scope:

This International Standard specifies a procedure for determining the sulphated ash from unused lubricating oils containing additives and from additive concentrates used in compounding. These additives usually contain one or more of the following metals: barium, calcium, magnesium, zinc, potassium, sodium, and tin. The elements sulphur, phosphorus, and chlorine may also be present in combined form. Application of this method to sulphated ash levels below 0,02 % (m/m) is restricted to oils containing ashless additives. The lower limit of applicability of the method is 0,005 % (m/m) sulphated ash. The sulphated ash may be used to indicate the concentration of known metal-containing additives in new oils. If phosphorus is absent, barium , calcium, magnesium, sodium and potassium are converted to their sulphates and tin and zinc to their oxides. Sulphur and chlorine do not interfere, but, if phosphorus is present with the metals, it remains partially or wholly in the sulphated ash as metal phosphates.