vent clearnace

Hi All,
When the water heater vent pipe clearance is ok, is a metal flashing the proper way to complete the fire rating of the wall or ceiling. Also shounld the flashing be sealed with high temp caulking or sealant.
Thanks so much,

Metal flashing is common in my area. If it is going through a wall or ceiling that suppose to be fire rated, it will need to be caulked.