000 litres which only ever have 150 litres of oil stored would have to comply. Similarly domestic properties with a storage tank greater than 2500 litres that only ever have 1500 litres of oil stored would have to comply.

What is the definition of a mobile bowser?

For the purposes of these regulations, a mobile bowser is defined as an oil storage container that cannot move under its own power ie it is not a rigid or articulated road tanker, but is specifically designed to be capable of storing and dispensing oil and being able to be moved between various locations. A mobile bowser must meet the requirements of the regulations and should be specifically designed to be capable of containing oil safely while it is being moved ie its design should not allow oil to be lost from the container in the event of a collision, drop, roll over etc.

Mobile bowsers may be provided with wheels or be transported on or by another vehicle or by similar means. Trailer tankers that are towed by road tankers of a similar size are not considered to be mobile bowsers.

Please be aware that Carriage of Dangerous Goods (ADR) legislation may apply if you are using a mobile bowser on the public highway.

Can I store oil in a road tanker without secondary containment?

The regulations define a container as a fixed tank, a drum, or a mobile bowser or (even if it is not connected to fixed pipe-work) an intermediate bulk container. Although not specifically exempt, road tankers are not designed to store oil for any length of time and we actively discourage their use for such activity. 

Does an empty tank have to comply with the regulations?

The regulations exist to prevent oil escaping to the environment so while an empty tank should technically comply with regulations, we would expect common sense to prevail. Most abandoned tanks will have an oily residue at the bottom which could cause pollution so we advise that redundant tanks are properly decommissioned and removed in accordance with the Waste Duty of Care. Where removal is not possible they should be filled with a material that ensures they cannot be brought back into use.

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Secondary containment

How do I know if my double skinned tank complies with the regulations or not?

A double skinned tank alone is unlikely to provide adequate secondary containment. True secondary containment includes containment for the ancillary equipment associated with a tank as well as the tank itself. This would include having sight gauges and valves within the secondary containment facility. In addition the regulations also require that vent pipes are arranged so that any discharge is contained within the secondary containment system. A double skinned tank would not prevent loss of oil from overfilling, but one with true secondary containment would.

Where can I get more information on how to build a bund?

Standards are set out in the SEPA/CIRIA information notes Masonry and Concrete Bunds For Oil Storage Tanks, which are taken from the CIRIA report 163 Construction of Bunds for Oil Storage Tanks. The relevant British Standards must be complied with.

What is an acceptable impermeability for a constructed bund?

The regulations do not specify any particular materials that a secondary container should or should not be constructed from, only that its base and walls must be "impermeable to water and oil".

A conventional bund constructed from bricks and mortar is unlikely to be impermeable without rendering of some kind. Information on coatings and surface treatments to achieve a satisfactory impermeability can be found in Masonry and Concrete Bunds For Oil Storage Tanks, which are taken from the CIRIA report 163 Construction of Bunds for Oil Storage Tanks.

Can I take the volume of the primary tank into account when calculating secondary containment capacity?

Yes, the regulations state that the secondary containment system "must have a capacity of not less 110% of the container's storage capacity". The volume provided by the primary container can be taken into account where applicable. Most proprietary tank systems are designed so that the oil finds its own level in both containers if the primary container leaks. In this instance the primary container contributes to the total containment capacity. A similar position is achieved in a conventional bund where the tank is situated towards the bottom.

However, you should take into account that such systems may only provide a 10% containment capacity in the event of overfilling. For example, a maximum volume delivery made to a tank more than 10% full will result in a loss of oil from the secondary container. The use of an overfill prevention device is good practice and you should consider these or other additional pollution prevention safeguards, such as additional containment capacity.

Another important issue in determining if a proprietary tank system is acceptable is whether the ancillary equipment is adequately managed, such as being within the secondary container, which some proprietary tank systems may not provide.

What containment capacity is required if I have more than one tank in a storage area?

If the tanks are not hydraulically linked but are in the same secondary containment system, the containment capacity must be at least 25% of the total capacity or 110% of the capacity of the largest tank, whichever is greatest.

If the tanks are hydraulically linked but situated within the same containment system, they should be treated as one tank and the containment capacity should be at least 110% of the total capacity of the tanks.

Where tanks are hydraulically linked but in separate containment systems, the capacity of each containment system must be capable of containing at least 110% of the potential spillage that could occur within that system. This means that, where oil could pass from one tank to another, containment of at least 110% of the total volume stored will be required at each location that could receive this volume. It may be beneficial to hydraulically link the containment systems.

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Ancillary equipment, pipe work and pumps

Can an isolating valve and filter be outside the secondary containment?

Yes. In a situation involving a fixed draw off from a prefabricated tank the isolating valve and filter can be outside the containment. In this instance they would be regarded as ancillary to the down stream equipment. The isolating valve needs to be accessible in an emergency so can be outside the prefabricated system but we recommend that they are put inside the secondary containment if possible.

What is a mechanical joint in underground pipe work?

A mechanical joint is any join in a pipe where two or more pieces of pipe have been put together using a fitting attached to the ends of both pipes and which can be taken apart. Compression and threaded fitting are examples of mechanical joints. Welded, braised or soldered joints are not considered to be mechanical. They will not include continuous pipe work made from metal or plastic.

For further information see British Standard 5410 Part 1: 1997 Section 8.2, Code of Practice for Oil Firing: http://www.bsi-global.com/en/Shop/Publication-Detail/?pid=000000000030093974

How can I test my pipe work for leaks?

The regulations require that underground pipe work is tested for leaks every 5 or 10 years depending on if there are mechanical joints present.

Where pipe work manufacturers' test instructions are not available, British Standard 5410 Parts 1 and 2 have information about pressure testing of pipe work for oil firing installations. A competent person should undertake pressure testing. Pipe work made from plastic, copper and steel will require different types of testing, as will different size pipes. We recommend that the same method should be adopted for non-oil firing applications such as refuelling facilities.

How can I show that my underground pipe work complies with Regulation 6 (7) (b) ii?

The purpose of this section of the regulations is to discourage the use of mechanical joints in new underground pipe installations following some serious pollution incidents caused by corroded or damaged underground pipe work.

The regulation does apply to existing underground pipe work. Existing oil firing systems should have been installed in accordance with the relevant sections of British Standard 5410 Part 1: Section 8.2.4 or Part 2 Section 38.2.4 which are site specific, or with OFTEC TI/134 Installing oil supply pipes underground. These standards stress the importance of laying pipes in accessible ducts where possible. If you cannot demonstrate that pipes have been installed in such a manner then further investigation may be needed, taking into account industry standard lengths of pipe work and the accessibility of the pipe.

Does my tank need an overfill prevention device?

The regulations require that if the tank and vent pipe cannot be seen from where the filling operation is controlled, such as at remote fill points, then an automatic overfill prevention device must be fitted to the tank. Fixed tank probes that send a signal to the point where delivery is controlled are acceptable. We encourage the use of fail–safe overfill prevention devices and overfill warning alarms.

It is good practice to have an overfill prevention alarm fitted to all systems, even if not required by the regulations.

What is meant by a screw fitting for tank filling being in "good condition"?

The regulations do not define "good condition". However we think it is sensible to consider whether a fitting is fit for purpose in the broadest sense. You should make sure the screw thread is usable and that deliveries to the tank using the fitting can be made safely and securely. Using the screw fitting should not increase the risk of oil spillage or jeopardise operator health and safety, for example from working at height. You should discuss the suitability of the tank's screw fitting with your oil delivery company.

Does my pump have to be within the secondary containment?

Regulation 6 (4) does not require pumps to be situated within the secondary containment system. However, it is good practice to make sure that any foreseeable oil leak would be contained within secondary containment, for example a bund or drip tray, and could not cause pollution.

Please check Regulation 6 (7) (f) for specific requirements for pumps used with fixed tanks, Regulation 6 (8) (b) (ii) for separate requirements for pumps used with mobile bowsers and Regulation 6 (7) (e) for requirements for containment for flexible pipes from delivery pumps.

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Enforcement

Are distributors committing an offence by delivering to a non-compliant tank?

No, it is the non-compliance of the tank that constitutes the offence. However if a pollution incident occurs during or following a delivery, we will look closely at the circumstances to determine if the distributor used appropriate judgements to decide if the tank was fit to receive the delivery.

Will SEPA expect oil delivery company drivers to have sufficient expertise in the regulations to be able to identify a non-compliant tank?

We expect drivers to have suitable training to undertake the job. That training should include appropriate industry guidance. The key requirement is to use common sense when handling a product that has a big environmental impact.

Who is responsible for a tank that is loaned to a customer?

It depends on what exactly is meant by loaning and what agreements and conditions are attached to the loan. A company supplying an unbunded tank to a customer would not necessarily be in breach of the regulations because it is the customer who has custody or control of the oil (not the tank). A company supplying tanks without bunds is unlikely to be in breach of the regulations, subject to any agreement/contract regarding the loaning of the tank.

We would urge customers to insist on being supplied with bunded tanks to reduce their liability under the regulations. A supplier could provide a tank that was not bunded for a user to install in a bund. The ultimate responsibility must rest with the site operator who has custody or control of the oil.

What legal requirements are there for maintenance of tanks?

There are no legal requirements for maintenance in the regulations but there is guidance in Pollution Prevention Guidance Note 2 Above Ground Oil Storage. OFTEC qualified registered technicians do an annual check on tank installations when they routinely inspect a boiler and they also produce a tank checklist.

We expect visual checks to be carried out at least weekly and would encourage tank checks to become part of the routine maintenance schedule.

The person with custody of the tank is still required by the regulations to ensure that the container is of sufficient strength and structural integrity that is unlikely to burst or leak in ordinary use.

How will SEPA enforce the regulations?

We are responsible for enforcing The Water Environment (Oil Storage) (Scotland) Regulations 2006 in Scotland. Failure to comply is a criminal offence and you could be fined up to £40,000. We will provide advice and guidance to assist you with compliance if you are concerned that your oil storage facilities may be inadequate.  

The regulations apply minimum prescriptive standards for storage of oil in above ground fixed or mobile tanks. This means that we will not need to make a special visit to individual sites to assess risks, but will draw awareness to and enforce the regulations during routine visits.

The regulations come into force in 3 stages (as detailed in Timescale for compliance with regulations) and will be fully implemented by April 2010, by which time all relevant oil storage must comply with the regulations. 

Therefore until April 2010 our priorities for these regulations are to ensure that our customers who are subject to them are made aware of their scope. In targeting enforcement action our priorities will be risk based and sites of principal concern will therefore be:

  • sites which have caused water pollution;

  • sites where there is a serious potential for pollution, for example less than 10m from surface waters or less than 50m from a well or borehole.

However this does not preclude us from taking enforcement action at other sites. 

Following the full implementation of the regulations in April 2010 the number of sites subject to the regulations will significantly increase. In addition to the priorities identified above, we will also focus on sites in areas which have been identified and targeted for pollution prevention work, such as those where there is a history of pollution incidents.

We would, in most cases, seek voluntary compliance but if you fail to act we may serve an enforcement notice requiring that the facilities be brought up to standard or we will seek prosecution for non-compliance with the regulations. Failure to comply with such a notice is a criminal offence and may result in prosecution. 

We will keep this approach under review and may publish amendments in the light of operational experience. We expect compliance to improve as awareness of the regulations grows.

What is SEPA doing to promote the regulations?

We are working with oil suppliers and companies that supply oil storage products to raise awareness of the regulations. Publicity and promotional material will include articles, press releases and website information.  

More information

For more information please contact Janine Young at janine.young@sepa.org.uk or call 01786 452442

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