Research & Development

Degaussers are used for the complete erasure of data and other signals on magnetic media. Degaussing is used for security purposes in the military, as well as in the private sector. For security purposes, sensitive data is totally removed and/or the media is rendered totally obliterated. It is also proven to be cost effective, in environments enabling the media to be recycled, rather than discarded.

In the recording process, a remanent or residual magnetic flux with a unique relationship to the original program material is recorded on the medium. Media that is recorded to its saturation level is magnetized with its maximum remanent flux. The density of this remanent flux is measured in “gauss”. Therefore, reducing the remanent flux back to zero is technically known as “degaussing” and often referred to as “erasing the media”.

Degaussing is accomplished by applying a strong enough magnetic field to reduce the media’s remanent flux back to zero. During degaussing the magnetic media is passed through a powerful alternating magnetic field to rearrange the pattern of the magnetic particles, completely removing any resemblance to the previously recorded signal.

The strength of this magnetic field is determined by the “coercivity” of the media’s magnetic particles. Coercivity is measured in units known as “oersteds”. The higher the oersted rating of the media, the more difficult it is to change the remanent flux back to zero.

Deciding on which degausser is best for your particular needs to properly destroy electronic data for federal compliance can be a daunting task even if you are familiar with the various terms that can be used to describe the strength of a degausser – gauss, oersted, tesla, kiloamps!

Before 1930, there was much confusion about the difference between the terms gauss and oersted. At its meeting in Stockholm in 1930, the Advisory Committee on Nomenclature of the International Electrotechnical Commission (IEC) eliminated all ambiguity by adopting gauss (G) for the unit of magnetic flux density and oersted (Oe) for the unit of magnetic field intensity. Unfortunately, eighty years after the adoption of the IEC language, there is still much confusion! You may notice that the strength of a degausser is sometimes described in product and technical literature as magnetic fields (Oe) and sometimes as magnetic flux (G). In air, the magnitudes of magnetic field (Oe) and magnetic flux (G) are numerically equal, so the terms are sometimes used imprecisely, leading to the confusion that exists today.

The US National Security Agency (NSA) when evaluating a degausser requires a magnetic flux density (G) that is three times (3X) the magnetic field intensity (Oe). Thus, 10,000 G can only be relied upon and approved to erase 3,333 Oe media, not 10,000 Oe as is sometimes incorrectly stated on product literature. When purchasing a degausser, it is critical to get both the magnetic flux density (gauss) and the magnetic field intensity (oersted) measurements.

Technology has come a long way since 1930! As new Terabyte hard drives are introduced the power to destroy the data on these drives must also increase. Today’s degaussers have moved from gauss to tesla (T) units for the magnetic flux field. Fortunately, the conversion factor is simple i.e. 1 T = 10,000 G or Oe. Metric measurements add to the confusion on product and technical literature and are sometimes expressed in kiloamperes per meter (kA/m) where 1 kA/m = 12.57 G or Oe.

If you see degaussers that state only one measurement like magnetic field of 8,500 Oe or .85 T or 676.2 kA/m they probably mean magnetic flux density which converts to a real magnetic field intensity of 2,833 Oe (not 8,500 Oe). Keep it simple! Get both the flux field density and magnetic field intensity measurements when evaluating degaussers. We hope this attempt at an explanation helps remove some of the ambiguity surrounding degausser strength ratings. Proton has been the trusted name for data destruction products since 1987 and we intend to keep setting the industry standard. Feel free to contact us (info@protondata.com) for further information.