What is the procedure for engaging Class A foam using an on-board foam tank?

Engaging Class A foam using an on-board foam tank involves a specific sequence of actions to ensure proper mixing and application of the foam. The correct procedure typically includes engaging the water pump transmission first, which allows for the water system to be operational and the appropriate pressure to be established in the system. Recirculating before flowing water helps to ensure that the foam concentrate is properly mixed with the water before it reaches the discharge.

By recirculating water through the system, particularly when using an onboard foam tank, the foam is better integrated into the water stream, allowing for an even distribution of foam when it is subsequently flowed. This method is critical because it ensures that the foam is not only present but is also effectively delivered to assist in fire suppression. Flowing water after these steps ensures that the system is fully operational and that the foam solution is ready for immediate application.

In contrast, other choices may suggest alternative sequences that do not fully establish the correct operational parameters necessary for effective foam application, compromising the performance and effectiveness of the foam in firefighting efforts.