How frequently must mainline strainers be inspected after any flow condition occurs, including 2" main drain testing?

The correct answer is that mainline strainers must be inspected annually after any flow condition occurs, including during 2" main drain testing. This requirement is based on the need to ensure that the strainers are functioning effectively and not clogged with debris, which can hinder the performance of the fire protection system. Regular inspections help maintain the integrity of the fire sprinkler system and ensure it remains operational in an emergency.

Annual inspections are designed to align with standard maintenance protocols that balance thoroughness with achievable frequency, given the importance of the components involved. Inspecting strainers after flow conditions ensures that any potential issues are identified and addressed promptly. In particular, the flow tests can dislodge sediment that may clog the strainers, so checking them soon after these tests is critical to maintaining system reliability.