Shock and vibration

Learn how to plan for possible shock and vibration in your data center.

It might be necessary to install information technology equipment in an area that is subject to minor vibrations. Learn about shock and vibration limits for your equipment and some basic definitions that are related to vibration. The vibration levels that are normally present in computer rooms 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 contact the manufacturer of such equipment to ensure that vibration factors do not exceed the specifications that are provided in Table 1 and Table 2.

Some useful definitions of vibration include the following definitions:

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. is the unit of acceleration that is caused by the force of gravity.

Continuous

Vibrations present 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 unit.

Normally used to measure floor vibrations 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 value can be expressed as peak-to-peak in cases of sinusoidal vibration displacement.

Random

A complex vibration wave form that varies 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 before 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

Vibrations with the characteristic shape of the classical sine wave (for example, 60 Hz ac power).

Transient

Vibrations 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 above definitions, contact a mechanical engineer, a vibration consulting engineer, or your seller.

The five classes of a vibration environment are shown in Table 1.

Table 1. Vibration environment
Class	Vibration environment
V1	Floor-mounted equipment in an office environment.
V2	Products that are used on desks or tabletops; portable and wall-mounted equipment.
V3	Products that can be operated in moving vehicles or mounted on heavy industrial equipment, and hand-held devices.
V4	Limited-usage subassemblies that are mounted directly on the computer mainframe.
V5	Wide-usage subassemblies that are mounted directly on the computer mainframe.

A summary of the vibration limits for each of the five classes is shown in Table 2.

Note: Vibration levels at any discrete frequency must not exceed a level of one half the G rms values for the class that is listed in Table 2.

Table 2. Operational vibration and shock limits
Class	G rms	G peak Sine	Shock (pulse width)
V1 L	0.10	0.06 @ 50 or 60 Hz	3.5 g (3.0 ms) (vertical axis) Five shock inputs
V1 H	0.05	0.03 @ 50 or 60 Hz	3.5 g (3.0 ms) (vertical axis) Five shock inputs
V2	0.10	0.06 @ 50 or 60 Hz	30.0 g (3.0 ms) (vertical axis) 15.0 g (3.0 ms) (horizontal axes) Two shock inputs per axis, one in each direction, six total
V3	0.27	None	N/A
V5L ≤ 20 kg	0.67	None	15.0 g (5.0 ms) Two shock inputs per axis, one in each direction, six total
V5H ≥ 20 kg	0.43	None	15.0 g (5.0 ms) Two shock inputs per axis, one in each direction, six total

L: Light, weight that is less than 600 kg (1322.8 lb) (unless otherwise specified).
H: Heavy, weight that is equal to or greater than 600 kg (1322.8 lb) (unless otherwise specified).
g rms: Overall average g level over the 5 - 500 Hz frequency range.
g peak: Maximum real-time instantaneous peak value of the vibration time history wave form (excluding events that are defined as shocks).
Mils: Peak-to-peak displacement of a discrete frequency in the 5 - 17 Hz range. 1.0 mil equals 0.001 inches.
Shock: Amplitude and pulse width of a classical one half sine shock pulse.

The values that are given in Table 2 are based on worst-case field data that is measured at customer installations for current and previously released products. The shock and vibration environment will not exceed these values except for abnormal cases that involve earthquakes or direct impacts. Your seller can contact the IBM® Standards Authority for Vibration and Shock for any specific technical questions.

Earthquakes

Special frame-strengthening features or RPQs 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 physical planning documentation of the product, contact with your seller.