Advanced Pressure Regulating Valves to Reduce Water Loss at DoD Industrial Installations
Gary Anguiano | Naval Facilities Engineering and Expeditionary Warfare Center
The objective of this project, EW-201715, is to demonstrate an Advanced Pressure Regulating Valve (APRV) deployed on Department of Defense (DoD) installation’s water distribution systems to reduce water losses during off peak hours. During periods of low demand (night, weekends and holidays), water pressure throughout the distribution and service mains approaches static conditions. This condition can result in both higher downstream pressures and water losses in aged water distribution systems. This project will investigate the feasibility of managing water pressure through employment of APRV technology that meets system needs by providing higher pressures in response to higher demands for water and reduced pressure when needed to decrease water leakage (as well as save money). A controlled pipeline test bed located at the Engineer Research Development Center (ERDC), Vicksburg MS will be used to validate leak reduction performance and reliability of valve operations. A full scale demonstration in an operational environment will be used to evaluate field applications and develop guidance for deployment of this technology at DoD installations.
The technology modulates water pressure in response to real-time demand through the use of an APRV. The APRV automatically reduces downstream water pressure during hours of low water demand to reduce water loss due to leaks as well as to minimize undue stress on pipes and fittings. APRV technology provides high pressure for installation operations and fire protection purposes when needed. There is a direct correlation between pressure and the flow rate of water through a given pipe opening, such as a hole in a pipe, or a failed seal/joint (leak). Greeley's formula establishes the relationship between pressure and flow rate (summarized in the American Water Works Association [AWWA] Manual of Water Supply Practices M36: Water Audits and Loss Control Programs ):
Q = (30.394) * A* P0.5
Where: Q = flow rate
A = area of pipe opening
P = pressure of pipe.
Some tests have shown that Greeley's formula is conservative as the size of holes actually increases with increased pressure, thereby generating larger leak flows (pressure “P” can be to the power of 1 and higher). APRVs reduce water pressure in the distribution system during periods of low demand, reducing the flow rate through leakage points and reducing water loss from leaks under such conditions.
The APRV is innovative as it employs two pressure-setting pilot valves to control outlet pressure based on real-time flow demand downstream of the valve on single feed water distribution systems. This technology has the capability to automatically increase downstream pressure during peak water demand or decrease the pressure in the line during non-peak hours. APRV can be installed on pipelines leading to industrial or residential areas to reduce leak rates. Reduced pressure in distribution systems also reduces stress on pipes, and frequency of repairs. This technology is run completely hydraulically, which has an advantage over solenoid valves that require electricity.
DoD currently has approximately 160 installations in the U.S. with extensive water distribution systems through industrial areas that could benefit from the application of the APRV technology. Initial costs are limited to cost of purchase and installing APRVs on main lines in distribution systems. By alleviating pressure of distribution systems during periods of lower demand, APRVs reduce leakage, the physical stress on pipes and the frequency of failures in the distribution system. Since the vast majority of DoD installations purchase water from regional suppliers, APRV would provide direct savings on water purchases. In addition, as suppliers adopt progressive pricing, reductions in water use may result in additional cost savings by avoiding surcharges.