What is each fire pump impeller in a housing commonly referred to as?

The term "stage" refers to each fire pump impeller within its housing. In fire pump systems, especially multi-stage pumps, each impeller contributes to the overall pressure and flow of the pump. A multi-stage pump incorporates several impellers arranged in a series, and each individual impeller is called a stage. This design allows for increased efficiency and greater pressure output compared to a single impeller design.

Chamber is a general term that might be associated with areas within the pump but does not specifically refer to the impeller. Unit refers to the entire pump system rather than individual components. Propeller is more commonly used in reference to marine applications or specific types of hydraulic devices and does not accurately describe the function of a pump impeller. Therefore, "stage" is the precise term that captures the role of each impeller in enhancing the pump's capabilities.