By Peter Spencer, European Technical Services Manager for CPFilms, CPFilms Solutia UK Ltd.
SubscribeGlass provides a good barrier to the elements: wind, rain, snow, cold. But it provides little barrier to electromagnetic radiation - which allows electronic eavesdropping of sensitive commercial and personal information.
Electromagnetic Radiation
As we all know, white light is a mixture of the colours of the rainbow; all of these colours are part of the electromagnetic spectrum. Electromagnetic radiation is not the radiation from nuclear energy, but it is all around us and includes visible light, UV, infrared, radio waves, TV transmissions, radar and X-rays.
The Problem: Glazing and Electronic Security
Sensitive information is literally leaking out through our windows!
Computer workstations, monitors, laptops, wireless networks and PDA's are all subject to electronic eavesdropping. Glass easily transmits the electromagnetic emissions from these types of electronic equipment - and modern technology can exploit all these emissions to obtain sensitive information, even if the emissions are at very low levels. For example:
| Source | Eavesdropping technology can use |
|---|---|
 | Laptops and workstations: Radio frequency and infra red emissions |
 | Computer Monitors: Radio frequency and optical emissions |
 | Wireless networks: Radio frequency emissions |
 | PDA's: Radio frequency and infra red emissions |
 | Mobile phones and cordless telephones: Radio frequency emissions |
Note how these types of emissions can be exploited:
- Computers can be adapted to enable them to tune into any radio band simply using a plug-in aerial and some free software.
- Casual wireless notebook users can hitch onto a wireless network hotspot and use a company's bandwidth for free
- Network and radio scanners can eavesdrop on any unprotected wireless networks, laptops, computer workstations, computer monitors, PDA's, etc.
- Visible Light from computer monitors and laptop screens can be seen through glass
Electronic eavesdropping equipment is cheap!
A few hundred pounds will buy a network scanner, a radio scanner, or equipment and software to adapt a computer for scanning electronic emissions. Anyone can eavesdrop with minimal technical knowledge.
The Solution: LLumar window films
LLumar films improve electronic security of glazing by reducing transmission of electromagnetic emissions. Table 1 shows the performance of selected LLumar films for increasing electronic security.
As shown in Table 1, LLumar films can increase your electronic security:
- High RF attenuation - up to 36 dB (> 98 % filtering of RF signals)
- Attenuating a wide range of electromagnetic frequencies, not just one or two specific frequencies - the high RF attenuation and the wide frequency range covered offers excellent electronic eavesdropping mitigation
- High infrared attenuation - up to 93 % total IR shielding and up to 88 % IR shielding at 940 nm
- Optical security:
- High optical attenuation - up to 83 % visible light reduction, and/or
- Optical diffusion
- Most LLumar films for electronic security have high optical reflection so that reflected daylight 'swamps' any optical transmissions
Table 1: Electromagnetic Shielding and associated properties for selected LLumar films
Lluma Film Property | N1020B SR CDF | R20 SR CDF | R35 SR HPR | N35AG SR HPR | VS60 SR CDF | NRM PS2 | SSI20 SR PS4 | SSI20 SR PS8 | SSI35 SR PS4 |
|---|---|---|---|---|---|---|---|---|---|
| Visible Light Transmission | 19% | 15% | 28% | 33% | 60% | 69% | 15% | 15% | 28% |
| Visible Light Attenuation | 78% | 83% | 68% | 63% | 32% | 22% | 83% | 83% | 68% |
| Optical Diffusion | No | No | No | No | No | Yes | No | No | No |
| Electromagnetic Shielding Attenuation | 33-36 dB | 27-31 dB | 25-28 dB | 29-31 dB | 24-26 dB | 0 dB | 27-31 dB | 27-31 dB | 25-28 dB |
| Infra-red Shielding, total | 93% | 93% | 90% | 92% | 93% | 31% | 93% | 93% | 90% |
| Infra-red Shielding, 940 nm | 88% | 86% | 82% | 86% | 83% | 33% | 86% | 86% | 82% |
| UV Transmission | <1% | <1% | <1% | <1% | <0.1% | <15% | <1% | <1% | <1% |
| Total Solar Energy Rejection | 77% | 79% | 69% | 69% | 49% | 28% | 79% | 79% | 68% |
| Explosion Protection; Anti-shatter; Safety; etc. | No | No | No | No | No | See note 3 | Yes | Yes | Yes |
Notes:
1. Values are typical and have been estimated from specimens of standard production films (applied to 3 mm clear float glass where applicable).
2. Visible light transmission range: 400 - 780 nm; Infrared transmission range: 780-2500 nm; Electromagnetic shielding range: 200MHz - 12 GHz; UV Transmission range: 300-380 nm
3. NRM PS2 is also available as NRM PS6 safety film version and RM PS2, a combination of R20 SR CDF and NRM PS2 to give both optical diffusion and electromagnetic shielding.
LLumar films solar control and safety benefits
Apart from the high electromagnetic shielding, LLumar films can also reduce solar heat gain, thereby saving energy costs of running air conditioning systems. UV transmission is also reduced which not only protects the film and increases its durability, but protects furnishings, pictures and similar objects.
Safety film versions of LLumar films upgrade plain float glass for explosion protection and are approved by the UK and many other governments. These films not only increase your electronic security but also the physical security of your building! CPFilms also offers edge retention systems to further enhance the explosion protection performance of LLumar safety films.
All our safety films are tested to BS EN 12600 (which has replaced BS 6206) for safety against human impact and therefore can upgrade glass to comply with the safety requirements of BS 6262 Part 4, Building Regulations Approved document N, and Regulation 14 of the Workplace (Health, Safety and Welfare) Regulations.
