What type of standpipe is not required to be hydrostatically tested at 200 psi or 50 psi in excess of 150 psi?

• A. Dry standpipe
• B. Wet standpipe
• C. Combination wet sprinkler/standpipe
• D. Portable standpipe

Answer: (C)

Hydrostatic testing pressures for piping are chosen based on how the system is used. Standpipe piping is built to withstand a high pressure to simulate firefighting conditions, so dedicated standpipe systems (dry or wet) must be hydrostatically tested at the standard standpipe pressure (200 psi, or 50 psi above 150 psi if that dictates the test).

A combination wet sprinkler/standpipe system is designed to serve both sprinklers and standpipe outlets from the same piping. Because its primary design is tied to sprinkler system testing criteria, the standpipe portion does not have to be hydrostatically tested separately to the standpipe-specific 200 psi. In other words, the standpipe portion of a combination system isn’t required to undergo that standalone high-pressure hydrostatic test, even though dedicated standpipes are.