Design Considerations.
Probably the most obvious and powerful restraint in the design of
any CCTV
system is that of available finance. Having therefore defined
the maximum
number of cameras that it is possible to install, we need to look at
the location of
those cameras. It is often the case that the first locations
chosen to install
cameras will be on buildings. This can often appear to reduce
the costs by not
requiring the installation of specialist camera columns, however, by
installing on
the building we can incur major hidden costs, because of the
complexity of the
process required to obtain Way Leaves. A perfect
example of which is, a
national chain of chemist shops in a building in the West of England
who are
leasing the property from the owner who is a County Council in the
East of
England. The hidden costs therefore, are those involved with
the lengthy
negotiations between the solicitors of the three parties involved,
along with those
of extending the contract because of delays caused by the
negotiations. Thus it is
often the case that the use of a specialized camera column will give
a lower total
cost than installing the camera on the building. The other
added benefit is that
when a camera is mounted on a column in the pavement, we will often
find that
the views afforded from this vantage point are better than would be
obtained
from the building mounting, because of the shape of the buildings in
both
directions up the street.
If the intended building is a listed building, then
we have even more potential
complications. We have not only to obtain a Way Leave, but
also permission to
mount the camera on the listed building, which involves at least two
more
interested parties the Local Authority planning department and
English Heritage.
Street Furniture
In many towns there are conservation areas where the indiscriminate
installation
of camera columns without consideration for their design would
constitute a
major problem. The design, by Welding Engineering Limited, of
a cabinet based
column to enable the mounting of transmission equipment, electricity
board
supplies as well as telemetry receiver equipment, has meant that
only one new
piece of street furniture is required, rather than the three pieces
that were
previously required (column, transmission cabinet and Electricity
board pillar).
There has also been the recent development of the dual function
camera column.
This enables an existing street lighting column to be removed; it
can then be
replaced by a column, with a camera mounting position at say 6 m and
a street
light mounted on an extension above the camera at 8 m. The
electricity supply
for the street lighting is then re-connected and now supplies the
camera as well
as the street light. Where the camera is being located in a
conservation area it is
also possible for the column to be painted to match surrounding
street furniture
and the design to include gold or silver banding, scroll work and
finials. A
similar philosophy of blending building mounted camera bracketry to
match
existing lighting fixtures can be applied.
Such customised metal work and finishing, can be made by these
specialist
manufacturers, to suit any location or match any existing
design. But bear in
mind that the more unusual the design, the larger the bill will
be. It is therefore
very important to ensure that if there are any areas within the
scheme, that may
require input from the Heritage section of the
Authority, that such input is
sought before the contract goes to tender. The costs will
therefore be kept to a
minimum because there are no extras and no hidden costs
due to delays.
Two brief words of warning. First, consider whether to
install anti-climb spikes
because some individuals consider it a challenge to climb a 6 m
camera column
to get to a camera. Second, ensure that the camera mounting
nuts and studs are
below the finished ground level, because there have been incidents
where
exposed nuts have been undone.
Overt or discrete
There is always the quandary as to whether the system should be
overt or
whether it should be more discreet and blend into the
background. A problem
with the overt (conventional pan & tilt) is that whilst it has a
reasonable deterrent
effect, the nature of the assembly is such that it is obvious which
way it is
pointing. As a result there have been incidents where a couple
of friends appear
to start a fight to catch the attention of the operator, while
others in the group can
see the camera pointing away from them while they commit a Smash
& Grab
raid.
One may be led to believe that dome cameras are the answer.
Such is not the
necessarily case. Dome cameras have their own peculiar set of
problems such as
the optical quality of the dome , which means that they should not
be used with
very long focal length lenses. Keeping the dome clean is
always a problem, the
person who can design an effective windscreen wiper for a dome,
could make a
fortune. Dome cameras do however, blend into the background
more easily and
they have the benefit of not obviously showing the direction in
which they are
pointing.
When at last, the system goes live, the usual blaze of publicity
is more than
enough to send a warning to the bad guys of the
area. Having had this warning
the bad guys will be able to spot the cameras whether
they are overt or
discreet. The casual wrong doer is probably drunk and does not
care whether he
can be seen or not and probably couldnt spot an overt camera
unless pointed
out. So does this mean that the cameras should blend in
discreetly, matching
surrounding colors where possible, whether they are conventional
design or
dome type cameras?.
The Help Point
With the advance of technology regarding transmission equipment, we
now have
the opportunity of multiple services on a single optical
fibre. There are an
increasing number of CCTV systems that are having a Help Point
system
integrated with their video transmission. The Help Points can
be located either in
the street, usually mounted on the camera column, or in car parks
monitored by
the CCTV system. The usual form is a weatherproof intercom,
which when
triggered will signal the operator and will often automatically send
the nearest
camera to a preset position showing the Help point in use.
These can be used as
either panic points or for general information. They are yet
another way of
reducing the fear of crime in public areas and increasing public use
of town
centre areas.
The Control Room
There is, as yet, no standard for the design of the CCTV Control
Room.
However, there are an increasing number of CCTV Control Rooms that
are being
called upon to fulfill many other functions in addition to monitoring
CCTV
cameras, so the basic philosophy is sound. Alarm receiving,
video confirmation
of alarms, key holding and social alarms are some of the other
functions fulfilled
by the sometimes over stressed CCTV operator.
Does the Control Room require heating in the Winter?
Possibly only a small
amount because of the heat generated by all the equipment, but it
must be
considered.. The heat dissipated by all the equipment needs to
be calculated for
the absolute maximum capacity of the system, to ensure that the
air-conditioning
or cooling system is correctly sized for all of the equipment and
people expected
in the room.
While considering the amount of power dissipation, it is wise to
consider the
total amount of power required by the control room. This will
enable an
Uninterruptible Power Supply (UPS), to be sized for either the
maximum likely
power cut duration or to enable standby generators to be started and
reach full
output capacity.
Data Protection
A consideration that has previously not being taken into account in
the layout of
many control rooms, is that of tape review. Often the review
suite is no more
than a desk with a VCR, multiplexer and a monitor in the corner of
the control
room. Under the Data Protection Act 1998 the majority of town
Centre CCTV
systems will have to be registered for the collection of personal
data (video
images of people stored on tapes). This means that the data
subjects (people)
have the right to check the accuracy of the personal data (video
images) held
about them. The data subject (person) does not have the right
to view personal
data relating to any other data subject. Thus, by having the
review suite in the
control room, the data subject wishing to check his or her personal
data, will
have sight of personal data being collected relating to other data
subjects ie.
images on the monitor screens, to which they have no right.
There is also the
added complication that any visitor to the control room, can be
called as a
witness to an incident if they were to see it during their visit to
the control room.
Tapes
Tape storage and management is another area that can be easily
overlooked. A
typical town centre CCTV system with say, 50 cameras will require
seven time
lapse VCRs, each requiring three tapes per day, plus at least three
real-time
VCRs for incident recording, again, each requiring three tapes per
day. When
tapes are archived for a period of at least 28 days, we have a total
requirement of
840 tapes. For every incident requiring video evidence from
tape, we will lose
two tapes to the Police or Courts, so with one such incident a week
we will need
a further 104 tapes, which will need replacing annually, making
almost a total of
1000 tapes a year. As a further requirement of the Data
Protection Act, the
personal data we collect must be held securely so that access must
be restricted
to authorized personnel only.
These are some of the major design considerations required for
any town centre
CCTV system. There are any number of others, which is why it
always pays to
employ a specialist consultant to ensure all aspects are covered.