The type of auxiliary valve most often used is directly connected to the hydrant by what type of connection?

• A. a threaded connection
• B. a welded connection
• C. a flanged connection
• D. a compression fitting

Answer: (C)

Auxiliary valves on hydrants are designed to be easily isolated and maintained without tearing apart the main line. A flanged connection provides a strong, leak-tight, bolted joint that can be quickly disassembled for maintenance or replacement of the hydrant or valve. This robustness and serviceability are why flanged connections are the most common choice for directly linking the auxiliary valve to the hydrant. Threaded joints can leak and are harder to seal reliably on large hydrant lines; welded joints aren’t easily disassembled for maintenance; compression fittings are generally not suitable for main-line hydrant connections due to size, strength, and disassembly needs.