Transport index is the maximum radiation level in mSv/hr, at a distance of 1 meter from the external surface of the package, multiplied by 100

TI = Radiation level at 1m (mSv/hr) x 100

TI 0.05 can be considered as 0

The packages can be categorized based on the Transport Index

What is package?
The packaging with its radioactive content as presented for transport

what is packaging?
The assembly of components necessary to enclose the radioactive contents completely

Packaging + radioactive content = package

Packages are categorized based on TI into three categories
I – white
II – yellow
III – yellow
III – yellow (exclusive use)

Transport Index	Maximum dose rate on the surface	category
0	upto 5 µSv/hr	I – white
> 0 to 1	> 5 µSv/hr to 0.5 mSv/hr	II – yellow
> 1 to 10	> 0.5 mSv/hr to 2 mSv/hr	III – yellow
> 10	> 2 to mSv/hr to 10 mSv/hr	III -yellow (exclusive use)

UN classification number: class 7 for radioactive materials

Reference

Rajan, KN Govinda. Radiation Safety in Radiation Oncology. CRC Press, 2017.