ISO 5313:1986

High nitrogen content, straight ammonium nitrate fertilizers — Determination or oil retention

The result of the method is a measure for the porosity of the material. The method is applicable to substances which do not contain materials soluble in gas oil and which are prilled or granular. It consists in total immersing of a test portion in gas oil for a specified period, followed by the draining away and the removal of surplus gas oil under specified conditions, and measuring of the increase in mass of the test portion.