An exercise seldom undertaken by the
management of small and large business alike in Southern Africa is the impact
assessment of a lightning strike to the business premises. The cost implications
of down-sizing, outsourcing, franchising, brand-building, employee motivation
and globalisation on the internet top the agenda at the Monday morning
management meeting. The negative impact of equipment theft, warehouse fires, bad
debts and other potential business-damaging events are well understood and
insured against. With so many important issues to address, it is not surprising
that the almost obscure event of a direct lightning strike to your business
premises is largely ignored...until it happens, that is! The truth of the matter
is that to a business, the damage that a lightning strike is able to inflict
could be crippling in a multitude of unforeseen ways. The good news is that it
is largely preventable. This article will outline the importance of conducting a
simple impact assessment and investigate methods of preventing damage to the
assets vital to your business.
Like any good business decision, the first
thing that is necessary is to identify the risk and put a well thought out plan
into place to achieve the desired results. This could be done using the
following steps:
- Quantify the risk of a lightning strike to your business
premises
- Identify vital equipment which could be damaged in the
event of such a strike
- Accurately estimate the impact in terms of both cost and
image that downtime due to a lightning strike could have on your
business
- Develop and implement a strategy to limit the impact of
such a strike
- Schedule a future reassessment to ensure that your
strategy keeps pace with the growth of your company and maintenance is not
neglected
We shall now look at how each step of the
impact assessment is performed.
Quantifying the risk to your building
Fortunately, a fair amount of academic
research has been undertaken in this field so that it becomes possible to put a
number to your likelihood of being the victim of lightning damage. Lightning
damage may occur either as a result of a direct lightning strike to the building
or, more subtly and more commonly, as a result of the induced effects of a
lightning strike some distance away. Lightning which strikes kilometres away may
cause damaging electrical surges which travel long distances on power and
telecommunications lines. Although a proper detailed risk analysis* is outside
of the scope of this article, there are some simple calculations which may be
performed and basic reasoning which may be employed. Firstly, look up the
lightning ground-flash density (LGD) of your area. Lightning ground flash
density is simply a number which represents the average number of direct
lightning strikes to a square kilometre of your area in one year. The LGD for
Johannesburg is approximately 7 strikes/square km/year while Durban and Cape
Town drop down to approximately 3 and 1 strikes/square km/year respectively,
indicating a significantly lower risk in these two areas. The next step is to
investigate the geography of your area and use the rules outlined in the
standards (SABS IEC 91024-1) to work out what percentage of those strikes to
your area are likely to terminate on your building and what percentage are
likely to cause induced surges which may damage equipment connected to power or
telecommunications cables in your office. Should the standards be too technical
or if you simply don’t have the time or inclination, earthing and lightning
protection companies will perform the service at relatively inexpensive rates or
even free of charge as it leads to further business for them. Quantifying the
risk will allow you to make an educated financial decision about the lightning
protection measures which need to be employed in your business.
Adding up the cost of lightning damage
Once the lightning risk has been determined,
the next step is to calculate the costs should lightning damage occur. These
costs may be split into two types, direct and indirect costs:
Direct
costs are incurred when lightning damages
equipment, buildings and causes lost productivity. Common equipment fatalities
in the business environment include:
- computers and peripheral equipment such as scanners and
printers
- modems
- network equipment
- fax machines
- alarm systems
- electric fence energisers
- CCTV cameras and equipment
- electric gate motors
- intercom systems
- telephones
- PABX’s
- Specialised electronic equipment unique to your type of
business
Additional direct costs include:
- Repairs to damaged wiring and building
superstructure
- Lost productivity resulting in lost income
A commonly heard response during this exercise
is "My insurance will pay so it is of no real concern to me." This is only true
in some cases as most insurers now state in their contract that they will only
cover the eventuality of lightning damage provided that adequate lightning
protection systems were in place. Lost productivity is also a direct cost which
few businesses are covered for. The figure you have arrived at for your business
represents an estimate of the immediate cost which you will probably incur every
X years where X is the result of your lightning risk analysis outlined above.
Not so easy to quantify, however, are the indirect costs.
Indirect costs represent losses to the business in ways which are not so easy to put a figure
to. Some of these may include:
- Downtime of the phone and PABX system - most businesses
rely heavily on their incoming phone lines as a source of new business and
client contact. Phone downtime loses customers and damages service
reputations.
- Downtime of computer systems and networks - once again,
if your emails go unanswered, your website is unavailable and your staff are
sitting helplessly behind blank screens, customers and reputations are
lost
- Lost data - a massive hidden cost to any company
operating computers (who isn’t?). Not only is the information lost but if no
adequate back-up strategy is in place, months or even years of work may be
lost as well.
- Lost productivity may also be classed as an indirect cost
as late deliveries also ruin reputations. If you operate expensive imported
machines where spares and repair expertise are not freely available, your
company should be especially wary of this point
- Breach of office security - When the electric fence, CCTV
cameras, electric gates and alarm system are out of action, your premises are
exposed to a high security risk
- Health - although rare when compared to the frequent
damage of sensitive electronics, lightning strikes sometimes claim human
victims which is unforgivable when it is easily preventable.
Developing and
implementing a lightning protection strategy
If the preceding steps have been investigated,
you should have a decent idea of the impact of the lightning threat on your
business. The next step is to analyse what you know and put a simple but
effective strategy into place in order to deal with the threat. Such a strategy
is proposed below:
- Get a reputable and qualified consultant to check the
earthing system of your premises. The earthing system is vital to both general
electrical safety and the correct operation of lightning surge protectors.
Many companies will do this testing free of charge in exchange for the
contract to supply earthing or surge protection equipment.
- Install decent surge protection on all of your valuable
equipment. Something to note about surge protection devices is that, like any
product, you get the poor quality, badly designed and the decent products.
Finding out which is which may be difficult but asking for properly tested,
SABS approved equipment is a good start. Another good strategy is to ask for
advice from the technical department of a number of companies and compare the
different answers. You could also contact the local university, the SABS or
the CSIR or equivalent bodies and ask the advice of the electrical engineering
departments. This technique will help you to isolate the competent companies.
In general, the cost of installing decent surge protection will be a fraction
of the cost of the equipment being protected and should be viewed as a vital
form of physical insurance. Remember, most insurance companies will not cover
equipment damaged by a lightning strike unless lightning protection devices
are installed.
- If the risk analysis indicates that the expected number
of direct lightning strikes is high due to your geographical situation, you
should also consider installing an external lightning protection system if one
is not already installed. This system comprises a series of interconnected
conductors running from your buildings roof, down the walls and into an
earthing system. An external system of this type is designed to divert the
lightning currents safely to earth on the outside of the building and prevents
damage to the superstructure, dangerous side-flashes and touch-potentials
inside the building and minimises the risk of damage to equipment. An external
lightning protection system is not a substitute for surge protection devices
but is rather an additional and vital level of protection which complements
the operation of the surge protection and decreases the overall risk of
lightning damage to your building as the path of the lightning current is
controlled and diverted directly to earth.
- Finally, a maintenance strategy should be put into place
to check that the earthing system and surge protection devices remain in good
working order. Earthing systems degrade with time due to corrosion, theft
(they comprise mostly copper!) and accidental disconnection during non-related
electrical work. They should be checked on a regular basis. Surge protection
devices degrade with use like any other physical product and should be
maintained and replaced accordingly. Some products have failure indicators
built in which visibly indicate failure. Maintenance strategy should include
the checking of all surge protection devices after big storms, checking the
devices and the earthing system after the summer lightning season and possibly
the replacement of all surge protection every 1-3 years regardless of visible
condition.
Conclusions
The negative effects of direct and indirect
lightning strikes to a business can be minimised. In fact a lightning strike is
one of the only forms of natural disaster in which no damage to person or
property is necessary, provided the correct technology and strategy are employed
beforehand. At the end of the day, the risk of damage must be weighed up against
the cost of installing and maintaining a lightning protection system and each
business requires a unique strategy to combat this threat.
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