Impact of Electro Magnetic Fields & Different Ways of EMF Shielding

A Brief Report

On

Impact of Electro Magnetic Fields

And

Different Ways of EMF Shielding

Submitted by: Punpreet Singh

Date of submission: 19/09/2007

Submitted to: Dr. R. M. Mehra

Impact of Electro Magnetic Fields & Different Ways of EMF Shielding

List of Contents

What is EMF………………………………………………………. Page 1

Different Sources of EMF…………………………………………. Page 2

Effect of EMF on Human Body…………………………………… Page 7

EMF Shielding and Products Used………………………………... Page 8

Conclusion…………………………………………………………. Page 11

References…………………………………………………………. Page 12

Illustrations………………………………………………..

Figure 1 Electric & magnetic fields around a wire when there is current

flowing…........................................................................................... Page 1

Figure 2 Lightening and

Thunderstorm……………………………………………………… Page 2

Figure 3 Kitchen Appliances………………………………………. Page 3

Figure 4 Air Conditioner…………………………………………… Page 3

Figure 5 High Tension Electric Wire Poles………………………… Page 4

Table 1 Typical electric field strength of household appliances at various

distances.......................................................................................... Page 5

Table 2: Typical magnetic field strength of household appliances at various

distances.......................................................................................... Page 6

2

What is EMF?

According to WHO (2007), Electro Magnetic Fields also, known as EMF, are a combination of both electric as well as magnetic fields. Electro magnetic fields are energy waves with frequencies below 300 hertz or cycles per second.

Current, by definition, is the flow of charge. One amp of current is produced when one coulomb of charge passes by a point in one second. As current flows down a wire, the charge density at any point along the wire changes, as a function of the current at that point in time. This charge density creates a field that radiates as a vector directly away from the wire (see Figure 1). Electric fields are created by difference in voltage; with rise in voltage the electric filed becomes stronger. This field remains constant even if the current is not present.

Figure 1: Electric and magnetic fields around a wire when there is current flowing.

Source: Brooks, D. (n.d.)

When current flows, there is also a magnetic field that is generated around the wire. This is the fundamental concept behind an electromagnet. This magnetic field radiates away from the wire in a circular fashion (Brooks, n.d.). Stronger the current, greater is the magnetic field.

The combination of these two fields creates an electromagnetic field. It is not possible to have a current flow without an electromagnetic field. The magnetic field can’t get out in front of or lag behind the electric field. The electrons can’t get in front of or lag behind either of field. All three must travel together. That is why signal propagation time is determined, not by how fast the electrons can travel in a wire, but by how fast the electromagnetic field can travel in the medium it travels through.

1

Different Sources of EMF:

Electro Magnetic Fields are everywhere in the environment. They are not only outside our homes but are also found very much inside. Electric fields are produced by the local build-up of electric charges in the atmosphere associated with lightening and thunderstorms. The earth's magnetic field causes a compass needle to orient in a North-South direction and is used by birds and fish for navigation as the magnetic waves travel from North towards South.

Figure2: Lightening and Thunderstorm

Source: http://outdoors.webshots.com/photo/1063733330030054305yTAiaD

Beside natural sources these Electro Magnetic Fields are produced through man made products which consist of electrical use. For example: Electrical appliances which are daily used like Microwaves, Mixers, Juicers; Geysers, Television, Mobile phones and bases. These fields are also created through Medical equipments like X-ray Machines, Cancer treating machines, CT Scanners, Ultra Sound Machines etc. In Brief, each and every product which runs on current produces these electro magnetic fields.

Some of the regularly used appliances can be seen in the following pictures:

The following picture (Figure 3 clearly depicts kitchen appliances like electric gas, oven, dishwasher.

Figure 3: Kitchen Appliances

Source:http://www.ajmadison.com/?mv_pc=gg&cm_mmc=gg-_-General+Appliance+Terms-_-Home+Appliances

Another major EMF producer is an Air conditioner (Figure 4). It is a devil in disguise as has become more of a need than luxury in present times.

Figure 4: Air Conditioner

Source:http://

www.ajmadison.com/b.php/Window_Wall+Air+Conditioners/N~57

The major part of the electro magnetic waves are created by the man made high tension cables( Figure 5), which are carriers of enormous amount of electric current.

Figure 5: High Tension Electric Wire Poles

Source: http://www.freefoto.com/preview/13-18-74?ffid=13-18-74

Following tables (Table 1 and Table 2) provide a basic view of the strength of the electric and magnetic field produced by the appliances and the impact of the waves from different distances.

Table 1: Typical electric field strength of household appliances at various distances

Distance from Source

(Strength in mG) - median

readings6" 1' 2' 4'

Hair dryers 300      

Electric shavers 100 20    

Blenders 70 10 2  

Can openers 600 150 20 2

Microwave ovens 200 40 10 2

Electric ranges 30 8 2  

Refrigerators 2 2 1  

Toaster 10 3    

Washing Machine 20 7 1  

Vacuum cleaners 300 60 10 1

Color TV's 7 2    

Electric blankets 3      

Drills 150 30 4  

Power Saws 200 40 5  

Fluorescent Lighting 6 2 2 1Source: http://www.energpolarit.com/why_protect_against_emf.aspx

This table clearly shows the effect of the electromagnetic waves from different areas. Farther the product from the body, lesser is the EMF effect.

Table 2: Typical magnetic field strength of household appliances at various distances

Electric appliance

3 cm distance

(µT)

30 cm distance

(µT)

1 m distance (µT)

Hair dryer 6 – 2000 0.01 – 7 0.01 – 0.03

Electric shaver

15 – 1500 0.08 – 9 0.01 – 0.03

Vacuum cleaner

200 – 800 2 – 20 0.13 – 2

Fluorescent light

40 – 400 0.5 – 2 0.02 – 0.25

Microwave oven

73 – 200 4 – 8 0.25 – 0.6

Portable radio

16 – 56 1 < 0.01

Electric oven 1 – 50 0.15 – 0.5 0.01 – 0.04

Washing machine

0.8 – 50 0.15 – 3 0.01 – 0.15

Iron 8 – 30 0.12 – 0.3 0.01 – 0.03

Dishwasher 3.5 – 20 0.6 – 3 0.07 – 0.3

Computer 0.5 – 30 < 0.01  

Refrigerator 0.5 – 1.7 0.01 – 0.25 <0.01

Colour TV 2.5 – 50 0.04 – 2 0.01 – 0.15

With most household appliances the magnetic field strength at a distance of 30 cm is well below the guideline limit for

the general public of 100 µT.

(Source: Federal Office for Radiation Safety, Germany 1999 citied in http://www.who.int/peh-emf/about/WhatisEMF/en/)

Note: Normal operating distance is given in bold

Effect of EMF of Human Body:

Tiny electrical currents exist in the human body due to the chemical reactions that occur as part of the normal bodily functions, even in the absence of external electric fields. For example, nerves relay signals by transmitting electric impulses. Most

biochemical reactions from digestion to brain activities go along with the rearrangement of charged particles. Even the heart is electrically active - an activity that your doctor can trace with the help of an electrocardiogram.

Impact of electro magnetic fields on the human body is a very controversial subject. There had been many researches done to understand the impact and the amount of effect it can cause to the human body. Heating is the main biological effect of the electromagnetic fields of radiofrequency fields. In microwave ovens this fact is employed to warm up food. The levels of radiofrequency fields to which people are normally exposed are very much lower than those needed to produce significant heating. The heating effect of radio waves forms the underlying basis for current guidelines. Scientists are also investigating the possibility that effects below the threshold level for body heating occur as a result of long-term exposure. To date, no adverse health effects from low level, long-term exposure to radiofrequency or power frequency fields have been confirmed, but scientists are actively continuing to research this area. (WHO, 2007)

At the same time there are other sources which have come up with the following findings:

Just 2 hours of exposure to Cell phones caused brain cancer in rats.

Brain Cancer and Brain Tumor have increased 25% since the release of the Cell phone.

Sleeping on an electric blanket is being immersed in EMF Waves the entire night.

Hands-free devices DO NOT reduce the danger, in fact they increase it by acting as an antenna drawing more EMF

Testicular Cancer has increased 50% since the release of the Cell phone.

Younger people are more vulnerable to EMF waves due to skull-thickness, which is maturing and growing.

35% of Americans rank EMF as their #1 Environmental Health Concern - USA Today. (Emf Buster, n.d.)

This shows that this subject is surely very controversial but also that the low frequency electro magnetic fields do not cause any adverse effect but the high level surely do. Therefore, the best option is to take precautions and maintain reasonable distance from these waves.

EMF Shielding and Products used:

Even if it can be said that the subject of EMF is controversial but still there are many scientific reasons like the magnetic waves from North towards South and proven

movements of electrical as well as magnetic fields, which makes us to consider the impact of EMF on human body more seriously. The procedure and ways by which one can safeguard from the effect of electro magnetic waves is known as Electro Magnetic Shielding. This shielding is very helpful to control the adverse impact of EMF on the physical and mental health.

Following are some of the products which can be used to shield oneself from this impact:

1) Magnetic Shielding Film:

These films are suitable for applications or appliances requiring high saturation and good permeability. They can be used small shields on magnets, motors, speakers and appliances such as refrigerators, vacuum cleaners etc. Also, great for lining car floor or firewall. Perfect for full or partial wall / floor shielding in rooms. Can be glued, taped, nailed, screwed or riveted into place. Could even be used to make a (heavy weight) vest to shield a person's torso! Works with AC or DC magnetic fields (0-1000 Hz), and will tolerate temperatures from 32° to 122°F. Coating is UV sensitive, cover if installation is exposed to direct sunlight.

2) Magnetic Shielding Foil:

Used for years in industry to shield delicate electronic components from EMF, magnetic shielding alloy is now available at affordable prices for home and office use. This 80% nickel alloy is easy to trim with scissors and shape by hand. This can work as magnetic barriers on cellular phones, microwave ovens, doorbell transformers, VDTs, buried wiring, and more. With snug fitting shapes, get as much as 75% attenuation of the magnetic field with one thickness. Multiple layers can be used for even greater reduction. (Less emf.inc, 2007).

3) High-Frequency EMF Pollution Reducer:

High-frequency EMF pollution that is carried in wiring has been shown to be the source of electrical sensitivity symptoms for some people. This high-frequency EMF pollution is produced by common household items such as electric motors (found in hair-dryers, blenders, can openers, etc), loose wires, and especially dimmer switches. The pollution reducer does not use electricity. It can reduce the electricity bill and do not interfere with any computers, TV's. or other appliances. Installation is simple and enables you to avoid expensive electrician

service calls. The suppressors are portable, so can be moved from one site to another. This is NOT a bio-energetic device. Special electronic circuitry simply drains the high-frequency pollution out of the wiring system (Less emf.inc, 2007).

4) Full Spectrum Radiation Shield/ Contour Filters:

Contour Filters are custom-fitting glare and radiation screens designed to fit both flat and curved monitors. Unique mount slides easily over any shaped monitor and stays firmly in place. They are manufactured of high quality, optically pure annealed glass, with multiple thin film Anti-Reflective coatings on both sides for sharp image display (Less emf.inc, 2007).

5) Different EMF Shielding Fabrics/ Dress Material:

a) Natura Shield Fabric:

Advance technology has created a fiber which has the conductive components on the inside, with pure natural cotton on the outside. The result is a fabric which is gentle to the skin, has a great feel, and still provides 20-35 dB from 100 MHz to 2.2 GHz, and residual performance up to 10 GHz, according to independent test results. Surface resistivity is 109 Ohm/sq. Perfect for bedding, clothing, drapes and most other applications where you want shielding without the harshness of metallized fabrics. Completely machine washable and dryable (cool) without losing shielding performance, cuts and sews like ordinary cotton, 125 g/m², 60" wide, white as snow with a fine grey grid (Less emf.inc, 2007).

b) RF Suit:

It is a 2-part RF shielding garment. It consists of a long sleeve T-shirt and long pants with comfortable elastic waistband. It is made from very comfortable 90% cotton and 10% Silver with no other toxic metals or additives. Garment achieves 99% RF attenuation over the frequency range from 800 MHz to 18 GHz. In addition, the high conductivity of silver causes this suit to have antistatic behavior, plays an important role in minimizing body odor, and has a strong inhibitory effect on the growth of bacteria (actually acts as an antiseptic!) (Less emf.inc, 2007).

c) Apron:

This unique apron is constructed using a special cotton based shielding fabric which is a highly effective RF shield, providing 25-

35 dB from 200 MHz to 3.3 GHz according to independent test results. Soft feel and gentle to the skin. Completely machine washable and dryable (cool) without losing shielding performance. Generously cut for comfort and great "neck to hip" protection for pregnant women, computer and microwave oven users, TV or radio station workers, research and hospital workers, or anywhere people are exposed to RF radiation (Less emf.inc, 2007).

d) Scarf:

This scarf is pure Silver Lining fabric, nicely hemmed. Light and airy and very unobtrusive, this scarf is very user friendly. It provides 90% or better shielding to 1 GHz and beyond (Less emf.inc, 2007).

6) Conductive Glass:

Conductive glass can be used as windows (in conjunction with shielded external walls), internal partitions or enclosures to provide very good attenuation using the "Faraday Cage Principle". Helps prevent spying into information held on computers and loss of data or other equipment malfunction due to Radar, Cell Phone or other interference, and reduces human exposure to unwanted electromagnetic radiation. The complete absence of any metal mesh and high light transmission make the product unique (Less emf.inc, 2007).

7) Shielding Window Film/ Tint:

Most RF entering or leaving a room will go through the windows. Shielding the windows is the logical first step to reduce your exposure. The benefits of window shielding include controlling heat gain or loss, and improved safety, security, energy efficiency, and appearance of your building. Window tint transmits approximately 50% of visible light and rejects up to 79% of the heat that would otherwise come through the window. That can translate into a savings of about one ton of air conditioning for every 100 square feet of glass exposed to sunlight. Window film also keeps the premises warmer in the winter months by reflecting manmade heat back into the building. This can reduce heat loss by up to 30% to save you money and improve occupant comfort. By blocking out 98% of UV light, it protects from the sun's harmful rays and significantly reduces fabric and furniture fade. In addition, window

films reduce glare to improve indoor visibility, especially with respect to computer monitors and televisions (Less emf.inc, 2007).

The above mentioned examples are some of the products of the never ending list of products, which are used for the EMF shielding purpose. But, surely they provide help and protection from any effect caused by the electro magnetic waves.

8) High Frequency Shielding Paint:

These paints are easy to apply water-based paint for walls, ceilings, doors and other interior OR exterior surfaces. Very effective for blocking cell phone signals, CB, TV, AM, FM signals, radiofrequency radiation and microwaves. Tested highly effective up to 18 GHz. Based on a high quality pure acrylic binder, this shielding paint offers a perfect compromise of excellent attenuation, high water resistance and good ecology. Good adhesion on many surfaces and substrates like latex paint, construction boards, cement, plaster, polystyrene, masonry surfaces, etc.

Conclusion:

Electromagnetic waves are created not only by natural but also by man made reasons. Everyday activities of Human beings revolve around appliances which regularly produce elector magnetic waves. It has been found that the low level waves do not affect the human health but high level do effect. Still there is a lot of controversial angle towards this. To conclude it can be said that since human beings are so used to luxurious life that the products which used to be luxury some time back have become necessity in today’s time. But, while enjoying the lap of luxury and good comfortable living it is very important that these electrical products should be properly used. While using these products everyone should follow the correct procedure to shield oneself from the effect of the electro magnetic waves by using EMF shielding products like EMF shielding clothes, screens, paints etc so that each human being can lead a healthy and tension free life along with enjoying environment which is electrical pollution free.

References

Brook, D. (n.d.) Electromagnetic Field Basics: The Good, the Bad, and the Ugly [Internet]. Available from: <http://www.ultracad.com/mentor/electromagnetic%20fields.pdf> [Accessed on 10 September 2007].

Ener-G-Polari-T (2006) Why Protect Against EMF [Internet]. Ener-G-Polari-T. Available from: < http://www.energpolarit.com/why_protect_against_emf.aspx> [Accessed on 10 September 2007].

EMF Buster (n.d.) Know The Dangers [Internet]. EMF Buster. Available from: < http://emfbuster.com/emf_shield.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) Personal EMF Shielding Devices [Internet]. Less EMF Inc. Available from: <http://www.lessemf.com/personal.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) EMF Shielding for CRT Computers & TVs [Internet]. Less EMF Inc. Available from: < http://www.lessemf.com/computer.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) High-Frequency ElectroMagnetic Pollution Remover [Internet]. Less EMF Inc. Available from: <http://www.lessemf.com/suppress.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) Magnetic Field Shielding [Internet]. Less EMF Inc. Available from: < http://www.lessemf.com/mag-shld.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) Best selection, great prices on Conductive Plastic & Glass

EMF Shielding Devices and Materials [Internet]. Less EMF Inc. Available from: < http://www.lessemf.com/plastic.html> [Accessed on 11 September 2007].

Less EMF Inc. (2007) EMF Shielding & Conductive Fabrics [Internet]. Less EMF Inc. Available from: <http://www.lessemf.com/fabric.html> [Accessed on 11 September 2007].

WHO (2007) What are Electromagnetic Fields [Internet]. WHO. Available from: < http://www.who.int/peh-emf/about/WhatisEMF/en> [Accessed on 11 September 2007].