100 mm

IntroductionLight permeability of coloured lensesDepending on the respective light source and the various lens colours, the following percentage of light typicallypenetrates through:Colour Filament lamp Halogen lamp Xenon lampclear 100 % 100 % 100 %yellow 95 % 94 % 93 %amber 70 % 70 % 70 %red 17 % 27 % 23 %green 12 % 15 % 25 %blue 15 % 20 % 24 %This reduction in the light intensity must be taken into consideration when selecting the right signaling device!Due to the narrow spectrum of LED light sources, only a small reduction in the light is to be expected if the colour ofthe lens corresponds to the colour of the LED.Planning visual signalingEN 54-23 (draft) for Europe and NFPA 72 for the USA offer a tangible basis for the design of visual signaling:The table below is based on the following calculation equation and can also be used for other room sizes ordistances:d = √ I Eff/ Ed is the distance between the observer and the alarm device in metres [m]I effis the effective light intensity in Candela [cd]E is the illumination intensity in Lux [lx]The illumination intensity E must not fall below 0.4 lx at any place within the defi ned signal reception area.Examples of the signaling devices to be used, depending on the room sizemaximum minimum light intensity (effective intensity [cd])room size3 lights/room(m x m) 1 light/room 2 lights/room(synchronised)6 x 6 15 not permitted not permitted12 x 12 60 30 1518 x 18 135 95 3024 x 24 240 135 60Due to the complexity when considering visual signaling, we recommend checking the effi ciency of the alarmon-site by using a representative group of people. In doing so, a ‘worst case’ scenario must always be performedbased on the environmental conditions.24