Which fitting is commonly used to extend a larger hose line by connecting a smaller hose line to the end?

The correct answer is the device commonly known as a reducer. This fitting is specifically designed to connect a larger hose line to a smaller hose line, allowing for effective extension of the water supply while ensuring that flow rates and pressures can be managed effectively. Reducers are essential in firefighting scenarios where it is necessary to draw from different sizes of hoses, accommodating the flow from a larger diameter hose to a smaller one for easier handling and strategic deployment.

While elbows, T-wyes, and adapters serve important functions in fire service operations, they do not serve the specific purpose of connecting different hose sizes. Elbows are used to change the direction of the hose layout, T-wyes create branch lines, and adapters facilitate the connection between two hoses or nozzles of similar diameters or functionalities. Each of these fittings has its unique applications, but when it comes to extending a hose line by reducing the size, the reducer is the appropriate choice.