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Recently I am building equipment. It is as large as two refrigerators with aluminum extrusion frame. Unfortunately, it has visible resonance vibration. After measuring I find on the floor there is a 16.5 Hz vibration, probably from elevator motor above floor, or ventilation motors about 20 meters away.

So, I want to change my design, enhance rigidity to increase resonance frequency. Customers may install it near a normal vibration source. But, what are the low frequency of building vibration? I need to know it first to avoid it. Does anyone know the range of building low frequency? Usually from the elevator, transformer, ventilation motor, or water pump. Or is there any general frequency standard based on experience that a product resonance frequency should be higher than it to avoid resonance vibration?

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  • $\begingroup$ Anything above 0Hz. $\endgroup$
    – Solar Mike
    Commented Sep 10, 2021 at 7:13
  • $\begingroup$ This is a forced vibration problem where the 16.5Hz is coming from some other component. The building does not need to have a resonance at or near 16.5Hz to transmit the vibration. Most building structures can transmit a wide range of frequencies from 0 up to tens of kHz. You need to understand how vibration isolators work. Increasing the rigidity of your refrigerator structure will make the problem worse, not better. $\endgroup$
    – alephzero
    Commented Sep 10, 2021 at 19:13

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As an equipment supplier, your responsibility is to avoid the resonance to occur between the equipment and its support, whether a skid or a frame that is to be supplied by you. It might be a problem down the road, but it's out of your hand to evaluate the fundamental frequency of an industrial building, which may have numerous vibratory equipment and excitation sources.

You shall clearly indicate the vibration characteristics (operation frequencies) of your equipment including its support, and the associated parameters (mass, geometries) on the vendor drawing though.

For troubleshooting the vibration problems in a building, the owner shall engage a lab or engineering consultant to perform the measuring and analysis.

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The major source of vibration especially in modern light floor structures with +25ft spans is the floor vibration under foot traffic.

foot traffic frequency is about 1.25 hertz. so most of the modern designs go for a natural frequency of 3 to 5 hertz for the floors. source

You want to design frequency outside of the resonance range with these floors.

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