What diameter should a trip test connection or manifold pipe have at minimum?

The minimum diameter for a trip test connection or manifold pipe is established to ensure that adequate flow and pressure can be maintained during testing of fire protection systems. A diameter of 1/2 inch is typically sufficient to allow for the necessary water flow, enabling reliable testing without introducing excessive resistance that could skew test results.

In the context of sprinkler systems, the trip test connection is crucial for verifying that the system can function properly in an emergency, which is why it is essential that the pipe size meets or exceeds the minimum requirements outlined in codes and standards. This ensures that any of the necessary tests—such as flow tests—can be conducted effectively, thereby maintaining the integrity of the fire protection system.

Larger diameters, such as 3/4 inch or 1 inch, may also be functional in such applications, but they exceed what is deemed necessary for a basic trip test connection and may not represent the most efficient use of materials for this specific purpose.