This International Standard specifies a method for the determination of the corrosiveness to copper of liquid petroleum products and certain solvents. Volatile products, having a maximum vapour pressure of 124 kPa at 37,8 ℃ are included. Volatile products with a vapour pressure above 124 kPa at 37,8 ℃ should be tested according to ISO 6251 (see caution below). Electrical insulating oils should be tested according to ISO 5662. CAUTION — Some products, particularly natural gasolines, may have a significantly higher vapour pressure than is characteristic for their class, even if below 124 kPa at 37,8 ℃. For this reason, extreme caution should be exercised to ensure that the pressure vessel containing such material is not placed in a bath at 100 ℃. Such samples may develop sufficient pressure at 100 ℃ to rupture the pressure vessel and cause damage and/or injury.