However, the acoustical performance of acoustical lagging systems must be known so the gas-transmission companies can specify material requirements to achieve their intended performance requirements. In similar industries where centrifugal compression is utilized, such as in gas-processing plants and petrochemical complexes, the same approach occurs.Ī lot is known about the acoustical performance of silencers, but relatively little is known about the acoustical performance of laggings. The responsibility is usually left to the facility owner as part of his design, hereby being the gas transmission company. Furthermore, acoustical lagging performance is not designed by or guaranteed by material manufacturers or by industrial insulation contractors. The responsibility for piping-radiated noise is not addressed by any packager, supplier or O.E.M. As in-line silencers typically have unacceptable pressure drops imposed upon the gas stream, acoustical pipe lagging becomes the preferred alternative. or by the equipment packager, attempting to achieve an overall acoustical performance requirement that usually has been specified by the gas transmission company as the purchaser. The contractual responsibility for silencer design and supply is usually accepted by the silencer O.E.M. The solutions to the piping-radiated noise problem are acoustical silencers and acoustical laggings. The primary noise radiator is the relatively thin-walled process piping which is the focus of this article. Noise is generated by the turbulence of the rotating wheel or impellers of the large turbocompressors but only a minimum amount of this noise is then radiated by the sufficiently thick compressor casing. One component that is a predominant contributor to environmental noise is the gas piping associated with centrifugal compressor packages at gas turbine-driven compressor stations. legislation by the FERC set maximum levels at 55 dBA Ldn and similarly, Canadian legislation by the AEUB in Alberta and by the MOE in Ontario set maximum Permissible Sound Levels from gas transmission operations between 40 to 50 dBA Leq, based on the ambient noise environment. Radiated noise from natural gas transmission compressor stations, meter stations and regulator stations is a problem of increasing concern, due to stricter regulatory enforcement as well as due to greater public awareness of noise as an environmental problem. As opposed to the massive panels typically used for acoustical enclosures on turbocompressor packages, acoustical laggings utilize lightweight and often removable materials. Significant experience has been gained regarding material selection and system performance. Insertion loss is a method of testing and comparison developed for piping and equipment. With the advent of innovative testing techniques, installed lagging system insertion losses have been obtained. However, very little information exists in the industry regarding the acoustical performance of site-installed acoustical lagging systems. Piping and compressor casings on numerous gas turbine-driven turbocompressor packages as well as piping at meter stations and regulator stations have been treated using acoustical laggings, as a retrofit as well as during design. Although the noise generation is due to the internal geometries and flow conditions of the rotating equipment or due to the orifices or valves, the acoustical radiator is the piping. A significant source of noise at pipeline facilities is piping radiated noise.
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