Leak practice

Forecourt owners need to be more proactive in their approach to their tanks and pipework to prevent problems from happening, according to Steve Watts, UK sales director at Torex Retail. "We can all be guilty of waiting for an event to happen before doing anything about it, but cleaning up after a leak can be a very expensive business," he says.

It’s also costly to the environment and can attract hefty fines, as Shell recently found out. The oil giant was fined £30,000 after almost 3,500 litres of fuel were unaccounted for following a leak from a tank at a Bishops Stortford site, which polluted environmentally-sensitive groundwater.

The leak came from an underground storage tank at Shell’s Oaklands Park petrol station. It polluted a major aquifer within the ’zone of uncertainty’ which, although outside the published groundwater source protection zone for the area, could potentially have been used for drinking water. In November 2006 Shell was fined £30,000 and ordered to pay £5,608 in costs by St Albans Crown Court.

The leak came to light after a series of tests on the tank, after which Shell reported the incident to the local fire authority and the Environment Agency. Wet stock records for January 2004 to January 2005 showed a variance in the tank levels of 3,498 litres. Though some of this could have been down to things like fuel temperature changes, the company accepted that there had been a leak of mixed hydrocarbons into the groundwater.

Shell reported that it first suspected a leak after staff detected fuel odours in February 2005 from monitoring boreholes around the petrol station. Engineers managed to locate the leak to an underground fuel tank storing unleaded petrol.

Says Steve Watts: "We need to have more routine inspections of tanks and lines. Forecourt operators need to be proactive rather than waiting until they’ve got a problem."

There are of course many sites operating with top-notch equipment like automatic tank gauges, leak detectors and wet-stock management systems, but there are probably just as many where operators still use brass dip sticks in their tanks.

"Do these sites carry on and hope they’ll spot a problem before it becomes too big?" asks Watts. "Or do they invest in modern equipment? It’s a dilemma that many older and smaller sites face, but to be fair there are fewer of these around as many have been sold off for alternative use.

"The best-case scenario is that an operator finds a problem within two hours of it happening - the worst is that it’s been going on for weeks or months. A gradual leak starts with a tiny hole - like rust on a car - and then turns into a major problem."

Watts says Torex staff are available to advise operators on the best solution for them. "An all-singing, all-dancing system won’t be for everybody and we are not in the business of selling people things they don’t need. Plus if we advise someone to buy something, they don’t have to buy it from us."

Torex also offers a tank re-lining service where the company empties the tank, de-sludges it, cleans and sandblasts it, then re-lines it with a resin-based double skin. "The tank would then be guaranteed for 10 years and it’s a lot cheaper than putting a new one in," says Watts.

From age-old problems to new ones and Watts reckons the use of ethanol additives in fuel could bring headaches: "These additives have quite a high water content and they also attract water. If left, the ethanol will become saturated with water and it will degrade." He says there could also be a problem with fungal growth.

However one company that reckons it can help forecourts cope with this emerging problem is Cyrus Energy with its Eradicate product.

Managing director Alan Stewart explains: "There’s a type of bacteria in fuel caused by water and biofuels that forms slime and sludge in the tank. We had a problem with it at a truckstop where lorries filled up, drove away and came to a halt just down the road - the fuel was not working properly."

Stewart says that it’s a problem that’s getting worse: "Operators don’t know what to do - they change filters, they empty their tanks but it doesn’t solve it. Condensation and the prolonged warmer weather we’ve been having have just added to the problem."

Eradicate is a fuel biocide - the fluid hits the contamination and kills it off, taking about 24 hours to work. A one-off treatment costs £208 for five litres, which would treat 20,000 litres of fuel.

Cyrus Energy also offers a fuel treatment called Cyrus Fleet. This is a water dispersant based on organic solvent, which absorbs the water like blotting paper, soaks into the fuel and passes through without damage. Stewart recommends sites use it once a month to keep problems at bay. It costs £57.50 for five litres with 10 litres enough to treat 40,000 litres of fuel.

Meanwhile, Nigel Plumb, director at David Plumb & Co, reckons the forecourt industry is wasting millions of pounds a year by disposing of perfectly serviceable fuel storage tanks instead of cleaning them when they have a sludge problem.

"This is done for the best of reasons - safety - but over the years we have proved time after time that tank cleaning can be done in perfect safety as well as cost-effectively. The problem is that the only real way to clean a fuel storage tank is for a person to go inside and physically clean it. But as even empty tanks contain an explosive mixture of fuel vapour and air, many companies have adopted a policy, when they have a sludge problem, of solid filling their tanks, removing them, expensively disposing of them and replacing them with new ones. In our view this is like changing the car because the ash tray is full."

Plumb insists that the cleaning method his company has developed saves all this expense and can be done in perfect safety: "We would never put one of our people in danger. After 39 years of operation, we know what we are doing."

Putting men into tanks is undoubtedly risky which is why some oil companies have stopped doing it altogether. Mark Orr, corporate development director at Liquid Cargo Management, comments: "Petrol companies are much more risk averse today and feel a corporate responsibility to avoid tank entry unless it’s absolutely necessary.

"This is why we have formed a partnership with Tanknology UK and together we sell and operate Petroscope, a remotely-operated camera that goes into a tank, purged with nitrogen, to carry out high-quality remote inspections. The results of these inspections are passed to a corrosion engineer who then reports on the findings and makes recommendations on future maintenance."

Darrin Francis, general manager at Tanknology, adds: "It’s new to the UK but used widely in the US. We used it around 30 times here in 2006."

He says the cost of using Petroscope is dependent on the size of the tank but reckons you get a much fuller picture of your tank from using the camera rather than putting a man down. "Customers get a DVD of the inspection so they have the opportunity to judge their tanks for themselves."

Meanwhile Orr says that LCM is still doing a lot of de-commissioning and it remains his company’s main focus. However, he adds: "Tank inspection, tank maintenance and tank lining are very important aspects of giving clients a total service package for their tanks."

When it comes to pipework, Orr says the major problems are poor maintenance or poor installation. "Maintenance is expensive and it is sometimes not done when it should be, so problems build up over time. They then cost more to fix than if the ongoing maintenance was done. Agreeing a standard between all operators would make installations simpler. But we have a lot of old garages that have changed owners many times and as a result there are sometimes terrible difficulties in sorting out the pipework."

Continuing with pipes, and PetroTechnik says its UPP is a complete leak-tight sump-to-sump system that will last the lifetime of any site, ensuring cost-efficient fuel delivery and complete protection for the surrounding environment. Manufactured from high-density polyethylene, the UPP system is tough, corrosion resistant and, once installed, is said to need no further maintenance.

The company’s existing UPP pipework system has secured UL and cUL 971 approvals from the Underwriters Laboratories in the US. While PetroTechnik says many competitors have designed completely new systems, it has just made some minor changes to its existing UPP pipework system, keeping the basic pipe construction the same.

A spokesman for the company says: "Not only does this mean that our customers have access to a well-proven pipework system - as this generation of pipe has been in the field since 1996 - it also means that UPP UL-approved pipework is available at very competitive prices."

The new UL-approved UPP System is still entirely electro-fusible and existing fittings and electro-fusion seals are all compatible.

In tanks, PetroTechnik has introduced a new UPP polyethylene tank access chamber. The riser section is electro-fused to the base meaning no multiple boltholes and foam gaskets - the average two-piece tank chamber has 24 holes drilled into it to allow the riser and base to be bolted together. The company reckons this fusion system reduces installation time. No scraping is needed of the surfaces to be fused as the components are packaged with protective covering. Instead of drilling holes and using corrodible metal fixings to join the chamber riser to the base unit like all other two-piece chambers, the UPP Electrofusion chamber welds together in a single nine-minute weld. Once cooled 20 minutes later, it gives a perfect seamless joint, with no holes, no bolts and no leak paths. The base of the chamber is 425mm (16.7") high, allowing for easy installation of pipework before the riser is fused on. The burial depth of the complete system is 1.75m (5.75 feet) maximum or 1.3m (4.25 feet) minimum.

Meanwhile, PetroTechnik subsidiary, Cookson & Zinn, has won the BP Bovis Alliance Incident and Injury Free Award for best new idea and the APEA award for Innovation on the Forecourt for its new base frame tank. Base frames and holding down straps are factory-fitted to conventional underground storage tanks, eliminating the need for site personnel to enter an excavation area while tanks are being placed in position. Once in situ, concrete is poured from above to cover the base frame.

Previously, one of the main areas for potential accidents has been while attaching the crane hooks and guide ropes when the tanks arrive at the site. This is normally done by climbing a ladder which can slip causing the person involved to fall. CZ now attaches the lifting slings, shackles and guide ropes at the factory, securing the slings on the vehicle bed for transportation.

The crane hook can then be attached at ground level, eliminating the need for anyone to climb onto the tank on site.

Finally, PetroTechnik’s customers can now find quality-assured installers at the click of a button following the company’s investment in a secure online installer-training database.

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=== Tank talk with edensure ===

Martin McTague, managing director of Edensure, says part of the problem with underground steel storage tanks is that they have a limited life expectancy. "Corrosion can begin from the time they are installed. More disturbing for the owner, is that they can do nothing about it, except line the tank or excavate the site and replace it. Either way, the associated disruption, unscheduled on-cost, loss of trade and bottom-line impact, can seriously damage business. Many owners simply hope for the best, others buy an automatic tank gauge. They then wait until the signs of a leak appear in the hope that when disaster strikes they will discover it quickly and the damage is not too costly to clean-up."

He says line leaks are very common too. "They can sometimes be caused by corrosion, although in most cases the cause is poor installation. Early signs are pumping problems and as they are generally smaller, the leaks can go undetected for longer.

"About 60% of underground tanks in the UK are single-skin and old. External pitting corrosion is the most common cause of failure and this starts as a tiny pin-hole usually in the lower half of the tank. With the storage of slow-moving products like Super Unleaded and LRP, there is a new risk of internal corrosion caused by microbial attack. Exposure to this risk will increase as the tank population gets older. Low margins mean owners do not have resources to invest in new tanks/lines. Weak enforcement of legislation will allow poor operators to take risks with safety and the environment."