WA FFCC.Com member, who is a noted expert in FIRE COMMUNICATIONS wrote us:
I don’t know if you’ve covered this before, but I am aware of paneling marketed to restaurants and theaters that is designed to effectively block the transmission of cellular calls. This is installed in order to limit cell phone use in areas where such use is considered rude or disturbing. Unfortunately, such products can also effectively block 2 way radio communications, especially for departments using 800 MHz radio systems, since they operate in a very similar spectrum. I don’t know of any issues caused by this yet, but wanted to give you and yours a heads-up. From my vantage point any pre-fire inspection should always include a check of where your radios will and will not operate. This is a significant safety factor that is often overlooked, but one that can have serious implications during the “real thing.”
RADIO SIGNAL BLOCKING INVENTION
A team of Japanese engineers has come up with a way of blocking mobile phone signals using wood panels containing magnetic material. The panels would be useful in cinemas, theaters, or anywhere where ringing mobile phones cause exasperation. They work by sandwiching a layer of nickel-zinc ferrite between thin slices of wood, New Scientist magazine reports.
The magnetic ferrite absorbs much of the energy of the radio signal, cutting the phone dead in most cases.
Hideo Oka and his colleagues at Iwata University in Morioka, Japan, tested the composite panels by placing them over antennae used to transmit radio signals at frequencies typical for GSM mobiles, Bluetooth and Wi-Fi computer networks. He chose wood as a natural material which could be used for furnishing. Tests showed a four-millimetre sandwich of wood and ferrite stopped 97% of the power of a test microwave signal. Mr. Oka hopes the shielding panels will eventually be sold in hardware stores. They could be used to build doors, walls and rooms in which it would be impossible to carry out a mobile phone conversation. They might also be useful to shield wireless computer networks from each other. Mr. Oka told New Scientist he wanted to make the panels cheaply and cut their cost even further by using recycled materials.
In many public places in Japan – such as trains and cinemas – customers are asked to switch off their mobile phones or put them on silent tone. However, until now, there has been no way of enforcing silence.