Frequently Asked Questions

Fuel Storage Tanks: Bunded Oil Tanks

Fuel Storage Tanks: Waste Oil Tanks

Diesel Tanks

Waste Water Treatment Systems

What should I know before buying a Bunded Heating Oil Tank?

Before purchasing an oil tank, it is worth consulting The Oil Firing Technical Association (OFTEC) for relevant information surrounding the storage of heating oil.

Not all domestic heating oil tanks are the same. Some are made from steel, some from plastic, some are thicker than others, some are single skin, and some are bunded.

Firstly, you need to know if you want a steel tank or a plastic oil storage tank. Harlequin manufacture rotationally-moulded plastic oil storage tanks as they are not susceptible to the same levels of corrosion as steel tanks. They are also lighter and easier to transport, not to mention being more economical.

Harlequin oil tanks are made from medium density polyethylene (MDPE). Materials and components used in the manufacture of Harlequin Oil Tanks are resistant to the potentially damaging effects of the liquids they are designed to contain. MDPE displays excellent chemical and impact resistance qualities. All Harlequin Oil Tanks are manufactured only from premium grade, virgin materials.

You also need to consider whether you wish to purchase a single skin oil tank or a ‘bunded’ oil tank. Single skin oil tanks are made using just one tank wall, i.e. the tank skin. Bunded oil tanks consist of a ‘tank within a tank’ design, which means that your oil and the surrounding environment are protected in the unfortunate event of the inner tank splitting. Single skin tanks are a more environmental hazardous purchase option, as no protection against tank splits and oil spills are offered.

Should your oil tank split and should an oil spill subsequently occur, the clean-up costs in such an event can reach as much as £50,000 and may not be covered by your home insurance policy.

Harlequin believes that the materials which it uses to manufacture its tanks, as well as the structural design of its tanks, make them the first choice for oil tank installers across the UK and Ireland.

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What types of fuel can be stored in a Heating Oil Tank?

Harlequin Oil Tanks are suitable only for the storage of:

  • Kerosene (C1/C2)
  • Agricultural Fuel Oil (A2)
  • Diesel (D)
  • Home Heating Oil

All Harlequin Oil Storage Tanks must be installed in accordance with supplied instructions, the requirements of OFTEC Technical Instruction Book 3 and prevailing statutory requirements. Please note that Harlequin Heating Oil Storage Tanks are not suitable for connection to a fuel delivery system incorporating a flexible hose and automatic trigger nozzle.

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What is a Bunded Tank?

A bunded heating oil tank simply consists of a tank within a tank. The fuel is stored in the inner tank and the outer tank acts as a failsafe so that in the event of a spillage, excess fuel will collect in the outer tank – thus averting a pollution incident.

Bunded heating oil tanks have been proven to significantly reduce the risk of pollution at oil storage installations. They are a requirement at commercial, industrial, institutional and commercial premises; all installations in the Channel Islands; and, at most domestic installations in the United Kingdom and Republic of Ireland.

Single skin tanks on the other hand, consist of only one shell or skin. This means that in the event of a tank split, valuable heating oil will be lost and the surrounding environment will be polluted by the heating oil contained within it.

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What is the difference between a Top Outlet and a Bottom Outlet Tank?

Top outlet bunded oil tanks are quite simply oil tanks which have the outlet to the burner placed at the top, rather than the bottom of the tank. Oil is then drawn out, as opposed to being gravity fed through the outlet at the bottom. All Harlequin bunded oil tank models can be provided as either top outlet (ITT) or bottom outlet (ITE) tanks.

Top outlet oil tanks are suitable for use with most pressure jet burners – we recommend installing a Tiger Loop de-aerator, to eliminate the need for a return line to the tank. Pressure jet burners are fitted to most oil boilers sold today in the British Isles.

Top Outlet Bunded Oil Tanks are not compatible with vapourising (or wick) burners, fitted to some oil fired stoves. At such installations, a bottom outlet bunded oil tank should be fitted or else an oil lift device should be incorporated within the oil supply line.

If you are in any doubt as to the compatibility of top outlet or bottom outlet bunded tanks, consult the appliance manufacturer or OFTEC.

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How close to a boundary can I place my Heating Oil Tank?

If the tank is less than 3500 litres in capacity, it should not be placed within 760mm of a combustible boundary e.g. a fence.

This distance assumes that there are no flu outlets or buildings between the tank and the boundary. Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided, by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

For tanks with a capacity greater than 3500 litres or for fire barrier construction requirements, please contact OFTEC for advice.

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How close to a flu outlet can I place my Heating Oil Tank?

Oil Storage Tanks with a capacity of less than 3500 litres should not be placed within 1.8 metres of a flu outlet.

Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

For oil tanks with a capacity over 3500 litres or advice on constructing a fire resistant barrier, please contact OFTEC.

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How close to a building can I place my Heating Oil Tank?

Oil Tanks with a capacity not greater than 3500 litres should not be fitted any closer than 1.8 metres to non-fire rated (30 mins. minimum) walls or eaves.

Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minute fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

It will be necessary to protect exposed eaves forming part of a roof within 1.8 metres of the top of an oil storage tank to provide a 30 minute resistance to fire. Cladding can be applied to the eaves in order to prevent fire spreading to the roof.

If the tank capacity is greater than 3500 litres or you require further advice, please contact OFTEC.

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Where can I put my Heating Oil Tank?

Your oil tank should be located 1.8metres from the nearest dwelling and 760mm from a boundary (e.g. wall or fence). If this is not possible, then a 30 minute firewall is required, which must extend 300mm above and beyond both ends of the tank. Your local building control authority can provide further advice.

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How should I maintain my Heating Oil Storage Tank?

Oil tanks should be maintained yearly, by an OFTEC certified tank installer. You can ask your tank installer to provide a tank check as part of your boiler service.

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What should I do if my Heating Oil Tank has split?

If you have noticed a split or a point of leakage on your oil tank you must act quickly, as an oil spill can severely damage the surrounding environment and can lead to expensive clean-up costs.

Contact your nearest approved oil tank technician to arrange an emergency call-out. You can also contact OFTEC for advice in such situations.

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Can I buy a Heating Oil Tank manufactured by Harlequin online?

Yes, there are several approved online resellers of Harlequin products. You can also locate your nearest stockist of Harlequin tanks when viewing a specific product.

You can click the ‘Buy Online’ tab when viewing any product listing in order to be directed to a list of online suppliers of the specific product you are viewing, or you can visit our ‘Buy Online’ page and answer a couple of brief questions in order for us to determine your tank needs.

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Do Heating Oil Tanks manufactured by Harlequin have an OFCERT License?

Yes. Harlequin bunded oil tanks each have an OFCERT license, meaning they have gone through rigorous testing processes by industry body and leader OFTEC in order to gain approval for use.

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Can I place my Heating Oil Storage Tank indoors?

Internal oil tanks should never be installed in a habitable area, and should always be contained within a specially constructed, purpose designed, enclosed chamber. Detailed requirements exist for the installation of oil storage tanks within habitable buildings and domestic garages.

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Can I install the Heating Oil Tank myself?

Oil tanks should always be installed by a trained technician, preferably an OFTEC approved tank installer. We can recommend an OFTEC-certified tank installer as we work very closely with several installers. This allows us to recommend only the best and most reliable installer to our customers.

As a minimum, all plastic heating 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 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. Piers are not suitable for this purpose and will cause irreparable damage to the oil tank, resulting in premature failure and catastrophic product loss.

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

With our Harlequin ITE range of oil tanks, there are three types of gauges within the tank pack:

Apollo Standard Tank Pack
Includes an Apollo standard oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. The tank transmitter constantly checks the level in the tank and transmits this to a plug-in receiver unit which displays the level on the easy to read LCD screen.

Apollo Visual Tank Pack
Includes an Apollo Visual oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Visual as well as reporting the fuel level to a plug in receiver also has a built in LCD display on the transmitter incorporating an on tank level.

Apollo Smart Tank Pack
Includes an Apollo Smart oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Smart Receiver Unit benefits from a mains power supply, and simply plugs into a standard socket, allowing you to monitor oil heating usage from almost any room in your home or office.

*Please note – the Harlequin HQi range does not include a tank pack.

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Can tanks manufactured by Harlequin be damaged by sunlight?

All Harlequin oil storage tanks are manufactured from a material which incorporates UV inhibitors. These prevent ultra-violet rays from permeating the structure of the tank, thus preventing fuel degradation.

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How secure are Heating Oil Tanks manufactured by Harlequin?

Harlequin oil tanks are the most secure tanks you will find in the market. All our bunded oil tanks are lockable at both the fill and inspection points. We also provide a range of added security accessories.

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What should I do if water gets into my Heating Oil Tank?

Water will form in any oil storage tank. It is perfectly normal and occurs as a result of the tank warming up during the day and then cooling at night. In single skin oil tanks it will collect in the base of the tank; in bunded oil tanks it may additionally collect between the inner and outer tanks.

All bunded oil tanks should be inspected annually for the presence of water either inside the oil tank or in the case of bunded oil tanks, between the inner and outer tank. Failure to remove any condensation may result in fuel contamination and irreparable product damage.

Condensation can be removed by most oil tank installers, technicians and most fuel distributors. We can recommend an OFTEC-certified tank installer for you as we work very closely with a number of installers. This allows us to recommend only the best and most reliable installer to our customers.

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What is the maximum temperature of liquids which can be stored in a Heating Oil Tank?

55 Degrees Celsius is the maximum temperature for liquids stored in oil tanks manufactured by Harlequin.

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Can I buy replacement filter for Waste Oil bottom outlet fitting kits?

Yes, your Harlequin stockist can supply these for you.

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Can I use a Waste Oil Tank to dispose Petrol or Diesel?

No, Harlequin Waste Oil Tanks are only suitable for the storage and disposal of industrial waste oil. To dispose of petrol or any other flammable liquid, please contact your local environmental authority.

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What do I do if there is a red light flashing on my Waste Oil Tank?

This signifies that the tank is full. Arrangements should be made for the tank to be emptied immediately.

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Are Harlequin Fuel Points & Fuel Stations compliant with Control of Pollution Regulations?

Yes, all Harlequin fuel points and fuel stations are compliant with all aspects of the Control of Pollution Regulations for England, Wales, Scotland and Northern Ireland.

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Can Harlequin Fuel Points/Fuel Stations be locked?

Yes, Harlequin fuel points and fuel stations are supplied with a metal spigot, adjacent to the cabinet door, which are capable of facilitating padlocks. Harlequin can also supply a lock pack on request.

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Can I store Kerosene in a Fuel Point/Fuel Station?

No, fuel points and fuel stations are not suitable for the storage of kerosene.

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Can I store Petrol in a Fuel Point/Fuel Station?

No. Harlequin fuel points and fuel stations are only suitable for storing and dispensing diesel or biodiesel blends not exceeding B7 (i.e. a bio-element not exceeding 7% concentration), and those which are manufactured in accordance with BS ISEN14214. BioDiesel tanks are suitable for storage of BioDiesel blends up to B100 and those which are manufactured in accordance with BS ISEN14214.

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Do all Diesel Tanks come with an automatic shut-off nozzle as standard?

Yes, all diesel tanks come with an automatic shut-off nozzle as standard.

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What should I do if there is water in my Diesel Tank?

You should contact your local fuel distributor, who will be able to arrange for removal.

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There is a two pinned socket on the front of my Fuel Point/Fuel Station. What is this for?

This permits the tank to be connected to the SecuTech LRC Overfill Prevention System, used by an increasing number of fuel distributors. This connection is not for consumer use.

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What are the power requirements for mains powered Fuel Points & Fuel Stations?

A 13 amp, single phase, mains power supply with a Residual Current Device (RCD) fitted at connection point to the power supply is required.

All mains electrical installations must only be undertaken by a qualified electrician and must be inspected and tested regularly in accordance with regulatory requirements.

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What filtration devices are supplied on Fuel Points/Fuel Stations?

All fuel points can be supplied with a 10-micron particulate filter on request and as an added cost extra. Fuel stations are also supplied with a 10-micron particulate and water filter as standard.

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What is Sewage Treatment?

Sewage treatment is the physical, chemical or biological process of removing contaminants from wastewater or sewage. This can be required for domestic, agricultural or commercial properties. The objective is to produce an environmentally safe fluid.

Mains Drainage
The majority of houses in the UK are linked to the public sewerage system. You pull the plug, flush the toilet, pay the monthly bill and have little more to worry about. This is known as mains drainage.

Off-Mains Drainage
In rural areas many homes and villages are self-contained. Either a cesspool, septic tank or sewage treatment plant will be used. This has no connection to the public sewerage system and is known as off-mains drainage.

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Can I use normal detergents and cleaners and will they affect my plant’s performance?

Yes, normal domestic use of these products is acceptable to the plant biology. If higher than normal quantities are expected, you should contact Harlequin before purchase.

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How much electricity does the plant consume?

Septic Tanks do not utilise any power. 6 population plants such as the HydroClear utilise 60-80watts, like that of a light bulb.

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Will paper towels, sanitary towels, etc. clog up my system?

Sanitary towels and similar non-biodegradable products should not be flushed into any wastewater treatment tanks.

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Does the plant make a noise?

Modern compressors are virtually silent, contained within housings further reducing noise levels.

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What can I do if my site fails the ‘percolation test’ and I do not have a watercourse to discharge into?

There is provision in the building regulations to construct an artificial ‘soakaway mound’, although this will need to be properly designed by a competent engineer or specialist drainage consultant.
Another option is to pump the treated wastewater to a location with suitable porosity or available surface water discharge point. Pumping to a main sewer connection may also be an option.

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What distance from the property does the plant need to be?

A minimum of 7m should be used, increasing to 25m if serving more than one building. Some local authorities will permit significantly closer installations if it is as far as is practicably possible. Your building control officer should always be consulted early in the planning stage regarding the location of the treatment plant.

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What is the difference between a silage tank, a septic tank and a sewage treatment plant?

A silage tank or cesspit collects and stores all the raw wastewater and must be emptied when full. These are not permitted in Scotland. A septic tank physically separates the solids from the liquids; the liquid is allowed to flow out of the tank, usually for dispersal by a network of underground perforated pipes called a soakaway. A sewage treatment plant works like a septic tank but has an additional stage to treat the liquid removing the dissolved constituents. The quality is then enough for direct discharge to surface waters.

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Will a soakaway drainage system become blocked up after several years of use?

If the soakaway system is laid properly according to the percolation test and BS 6297:2007, it will last for many years. Organic matter can eventually build up with the distribution network; it is therefore important to recognise that a soakaway system will not last forever. Proper maintenance and desludging of the tank is the most important factor in maximising the life of the soakaway.

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My septic tank/treatment plant smells. Why is this happening?

The most common reasons are an incorrect venting arrangement, a lack of maintenance or incorrect operation. The wastewater tank as well as the drainage pipes need to be sealed, venting to an appropriate dispersal point. This includes sealing all access points in the drainage pipes and u-bends on pipes in the dwelling. Maintenance and correct operation (use of detergents etc.) is vital to ensure that the system is physically and biologically treating the wastewater correctly.

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How does the HeatStream produce pressurised water?

The HeatStream utilises mains water pressure to produce pressurised hot water instantaneously through a high surface area extraction coil.

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Is the HeatStream a Thermal Store?

No, the HeatStream incorporates a static heat transfer medium in order to ensure that no header tank is required, thus utilising the best parts of an unvented cylinder and a thermal store. The Harlequin HeatStream also operates at temperatures like an unvented cylinder, thus reducing costs compared to most thermal stores.

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Can the HeatStream create better flow at my taps than an Unvented Cylinder?

HeatStream will produce similar flows to that of an unvented cylinder, and at similar pressures. Flow rates are generally a function of mains water pressure.

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Why does the HeatStream use Polypropylene in its design?

As with plastic pipes, we believe that Polypropylene is a much more suitable product for hot water storage, and it also lets us produce a better designed hot water storage shape; a more compact, square and much more ergonomic design.

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How suitable are the Heat Transfer Coils?

The Heat Transfer Coils which provide the heart of the product are manufactured using only a high-quality Stainless Steel. The coils themselves have been designed to maximise heat transfer and have an unparalleled heat transfer surface area.

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Can I attach an uncontrolled heat source to the Harlequin HeatStream?

Yes, it can absorb an uncontrolled heat source in its Triple range of products. The Harlequin HeatStream Triple can also be connected to a gravity circuit. As the heat transfer fluid is open vented, an uncontrolled heat source such as a solid fuel back boiler can be used. The Triple Range will be available in the future.

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Can I get any grants or tax allowances for installing a system?

At present there is no funding directly aimed at Rainwater Harvesting. It does however qualify for 100% capital allowance relief on commercial premises.

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How much does it cost to run the pump?

It typically takes 1.5- 2.0 kWh to pump 1 cubic meter of water (1000 litres). For a typical house using rainwater for WCs, washing machine and the garden, pumping costs are between 5-10p per week.

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How often does a system need topping up with mains water?

A well-designed system with a good match between supply and demand will only need topping up when it has not rained for some time. Severn Trent monitored a domestic system and found that it only occasionally needed to be topped-up. Most of the time the tank was around 50% full (i.e. an ideal balance between having plenty of water to use, and plenty of space to accommodate the next rainfall).

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How long will a Rainwater Harvesting System last?

The buried components, indefinitely. Components such as the control system, pump and filter have an extremely long working life, and are easy to replace should the need arise.

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What maintenance is required?

Typically, washing off the filter (5-minute job with a garden hose) once a quarter is all that is required.

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Is there a danger of Legionella?

No, the system does not provide the conditions necessary for the cultivation of Legionella. With the water stored underground it is dark, cool and is kept well oxygenated. Legionella cannot cultivate in these conditions.

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Is Rainwater Harvesting only for new builds?

Systems are best designed-in from the outset but can be retrofitted depending upon the accessibility of pipe work.

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What happens during a dry spell?

When there is insufficient water in the storage tank the Rainwater Harvesting System automatically draws water from the mains so that, from the point of view of the user, no difference is apparent.

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Can I drink the Rainwater?

In the UK, rainwater is not usually harvested for drinking purposes, so it is therefore not normally recommended.

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Is the Rainwater clean?

The tanks have filters that remove all debris and particles from the water so that the water remains clear. Please note that in the UK, rainwater is not usually harvested for drinking purposes so it is therefore not recommended.

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How should I store AdBlue™?

As AdBlue™ is very sensitive to contamination, it is important that it is stored in a containment system which can protect it from contamination threats, and which can maintain the AdBlue™ at an optimal condition.

The de-ionised elements of AdBlue™ can draw ions from the materials in which it is stored. This can change the chemical composition of the AdBlue™ and causes salts to form which in turn clog the ceramic head on the SCR.

A common cause of premature SCR failures is the incorrect material selection in AdBlue™ Storage. Inert materials should always be used to handle AdBlue™.

Harlequin AdBlue™ storage and dispensing tanks have been designed specifically for the safe and secure storage of AdBlue™. In addition, all AdBlue™ dispensing equipment has been selected in order to protect both the AdBlue™ solution and the equipment itself.

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What Is AdBlue™?

AdBlue™ is a trade name for AUS32 (Aqueous Urea Solution 32.5%). It is injected into the exhaust gases of modern diesel engines as a post combustion process. Its purpose is to reduce the percentage of harmful NOx (Nitrous Oxides) present in a vehicle’s emissions.

The reaction takes place in a special piece of equipment called a SCR. The requirements to reduce vehicles harmful emissions (pollutants) are specified in European legislation, namely Euro 4, 5 and 6.

In order to reach the reduced levels of pollutants as defined within current and future European legislation, vehicle manufacturers need to call on one of two types of technology: either SCR (Selective Catalytic Reduction) or EGR (Exhaust Gas Recirculation).

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What Is A SCR?

SCR stands for Selective Catalytic Reduction. Vehicles which are equipped with a SCR will carry an AdBlue™ storage tank in addition to the standard fuel tank. AdBlue™ is transferred from the storage tank and injected under pressure into the exhaust gases where a series of chemical reactions take place.

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What Regulations Should I Be Aware Of?

ISO 22241-1 Standard for AUS32
ISO22241-2 Standard for Quality Testing of AdBlue™
ISO 22241-3 Standard for Handling, Transportation and Storage of AdBlue™

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