In the case of an emergency signal, this is always understood as a combination of sound and light signals. The light may be blue or alternating blue and red. In the case of a emergency blue light, the audible signal is a device emitting two different basic tones alternately for the same duration, but continuous pitch change (sliding mode) is also appropriate.
How to set up a blue lightbar?
Blue lightbars are available in sizes between 40 and 180 cm, depending on the product type and the width of the vehicle. Mini blue beacons of 30-40 cm in length are also available in a magnetic version, but larger sizes are recommended to be mounted with a fixed, drilled-in fixing. The primary consideration when selecting the size of the blue lightbar is the width of the vehicle roof.
In most cases, primary blue beacons are of modular design, so that the desired blue beacon can be assembled according to the user's needs or the application. In Europe there is no specification on the number of modules, only that the flashing pattern must be synchronised. In many cases, the flashing pattern includes pre-programmed timings that can be chosen by the user or the installer, taking into account the country's specification.
Most of the police flashers are available in different colours depending on the type and manufacturer, in most cases blue and/or red LED modules can be selected with a clear housing, but manufacturers also offer yellow or white LED modules that can be used for house number, alley or passenger compartment lighting. Multicolour LED modules are also available today, which means that 2 to 3 or 4 colours can be displayed within the luminaire body. This design allows the vehicle using the emergency sign to give a warning signal or to provide traffic diversion at the scene of an accident, or to provide area lighting by switching on the white light.
The blue lightbar with a coloured bar or the lightbar with a blue/red bar is most typical of police flashers used by the police to emphasise the 'police character', in itself indicating the presence of police to reassure motorists or pedestrians in public areas.
In addition to the light signals, a siren loudspeaker can also be installed in the fixed blue lightbar. Nowadays it is also possible to install an integrated loudspeaker in flat lightbar, which has several advantages. The first and most important advantage is that it is located at the highest point of the vehicle, where the sound is most easily heard. Last but not least, it is easy to install and replace. However, the biggest disadvantage of the blue light bridge is that the noise in the passenger compartment is almost unbearable, which is admittedly not very pleasant for the passengers inside, so the loudspeaker is nowadays mostly located in the engine compartment.
Regulation of the use of the blue lightbar
The use of the blue lightbar is regulated by IRM Regulation 12/2007, which distinguishes between users who can install it without an official permit and users who can only install it with an official permit. The standard MSZ 07-4009:1982 provides for the required sound pressure of the distinctive audible warning, in this case the blue police flashing light. The standard states that the maximum sound pressure level to be measured should be between 0.5 and 1.5 metres from the ground. A sound pressure level of 103dB(A) should be measured in the area opposite and at an angle of 45 degrees to the vehicle, and a minimum of 98dB(A) should be measured 90 degrees to the side of the vehicle. In the absence of these, the vehicle shall not pass the sound pressure measurement.
A blue or blue and red lightbar shall comply with photometric regulation R65 and electromagnetic compatibility regulation R10. The R65 standard guarantees that the flashing light signal itself was sufficiently visible visually. The importer must provide a declaration of compliance with these standards.