Question about radiation

Flying

Hi,friends:

I am modeling a torch with CFX5.7. Radiation is the most important for me, especially the radiation intensity decides the safety distance. Now I find the "radiation intensity" in CFX5.7 is directional radiation instansity, and its unit is W m^-2 sr^-1. CFX5.7 gives "incident radiation", and I don't know what it means.

Could you give me some advice about it? How can I get radiation intensity correctly?

Thanks!

Flying