Fuel quality testing is one of the most cost-effective ways of protecting your engines against costly damages. Freshly produced fuel from the refinery meets the standards of cleanliness, which includes a maximum acceptable level of unavoidable contaminants. However, Fuel quality may be compromised in the transport process and any time the fuel is transferred between containers.

Contaminated fuel is one of the leading causes of engine failure and disruptive equipment, especially in sea vessels and emergency power supply units. However, you can avoid these challenges by conducting regular fuel testing as it will help you identify contaminated fuel before the damage is done.

This article will help you understand the importance of fuel testing, the types of fuels that need regular testing and what is involved in fuel quality testing.

Why Should I Have my Fuel Tested?

Testing your fuel is now more important than before because of the EN590 fuel regulation amendment. This amendment encouraged lower use of sulphur content in fuel and increasing FAME biodiesel content.

Scientists believe that these actions will expose fuel to the risk of increased contaminants that will decrease its quality.

The contaminants in fuels can lead to increased wear and cause damage to some parts of the engine. They also cause the clogging of filters, which will eventually lead to fuel starvation. Testing the quality of your fuel is one way of ensuring that your engines run efficiently, plus it will help you prevent premature engine failures.

Types of Tests

Different fuels can have different standards when it comes to fuel quality testing. Below are some of the common types of tests.

Water and Sediment

As the name suggests, this test measures water and sediment in the fuel. The test is specifically important for agencies that store emergency fuel as it ensures the smooth operation of machinery when needed. A high amount of water and sediment can cause corrosion of storage tanks and also damage equipment.

Microbial Contamination

This test helps in determining the number of microbes in a unit of fuel. Since the test used biocide to determine the presence or absence of microbes, polishers run it on finished fuel as it will confirm if the biocide worked as intended.

Flash Point

This test helps in determining the temperature at which the fuel vapour will ignite. Each type of fuel has a standard minimum flashpoint, and failure to meet this flashpoint shows that the fuel is contaminated. Such fuel cannot burn properly in the engine.

Cetane Number

This test is most common in stored diesel fuel as it shows the capability of the fuel to run properly in a diesel engine. Your stored diesel should meet the required minimum Cetane rating to prove that it is of acceptable quality. The calculation of the Cetane index combines the distillation value of the fuel and its density.

Cloud Point

This test is crucial during cold weather as it helps you prevent your fuel from gelling up to the point of shutting your engine down. Cloud point is the temperature at which the fuel becomes cloudy as a result of wax crystals dropping out of solution. A majority of fuels only have a narrow temperature gap from cloud point and the temperature at which the fuel gels up.

How to Take Samples

The only way of ensuring that you can accurately identify the health of the fuel in a storage tank is by taking samples from the top, the middle and the bottom of your storage tank.

The bottom sample will help analysts in detecting contaminants such as water and particulates, and the middle sample will show the degree of settlement of any contaminant present. Analysts use the top sample to determine what is achievable if the fuel was to be polished.

Unlike emergency storage tanks where contaminants are concentrated at the bottom, tanks that receive frequent deliveries may require more samples as they have will have contaminants dispersed throughout the fuel.

How Often Should I Get My Fuel Tested?

The major factors that determine the frequency of fuel testing are its application, the industry and the amount of fuel consumed. Stored fuel can be used regularly or may be stored for longer periods when it is intended for emergency use.

Stored fuel requires regular testing as it is most likely to be compromised by many issues like rainwater, condensed atmospheric moisture and dust/dirt that may find its way into the storage through breathers and poorly-fitted inspection hatches.

It is advisable to regularly test your fuels (at least twice in a year) if you have stored it for emergency uses like back-up power. You can do the first test at the start of winter months when you are switching to winter-grade fuels and the second test when switching back to normal blend.


Since fuel is prone to contamination during transfer and storage, anyone who stores fuel for later use has a responsibility of regularly testing to for contaminants like water, microbial contamination, mineral sediments and many more.

Regular oil analysis can help you identify harmful contaminants before they cause a major problem in your machines, thus saving you huge amounts of money that you would spend in repairs and replacement of parts. Without regular testing, you will not know when your fuel is contaminated with intruders like water and dirt.

You can hire professionals to do these important tests for you if they are not part of your fuel supply package.