Site Lighting ~ this can be used effectively to enable work to continue
during periods of inadequate daylight. It can also be used as a deterrent
to would-be trespassers. Site lighting can be employed externally to
illuminate the storage and circulation areas and internally for general
movement and for specific work tasks. The types of lamp available
range from simple tungsten filament lamps to tungsten halogen and
discharge lamps. The arrangement of site lighting can be static where
the lamps are fixed to support poles or mounted on items of fixed plant
such as scaffolding and tower cranes. Alternatively the lamps can be
sited locally where the work is in progress by being mounted on a
movable support or hand held with a trailing lead. Whenever the
position of site lighting is such that it can be manhandled it should be
run on a reduced voltage of 110 V single phase as opposed to the mains
voltage of 230 V.To plan an adequate system of site lighting the types of activity
must be defined and given an illumination target value which is
quoted in lux (lx). Recommended minimum target values for building
activities are:-Such target values do not take into account deterioration, dirt or
abnormal conditions therefore it is usual to plan for at least twice
the recommended target values. Generally the manufacturers will
provide guidance as to the best arrangement to use in any
particular situation but lamp requirements can be calculated thus:-Total lumens
required =area to be illluminated (m^2 )¾t arg et value (lx)
utilisation factor 0„23 [dispersive lights 0„27]After choosing lamp type to be used:-Number of
lamps required=total lumens required
lumen output of chosen lampSite Lighting