Builder Bob
SAWHORSE
Currently reviewing a won door being installed as a three hour opening protective between wings of a school - Fire wall cut buildings in half for area limitations. The termination wall has a recessed pocket receiver that cuts the depth of the 8 inch blow down to 3 5/8" thickness if filled solid with grout - Calculated fire resistance of the IBC indicates that this is only good for 1 3/4 hr. rating at this point. The Evaluation report from ICC indicates that the door and related materials have been tested for the time periods listed - The fire door (won door) is slightly offset and terminates into a 8 inch block wall that will carry a 3 hour rating UL U904.

Am I really just overthinking this?
Builder Bob

Am I really just overthinking this?
Builder Bob