Fire-rated window assemblies close to side property line.

[Mike NY]

We are designing a new project located in Mamaroneck, NY. It is a 4 story mixed use building. It is a R-2 IIIB Construction. The interior is sprinkled. We need to put windows in a wall that is located 3'2" from the side property line. The total wall opening % for the windows is around 22%. The approach we are taking to get to less than 15% protected openings is to make most of the windows 45 minute fire-rated assemblies and for the remaining windows to be 1 hour rated assemblies so that these can qualify as a wall and not count as an opening. Is this the right approach in regards to the fire-ratings? We are trying to use steel frame windows made by Optimum.
Thanks.

[Jerry Peck - Codeman]

[Mike NY]

Thanks for your answer. The sprinkler system is NFPA 13, Not NFPA 13R, according to the sprinkler plans.
There is one thing that I am not clear about. If a window assembly is one-hour fire rated for both sides, does it technically count as a wall and not an opening?

[Jerry Peck - Codeman]