Approved backflow protection assemblies are generally not required for AWWA fire system classes:

In the context of fire protection systems, particularly those classified by the American Water Works Association (AWWA), certain classes of systems are designed for specific applications and under certain conditions that may influence the need for backflow protection assemblies.

Classes 1 and 2 fire systems typically operate under conditions where the potential for backflow into the potable water supply is minimal, such as when only city water or non-hazardous fluids are involved, and the risk of contamination is low. Therefore, these systems do not mandate the installation of approved backflow protection assemblies, as they are considered to be low-risk scenarios.

On the other hand, higher classes, such as Class 3 and above, may deal with more substantial water flow and potential hazards, which increases the risk of contamination of the water supply, thus requiring backflow prevention measures to ensure public health and safety.

Understanding these classifications helps clarify why classes 1 and 2 are treated differently with respect to backflow protection requirements in fire suppression systems.