1. Intrinsic features
1.1. The light emitted by a sign shall produce a luminous contrast which is appropriate to its environment, in accordance with the intended conditions of use of the sign, but without producing glare or an excessive amount of light or poor visibility as a result of insufficient light.
1.2. The luminous area emitting a sign may be of a single colour or contain a pictogram on a specified background.
1.3. The single colour shall correspond to the table of colours and their meanings set out in paragraph 3 of Part A.
1.4. When the sign contains a pictogram, it shall comply with all the relevant requirements of Part B.
2. Specific rules governing use
2.1. If a device can emit both continuous and intermittent signs, the intermittent sign shall be used to indicate a higher level of danger or a more urgent need for the requested or required intervention or action than is indicated by the continuous sign.
The duration of each flash and the frequency of the fla
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