The ISO 4406 Cleanliness Codes are national standards that provide guidelines for the level of diesel cleanliness that must be maintained in vehicles, equipment and machinery to limit emissions. There are three different sets of ranges: ISO 22/21/18.

These codes have been derived from International Standard ISO 4406:99 and are used as a way of quantifying levels of contamination per millilitre of fluid. The contaminant particles are tested at 3 sizes 4, 6 and 14 micron, with a specified number of these particles allowed to be present in 100 ml of fuel or oil in vehicles, equipment and machinery. The 4-micron particles are referred to under code 22, the 6-micron particles under code 21 and the 14-micron particles under code 18. If fuel or oil is tested showing a higher level of particles being present than the codes outline, then diesel cleanliness is deemed to be unsatisfactory.

ISO 4406 Cleanliness Codes are essential to keep emissions under national standards, as well as to avoid resources being drained unnecessarily because of fluid contamination issues causing poor vehicle or machinery performance. 

It's important to maintain your vehicles, equipment or machinery's hydraulic or lubrication systems at a high standard of fuel cleanliness. Having an efficient filtration system is a critical factor in keeping cleanliness standards. Contaminated fuel can block fuel filters, reduce the engine’s air flow and needlessly increase wear and tear on engine components.

To ensure your vehicle or machinery's fluid systems are maintained to ISO Fluid Cleanliness Standards, finding a quality fuel storage and filtration system is essential. To achieve this, we conducted 6-month tests on our Final Filtered Diesel^® and exceeded ISO compliance, using our state-of-the-art fuel filtration system built in conjunction with our filtration partner HYDAC. The details of these tests, and the results that came out of them, are available in our Final Filtered White Paper.

Sign up to our Bulk Fuel Australia's white paper which provides an in-depth look at the filtration process and final filtration or filtering diesel at its final exit point before it reaches the fuel tank of your machinery or vehicle.