Vibration Studies

West Point Effluent Pump Station Vibration Study

JGL Acoustics, Inc. provided field vibration measurements on four 2000 HP centrifugal pumps at the West Point Sewage Treatment Plant in Seattle, WA in 1994. This work involved measuring pump and pipe vibrations over a wide range of operating conditions. In addition, the natural frequencies of the impeller blades were also measured as part of a troubleshooting program to determine the cause of excessive vibrations under certain operating conditions.

Deaconess Hospital Vibration Study

JGL Acoustics, Inc. provided field vibration measurements and design services for a new MRI installation on an upper level floor in Deaconess Hospital in Spokane, WA. The main scope of work was to ensure that ambient floor vibrations caused by the operation of mechanical equipment and people walking inside the building would not generate floor vibration levels that exceed the vibration criteria established by the MR manufacturer. The results of the study verified that the existing structure was not adequate to achieve this goal, and additional stiffeners would need to be added to the existing beams in the vicinity of the MR unit.

Health Club Floor Vibration Study

JGL Acoustics, Inc. was retained to assess an existing floor vibration problem in a large health club in the local Seattle area in 2003. The study found that the floor structure design was inadequate for certain types of high-impact activities such as group aerobics and treadmills. Field vibration measurements revealed that the natural frequency of the floor was less than 50% of the recommended minimum value for activities of this type. Vibration measurements revealed that certain types of exercise equipment would function in an acceptable manner in this area, and the problem was resolved by moving the high-impact equipment to another location in the building.

Intel FM6 Building Vibration Study

JGL Acoustics, Inc. conducted a building vibration study for Intel Corporation at their FM6 office building in Folsom, CA in 2004. The owner contended that vibrations from several rooftop HVAC units were generating unacceptable vibration levels on the lower floors of the building during certain operating conditions. Field testing verified that the vibration from these units was within normal guidelines, but the testing revealed that excessive floor vibration was generated by people walking in the building. The natural frequency of the floor was measured in several locations, and it was determined that the floor design was not sufficient to ensure acceptable footfall-induced floor vibrations in all areas of the building.

Thunder Valley Casino

A vibration study was conducted by JGL Acoustics, Inc. in 2004 on behalf of a major HVAC manufacturer who provided ten large rooftop units for the Thunder Valley Casino near Sacramento, CA. The study was initiated by complaints of noticeable vibrations of large chandeliers hanging from the roof structure. Vibration measurements inside the air handling units and on the roof revealed that the excessive vibration was caused by the fans running at a poor operating point. Field testing verified that the excessive vibration could be eliminated by running the fans at a lower speed and adjusting the return and exhaust air dampers in the proper fashion to avoid pushing the fan into the unstable operating point.