Download it here - Anglican Church Southern Queensland

Issue No.9
Sept 2001
HANDY HINTS
FOR
SCHOOL ADMINISTRATORS
CHURCHWARDENS AND
PARISH COUNCILLORS
(Protecting your Assets)
(From the Board of Management of the Diocesan Insurance Fund)
REMOTE CHURCH BUILDINGS
In issue No. 8, June 2001 under the above heading, we talked about securing exterior doors in
such a way that they cannot be opened to remove contents if a thief gained access through a
window. It has been brought to our attention that we failed to mention that all doors which are
designated for fire exit purposes must of course remain as such with immediate access in the
event of an emergency.
For your information, we advise that in a discussion with a Fire Brigade Public Safety Officer, we
were advised that there are locks for exit doors which are a deadlock from the outside but are
opened by a lever from the inside and maybe appropriate in particular circumstances.
GRAFFITI REMOVAL
Graffiti Removal kits are available for loan from all Brisbane City Council Ward Offices. There is no
charge for the kit – you can borrow it as many times as you like. If Parishes/Schools in the BCC
area have need of one these kits, please contact your nearest Ward Office. If you are under a
different local authority, you should contact them to see if they offer a similar service.
OCCUPATIONAL HEALTH & SAFETY
To fulfil your responsibility, keep in mind your duty to provide a safe place for people who are on
your premises and a safe system of work for Employees (including Volunteers) and be diligent in
identifying hazards and eliminating them.
The most common accident cause on our properties is trips and falls. The contributing factors are:
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Uneven floors or pathways
Slippery surfaces
Poor lighting
Hidden obstacles
Please do all in your power to reduce or eliminate these risks.
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PROPOSALS FOR LIGHTNING PROTECTION
Why bother with lightning protection, doesn't our insurance pay for any damage?
The cost to recover from losses caused by lightning can be very high. In addition to repair of
actual damage to electrical or electronic equipment, there are other costs such as loss of data
held on computer, delays whilst staff cannot use their computers, make or receive phone calls,
send or receive faxes etc.
These losses are not always covered by insurance and the inconvenience, stress and long hours
to co-ordinate repairs and catch up, are almost certainly excluded.
One of our schools had a recent claim where a lightning induced surge current entered through
both phone lines and power supply causing extensive damage.
The extent and cost (excluding GST) of the damage was:Damage to switch units $17,000
Damage to Computer equipment $6,500
Damage to Fire Alarm power supply $1,000
Damage to Alarm System $1,800
Miscellaneous Costs $2,000
Total labour cost for repairs and installation $6,000
The total claim was almost $40,000
The total time taken to settle this claim from the incident date was 6 months. You can see that the
inconvenience and disruption was great.
It is therefore in everyone's interest to identify cost effective ways to reduce the incidence and
severity of lightning damage.
How does lightning cause damage to electrical and electronic equipment?
A lightning strike is an electrical discharge resulting from a build-up of electrical charge in a
thunderstorm. This discharge can be from cloud to cloud or cloud to ground. The current that
flows from cloud to ground can be very high, sometimes even in the hundreds of thousands of
Amps, but the duration is often less than one tenth of a second.
When lightning strikes the ground or a structure, it causes the voltage at that point to rise
dramatically, causing electrical current to flow from the that point to points further away from the
strike.
If lightning strikes a structure or the ground close-by and that structure has electrical cabling
connecting it to another structure further away, the increase in voltage at the point where the
lightning strikes, will cause current to flow along the cable. This can cause damage to equipment at
both ends of the cable.
A lightning strike also creates electrostatic and electromagnetic fields which can induce currents in
exposed cables, again causing damage to equipment at both ends of the cable.
How do we reduce the effects of a lightning strike on electrical and electronic equipment?
One of the major suppliers of lightning suppression equipment suggests the following steps:-
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1. Protect Power Lines
The most common source of damage to electrical and electronic equipment as a result of a
lightning strike is the power supply. A surge or spike entering the incoming power lines has
the potential to damage every electrical and electronic item connected to those power lines.
The first and most important stage of protection is a surge diverter located inside the
main electrical switchboard. Surge diverters direct to earth most of the energy of a surge
or spike at the point of entry to a building or major power distribution point. Surge diverters
typically cost around $500.00 plus installation.
Whilst a surge diverter can substantially reduce spikes entering electrical and electronic
equipment, considerable damage can still be done to voltage sensitive equipment and it is
therefore necessary to also install a surge filter for each item of sensitive equipment. Surge
filters can either be installed in power distribution boards or can be free-standing with a
flexible lead for plugging into a standard general purpose power outlet.
Free standing surge filters typically cost around $250.00 and those installed in a distribution
board around $300.00 and will reduce surges down to 240 volt per phase, which is the
standard operating voltage in Australia for electrical and electronic equipment. A surge filter
located in a distribution board can provide filtering and is therefore a lot more cost effective
to all devices connected to that power circuit (eg. several computers).
The next stage of power line protection and an absolute must is a surge diverter
located in the main switchboard. The third stage of protection for electronic equipment is
a surge filter for each electronic device, the filter being located either inside the power
distribution board where the electronic equipment derives its power or connected into a
general purpose power outlet.
2. Protect Signal/Data Lines
Protection of power lines does not prevent surges entering electronic equipment along
signal and data cables. Even with power line protection, damage to computer networks can
be extensive if a surge enters data cabling connecting a number of computers together. A
surge can also enter a computer through a telephone line if the computer is connected to a
modem. It is therefore also necessary to protect against damage to electronic equipment
from this source.
Surges can also enter telephone networks via incoming telephone lines and there is a range
of protection devices that can be mounted inside telephone main distribution frames.
As a voltage surge can occur at either end of a signal or data cable causing electrical
current to flow in either direction, it is necessary to protect electronic equipment at both
ends of the cable.
Costs vary depending on the signal and cable type, however, to protect ten incoming
telephone lines with protectors mounted inside the main distribution frame, a typical cost is
around $200.00 and for a computer it costs around $100.00 for network connection
protection and $80.00 for modem connection protection.
A typical example of lightning surge protection.
We will consider a site with two low set buildings, each with its own incoming electrical power and
switchboard, with computers communicating between buildings via a local area network and with a
telephone PABX in one building with telephone extensions in the other.
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A surge diverter should be installed in the electrical switchboard of each building. Power to each
electronic device should be protected by a surge filter either located in the power distribution board
providing power to the device or located adjacent to the device as a free-standing component
plugged into the nearest general purpose power outlet via a flexible lead.
Incoming telephone lines connected to the PABX should be protected by signal line protectors
mounted in the main distribution frame where the incoming telephone lines are terminated and
each extension line to a telephone in the other building should be protected in a similar way at the
PABX end only. Due to the relatively low cost of the telephone handsets themselves, it would not
be necessary to provide protection at the telephone handset end of the extension cables.
Where there are only 1 or 2 telephone lines without a PABX, the protection to be applied to
incoming telephone lines could include the provision of a Surge Guard device which plugs into the
same power outlet as the computer, modem or telephone, and through which the telephone lines
are connected. This has the ability to protect against moderate surges, which might enter the
equipment via either the power supply or the telephone line. (Such devices cannot protect against
larger surges, as explained elsewhere.)
Data line protectors should be installed at the termination point of each computer connected to the
local area network.
What About Fibre Optics?
For new installations or installations where there are long cable runs between buildings, fibre optics
can be considered. As the optical fibre cable sends signals by modulating light rather than
electrical current, the cable is unaffected by lightning. Typical costs are $1,200.00 each end for
termination and conversion to electrical signal plus around $7.00 per metre for cable.
Even if fibre optics is used, it is still necessary to protect power lines.
Conclusion
Damage from all but the most intense lightning strikes can be eliminated by the adequate
protection of power, signal and data cabling. It is therefore within your power to prevent the stress
and sleepless nights when trying to return to normality after a lightning strike takes out your
computer systems, telephone system, burglar alarm, access control system, fire detection system
and facsimile machine.
Who do I go to for assistance?
The following two companies supply a full range of lightning protection equipment and can provide
advice and prices:SCA Distributors Pty Ltd, 178 Wecker Road, MANSFIELD QLD 4122
Telephone: (07) 3849 5077
Facsimile:
(07) 3849 7035
No Virus Technologies Pty Ltd Agents:
Queensland PowerCom (Qld) Pty Ltd
Telephone:
(07) 3851 3144
There are many local fibre optics suppliers and installers. We have therefore not included any
specific companies.
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