What is the minimum diameter for the connection pipe from the air supply to the DPV?

The minimum diameter for the connection pipe from the air supply to the double check valve assembly (DPV) is established to ensure adequate air flow and pressure regulation necessary for the proper functioning of the sprinkler system. A 1/2 inch diameter is sufficient to allow for the necessary volume of air to operate the system effectively while avoiding issues with flow restriction that could occur with smaller diameters.

When the pipe diameter is too small, it can lead to decreased performance, including insufficient pressure levels or delays in response times of the system, which are critical during a fire emergency. Ensuring that the connection pipe meets the specified minimum diameter helps maintain the efficiency, reliability, and safety of the sprinkler system.

Other diameter choices might not provide the same reliability or may not comply with the safety standards set for such systems, which is why 1/2 inch stands out as the appropriate choice.