Diesel and domestic heating fuels. Determination of cold filter plugging point. Stepwise cooling bath method
The determination is carried out until the temperature at which the wax crystals released from the solution onto the filter stop or slow down the flow of the fuel to such an extent that the filling time of the pipette exceeds 60 s or the fuel does not drain completely into the test vessel.
The European standard EN-116 establishes a method for determining the limiting filterability temperature on a cold filter for diesel and domestic heating oils.
The method is applied to distillate fuels, including fuels with flow improvers and others for diesel engines and for domestic heating systems.
Usually, the lowest temperature at which the fuel starts to flow poorly is estimated. Diesel fuels tend to perform close to the temperature at which they are unusable, unless the fuel system, for example, has a filter paper escaping to the atmosphere.
Domestic heating systems are generally less hazardous and often operate satisfactorily at temperatures slightly lower than those specified in this method.
The method consists in gradually cooling the test fuel at 1 °C intervals under specified standard conditions and draining it through a standardized filter wire mesh at 20 mbar vacuum.