Vibration Isolation in Data Centers
Vibrations in Data Centers Vibrations in Data Centers can be produced by nearby construction works, heavy traffic, railways or even the own cooling units inside or next the room and other equipment in the same Data Center introducing vibration noise in the room. Additionally, the Seismic Hazard, as can seen in the following World Seismicity Map.
Effects of vibration in disk drives The following data indicate that peak accelerations greater than 0.5 g (1 g = 10 m/s2) in the servers would be subject to forces that could cause permanent damage and loss of data readable. The forces generated by low frequency seismic waves are generally more destructive than higher frequency vibrations because of their longer periods generated with larger amplitudes.
Effects of vibration in disk drives According to various manufacturers, Disk Drives Units have a limit even lower than the servers, see for example the values of HITACHI 9900 Disk Unit (formerly SUN 9900) indicating its limit in 0.49 m/s2, considering that in normal operation has a value of 0.10 m/s2.
Effects of vibration in disk drives Latency study in SUN Disk Drives Units, the effect produced after suffering vibrations within the range accepted by the manufacturer, which is results in loss of time while discs are looking for position to read or write, some studies report up lost hours in 1-10-50 TB copies.
System's natural frequency and vibration isolation solutions The vibrations cause the system to oscillate at its own vibrational frequency (each oscillation time or period corresponding to the inverse of the frequency itself). If the period (or frequency) of the structure matches that of the building or land where supports, is the phenomenon called "resonance" in which the effects of vibrations are increasing, increasingly expanding oscillations are becoming larger due to the accumulation of kinetic energy in the interior of the oscillating mass. Designing a proper anti-vibration system is to determine the minimum and maximum weight of the system to know the mass design elements absorb these vibrations taking into account the resonance frequency of these same elements. Depending on the characteristics of the room can choose protection systems such as individual springs (1), metallic frames (2) or concrete slabs (3), either vibration or seismic ones.
1. Individual Springs One of the proposed solutions are spring-based systems with or without sub-frame rated for the Maximum Weight of the rack, representing this a problem of effectiveness in racks with half or less density.
1. Individual Springs The springs installed have an Own Frequency of 4.5 Hz to full load. 4 individual springs per rack 1.98 KN=202 kg, total over 800 Kg
1. Individual Springs The graph shows the effect of a spring protection system installed individually in each rack. In red the vibrations observed on the ground (in German boden) produced by near construction works and in blue the signal filtered in the racks, with a value of 0.10 m/s2.
2. Anti-vibrations Metallic Frame The Anti Vibrations Metallic Frame is a low frequency isolation resonance with container elements and integrated isolators in their own frame, with a significant degree of vibration isolation. This type of suspension is best suited for a case like this where we do not have a real spectrum of vibrations to be produced, and a frame of this type have the ability to obtain a system with a low resonance frequency or natural frequency, while the weight is better distributed over the whole system frame, allowing racks have some half load without affecting efficacy.
2. Anti-vibrations Metallic Frame It maintains a low resonance frequency, having a significant variation in the weight of equipment supported on anti-vibration frame, for example for a Data Center whose load will be variable over time, with an estimated total load of the slab 10 Metric Tons (9 T the slab and 1 T IT equipment), it appears that we are about 4 Hz resonance frequency and this is so even if we have a significant change in weight.
2. Anti-vibrations Metallic Frame: Technical Features Ability to maintain overall stability while obtaining low resonance frequencies, which provides high performance anti-vibration, thanks to the great stability obtained by notably reducing the center of gravity of the system. Also increases the stability of the whole system placing supports more separated. Fast leveling system integrated in the frame. Different thicknesses of frames. Maintaining one low internal frequency even with large load variations.
2. Anti-vibrations Metallic Frame Possibility to vary the spacing between the Frame and the floor between 10 mm. and 50 mm. Natural frequency (Hz) Metallic Frame with integrated silent blocks. Metal container with high resistance system, safe and quick access. Containers with system registrable for replacement the silent blocks. Double set silent blocks for high and low frequencies.
2. Anti-vibrations Metallic Frame Anti-vibration protection system by common frame for all 10 racks of the company, along with its graphical function efficiency frequency.
3. Description Floating Slab System The high-performance floating slab is a floor isolation system with low resonance frequency and integrated isolators in container elements inside the concrete slab, with a high degree of vibration isolation. This type of suspension is best suited for Data Center environment in which we do not have a real spectrum of vibrations that will occur in an earthquake or possible nearby construction works, and a slab of this type have the ability to obtain a system with a low frequency resonance or natural frequency.
3. Floating Slabs: Other Applications Anti-vibration protection systems consist of Floating Slabs have been widely used by various industries for vibration absorption and attenuation impacts: radio studios, TV studios, recording studios, industrial washing machines, refrigeration equipment, electrical transformers with oil tank located between the slab and the transformer, boilers, elevators, gyms, bowling alleys, dance halls, cold rooms, machine tools, precision balances dynamic UPS machinery, printing presses, newspaper presses, and so on.
3. Floating Slabs: Main Specifications Concrete slab with integrated silent blocks in the slab itself. Metal container with high strength system, safe and fast in binding to mesh. Containers with recordable system for replacement of silent blocks. Double set of silent blocks for high and low frequencies. Levelling system integrated with the whole slab.
3. Floating Slabs: Technical Specifications Ability to maintain overall stability while obtaining low resonance frequencies, which provides high performance vibration, thanks to the great stability obtained by notably reducing the center of gravity of the whole system. Natural frequency (Hz)
3. Floating Slabs: Technical Specifications The silent blocks can be replaced by others with different charge or different natural frequency. Fast integrated leveling system of the whole slab. Different thicknesses of slab Standard thicknesses of slab H1 = 128 mm. and H1 = 148 mm. Other thicknesses can be supplied. Standard separation S = (from 1-5 mm). For special cases for further expansion. Natural frequency is maintained low even with large load variations Possibility to vary the gap between the floor and the slab and from 10 mm. to 50 mm. Can be built while maintaining a certain slope.
3. Floating Slab Floating anti- vibration slab was installed to protect from vibrations occurred in the Data center, communications equipment and other electronic equipment sensitive to vibration that occurred as a result of the construction works being carried next the room at the XXX Hospital. The project was focused on protection of jackhammers. The jackhammers work about 900 beats per minute, in this case as a result of this work, if we conducted vibration taking action, we would find that we would appear on the chart several peaks, which we would be saying we have in certain frequencies a vibrations "that marks the peak" high acceleration. As a result of the 900 beats, the maximum acceleration would have a 15 Hz and harmonics of these: 30 Hz, 45 Hz, etc.
3. Floating Slab On the other hand as a result of impacts and the time rock breakage we also produced peaks at acceleration in a frequency certain, this will depend on rock type and soil type where vibrations are propagated, in this case we had some peaks between 30 and 45 Hz. In addition, we must take into account the Compaction Process, which produces vibrations at frequencies 25 or 35 Hz, in depending on the manufacturer of the Compaction Machine.
Example TECHNICALDATA of Earthquake Protection Dimensionsslab(m) 10x15 ITEM 1: Slab anti-vibration, with earthquakes seismic attenuation to mediumlow level. Slabarea(m2) EQUIPMENTANDPEOPLEWeight(kg)maximumload EQUIPMENTANDPEOPLEWeight(kg)minimumload SlabWeight(Kg) 150 Totalweightsuspended(kg)maximumload 60.000 Totalweightsuspended(kg)minimumload 18.000 Over-useload(kg) 54.000 MaximumTotalLoad(kg) 114.000 Numberofsilentblocksperslab 72.000 41.000 RigidityCoefficientoftheSlabKN/m 155.000 RigidityCoeffiecientoftheSlabKg/mm. ResonanceFactorslab(r.p.m.)atmaximumload 76.462 ResonanceFactorslab(Hz)atmaximumload 7.646 ResonanceFactorslab(r.p.m.)atminimumload 245 ResonanceFactorslab(Hz)atminimumload 4,08 %Isolationfor25Hz 308 %Isolationfor50Hz 5,14 %Isolationfor100Hz Slabthickness(mm) (+)99% 150
Example of Earthquake Protection - In addition to the basic anti-vibration system slab, will be placed shock absorbers stainless steel wire with double slip soles, non-slip sole gives high isolation to the horizontal movements, in the case of slab fell few cm as these pads will be separated from the slab. -Bindings of the shock absorbers to the containers to prevent a possible shift in case of earthquakes of medium intensity. - Placement on the bottom of each shock absorber of spring container, attached to the spring and with anti-slip sole, but also a steel machined base is added to distribute loads and provide the joint between the two. This got protection against medium intensity earthquakes. We must stress that raised floor should be "screwed" to the slab, not just glued, to allow both feet and raised floor tiles move horizontally with the slab and avoid raised floor collapse.
Example of Earthquake Protection ITEM 2 (OPTIONAL): To achieve a higher degree of protection should perform a physical union of all racks with steel springs interposed stainless steel wire and replace leveling legs for machine feet dampers and stainless steel wire non-slip soles. In this way is achieved greater mass of the system and prevent them from tipping to large horizontal forces. Force is equal to mass by acceleration, by joining the mass, we decrease the accelerations and thus the movement of equipment in the Data Center, in addition braking by non-slip feet.
Example of Earthquake Protection ITEM 3 (OPTIONAL): anti-shock system to absorb the slab impact energy horizontally in case of a earthquake in the 2 horizontal axes X and Y. The greatest degree of protection to include a concrete wall of 200mm and the height from the slab to the raised floor, on which are placed horizontally elastic elements both on the side of the slab and in the raised floor tiles that move give up their energy to these horizontal elastic. The wall will be in charge of making the opposing force to the slab and withstand the shock. The perimeter space of the room will be protected with rock wool. ITEM 4 (OPTIONAL): Increase the seismic mass by increasing the slab thickness of 150 mm to 200 mm, to improve performance and isolation, further decreasing the level of acceleration.
Other Seismic Solutions: Platforms
Other Seismic Solutions: Floors
THANKS For any comment or doubt: Emilio Sapina CEO SECURE TECHNICAL ROOMS Tel: +34-657663442 info@securetechnicalrooms.com www.securetechnicalrooms.com