Final Report Lot 9: Public street lighting - Amper

• Street lighting luminaires need to redirect the lamp light output as much as possible
downward (DLOR) to the street surface or its surroundings in order to be useful. The
appropriate use of transparent protector material with reduced diffuse optic properties
and high optic transmittance.
• New multi-facet reflector technology for highly asymmetric light distribution. The
principle is easy: light is directed to a complex multi-facets reflector on top of the
luminaire (Figure 31). Innovation is included in the production and coating of these
reflectors. The main advantage of this kind of luminaire is that light can be distributed in
various and asymmetric light distributions. The total light output (LOR) is lower than
standard street lighting. The upwards light flux (ULOR) is very low which reduces light
pollution through sky glow. This high asymmetric light distribution can contribute to
high utilisation factors (UF) for particular street lighting situations.
• The use of more compact light sources will allow to design associated high performing
reflectors resulting in a higher UF. This can also be deducted when correlating the UF
values in chapter 4 to the light sources. Light sources with a high light intensity (e.g.
HPS and CMH in tubular clear envelope) have a significantly higher UF compared to
lower intensity light sources (LPS, CFL, HPM or HPS with fluorescent balloon
envelope). Advanced reflectors adapted to the light sources are designed using
computer simulation software.
Conclusion:
Further increase in UF can be expected, probably UF as high as 0,6
In general high intensity light sources (HID) provide higher UF compared to the lower intensity
ones (e.g. CFL, LPS). Despite their relative lower intensity, fluorescent lamps are still attractive
when optic reflector and refractors are used (for road classes S5 and S6). Wasted light can be
avoided when ULOR is limited (e.g. < 5 to 15 %) and DLOR is increased. Please note that
DLOR is only a first indication of luminaire efficiency but does not garantee an optimum light
distribution or UF.
6.1.4 Luminaires specially designed to reduce sky glow
As pointed out in 4.3.1.3 it is not only important to reduce the upward light output (ULOR) but
especially the light emitted between the horizontal and 10 degrees above when the objective is
to reduce sky glow. The reduction of near to horizontal light output is also beneficial for
reducing glare. In general the objective to reduce ULOR is in line with energy saving and is
therefore also in line with the previous section.
A problem did arise with luminaires with ‘curved glass’, ‘deep bowl’ or ‘refractor bowl’
transparent protectors because due to parasitic upward reflections from within the transparent
protector, these luminaires still have some very low ULOR and unfortunately in the close to
horizontal angles.
A solution to this problem could be found in the application of flat glass transparent protectors
(see Figure 32) or ultimately outer screens or caps. Please note that the ideal installation
position for this luminaires is horizontal.
These transparent protectors were introduced in the last decades to increase the LMF (see 6.1.1).
The ‘curved glass’, ‘deep bowl’ or ‘refractor bowl’ transparent protectors were historically
introduced in order to have wide beam luminaires with reduced internal reflection and hence
increased efficiency(DLOR) because when simple, flat transparent glass protectors are used,
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