Which appliance merges two or more hoselines into a single hoseline?

• A. Wye appliance
• B. Siamese appliance
• C. Gate valve
• D. Water thief

Answer: (B)

The device that merges two or more hoselines into a single hoseline is a Siamese appliance. It’s a connector with two or more inlets and one outlet, allowing two separate lines to be joined into one larger line so water from both feeds can flow through a single hose or nozzle. This is handy when you need to combine flows from multiple sources (like two hydrants or two attack lines) into a single, high-volume supply.

A Wye appliance, by contrast, is used to feed two lines from a single source, effectively splitting a line into two. That’s the opposite of merging. The other options are valves or devices used for different purposes and don’t serve to combine multiple lines into one.