Main drain tests ensure water pressure aligns with the system’s design and previous performance. Thin-walled pipes in areas where air or water is trapped pose a higher risk of corrosion. Main drain tests can also help detect any blockages in the system, ensuring full capacity functionality, if needed. Testing requirements vary and are specified in NFPA 25. Annual testing is required for fire suppression systems without a backflow preventer as the main water source. Quarterly testing is required for systems where the main water source is through a backflow preventer.
Additional Resource: NFPA 25