TLDR, can I have a full size wood mantlet (5 in+) 12 inches away from the fireplace openings top?
I am reading the fire codes
Exposed combustible mantels or trim may be placed directly on the masonry fireplace front surrounding the fireplace opening providing such combustible materials are not placed within 6 inches (152 mm) of a fireplace opening. Combustible material within 12 inches (306 mm) of the fireplace opening shall not project more than 1/8 inch (3 mm) for each 1-inch (25 mm) distance from such an opening.
Does this mean if I had a 3 inch mantel, which is pretty stubby, I would need 6 inches + 21 inches? 27 inches is massive. My fireplace top opening is at 37, and my ideal height (top) is 53 inches, maybe 49 inches off the ground. Or is it saying that I can have at most 6/8 inches unless its over a foot away? The wording is super confusing.