# The 99% lie or why efficient screening is so important

Many suppliers try to fool their customers with percentage figures. Figures like "90% (10dB) or 99% (20dB) screening" try to impress with an allegedly high screening efficiency. Often, not even the corresponding frequencies are given, or the percentages are given with respect to "low" frequencies (MHz range or 1-2 GHz).

However, only at very high frequencies, a screening product can show its real capabilities. However, exactly here, many screening products show their weaknesses!

Rigorous architecture-biological exposure limits aren't even remotely reached with screening efficiencies as low as 90% or 99%, depending on the present radiation strength! However, particularly electro-sensitive persons need conformance with these standards and recommendations.

Not the amount of damping in percent, but conformance to exposure limits or recommendations should be the primary aim of screening efforts. This makes a big difference!

Only with screening efficiencies above 99,999% (50dB) or better, chances are that these standards are fulfilled. However, in many cases screening efficiencies of more than 50dB, like with Aaronia X-Dream (100dB), are necessary.

So, it is of CONSIDERABLE importance how many digits you see after the decimal point if screening efficiency is measured in percent, as every additional '9' means 10dB better efficiency. So, don't get fooled by various suppliers!

Rather, only consider the so-called dB figures, especially those in the higher GHz range (at 10 GHz and above, a screening product shows its real strength!). dB figures reflect the effective screening power much more "neutrally" than visually impressive percentages. Also, it is far easier to calculate the efficiency of various screening measures in dB.

The following example demonstrates the importance of a high screening efficiency, using the probably well-known dB(A) table:

# Table 1: Volume table in dB(A)

 Example: dB(A) reading: Perception/impact: Screening example: Jet plane 130dB(A) Hearing damage Jackhammer 120dB(A) VERY PAINFUL Rockband, Disco 110dB(A) PAINFUL Souped-up car 100dB(A) UNBEARABLE Assumed common electrosmog exposure Circular saw 90dB(A) UNBEARABLE 10dB screening (90%) High-traffic motorway, daytime 80dB(A) Hearing damage from 85dB 20dB screening (99%) Main road, daytime 70dB(A) Circulatory diseases 30dB screening (99,9%) Main road at night 60dB(A) VERY LOUD 40dB screening (99,99%) Quiet residential area, daytime 50dB(A) Communication problems. 50dB screening (99,999%) Quiet residential area at night 40dB(A) Issues with concentrating and learning 60dB screening (99,999.9%) Ticking alarm clock 30dB(A) Sleeping disorders 70dB screening (99,999.99%) Whispering leaves 20dB(A) Quiet 80dB screening (99,999.999%) Normal breathing 10dB(A) Very quiet 90dB screening (99,999.999.9%) Silence 0dB(A) Unnoticable to 1dB(A) 100dB screening (99,999.999.99%) Notice: When working with dB(A) figures, 10dB mean a change by a factor of 10. Examples: 100dB(A) noise is 10 times stronger than 90dB(A) or a hundred times stronger than 80dB(A) etc. dB as a damping unit means a tenfold increase at 10dB, 20dB being ten times as much as 10dB, 30dB being 100 times as much as 10dB, etc. © Aaronia AG, D-54597 Euscheid, www.spectran.com, Phone: ++49(0)6556-93033

In our example, we will relate a common level of exposure to electrosmog with the noise level of a "souped-up" car perceived as unbearable at 100dB(A) (See table 1). So, if our screenings were made for damping noise instead of electrosmog, the following sample calculation would apply:

Using a screening with 99% (20dB) efficiency, there would still be a noise level of 80dB(A). This would still be roughly equivalent to causing hearing damage (caused by 85dB(A)).

Even when using a screening of 99,9% (30dB) efficiency, a noise level of 70dB(A) would still be present. This would be equivalent to traffic noise next to a main road which would cause circulatory diseases.

In contrast, using a screening product with 99,999% efficiency (50dB as with Aaronia-Shield), a noise level of only 50dB(A) would remain. This would "only" be equivalent to the noise exposure next to a quiet road in a residential area.
Even more, a 100dB screening efficiency, like Aaronia X-Dream offers, would actually give you a "perfect" screening.
Using our example, the following situations could be derived:

Screening canopies:

Would you like to be exposed to the noise level of a motorway or main traffic road when using a regular 20-30dB (99% to 99,9%) screening canopy, or maybe rather tolerate a quiet residential road using an Aaronia high-performance screening canopy with 50dB damping (99,999%) made from Aaronia-Shield?

Room screenings:

Would you like to be exposed to the noise level of a motorway or main traffic road when using a regular 20-30dB (99% to 99,9%) screening canopy, or maybe rather enjoy the "absolute silence" using a high-performance 100dB screening product like Aaronia X-Dream? We think that your answer is obvious in both cases...

# Damping specifications for Aaronia high-performance shielding products

 Product: Frequency: Damping in dB: Damping factor: Damping in %: Application example: A2000+ 1GHz 10GHz 20dB 10dB 100 10 99,0% 90% Indoor and outdoor shieldingLow exposure Aaronia-Shield® 1GHz 10GHz 50dB 45dB 100.000 30.000 99,999% 99,992% Textile applications (Canopies, clothing, curtains etc.)Low and high exposure Aaronia X-Dream® 1GHz 10GHz 100dB 80dB 10.000.000.000 100.000.000 99,999.999.99% 99,999.999% Indoor shielding, measurement chambersHigh to highest exposure Notice: when using the dB unit, an increase of 10dB is equivalent to a 10fold increase in strength. For example, 100dB is 10 times as strong as 90dB, or 100 times as strong as 80dB, etc.© Aaronia AG, DE-54597 Euscheid, www.spectran.com, Tel. ++49(0)6556-93033

# Damping specifications for Aaronia high-performance magnetic shielding products

 Product: Damping in dB: Damping factor: Damping in %: Application examples: Aaronia MagnoShield FLEX 7-8dB 5-7 50-70% Small screening cases Aaronia MagnoShield FLEX PLUS 7-8dB 5-7 50-70% Self-screening for small areas, or housing units. Shielding plate collisions and transitions Aaronia MagnoShield VERBUND 7-8dB 5-7 50-70% Large-scale screening and high-frequency fields by combination of materials (composite system) Aaronia MagnoShield DUR 10-14db 10-13 90-93% Large-scale screening of buildings, measuring chambers, transformer stations.For high to highest exposure. Notice: when using the dB unit, an increase of 10dB is equivalent to a 10fold increase in strength. For example, 100dB is 10 times as strong as 90dB, or 100 times as strong as 80dB, etc.© Aaronia AG, DE-54597 Euscheid, www.spectran.com, Tel. ++49(0)6556-93033