# Transport Index (TI)

**Published:** Oct 22, 2023

The **transport index** (**TI**) is a special number applied to the labels of Type A and Type B **radioactive** packages for transport (as specified by the ADR legislation and IAEA - "*Regulations for the Safe Transport of Radioactive Material*", 2018, SSR-6). The formal way of determining the TI is to measure the **dose rate** at 1m from the package, (from all sides that are reasonably accessible to obtain the highest value), in mSv/h. This value is then multiplied by 100 and rounded up to the first decimal place. **Example**: The maximum dose rate at **1m** from a package is found to be **0.0127 mSv/h**. This is multiplied by 100 to give 1.27, and this is then rounded up to give a **TI** of **1.3**.

An alternative method is to measure the dose rate in micro Sv/h and then divide this value by 10 and then round up as before. **Example**. The maximum dose rate at **1m** from a package is found to be **12.7 micro Sv/h**. This value is then divided by10 to give 1.27, and this is then rounded up to give a **TI **of **1.3** (as above).

The TI should be made up of the sum of all radiations present, which in the main will be **gamma** radiation but could also include **neutrons** (in the case of an **AmBe** source or a radionuclide such as Cf-252). Where possible the neutron dose rate should be measured with a neutron monitor, a TI calculated, and then summed with the gamma TI to provide the full transport TI. However, it is often common practice to infer the neutron dose rate from a known ratio of neutron to gamma dose rates (this having being determined by the source supplier or by the user where both gamma and neutron monitors are available periodically).