How to spot fuel contamination in your storage tanks

The good news is you don’t have to be Sherlock Holmes to spot if your fuel is contaminated, the bad news is if you can actually see the signs of contamination the problem is already serious.

On sites where power is critical (such as datacentres, hospitals and military bases) backup generators will be employed to cover any failures in the mains supply. Under normal conditions these units will run for just minutes each month as part of a maintenance programme. But this leads to the storage of large amounts of fuel over a long period of time. This practice carries a stark warning from engine manufacturers and even diesel suppliers that advise if storing fuel any longer than 6-12 months it will lead to fuel contamination. But how can you find out if your fuel is contaminated?

The safest, most accurate way is to have it properly tested with an IPU DieselCheck test. This is because once you start to physically seeing the signs of fuel contamination the situation has already become serious and your generator stops running. But if you haven’t had it tested a common first sign you’ll spot is when the fuel filter starts to become blocked by a greenish-black or brown slime, frequently accompanied by a foul odour. If left, this slimy, string-like colony can also plug sharp bends in fuel lines and fuel meters.

Another issue is that microorganisms can cause corrosion due to the acid by-products they produce. Some microorganisms will even pass through the standard fuel filters which can form deposits and cause damage in the fuel pump and injectors.

Additionally, as fuel ages colloid carbon particles naturally form., these are microscopic particles of carbon that will also pass through filters and damage fuel pumps by hindering lubrication and fuel injectors on compression burn.

Other indicators of contamination are:

  1. Slime deposits of a wax formation that can block fuel lines and seize fuel injectors. These deposits are usually greenish-black or brown and are slick to the touch.
  2. Black or brown “stringy” material suspended in tank water bottoms.
  3. Swelling or blistering of any rubber surface (washers, hoses, connectors, and so forth) that comes in contact with fuel.
  4. Sludge or slime deposits on filter surfaces.
  5. Foul odour resembling that of rotten eggs (hydrogen sulphide).

To ensure your fuel is reliable you should regularly test your fuel as part of your maintenance programme, but if you haven’t and you witnesses any of the above symptoms, you must contact IPU urgently. An IPU Fuel Test can provide you with a full report on the diesel in your tank and a recommended course of action. If your fuel is found to be contaminated our fuel conditioning programme can restore you fuel to ISO EN590 certified condition.