• Signalling index

    Perception of visual and acoustic signals

    The signalling index offers a simple method for selecting the right WERMA product. This index is derived from the measured values of the respective products and the subjective signal perception and will lead you quickly to the appropriate product. This makes it very easy to find the ideal product for your individual purpose.

    Why does WERMA incorporate subjective signal perception into the signalisation index? Because physical parameters alone or the signalling effect can only be compared to a limited extent.

    Visual perception

    For example, moving light is generally more strongly perceived than static light. This has the effect that the signal of a flashing light with the same luminosity is perceived as more obtrusive than constant light. This effect is even stronger in the case of EVS/flickering light.

    With regard to visual perception, the signalling index has a maximum of 10 gradations depending on the product group (grade 1 for low perception to grade 10 for excellent perception).

    Acoustics

    The indicated measurement values take the perceptive faculty of the ear into account, but the psychological effect of various series of tones and frequency changes are not considered. Various factors determine how well an acoustic signal can be heard:

    • The sound pressure level of the signal (in dB)
    • The frequency of the sound (in Hz)
    • The distance between the signalling device and the receiver
    • The ambient noise level
    • Other environmental influences (such as air humidity and wind direction)

    With regard to acoustics, the signalling index has a maximum of 10 gradations depending on the product group (grade 1 for low perception to grade 10 for excellent perception).

    Example of signalling index for the KombiSIGN 72 signal tower

    For the signal tower product group, the signalling index has a maximum of 6 gradations (whereby grade 6 denotes excellent perception).

    Example of signalling index for the Heavy Duty Combination with xenon flash

    For products in the combined visual/acoustic group, the signalling index has a maximum of 10 gradations (whereby grade 10 denotes excellent perception).

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