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Warewashing Equipment –
Pre-Rinse Spray Valves

Pre-rinse spray valves (PRSVs) are a component of the pre-rinse assemblies used in commercial food-service venues to remove solid food residue from soiled plates, flatware, and other kitchen items with a pressurized flow of hot water before they are loaded into a commercial dish- or ware-washer for thorough cleaning. PRSVs generally consist of a spray nozzle, a squeeze lever, an insulated handle, and a dish-guard bumper. The squeeze lever actuates the PRSV, thereby controlling the water flow. Most PRSVs also include a spray-handle clip that allows the user to lock the lever in the full-spray position for continuous use.

pre rinse spray valves

* Source: Energy Saving Ultra Spray, www.watermiser.com

While PRSVs themselves are not energy-using devices, PRSVs determine both the water consumption and the effective energy consumption of commercial pre-rinse assemblies by regulating the flow-rate of the hot water. Baseline PRSVs have flow rates ranging from approximately 10 to 20 litres per minute (Lpm) or 2.6 to 5.2 gallons per minute (gpm), while low-flow, or efficient PRSVs have hot-water flow rates of 6.1 Lpm or 1.6 (gpm)1,2. Dish-washing operations account for more than two-thirds of the total water consumption in typical restaurants, and PRSVs are in some cases estimated to consume nearly half of the total dish-washing water3. Additionally, PRSV water consumption nearly always translates directly to energy consumption because the water used in dish-washing is most often hot water. Low-flow PRSVs therefore consume substantially less water and energy per hour of use than baseline PRSVs.

A baseline PRSV can be converted to a low-flow PRSV through the addition of a flow restrictor or the redesign of one or more components, such as reducing the size of the outlet holes in the faceplate.  While redesigns typically involve substantial investment in research and development and facility conversion, the end-result will likely exhibit better performance than a retrofitted valve, because retrofitted PRSVs generally have the same flow pattern as baseline PRSVs, but at a lower flow rate, while PRSVs that were designed to be low-flow generally implement a fundamentally different spray pattern that is designed to be effective at low flow rates.  A typical life expectancy of a PRSV is 5 years4.

As of January 1, 2006, all pre-rinse spray valves in the U.S. must meet the maximum flow rating of 6.1 Lpm (1.6 gpm). 


1Flow rates are as measured according to ASTM Standard F 2324-03, which specifies a water-line pressure of 412 kilo-Pascals (kPa) (60 pounds per square-inch (psi)).
2These typical values for flow rate are commonly cited in PRSV literature. See, for example, “10 Ways to Save Natural Gas ”, Pacific Gas and Electric Company.
3Program Guidance on Pre-Rinse Spray Valves ,” published as a part of the Consortium for Energy Efficiency's Commercial Kitchen Initiative.
4 “A Report on Potential Best Management Practices”, prepared for the California Urban Water Conservation Council by Koeller and Company, August 2004.