I guess the question says it all.
There is a uniform code for the distance and throw of wood material from the fire box.
Is there a specific Florida requirement?

FBC, Residential 1001.11 ex. 4 - short answer is 6" min. clearance to combustible mantel or trim. there is other words about stuff but I really can't bring myself to understand them!

Yea it is really tough to interpret.
There are Graphical charts but they are so vague?
Some contractors say 1/8 inch projection per inch away is a rule of thumb.
But then they talk about from the firebox,Meaning that if you have a zero clearance wood unit. That means from the firebox(inner layer) not the outside dimensions.

There are many concerns with combustibles surrounding fireplace openings. 2007/9 FBC-Residential Chapter 10 governs chimneys and fireplaces. Section R1001.11 Exc.4. Governs combustible mantels. They can be no closer than 6" to the opening and if from 6" to 12" of the opening they shall project no more than 1/8" per inch of distance from said opening. Meaning that if a mantel is 11" above the opening then it can project past the face no more than 1-3/8"...think heat. As wood drys and chars from exposure to heat the more easily it combusts...similar to older romex TW insulation roasting in an attic and becoming brittle.

Good answer. Finally someone that seems to appear to understand this convoluted code.
Okay well think this then.
You have a firebox flush with say the drywall per say.
Then you have 4" brick on the face. so the fire box is recessed 4" from the get go because of the brick. Now you want to build a mantel surround.
What would be the Maximum projected lumber from the brick with a 8" clearance from the firebox on all sides?
We have 4" of brick projection from the face of the fire box to start with.
So is a 8" distance from the firebox still considered 8" so meaning the projection of lumber is only 1".

Almost correct...The face of the fireplace is the brick veneer face. The actual firebox is subject to other code but the mantel is from the opening in the face. So 8" from the opening would allow a 1" projection from the face. A normal fire drafts up the throat but all fireplaces are not equal...some work some don't.

Okay,old school mentality told me the actual face to measure from is the face of the firebox not the surface of the brick venneer.

Looking at this some more.
What happens to the projection once you get beyond the 12"?
I did not see a reference past the 11"
If you have a mantel that is 17" above the fireplace.

The mantel may extend more but within reason. This would become a judgement call on the inspector's part but the FBC-Mechanical does not address beyond 12" away from the opening. For a massive mantel you might consider stepping the stone or brick veneer out for mor protection and strength...Set some AFCI tamper-resistant receptacle above the mantel as well...