Pressure Reducing Valves

Fire protection pressure reducing valves are used in sprinkler, standpipe, fire pump discharge, hydrant, and foam systems to reduce higher inlet pressure to a controlled downstream pressure. Selection should be based on design pressure, required set pressure, design flow, available differential pressure, installation position, and supervision requirements of the fire protection network.

This category includes the Cla-Val 90-21, 90-FPX, and 90-42. The 90-21 and 90-FPX are pilot-operated pressure reducing valves that automatically modulate main valve position so that outlet pressure remains at the preset limit, independent of variations in flow rate or inlet pressure. The 90-21 is available in globe or angle pattern, with NPT, flanged, or grooved end connections. The 90-FPX is intended for fire pump regulation, system pressure regulation, and foam service.

The 90-42 is intended for fire protection service with seawater and is available in materials including ASTM A216 WCB, ASTM A536 ductile iron, ASTM B61 naval bronze, and ASTM B62 cast bronze, with Class 150 or Class 300 pressure ratings and flanged or grooved connections. Material selection should consider chloride content, galvanic corrosion risk, surface protection requirements, and elastomer compatibility with the service medium.

In fire protection systems, the pressure reducing valve should be installed with upstream and downstream pressure gauges. A downstream relief valve with suitable drain connection is required in accordance with Cla-Val series technical data. During maintenance, inspection should cover pilot lines, strainer, restriction assemblies, diaphragm, seat, set pressure, shutoff leakage, and possible blockage from suspended solids or corrosion products.