We're going to Fargo! For a dry system of course...

If you dump hundreds of gallons of city water into an unheated parking ramp dry system in the middle of a Minnesota January during a routine annual inspection, you aren't just an idiot—you're going to burst system branch lines and freeze out the jobsite. Yet, half the apprentices taking the journeyman exam lose points because they think a dry valve has to be tripped full-flow every single year. Today we’re breaking down NFPA 25 Section 13.4.4.2 so you know the exact line between the annual partial-flow test and the 3-year full-flow test when the state examiner puts the pressure on.Annual Partial-Flow Trip Test (NFPA 25 [2017], Section 13.4.4.2.2.1):A partial-flow trip test of dry pipe valves shall be conducted annually. To execute this test, the main control valve is partially closed (throttled) before releasing air pressure from the valve body trim. This allows the clapper to unlatch and trip off its seat to verify mechanical operation without filling the overhead dry piping system with water.3-Year Full-Flow Trip Test (NFPA 25 [2017], Section 13.4.4.2.2.2):A full-flow trip test shall be conducted at least once every 3 years, or whenever the system undergoes major modification. During a full-flow test, the control valve is wide open, air is discharged from the remote inspector's test connection, and the technician must record both the trip time of the valve and the water delivery time to the inspector's test outlet.Internal Cleaning and Inspection (NFPA 25 [2017], Section 13.4.4.2.2.3):The interior of the dry pipe valve body, including the clapper assembly, rubber facings, latching mechanisms, and intermediate chamber, must be opened, cleaned, and internally inspected every 3 years—typically performed concurrently with the 3-year full-flow trip test—or whenever the valve fails to trip properly during a test.Jake (Candidate Fitter): "Mac, on that cold-storage warehouse job in Bloomington, the lead inspector told me we had to trip the dry valve wide open, flood the roof piping, and time water hitting the inspector's test connection every single fall. Was he talking out of his ass, or is that what the state expects me to pick on the exam?"Mac (Senior Master Fitter): "He was talking straight out of his ass, Jake. Out in the field, guys confuse the 3-year full-flow requirement with the annual maintenance check because they don't bother reading NFPA 25. If you trip a dry valve full-flow every year without draining every low-point drip leg, trapped water freezes, ice expands, and you wreck the customer's piping.On the Minnesota Journeyman Exam, read the prompt carefully. If it asks for the ANNUAL trip test frequency, the correct code answer is a partial-flow trip test. A full-flow trip test where water actually reaches the inspector's test valve is only required every 3 years. Don't let some cowboy inspector's bad field habits burn your test score."Annual Requirement (1 Year) ➔ Partial-Flow Trip Test (Section 13.4.4.2.2.1). Control valve is throttled; verifies clapper mechanism without piping flood.3-Year Requirement ➔ Full-Flow Trip Test (Section 13.4.4.2.2.2). Control valve wide open; must measure & log trip time AND water delivery time at inspector's test.3-Year Internal Maintenance ➔ Open, Clean, and Inspect Valve Internals (Section 13.4.4.2.2.3).Quick Opening Devices (QODs / Accelerators) ➔ Tested annually (Section 13.4.4.2.4).Exam Trap Alert: If a test question mentions testing in freezing weather (13.4.4.2.1), the code mandates that the system piping must be thoroughly drained immediately after a full-flow test using auxiliary drains (drum drips). But remember: the default annual test is ALWAYS partial-flow!