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Fuel Sampling

Sampling for Water and Microbial Growth Management

Regular fuel sampling for visual signs of microbial growth, checking the fuel system for corrosion and testing for microbes is am imperative especially when free water is found in the system. If bottom samples reveal water, then the likelihood of microbial contamination is almost certain. If the fuel itself is found to be cloudy, dark or both then fuel degradation has reached a critical stage and immediate action needs to take place.

The combination of water in the tank, moderate to severe corrosion on system parts and cloudy or dark fuel indicates poor fuel quality. When fuel visually looks good it can be difficult to determine whether there is something else lurking. That is why microbial testing is so important. If it is caught early then biocides can be used to kill the infection and reduce the degradation process and the potential for system damage. Monitoring for microbial contamination is a necessary part of maintaining fuel quality. Field tests are an economical way of providing the information needed.

Bottom Sampling Basics

All fuel analysis requires proper fuel sampling. Generally, samples should be taken from the lowest point in the tank using a bottom sampler like the one shown below.

Additionally, samples can be taken mid-tank or upper-tank to determine the visual quality of the fuel and to test. When sampling fuel, a stainless or aluminum construction is preferred. Brass samplers can effect test results as the metal reacts with fuel. Porous materials are also not recommended. When sampling, use clear glass jars for visual inspection of the fuel. There are limitations to sampling. A spot sample only provides a sampling from one particular point in the tank. However limited, sampling remains the best approach to determine what is in your tank.