Vertical transmission of vibration and noise to a research laboratory from mechanical equipment room – analysis and mitigation case study

摘要

A newly occupied large public university research building received floor-vibrationrncomplaints from a laboratory located above a mechanical equipment room. Researchers,rnwho observed surface ripples in water glasses on lab shelves, investigated and foundrninterference in floor-mounted specimen incubators. Structural vibration and lowrnfrequency noise can effect sensitive laboratory equipment, degrade experimental specimensrnand reduce staff efficiency and productivity. Investigatory observations and measurementsrnwere undertaken during business hours to determine vibration and noise conditions andrndevelop a plan of mitigation. Measurement results were compared to permissible 1/3 octavernVibration Criteria (VC), which had been used for building design, and prominent narrowrnband (discrete) frequencies were compared. Central plant equipment, including pumps andrncompressors are on ground level. Chilled water pipes from remote campus chillers arernsuspended in a crawl space below. Building air handlers, exhaust fans and boilers are in arnpenthouse equipment room and on roof. Structure borne vibration and airborne noisernmay be transmitted to laboratory spaces via building columns and beams, in pipes andrnducts and through vertical duct and pipe shafts. Results are graphically shown on charts.rnMitigation measures implemented by the facility management are enumerated withrnsubjectively determined results.