# Page 132 - WaterSense at Work

4-38
October 2012
4.8
Pre-Rinse Spray Valves
Savings Potential
Water savings can be achieved by replacing existing pre-rinse spray valves. Because
water use of pre-rinse spray valves is dependent on facility operations and factors
such as average throughput, water savings will vary by facility. To estimate facility-
specific water savings and payback, use the following information.
Current Water Use
To estimate the current water use of a pre-rinse spray valve, identify the following
information and use Equation 4-16:
••
Flow rate of the existing pre-rinse spray valve. Pre-rinse spray valves installed af-
ter 2005 have flow rates of 1.6 gpm or less. Pre-rinse spray valves installed before
2005
can have flow rates of up to 4.5 gpm.
••
Average daily use time. This will vary by facility, but facilities typically use pre-
rinse spray valves for no more than 200 minutes per day.
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••
Days of facility operation per year.
Equation 4-16. Water Use of Pre-Rinse Spray Valve (gallons per year)
= Flow Rate of Pre-Rinse Spray Valve x Daily Use Time x Days of Facility
Operation
Where:
••
Flow Rate of Pre-Rinse Spray Valve (gallons per minute)
••
Daily Use Time (minutes per day)
••
Days of Facility Operation (days per year)
Water Use After Replacement
To estimate the water use of a more efficient replacement pre-rinse spray valve, use
Equation 4-16, substituting the flow rate of the replacement pre-rinse spray valve.
Efficient pre-rinse spray valves use 1.3 gpm or less.
Water Savings
To calculate the water savings that can be achieved from replacing an existing pre-
rinse spray valve, identify the following information and use Equation 4-17:
••
Current water use as calculated using Equation 4-16.
••
Water use after replacement as calculated using Equation 4-16.
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U.S. Environmental Protection Agency’s (EPA’s) WaterSense program. March 31, 2011.
Pre-Rinse Spray Valves Field Study Report
.
Page 19.
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