Vibration and shock

Use this information to plan for possible vibration and shock in the data center.

It might be necessary to install the information technology equipment in an area subject to minor vibration. The following information supplies vibration and shock limits for your equipment and some basic definitions concerning vibration. The vibration levels normally present in computer-room and industrial installations are well within the indicated levels.

However, mounting the equipment in racks, stackers, or similar equipment might increase the risks of vibration-related problems. It is important to consult the manufacturer of such equipment to ensure that vibration factors will not exceed the specifications provided in the following tables.

Some useful definitions of vibration follow:

Acceleration
Normally measured in g multiples of the acceleration because of the force of gravity. If the frequency is also known for a sine wave, acceleration can be calculated from displacement. (g: The unit of acceleration caused by the force of gravity.)
Continuous
The presence of vibration over an extended period and cause a sustained resonant response in the equipment.
Displacement
Magnitude of the wave shape; normally given in peak-to-peak displacement in English or metric units:
  • Normally used to measure floor vibration at low frequencies
  • If the frequency is also known, it can be converted to displacement g for a sine wave.
    Note: Many measuring instruments can convert displacement to g for either sinusoidal or complex wave shapes.
Peak
The maximum value of a sinusoidal or random vibration. This can be expressed as peak-to-peak in cases of sinusoidal vibration displacement.
Random
A complex vibration wave form varying in amplitude and frequency content.
rms (root mean square)
The long-term average of the acceleration or amplitude values. Normally used as a measure of overall vibration for random vibration.
Shock
Intermittent inputs that occur and then decay to zero prior to a recurrence of the event. Typical examples are foot traffic, fork lifts in aisles, and external events such as railroad, highway traffic, or construction activities (including blasting).
Sinusoidal
Vibration with the characteristic shape of the classical sine wave (for example, 60-Hz AC power).
Transient
Vibration that are intermittent and do not cause a sustained resonant response in the equipment.

If you need to make any calculations or require information regarding the previous definitions, consult a mechanical engineer, a vibration consulting engineer, or your seller.

The three classes of a vibration environment are shown in the following table.

Table 1. Vibration environment
Class Vibration environment
V1 Floor-mounted machines in an office environment
V2 Table-top and wall-mounted machines
V3 Heavy industrial and mobile equipment

A summary of the vibration limits for each of the three classes is shown in the following table. A legend follows the table.

Note: Vibration levels at any discrete frequency should not exceed a level of 1/2 the g rms values for the class listed in the following table.
Table 2. Operational vibration and shock limits
Class g rms g peak Mils Shock
V1 L 0.10 0.30 3.4 3 g at 3 ms
V1 H 0.05 0.15 1.7 3 g at 3 ms
V2 0.10 0.30 3.4 3 g at 3 ms
V3 0.27 0.80 9.4 application dependent
L
Light with weight less than 600 kg
H
Heavy with weight equal to or greater than 600 kg
g rms
Overall average g level over the 5 to 500 Hz frequency range
g peak
Maximum real-time instantaneous peak value of the vibration time history wave form (excluding events defined as shocks).
Mils
Peak-to-peak displacement of a discrete frequency in the 5 to 17 Hz range. One mil equals 0.001 inch
Shock
Amplitude and pulse width of a classical 1/2 sine shock pulse

The values given in the Operational vibration and shock limits table are based on worst-case field data measured at customer installations for current and previously released products. The vibration and shock environment will not exceed these values except for abnormal cases involving earthquakes or direct impacts. Your seller can contact the IBM® Standards Authority for Vibration and Shock in case of specific technical questions.

Earthquakes

Special frame-strengthening features might be required in earthquake prone areas. Local codes might require the information technology equipment to be tied down to the concrete floor. If sufficient information on equipment tie down is not provided in the product's physical planning documentation, consult with your seller.


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