ISO 6295:1983

Petroleum products — Mineral oils — Determination of interfacial tension of oil against water — Ring method

Specifies a procedure for the measurement, under non-equilibrium conditions, which has been shown by practice to give a reliable indication of the presence of hydrophilic compounds. This tension is determined by measuring the force necessary to detach a planar ring of platinum wire from the surface of the liquid of higher tension, that is, upward from the water-oil interface.