Is it neccesary to have masonry filled cells with rebar above and below window openings? Is there any code requirement for that ?
I see some builders add them and some don't.
Reinforcement at the sill and header generally allows for consideration of those elements as reinforced masonry.
If they are not reinforced, they would have to be justified as a non-reinforced section.
Typically in South Florida, I find that reinforced masonry is required for the high wind loads to meet strength and service requirements. At a 144 inch span, my gut feel would be that reinforcement is needed. The consideration for the header is made slightly more complicated if the masonry wall is load bearing.