It depends. FRTW may be required by code or selected by choice.

The authority-having jurisdiction (AHJ) determines through adoption of model codes (e.g, IBC, IWUIC, etc.) whether or not ignition resistant FRTW is required. This varies by city, county, and state, and is influenced by other factors like fire hazard severity zones (FHSZ-California), wildfire resiliency codes (WRC-Colorado), wildland urban interface designation (WUI), as well as other code amendments, design considerations, and client preferences.

In short, the best practice is to contact your AHJ (i.e., building and fire officials).