Noise control within building water supply lines

Successful treatment of fluid-borne noise in a building’s plumbing system reduces noise propagation throughout the building, which improves occupant comfort and extends component lifetimes. Circulation pumps and quick-closing valves contribute to noise in water systems. Pump noise is generally untreated. Quick-closing valves m may cause water hammer, which can be treated with a water hammer arrestor (WHA). Common WHA’s functions by adding a compliant gaseous volume to the system; the gas volume is sealed from the system by a free piston. Control of both water-borne noise and water hammer may be achieved by a flow-through device integrating a compliant, voided polymer. The performance of current WHAs diminish over time as (1) mineral deposits degrade sealing effectiveness and (2) the gas permeates the seals; a voided polymer WHA will not suffer from these drawbacks. Prior work has demonstrated that a voided polymer is an effective source of compliance for noise control in oil systems at the anticipated pressure and temperature range of water systems. Furthermore, the acoustic impedance of oil is similar to water. Basic modeling and performance data for a prototype device will be presented.