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Tesla Fields and Magnetic Shielding TESLA FIELDS AND MAGNETIC SHIELDING Oftentimes clients will ask about the effectiveness of vaults in shielding stored magnetic media from magnetic fields induced in the building by wiring grids, electrical transformers, lighting strikes to the building and of late solar flares. Here is a discussion with references from various web sites and FIRELOCK’s own research in this regard. Recent concerns about “Solar Flares” and tremendous magnetic fields associated with these solar flares One tesla is equal to 104 gauss. Magnetic field drops off as the cube of the distance from the source (for a dipole ). So that means that the critical factor is to eliminate magnetic fields near your media storage vault. The magnitude of a magnetic field is its strength; measured in Tesla. The critical point is that Magnetic Media is affected with an exposure to a field of 10 Milligausse over an extended period of time. A short exposure to a field of 500 to 1850 Oersteds will damage and then destroy the recorded magnetically recorded data. I would recommend that you not drive an electric car into the area surrounding magnetic media storage. These cars can emit a field that can affect the media. Clients often have staff who rotate media using personal vehicles and if that vehicle is an electrical vehicle then it poses a risk to the media. Fields over 1850 Oersteds can cause the media to lose the recorded message or damage it beyond normal use. I also suggest that you measure the magnetic field existing in your building due to electrical transformers, electrical lines not running through Arc Breakers or Ground Fault Circuits. An electrical storm can create dangerous magnetic fields. (FIRELOCK uses a Triaxial ELF Magnetic Field Meter to test our vault chamber interiors to ensure the vault is properly shielded in the field location.) For example, the magnet in an MRI system is 0.5 -Tesla to 3.0 -Tesla range, or 5,000 to 30,000 gauss. Extremely powerful magnets -- up to 60 Tesla -- are used in research. Compared with the Earth's 0.5-gauss magnetic field, you can see how incredibly powerful these magnets are. Because of the power of these magnets, the MRI suite ( 1.5 to 3 T Field ) can be a very dangerous place; if strict precautions are not observed. New research MRI units can reach 9T. Metal objects can become dangerous projectiles if they are taken into the scan room. For example, paperclips, pens, keys, scissors, hemostats, stethoscopes and any other small objects can be pulled out of pockets and off the body without warning, at which point they fly toward the opening of the magnet (where the patient is placed) at very high speeds, posing a threat to everyone in the room. Credit cards, computer media and anything else with magnetic encoding would be erased by most MRI systems. For this reason the recording servers, and PACS (Picture Archiving) must be removed from the immediate area of the MRI units. The magnetic force exerted on an object increases exponentially as it approaches the magnet. Imagine standing 15 feet (4.6 m) away from the magnet with a large pipe wrench in your hand. You might feel a slight pull. Take a couple of steps closer and that pull is much stronger. When you get to within 3 feet (1 meter) of the magnet, the wrench likely is pulled from your grasp. The more mass an object has, the more dangerous it can be -- the force with which it is attracted to the magnet is much stronger. A 500 Tesla Field would collapse your shelving and probably collapse your structure. Where would such a field come from? But suppose an MRI was opened next door to your center it would only emit, at most a 3 Tesla field but in the distance of your parking lot, and the field would be diminished such that your data would not be effected. Of late, there is special concern about Solar Flares and the fields they Tesla fields they create. Could a solar flare cause damage to stored media? Events in the power grid failures cause concern among scientists and data center managers as to the proper storage conditions for back up tapes. FIRELOCK Vaults are often utilized on nuclear sites where large power grids are in use and create magnetic fields. Using the magnetically shielded FIRELOCK Vault Chamber satisfies NFPA 232 and NQA-1 which require protection from all of the varied threats that can destroy computer media. A Graph developed and copyrighted by the Commonwealth of Australia Bureau of Meteorology, prepared by Richard Thompson shows the strength of such fields solar fields during recent solar IPS - Magnetic Field - A Solar Flare Effect 12/2/13 12:21 PM Home Space Weather Satellite Geophysical Solar HF Systems Products and Services Educational World Data Centre Educational FORECAST SOL: Normal MAG: Normal ION: Normal Looking for something? Site search Home Educational Magnetic Field Geomagnetic Activity A Solar Flare Effect Monday, Dec 02 2013 17:18 UT Space Weather Magnetic Field The Aurora What is Space Weather Space Weather Effects A Solar Flare Effect Space Weather Events The graphs below show an event which is known as a Solar Flare Effect or sometimes as a Magnetic Crochet. This example occurred on The Sun and Solar Activity General Info Nov 04, 1997 during an X2 class flare at around 06 UT. The upper panel shows the variation of the X-ray flux during the flare Sunspots indicating its very rapid rise starting at around 05:55 UT. The peak of the flare occurred near 05:58 UT - a very short time during Solar Cycle which the X-ray flux increased by a factor of 100. The lower panel shows the magnetic field recorded at Canberra at the same time. As Solar Flares the flare started there is a sharp jump in the magnetic field which peaked at about the same time as the flare reached its maximum; Magnetic Field and as the flare began to decline in strength the magnetic field also decreased towards its pre-flare level. By 06:20 UT the flare had Geomagnetic Activity ended with the X-ray flux back to C class levels. The magnetic field has already returned to its previous level by this time. Space Debris Meteors A magnetic crochet arises from the increased ionisation in the D and E layers of the ionosphere caused by the massive increase in X- Orbital Space Debris ray radiation generated by the solar flare. This ionisation changes the properties (especially the conductivity) of these ionospheric Near-Earth Objects layers allowing electric currents to flow more easily. It is the magnetic effect of these currents which produce the jump in the earth's Cosmic Rays magnetic field. As the flare declines, the ionospheric layers quickly return to their previous state, the electric currents in the layers Other Topics return to normal, and the change in the magnetic field ends. Transit of Venus Radio Communication Magnetic crochets are quite rare because they are only observed during large flares which rise to a peak very quickly. Also, they are Date of Easter About Eclipses mostly observed in locations close to the sub-solar point (i.e. the point on earth when the sun is overhead). In the case of the Others November 04 event, the sun at Canberra was well to the west. Similar magnetic effects were observed from many stations in the sunlit Related Sites hemisphere at the time. Educational Links Astronomical Events Links Section Information Latest News Help Pages flares. To see more information visit the following site: http://www.ips.gov.au/Educational/3/1/1 MaterialMagnetic prepared Media by Richard stored Thompson within a shielded Faraday Cage built into the vault shell helps to diminish magnetic fields. Computer Media stored in Faraday Cage Vault Chamber designs such as employed About IPS Feedback Contact Us Site Help Site News Careers Site Map Site search Acknowledgments Subscribe by FIRELOCK were unaffected in previous solar flares such as the one back in 1989. © Copyright Commonwealth of Australia 2013, Bureau of Meteorology (ABN 92 637 533 532) disclaimer privacy accessibility http://www.ask.com/wiki/Geomagnetic_storm#cite_note-4 On March 13, 1989 a severe geomagnetic storm caused the collapse of the Hydro-Québec power grid in a matter of seconds as equipment protection relays tripped in a cascading sequence of events.[2][12] Six million people were left without power for nine hours, with significant economic loss. The storm even caused aurorae as far south as Texas.[3] The geomagnetic storm causing this event was itself the result of a coronal mass ejection, ejected from the Sun on http://www.ips.gov.au/Educational/3/1/1 Page 1 of 2 March 9, 1989.[13] The minimum of Dst was -589 nT. So I would suppose your clients are referencing a NanoTesla which is vastly less than a Tesla. 1 - 100 µG 10−9 nanotesla 0.1 nT to 10 nT Solar flares will have a large effect on wiring systems, phone lines but not fiber optic lines. But shielding your media can prevent deterioration of the magnetic strength of the recorded data and protect the back up data sets. To erase recorded data, it is necessary for the strength of the degaussing field to be greater in value than the coercivity of the magnetic media. Simply stated, coercivity is the magnetic field strength, rated in oersteds (Oe), required to change the magnetic orientation of the magnetic material. FIELDS REQUIRED TO DAMAGE RECORDED DATA: LTO-Ultrium1, LTO5 tape 1850 Oe DLT tape III, DLT tape IIIXT 1540 Oe DLT tape IV 1850 Oe Super DLT tape1 1900 Oe If your media is exposed to a field of 1850 - 1900 Oersteds then the media is effectively destroyed.
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