EMF shielding materials
If you have concerns about electromagnetic frequency (EMF) radiation or feel that you are overly sensitive to its effects, there are a variety of shielding materials out on the market that can help you in reducing EMF in your home or business. These materials take a variety of forms, but all work on the same principle as a Faraday cage.
Basically, a Faraday cage is a shielded enclosure that is grounded and acts as a large antenna. EMF emissions in certain bandwidths will be received by this cage-like antenna and directed toward the ground, thus removing them from affecting anything inside.
The same principle can be applied by caging potential sources of EMF with shielding materials and thereby block or redirect the emitted energies. Here we will discuss the ins and outs of EMF shielding and provide advice on how to select the proper materials for your particular situation.
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Why you might need shielding
If you have the normal abundance of electrical and microelectronic devices in your home or business, there is likely a considerable amount of EMF radiation in your environment. These sources include large appliances, laptop computers, smartphones, tablets, WiFi routers, Bluetooth devices, and really any device with microelectronics, not to mention local television, radio, and cellular communications towers.
Electronic devices operate at relatively high emission frequencies due to both the amount of current flowing in the circuitry and the design of the device. Most electronic devices are simply enclosed in a plastic housing, which offers no shielding potential and is not meant to do so.
So, unless you intend to ship off to a remote South Pacific island or live in the rainforest in a hut, you are going to be exposed to EMF on a routine basis. It is an inescapable fact of modern life.
However, you can take steps to mitigate exposure in your home or workplace by use of some carefully placed shielding materials. These efforts will not make your environment EMF-free, but will substantially reduce the exposure levels you and your family or coworkers receive on a daily basis.
How To Choose Shielding Material
If you want to be absolutely 100% shielded from EMF, you could simply transform your house or business into a giant Faraday cage. Just had to mention the obvious, absurd, nuclear option for shielding before we proceed to discuss options that are not over-the-top.
If you want complete shielding in small, situationally-appropriate packages, superconductor materials are really the only types of shielding that block EMF and do not attract EMF energies toward them. However, superconducting materials are pricey and not always readily available to homeowners.
Before you splurge on shielding, we recommend that you do a thorough area survey. Buy (or better, rent) an EMF meter or hire a qualified consultant and assess where in your home you have EMF emissions, energy leaks, poorly-shielded wiring, and other problems.
A careful survey will alert you to problem spots, some of which may be fixed quite easily, and give you a general plan for how much shielding you need and where you need to put it. This is important when selecting shielding materials since you need to know what frequencies you are attempting to shield.
In choosing EMF shielding materials, consider the frequency of EMF to be shielded, the intensity of the emitted radiation, and whether you need to shield from electrical fields, magnetic fields, or both types of energy emissions.
Below, we will review the different types of shielding materials, their properties, and what they do and do not do as far as EMF shielding effects. The forms of materials we will review come in several types which include metal sheets, gaskets, meshes, and metallic foams.
Choice of Metals
Copper. Copper is fantastic as shielding and conducting material. That’s why the wiring in your house is made from it.
When I lived up in Wisconsin, north of me in the Upland Peninsula were copper mines where the ore was actually alloyed copper with a bit of silver. That combination was outstanding as a conductive material, so most of the ore mined went straight to wire.
Most of the houses in the US are actually wired with this copper alloy. If you find it for shielding, it is the best.
Copper has many interesting properties and can shield radio and magnetic emissions.
Aluminum. Aluminum is another good choice for shielding material and is decidedly more cost-effective to purchase than copper. However, it is not copper and is not as effective as copper.
Aluminum can block radio frequencies but is not really suited for containing magnetic fields. Think about it: How many aluminum magnets have you ever seen?
Galvanized Steel. Galvanized steel is effective for both magnetic and electrical field shielding due to its conductive properties. It is about half the cost of copper and nearly as effective.
Construction of galvanized steel shielding is a bit more prone to energy leakage since its plates are screwed or bolted together, whereas copper shielding can be soldered, offering a tighter seal.
Types of Devices
Gaskets come in many shapes and sizes and the ones you use should be specifically selected for your particular circumstances. They are essentially a shielding device between EMF emitting components and their housing and outputs (such as wires).
Gaskets are made of several different kinds of materials, which we will detail below.
Wire Mesh Gaskets
Wire mesh gaskets are typically made from aluminum or tin-plated copper and are generally very cost-effective solutions They can provide a broad range of shielding advantages across a breadth of radio frequencies.
Some gaskets are softer and more flexible, being made of nylon with an embedded metal mesh that allows them to be applied to curved surfaces.
Metal Radiofrequency (RF) Gaskets and Spring Contacts
Metal RF gaskets have very potent shielding efficacy and can endure large amounts of mechanical compression. As an assistive component, spring contacts are excellent choices if you must frequently access a location with an emitting device.
Electrically Conductive Elastomers (ECEs)
ECEs are excellent solutions for environmental sealing as well as EMF shielding. They can absorb frequencies up to 10 GHz at intensities of as much as 120 dB (decibels).
The filler part of the ECE sandwich usually is made of carbon fiber or elastomeric materials. Carbon filters include materials made from nickel-coated carbon, “passivated” aluminum, or silver-plated composites of aluminum, copper, glass, or nickel.
“Oriented” Wire
If you have a surface that you need to seal off from moisture or rain, the oriented wire is a great choice. It consists of metal wires embedded in silicone or an elastomer sponge.
Fabric-over-Foam (FoFs)
If you have an application where there is not a risk of mechanical compression, FoFs are a good choice. They consist of a conductive fabric laid over an adhesive foam layer.
FoFs are good solutions for equipment apertures and seams.
Form-in-Place (FiPs)
FiPs are good for enclosures of electronics that are irregular (round surfaces or complex corners) and also function well as environmental seals.
Board EMF Shielding
Board EMF shields are very effective for microelectronic circuitry. They are typically made from stainless or zinc-plated steel, silver, nickel, copper-beryllium, brass, or tin-plated aluminum.
Combined Shielding Materials
For any shielding project, a single shielding option will usually not produce all the desired reduction effects. Depending on the particulars of the situation, it is often best to combine shielding materials on a site.
To save time and hassle, many combined material shielding products are sold which will serve several purposes on a given project, such as environmental sealing, electrical shielding, and magnetic shielding. They tend to cost a little more, but the application is easier and the results more consistent.
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