With many oil tank installers reporting a tough and highly competitive market environment, it’s worth taking a closer look at the issue of where and when bunded tanks need to be installed and where they don’t, says Carbery Oil Tanks’ Mike Brennan. Whilst bunded tanks can help achieve regulatory compliance at some installations, at others they can represent an unnecessary expense, which hinders technician competitiveness.
To Bund Or Not To Bund?
Bunded heating oil tanks have existed in various guises for decades. Consisting of a tank within a tank, the inner tank serves as the primary storage tank, whilst the outer tank acts a failsafe in the event of a spill e.g. an overfill during refuelling.
The earliest bunded tanks were simply standard, single skin tanks surrounded by an oil resistant barrier. Even today, old fashioned masonry bunds still remain – and can be found frequently at commercial and industrial installations. Typically these comprise a steel or plastic tank surrounded by an oil resistant masonry wall and placed on a solid, oil resistant base. Whilst the theory behind such installations is sound, the reality is often very different. Typically, debris or rainwater accumulates in the area between the tank and the masonry wall. In the event of a spill, spilt fuel may not always be contained but instead flows over the top of the bunded area. That’s why many such installations have been largely replaced by fully enclosed plastic, steel or GRP bunded tanks.
The Answer Isn't Always Bunded... Sometimes It's Single Skin.
Today, across Ireland and the UK, we recommend bunded tanks should be fitted at all fuel storage installations at commercial, industrial, institutional and agricultural premises. Indeed, in many areas, this is now a legal requirement. But at many smaller, single family dwellings, there is no compulsion to fit a bunded tank by default. Subject to an on-site risk assessment, a more-affordable and homeowner friendly single skin heating oil tank can suffice and help to ensure compliance with prevailing statutory requirements.
By better understanding where a single-skin tank can be fitted and where a bunded tank must be fitted, proactive oil tank installers can frequently offer a more competitive quote, gaining business from competitors who exclusively fit more expensive and sometimes unnecessary bunded tanks. On-site risk assessments must only be undertaken by a competent, professional, oil storage tank installer who is independently trained and accredited. They are not designed to be completed by unskilled personnel, who can quite innocently overlook a site-specific hazard which may turn out to be important at a later date. Furthermore, an incorrectly completed assessment may invalidate the tank manufacturer’s warranty.
A typical risk assessment comprises a total of 8 questions. If you answer yes to any one of them, a bunded tank must be fitted. But if you can answer no to all of them, a single skin tank can ordinarily be instead installed.
Is the total installed on-site capacity greater than 2,500 litres?
It’s important to note the capacity threshold applies to the total on-site storage capacity. So if there will be say a 2,000 litres capacity tank supplying a heating system and a separate 1,000 litres capacity tank supplying an oil-fired stove, the total capacity will be 3,000 litres and both tanks will need to be bunded.
However, a quite legitimate work-around in this scenario and where no other risk factor applies, would be to install 2 smaller tanks, say a 750 litres capacity tank to feed the oil-fired stove and a 1,350 litres tank to supply the heating system. In this case, total installed capacity would be 2,100 litres, coming in 400 litres below the capacity threshold. It’s also useful to remember that modern condensing oil boilers are more efficient than ever before, so correspondingly smaller tanks can now be fitted.
Is the tank within 10 metres of controlled water?
Controlled water includes lakes, reservoirs, rivers, streams, the sea, lagoons and even drainage ditches whether or not water is physically present. If it’s not a garden pond and it might have water in it, then it’s almost certainly controlled water.
Superficially, this might appear to be one of the most difficult restrictions to work around. However, by resiting the tank, it is frequently possible to position the tank so it is more than 10 metres from a controlled water source, thereby in the absence of any other risk factors, eliminating the requirement to fit a bunded tank altogether.
Is the tank located in a position where a spill could run into an open drain or loose fitting manhole cover?
The definition of an open drain includes domestic drains and storm drains. And unless you’re certain that any manhole in close proximity to the tank is sealed, then legally it will almost certainly be defined as ‘loose fitting’. In such instances, a bunded tank will be required.
But by resiting the tank it might be possible to avoid the need to fit a bunded tank altogether. Or alternatively, it might be possible to seal the offending drain or manhole. This is often the case at older properties, where sometimes drains no longer serve a useful purpose. Whilst this might superficially appear an expensive option, it can still work out £’00s cheaper than opting for a bunded tank.
Is the tank located within 50 metres of a well, borehole or spring?
And additionally, can you be absolutely certain that it isn’t?
Fifty metres is a significant distance and not all wells, boreholes and springs are visible. So unless you can be absolutely certain that there are no wells, boreholes or springs within 50 metres… it’s best to be safe and opt for a bunded tank. That is, unless you can resite the tank to a different location. And of course, frequently you can.
Is the tank located over hard ground, which would allow spillage run off to reach controlled water?
There are some installations at which due to site topography, it is impossible to locate the tank anywhere other than in a position where a spill would run over hard ground to reach controlled water. But at many installations, the tank can be resited to eliminate this risk altogether and potentially allow for the fitting of a single skin tank.
Is the tank located in a position where the vent pipe outlet is not visible from the fill point?
Affected installations will include those, which incorporate a remote or offset fill point, as well as many underground oil tank installations too. But at most domestic heating oil installations, such arrangements tend to be few and far between.
Is the tank supplying a building other than a single-family dwelling?
As we’ve already said, if a tank is supplying premises other than a single family dwelling, it must be bunded. No ifs, no buts and no maybes.
Is there any other site specific hazard?
Site specific hazards can take many forms. It might be a steep slope adjacent to the tank or in England, it might be because the tank is set to be installed within a Groundwater Source Protection Zone 1. Where such a hazard exists, a bunded tank must be fitted.
The Difference Between Winning A Quote And Losing It
If the answer to any of the above questions is ‘Yes’, then a bunded tank must be installed. If you can answer no to all of them, a single skin tank will be permissible at most installations.
Sometimes that might mean the tank needs to be repositioned, or perhaps a smaller capacity tank fitted. But in these austere times, many consumers will happily consider such an approach, especially when the cost savings might run into many hundreds of pounds. For many heating oil tank installers, such savings will be the difference between winning a quote and losing it to a competitor.
Originally published by OilFiredUp Rural Energy News and reproduced by Derwent Weighing Limited T/A TankDepot.co.uk with permission. Copyright 2014 OilFiredUp Rural Energy News.