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SOURCE Summer 2012

onlineexclusive Vacuum Plumbing Systems: The Next Frontier in Water Savings By Bruce R. Blanchart, Yardley Pump and Vacuum, Inc. Iwater-conserving systems like a vacuum vacuum toilet. tary drain resulting in drain line blockage-flush has been insufficient to carry all of thesewage from the point of use to the saniif the facility had been designed with avacuum plumbing system incorporating an the world of plumbing design, vacuumis the next frontier. High performance, plumbing system can be a significant part in both the horizontal and vertical legs of of a permanent water saving program. A Construction Cost Savings drainage systems. vacuum plumbing system, also referred to as Offered as an alternative to conventional Depending on code, vacuum waste piping a vacuum drainage system, utilizes a vacuum gravity drainage plumbing, the design of materials can be pressure rated schedule toilet with a flush rate of 0.5 gpf. Additionally, a vacuum plumbing system is no longer 40 PVC, CPVC, Type M or better copper the vacuum plumbing drainage can include limited by the rules of a gravity drain system. or stainless steel; all with DWV pattern sinks, showers and washbasins. The vacuum plumbing system drainage fittings. can be lifted up and easily conveyed to Water Savings avoid restrictive site or structural issues. The vacuum waste piping is smaller in The most significant installations of vacuum Piping can be routed vertically and hori- diameter than gravity drain piping. The way plumbing systems are in jails and prisons. zontally and still maintain the necessary the vacuum drainage system functions is California, for example, has mandated that pipe velocity, virtually reducing to zero the that air becomes the transporting medium the design, construction and operation of chance of drain line blockage. for the gas and/or the suspended solids. all state-owned facilities be certified under The conventional 1.6 gallon-per-flush The negative pressure provides the energy LEED. For projects requiring LEED certifi- toilets have led to some unexpected prob- and by using smaller pipe sizes an optimum cation, several credits may be obtained by lems in older gravity piping. In some instal- transporting velocity is attained. using vacuum plumbing systems due to the lations, the conventional low flow toilet Continued on page 30 reduced flush rates. The conventional, low-flow, gravity drain toilet is 1.6 gallons per flush. A toilet in a prison cell is used and abused in multiple ways. A single inmate may flush his or her toilet as many as 25 flushes in a day. Many correctional institutional designers use 9,600 gallons per inmate per year as a measure in calculating total outflow from a facility. Each vacuum toilet has an electronic flush valve control system allowing the prison staff to remotely monitor and control the quantity of flushes per cell in the facility. Conventional flush valves have no such control capability, and the ultimate water consumption is dictated by the facility occupants. A design study done at one correctional facility with 1,650 toilets using the conven- tional 1.6 gpf rate showed a water savings of 19.5 million gallons of water per year www.ca-nv-awwa.org 29


SOURCE Summer 2012
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