This International Standard specifies a method of determining the viscosity of industrial cellulose nitrate, usuallyreferred to as nitrocellulose, the nitrogen content of which can vary between 10,7 % by mass and 12,6 % by mass,depending on the type.It also gives a classification system for industrial cellulose nitrate solutions (see annex A) which is based onviscosity measurements made using the method. The use of a standard procedure results in "standard" types andavoids classification differences which could be caused by the fact that there are many ways of determiningviscosity and a wide variety of solvents available.