If a site has the latest double-skinned steel tanks and double-skin piping it’s as secure as it can be against leaks, but too many operators are taking risks with much older equipment, warns Phil Prow, sales and marketing director at Vianet Fuel Solutions.

He says: "There is still a large installed base of single-skinned steel tanks and they are getting on in age. Some are 20, 30, or even 40 years old, and it’s not a question of if they will corrode, but when." With the expense of replacing or lining a tank, a reluctance to invest is understandable, but when it’s compared to the cost of putting right the environmental damage of a leak, plus the loss of valuable fuel and business while it’s being fixed, it can be a false economy.

Prow says that with the increasing amounts of ethanol in fuel, the risks will only increase. He explains: "When we clean a tank we nearly always find small pin holes in the older tanks, but they haven’t caused a leak because they have been clogged up by sediment, and we obviously fix them as part of the service.

"But ethanol has a cleaning effect and loosens up any dirt in the tank and therefore it’s more likely to cause a problem, and it can cause more problems with leaking joints on pipework."

For operators concerned about older tanks there is a decision to be made of whether to go for a replacement or lining. Prow says the advantages of lining is that it is generally half to two thirds the cost of a new double-skin tank, plus the lining work can often be phased to keep the site operational rather than closing while new tanks are installed. He adds that with modern standards, linings should last for decades.

One company that faced such a decision over its tanks was Certas Energy. Retail director Ramsay MacDonald explains: "When, in 2012, Certas Energy acquired a group of forecourts across the central belt of Scotland, we knew that many of the tanks were at least 20 years old. Although a well-made tank, carefully installed, can remain in good order for three decades or more, we had neither the first-hand knowledge of their installation or reliable maintenance records. The integrity of the tanks was therefore unknown and the potential risks of doing nothing too great to contemplate.

"Of the options available to us we chose to pressure-test the existing pipe lines and refurbish the tanks utilising an industry-proven double-skin system. The work carried a long-term guarantee.

"We then had to decide whether to close each site or stay open and try to work around the disruption. It’s a real dilemma knowing that if you close, the work can be undertaken inside a week or so, but it means no revenue stream and the anxiety that customers may not return. Alternatively, keep the business open while the work is under way in the knowledge that disruption to the site will last for up to three to four weeks. We elected to stay open on the majority of sites. It did impact on our throughput but meant we preserved a cash flow and our rapport with customers."

Once the work was completed, Certas Energy implemented a real-time wet-stock management programme along with regular pump and tank testing.

"I cannot overstate the value of real time wet-stock management," he continues. "Wet-stock loss is potentially the third largest cost drain on a forecourt and the pay back from working with companies such as Fairbanks and Vianet to manage stock can be pretty much immediate."

Gareth Jenkins, Fairbanks communications manager, agrees, saying: "Tanks and pipework are situated in a more hostile environment than we think. It’s easy to consider your tanks and pipework as safe, embedded into the ground, but the reality is that they are under constant strain from elements both inside and out. Fairbanks has encountered countless cases where pipes are perishing, dipsticks have punched through strike plates and exposed debris has penetrated even the most robust subterranean equipment.

"At Fairbanks, we have the expertise and knowledge to detect very small failures in the tank and pipework. Our new wet-stock management dashboard, Fuelstation365 can alert customers to when tanks and pipework are beginning to fail. We’re launching it this year and will combine the power of wet-stock management with pricing and margin analysis tools."

There has been little innovation in the tanks sector in recent years but a new lining system presented by Shell at the APEA (Association for Petroleum and Explosives Administration) conference last November has generated a great deal of interest.

Tokheim is working in partnership with the manufacturer of the Unmanned Bag Lining System and is the authorised installer. UK operations manager Andy Wallace explains that what has generated so much interest is that the system has been designed so it can be installed from above ground with no requirement for anyone to enter the tank. This brings benefits in terms of price and reduced down time, but the major driver is the health and safety benefits of not requiring anyone to enter the tank.Wallace says: "It’s the only type of lining we currently offer because we want to avoid the man entry, and there is no other way or method we are aware of that can be done without going into the tank."

The system works by inflating the lining within the tank. Shell has been piloting the system at several sites across Europe including one in the UK, at its service station at Epping in Essex. The UK pilot is only for the diesel tanks, and Tokheim is currently going through the application process to get approval for unleaded petrol use. Wallace says: "There is a pilot unleaded version at a German fuel station, so it is a case of getting it signed off by the authorities, and we’re expecting that early this year."

Explaining how the system is installed he says the first requirement is accurate measurements of the tank, because each bag is designed and manufactured specifically for the tank involved.

Before installation the tank has to be clean and dry, and then the first step is inserting an inflatable mattress into the tank. This is designed to guide the lining system into place, and can be negotiated into position using ropes and guide lines.

Next, the bag and its external fleece lining, which comes as one unit, is placed into the tank on top of the mattress. Once it’s in position it is inflated using standard air guns and the dome of the lining will come into place and is connected to the dome of the tank using a tension ring. Wallace says: "We then apply a vacuum which holds the liner against the walls of the existing tank. That’s then put on a monitoring system to measure the interstitial space and ensure there are no potential issues."

He says that Tokheim is already in discussions with a number of potential customers. He adds: "There was considerable interest at the APEA event on the back of the presentation and a demonstration that Tokheim had on its stand at the exhibition."

While the safety issue of not having anyone enter the tank is the biggest-selling factor, Wallace says there are also savings in terms of down time and cost. He says: "Our estimates are that it can be as low as 25% of the cost of some traditional lining systems and can be done in less than half the time."

Cookson & Zinn has introduced a new tank to help tackle the problem of biofuel attracting water. The Biobase is a double-skinned tank fitted on sloping cradles so any water collects in the lowest point in the tank, and then this is drawn off through pipes. Les King, petrol tank sales co-ordinator, says: "It’s better than trying to suck water out of a level floor. We also offer an internal coating, with all tanks, which gives much greater protection against corrosion."

The company has also been looking at ways to increase the amount of fit-out that is done in the factory. He explains: "More and more, the bigger customers are looking to reduce the amount of time sites are closed for refurbishment and so we have been looking at ways that the maximum amount of work can be done before delivery."

As well as helping fuel quality, tank cleaning enables inspections of tanks to be carried out, says Kathy Early, managing director of DP Fuel Tank Services (DP FTS). "There are two reasons to clean fuel tanks," she says, "as a precursor to lining or to reduce pump clogging and other problems due to biofuel issues and accumulated sediment. Once we have cleaned a tank, we routinely visually inspect the inside fabric, as well as using an ultrasound scanner. This is the only real way to check for, and possibly head off, impending problems.

DP FTS has built up a network of strategic partners who are specialists in their fields: Repair Protection and Maintenance (RPM), Thames Valley Petroleum (TVP) and TankCare UK.

The group can deal with a wide variety of forecourt projects, including tank cleaning, pipework, tank lining, fuel testing, biofuel issues, fuel polishing, gas-freeing, tank excavation, decommissioning, contamination remediation and full forecourt demolition.

The multi-disciplinary nature of projects, says DP FTS director Nigel Plumb, can be seen from the how it deals with biofuel problems. The fuel is tested by TankCare UK and polished if necessary but, because there is no point putting clean fuel back into a contaminated tank, DP FTS will clean the tank. While the tank is empty and clean, DP FTS will inspect its fabric, which may need lining by RPM. Entering the tank can mean temporarily moving or renewing pipework, which is carried out by TVP. Whichever company first makes contact with the forecourt owner will take the lead in the project.

"Every stage is carried out by experts in their field," says Nigel Plumb, "but with the convenience for the forecourt owner of dealing with a single contact.

Adblue’s added challenge

A trend towards operators introducing tanks for AdBlue is highlighted by both Alex Boudry, sales manager UK & Ireland at Franklin Fueling Systems, and Eurotank managing director Ed Wheeler.
Boudry says that with the increasing use of AdBlue for HGVs, and an expected rise in its use to help passenger vehicles meet increasingly stringent emission standards, oil companies are taking a lead by putting AdBlue dispensers on their forecourts. However, AdBlue is an aggressively corrosive liquid that will eat through steel tanks and destroy gaskets and any other steel components, so stainless steel or appropriately-lined mild steel tanks are required, together with appropriate pipework.
Eurotank can retrofit a steel underground storage tank with the Phoenix tank-lining system from US-based ZCL Composites to make a tank compatible with AdBlue.
Wheeler says Phoenix uses the same resins either side of a Parabeam interstitial space as ZCL’s Xerxes tanks. Parabeam is an advanced 3D fabric that can be monitored with a Class 1 pressure system. All other tank linings rely on a vacuum monitoring system to hold the inner skin of the lining in place.
He adds: "AdBlue quality is affected by temperature so storing it underground is ideal because the underground environment keeps it within its optimum temperature range all year round. Eurotank can retrofit existing steel tanks with the ZCL system as well as install Nupigeco AdBlue-approved pipework."

doubling up on Pipework

Double-skin tanks are the standard now, but people are still skimping by putting in single-skin piping, says Alex Boudry, sales manager UK and Ireland at Franklin Fueling Systems.
He explains: "If you install double-skin piping you can monitor the interstitial space for leaks, which warns you have a problem before anything reaches the environment. I would urge people to seriously consider double-skinning any pipework they put in the ground. Double-skin pipework is more expensive but it is a tiny extra percentage on the total cost of a knock-down rebuild."
He says all UPP plastic piping doesn’t corrode and it fusion-welds so won’t leak unless it’s poorly installed, and that would be detected during testing before going live. He adds: "Once it’s installed it shouldn’t ever leak the joints are stronger than the pipe, there’s no corrosion because it’s plastic, and it’s flexible so it takes ground movement without cracking, whereas with steel piping it can shear."