The RD13 Riser (with NPT connectors) is constructed from Listed CPVC products suitable for fire sprinkler services subject to the limitations and installation requirements of Flameguard® CPVC pipe and Spears® CPVC fittings. The RD13 Riser incorporates a VSR-SG flow switch, gauge, and drain/test valve. The VSR-SG flow switch is equipped with union connection to facilitate the installation and removal of the switch in confined spaces.