Health and safety
Health and safety in the deployment and use of computer systems in ECE Services requires little more than common sense and a strict adherence to the manufacturer’s installation and operation instructions.
The ECE environment is similar to many homes containing a group of small, very inquisitive, and often boisterous children. Any potentially harmful device shall be removed from spaces occupied by children or contained in such a way as to prevent physical injury or electrocution.
A sufficient number of correctly positioned data outlets and power sockets avoids lengthy trailing power and work-area cords, which not only create a tripping hazard but may also cause equipment to pulled onto a child.
Each data outlet should be closely associated with two dual power sockets.
Infrastructure cabling shall be concealed either in walls, below floors, and above ceilings, or within purpose-designed perimeter trunking.
Active equipment, such as the modem, router, and Ethernet switch, shall be installed in a lockable cabinet.
Wireless access points shall be installed in accordance with the manufacturer’s recommendations and these guidelines.
Unused work-area cords should not be left plugged into data outlets.
Computer monitors (CRT) should be restrained with purpose-made fasteners or industrial Velcro-type tapes to prevent toppling over during an earthquake.
Safe ICT equipment handling shall be practiced by all educators and children.
Irrespective of any RF exposure considerations, the base of most laptops gets too hot to be used comfortably in the lap. Manufacturers do not include warnings in their literature like, “Don't use this computer in your lap.” Being hot is, at best, simply uncomfortable but there comes a point where hot stops being uncomfortable and becomes dangerous. Sustained contact with the skin will cause burns and children should be encouraged to sit at a desk to use a laptop.
Prolonged laptop use can be especially hard on the user. The Cornell University Ergonomics website explains as follows:
“The reason is simple - with a fixed design, if the keyboard is in an optimal position for the user, the screen isn’t and if the screen is optimal the keyboard isn’t. Consequently, laptops are excluded from current ergonomic design requirements because none of the designs satisfy this basic need.”
While a child it is unlikely to sit typing at a computer for extended periods in the way that an adult will, good habits start young and the recommendations for adults to maintain a good posture apply equally to children. The following recommendations are made:
- Make sure that the user can reach the keyboard keys with their wrists as flat as possible (not bent up or down) and straight (not bent left or right).
- Make sure that the user’s elbow angle (the angle between the inner surface of the upper arm and the forearm) is at or greater than 90 degrees to avoid nerve compression at the elbow.
- Make sure that the upper arm and elbow are as close to the body and as relaxed as possible for mouse use - avoid overreaching.
- Make sure that the wrist is as straight as possible when the mouse is being used.
- Make sure the user sits back in the chair and has good back support.
- Check that the feet can be placed flat on the floor or on a footrest.
- Make sure the head and neck are as straight as possible.
- Make sure the posture feels relaxed for the user.
- These recommendations may assist with the selection of suitable computer furniture for use by children; an area not generally covered in the brochures on ergonomics provided with new computer equipment.
Detailed ergonomic information is available at CUErgo.
For another view see Ergonomics for Children and Educational Environments by a Technical Committee of the International Ergonomic Association General Recommendations for Computer Use (children) and Ergonomics for Teachers.
Instruction manuals for wireless devices typically include recommendations for their installation and operation. It is important that these recommendations are followed closely. The recommendations are directed not only at producing the best performance from the system but also at minimising exposure to electromagnetic radiation.
Measurements in New Zealand and overseas show that exposures are typically around one hundred thousand times lower than the exposure limit recommended for the public in the New Zealand radiofrequency field exposure Standard (New Zealand Standard 2772.1:1999 Radiofrequency Fields Part 1: - Maximum exposure levels 3 kHz - 300 GHz). This Standard is based on guidelines published by a scientific body recognised by the World Health Organisation for its expertise in this area, and includes a safety factor of fifty in the public limit.
The National Radiation Laboratory considers that the health research carried out to date shows that working and studying in areas with WiFi equipment poses no health and safety risks to adults or children.
Recommendations for Use
All authorities generally agree that the normal use of wireless networking equipment does not expose users to harmful levels of radiation. Although no special precautions are needed, individuals wishing to minimise their exposure may take the following simple steps to do so:
- Place the wireless access point up on a high shelf or away from where people might sit and work.
- When working with a WiFi-enabled laptop, place it on a table rather than directly on the lap.
- Purchase “CE” and “WiFi” marked equipment only and follow the manufacturer’s instructions for installation and operation. Proper installation and operation of wireless access points and wireless interface cards is required to minimise exposure.
- Do not touch or move antenna(s) while units are transmitting or receiving. Do not hold any component containing a transmitting radio such that the antenna is very close to or touching any exposed parts of the body, especially face or eyes. The considerate and careful use of laptops must be encouraged. Wireless interface card antennas should be orient so that it is at least 20cm away from the body.
Recommendations for Siting
As well as proper handling, appropriate siting of wireless devices and access points is imperative to safety and good performance. The major problem is likely to be interference from existing equipment using the same radio frequency band (2.4GHz) such as microwave ovens.
Recommended safe distances for operating devices are:
- Dipole antennas on base stations: 15cm from the body
- Antenna on wireless cards in laptops: 5cm from the body
Current information suggests that a wireless network client device working at one-fiftieth the power output of a mobile phone handset and 50cm away from the body is much less capable of affecting the cells of the body than a mobile phone.
Users should be aware that the parts of the human body considered most susceptible to RF radiation are the eyes, brain, nervous system, immune system, kidneys, ovaries and testes. Laptop computers should not be used in the lap if the base of the computer contains a wireless antenna requiring a clearance greater than 5cm from the body.
It is important to consider the level of radiation in the ECE and school environment given the amount of time children will spend in school.
Electromagnetic energy is all around us. Modern homes and offices have many radio frequency (RF) producing devices (e.g. computers, cordless phones, microwave ovens, fax machines). All radio equipment emits radio frequency electromagnetic energy. Spread spectrum wireless equipment is a very low power radio device by comparison. Some typical examples:
- Wireless base station 30mW
- Mobile (cellular) phone 600mW
- Mobile (cellular) phone car kit 3,000mW
- Microwave oven 500,000 to 1,000,000mW
(mW is a milliWatt, i.e. one thousandth of a Watt)
During a phone call a mobile phone may emit 20 times more energy than an active wireless base station (or 50 times more energy than an active wireless card client adapter). A mobile phone continues to emit radio energy even while on stand-by. However, most wireless networking equipment is only active while it is transmitting.
Disposal of obsolete equipment
ECE Services and schools are targets for well meaning businesses and others for disposal of obsolete computer equipment. The fact that the demands that ECE Services and schools put on computers often exceeds those of the business world, eludes donors.
ECE Services are advised to consider well the implications of accepting such equipment. Not only may the equipment not be capable of doing what is required of it but also the wasted time and money attempting to bring it into service may better be spent on new equipment.
Irrespective of its source, correct disposal of electronic equipment is important.
Many countries have already outlawed the disposal of computer waste in landfills. Most of the environmental concerns with computers lie with the monitor, specifically cathode ray tubes (CRT). Each colour monitor contains, on average, four to five pounds of lead, copper, and other hazardous materials including mercury, cadmium (a known carcinogen), and chromium.ECE Services should have a plan for the proper disposal of obsolete computer equipment. The first step is to realise that most computer equipment that is stored “for a rainy day” will almost certainly never be used. Any equipment not likely to be used should be tagged for disposal. Equipment with little or no value (e.g. dot matrix printers, CRT monitors, and pre-Pentium computers) should be sent to a reputable recycler. Some cities have a disposal centre where obsolete computer equipment can be disposed of. When planning to upgrade to new computer equipment, take advantage of manufacturer trade-in programmes which can reduce the combined cost of acquiring new equipment and responsibly disposing of old equipment.
Before disposing of computers, as a matter of the utmost security importance, destroy all business information stored on the hard disk drive. Simply deleting files does not prevent them from being recovered and files can easily be retrieved from reformatted drives with data recovery utilities or forensic programs. The simplest way to prevent data from being retrieved is to remove the hard drive and break it with a hammer.
Computers which are to be resold shall have all business data properly erased. There are a number of free security tools, available on the internet, that completely erase sensitive data from hard disk drives by overwriting it with carefully selected patterns. The software is released under the GNU General Public License.