I found this article which should help better understand the building code in Florida and where the 20 minute fire rating came from.
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But the way it is actually stated in the Residential Edition of the Florida Building Code is a “separation” between dwelling and garage, and as “not less than 1/2-inch gypsum board or equivalent. The International Residential Code (IRC) is similar.
Most homes have a 1/2” drywall panel installed in the attic access opening, which is fine. But when you put something else in the opening, it must be equivalent to 1/2” drywall, which has roughly a 20-minute fire resistance. The 1/4” plywood panel at most attic ladders does not meet that standard.
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So if you make any hole in your garage ceiling, if there is no living space above it, you need to fill the hole with 1/2" drywall or anything that has an equivalent 20-minute fire resistance. If there is living space above then you need 5/8" TypeX sheetrock and a 1hr fire resistance rating which is significantly more strigent is needed. The idea is to allow enough time to exit the residence in case of a fire. The insurance aspect is secondary.
The link to the article is here ->
Why are most pull-down attic ladders not approved by building code for installation in a garage?