Best Wi-fi Practice
We hope to build this page over the next few months to advise decision makers on how to install Wi-Fi safely, if they choose to use this medium for their work environment.
Firstly let me state that all Wi-Fi comes with risks and wired network connections would be more preferable for people in the at risk categories: i.e. children, pregnant women, the elderly, people with immune disorders or pre-existing medical conditions.
The best and safest form of connection for children's computers to the internet or other networks is a wired connection. Wired connections give off far less EMF and handle vastly more data as the demand will no doubt increase over the coming years.
Wired connections are more secure, ie: people can't steal packets out of the air. From our experience hackers are always 10 steps ahead of so called safe wireless networks.
Cost should not be considered over children's safety. This is a judgement you may have to live with in the future.
If you have to use Wi-Fi, use a reputable company, that shows interest in the environment that the equipment is to be installed in. You are entitled to be able to ensure that you are as safe as you possibly can be. Insist on drawn plans and design calculations.
Ask what experience the company has in the Wi Fi field, where else have they installed this type of equipment and more importantly "what qualifications do their staff have?"
The current NZ legal limits for spread spectrum devices under the general user licence is 4 watt, ideally you don't want to get anywhere near that output power, the NZ legal limit for non spread spectrum devices is 1 watt. The general use licence, stipulates that the "Power must not exceed that necessary to reasonably maintain communications.", this means turning the equipment down to the lowest possible level.
It is far better to use more lowered powered devices than several large transmitters and ideally the microwave radiation should only be directed into the areas that are needed i.e. not spilled into areas that children congregate or play. The choice of aerials is critical so again ask what type will be used and do your research.
In practice this will work out to 1 transmitter for every 10-20 children or users.
It is not good practice to use high powered transmitters to transmit the signal through walls - for obvious reasons.
We would prefer schools to adopt the 0.614v/m suggested by the bio-initiative report, this equates to 100nW/cm2. The current NZ standard is many times higher than this value and is honestly irrelevant. It is very outdated having been set in 1990's and technology has moved on considerably since then.
Some times a reduction in exposure can be obtained by simply switching off the parts of the system that are not required this will require staff and management education; however it can be easily and cheaply achieved by a card switch or key switch system at each access point or transmitter.
Ideally access points should be placed at a high level, well out of reach of a child, you can get low powered ceiling mounted transmitters, these would be ideally located in the middle of the classroom, and hence the transmission path would be in a downwards direction to the laptops, this would ensure a minimal exposure level to the children.
It is better to have many low powered transmitters than say only three high-powered ones to cover a whole school of 300+ children. A school that size would require 20 to 30 low powered devices or one per classroom. This does not necessarily mean more expense, as high powered devices are often very expensive.
From the NRL test I witnessed, I would suggest a safe approach distance for children to any Ubiquiti equipment set to an E.I.R.P. of 2.5watt would be in excess of 10 meters. If the equipment was set to 1 watt this would reduce to about 5 mtrs.
The safe approach distance is the closest a child can approach the equipment - in its path of transmission.
At all times children should be kept at a safe distance from transmission aerials - that is imperative. Sadly cases are now coming to light overseas of illnesses with children caused by close proximity to transmission aerials. Particularly where radiation from AP's is allowed to spill over into areas with metal climbing frames. There have been cases of metal framework greatly amplifying the signal.
Exposure levels can be measured and we would recommend this action before any children or employees are let back into the environment that the Wi-Fi has been installed into. A record kept of the readings should be available to parents and staff members at all times and a program of continual regular testing would be good practise for everyone's piece of mind.
Any further suggestions on how to improve the safety of Wi-Fi networks would be gratefully received.
Good Wi-Fi installation is very much about care and common sense.
The safest connection for a child is the wired connection.
