Excessive noise levels are also associated with patterns of increased irritability and aggression and decreased cooperation, according to researchers at the National Institute for Occupational Safety and Health.   The importance of acoustics and noise abatement to the quality of a building’s interior environment and to occupant comfort is also recognized by the USGBC, with noise mitigation credits available in several LEED rating system tracks.   In correctional facilities, a host of verbal communications and physical activities interact with architectural and structural elements to create variable degrees of environmental noise. Plumb Solution The noise associated with plumbing systems is generated by the transport of materials and system vibration as sound waves travel through the system and pass through the pipe wall. A 2001 study by Canadian acoustical consultants MJM found cast iron soil pipe, when installed with rubber gasket joints, proved 750 percent more effective in reducing plumbing noise than alternative plumbing materials, such as PVC and ABS pipes.   The MJM research study, which was sponsored by the American Cast Iron Soil Pipe Institute, compared the acoustical performance of various piping material solutions under laboratory conditions at Quebec’s Domtar Research Center. Hub and spigot cast iron pipe achieved vibration reductions up to 12 decibels per joint, while hubless pipe with elastrometric gaskets and stainless steel shields yielded reductions up to 9 decibels, according to study.   In addition to the cast iron system’s across-joint vibration reduction, the dense molecular structure of the cast iron mitigates the transfer or amplification of sound waves beyond the system. Cast iron pipe and fittings dampen the airborne noise produced by flowing water and inhibit noise transfer through the pipe wall.   Page 2 of 3 Print News Headline 5/29/2009 http://www.correctionalnews.com/ME2/Audiences/Segments/NewsHeadlines/Print.asp?M...