The document specifies a method for determining the viscosity of industrial cellulose nitrate, usually referred 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 which is based on viscosity measurements made using this method. The use of a standard procedure results in """"standard"""" types and avoids classification differences which could be caused by the fact that there are many ways of determining viscosity and a wide variety of solutions available.