Others

Certain impurities result in discolouration of the wall wash sample. The colour of the wall wash liquid is compared with unused wall wash solvent. Mostly the so-called Apha colour is measured. More details about Colour can be found here.

Used to determine if there are non-volatile impurities on the tank surface. A defined quantity of the wallwash liquid is evaporated. The weight of the residue, the so-called NVM (Non Volatile Matter), is detected by weighing. This is then divided by the original weight of the sample. The NVM content must not exceed the value specified by the loader.

Some companies have implemented a so-called COD test for determination of impurities. COD stands for Chemical Oxygen Demand. The impurities are extracted by means of a solvent and analysed with an oxidiser like potassium dichromate.