What device should be located closest to the Double Check Valve (DPV)?

The Quick Opening Device (QOD) is positioned closest to the Double Check Valve (DPV) to optimize the response time of the fire protection system in an emergency. The primary function of the QOD is to allow for a rapid flow of water into the system, which is crucial during a fire incident when immediate water supply is necessary for effective suppression.

The QOD works by bypassing the more gradual restrictions that other valves may impose, quickly filling the system and activating the sprinkler heads as rapidly as possible. By having the QOD in close proximity to the DPV, it ensures that once the suppression system is triggered, the water is readily available almost instantaneously. This arrangement is essential in minimizing delays which could compromise safety and effectiveness during fire situations.

In contrast, the other devices listed may have different roles that do not prioritize immediate water flow or speed in emergency responses in the same way as the QOD. This is why the QOD is the appropriate choice for being closest to the Double Check Valve.