What are the limitations of using excepted packages for radioactive materials (Class 7)?

Excepted packages for radioactive materials (Class 7) are subject to significant limitations regarding the type and quantity of radioactive material they can contain, the surface dose rate, and the packaging requirements, restricting their use to very low-activity shipments. The primary limitation is the quantity of radioactive material that can be included in an excepted package, which is significantly lower than the limits for other types of radioactive material packages. These quantity limits are specified in the IMDG Code and depend on the specific radionuclide. The surface dose rate, which is the amount of radiation emitted from the surface of the package, is also strictly limited for excepted packages. This limit ensures that individuals handling the package are not exposed to excessive radiation levels. The packaging requirements for excepted packages are less stringent than for other types of radioactive material packages, but they must still meet certain minimum requirements for strength and integrity to prevent leakage of the contents during normal conditions of transport. Excepted packages are typically used for transporting items such as smoke detectors, radiopharmaceuticals in very small doses, and certain instruments containing radioactive sources. They are not suitable for transporting larger quantities of radioactive material or materials with higher activity levels. The labeling and documentation requirements for excepted packages are also simplified compared to other types of radioactive material packages. However, they must still be marked with the word "Radioactive" and meet certain other marking requirements. Because of these strict limitations on activity levels, dose rates, and packaging, excepted packages can only be used for a very limited range of radioactive material shipments. For shipments exceeding these limitations, other types of radioactive material packages, such as industrial packages, Type A packages, or Type B packages, must be used, which require more stringent packaging, testing, and documentation requirements.