what might be considered a safe distance from the dome wall?

Dear Bob,
hi my name is Steve and I’m currently helping my friend Hetti who recently brought some domes from your company. We would like to install a wood burner into the dome and I have a query as to what might be considered a safe distance from the dome wall? Also would you recommend some sort of heat shield to protect the dome directly above the burner?
Kind regards Steve Wyse