The inspector’s test valve is a vital component of any wet fire sprinkler system. At the heart of this connection is the test orifice. A small but critical feature that certifies the system’s waterflow alarm functions correctly. Both NFPA 13 (Installation of Sprinkler Systems) and NFPA 25 (Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems) provide requirements that govern the size, purpose, and functionality of this orifice.

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When it comes to protecting fire sprinkler systems from over-pressurization, pressure relief valves are a key component. But for years, there’s been confusion about what the pressure rating on these valves actually means, especially when it comes to the opening and closing pressures.


metallic pipe. Trapped air can contribute to corrosion, leading to costly maintenance and potential system failure. NFPA 13 recognizes this and mandates at least a single air vent on wet pipe fire sprinkler systems, but the code allows the system designer to determine if additional vents are necessary.