FRTW is allowed by UL to be used in any listed wood-frame wall assembly. A recent test at UL has resulted in a unique listing for a 2-hour fire-resistance rated bearing wall assembly of Pyro-Guard fire-retardant-treated lumber and Pyro-Guard fire-retardant-treated plywood. This new listing, UL Design No. V314, covers the vast majority of structure exposures providing an alternative to those designers wanting an UL Design number.
Building construction and life safety codes are concerned with the types of materials used in buildings. Their concern is rooted in risk posed by fire to the structure and persons using it. Both aim to reduce property loss and protect life safety. Both codes incorporate a holistic implementation of fire protection and life safety requirements within the scope of each code. As a result, applications for combustible materials, such as wood, are limited, especially in unsprinklered and larger multistory structures. These codes and their referenced standards recognize the benefits of pressure impregnating fire retardants into wood. Fire-retardant-treated wood (FRTW) does not require water or electricity to protect the wood and therefore provides passive protection. When properly installed according to code requirements, FRTW never needs additional inspection or service and is free of these ongoing maintenance costs.
You can read more about UL Design No. V314 at UL's Website.