Section 5-9. Requirements for the use of light signals
If a device can emit both continuous and intermittent light signals, the intermittent signals shall be used to indicate a higher degree of danger or a more urgent need for the recommended/mandatory intervention or action than is indicated by the continuous light signal.When an intermittent light signal is used, the frequency of the flashes must be such as to ensure that the message is clearly perceived and that any confusion between different light signals is avoided.If an intermittent light signal is used instead of or together with an acoustic signal, identical signal codes must be used.Devices for emitting intermittent light signals in case of serious danger must be subject to special surveillance or be fitted with a spare lamp.
