Signs
2. Forms of Signs
2.3. Lights and acoustic signals
2.3.1. Characteristics and requirements of signal lights:
- The light emitted by a signal should provoke a luminous contrast that is suitable for the setting on the basis of foreseeble conditions of use.
- The luminous surface that emits a signal may be uniform in colour, or have a pictogram over a particular background.
- If a device can emit either a continuous or discontinuous signal, the intermittent signal is to be used to indicate a greater degree of hazard or danger with respect to the continuous signal or greater urgency in the required action.
- Two signal lights that may give rise to confusion are not to be used at the same time, nor is a signal light to be used near to another emission of light that is barely different.
- When an intermittent signal light is used, the duration and frequency of the flashes should allow the message to be properly interpreted, thus preventing it from being perceived as continuous or confused with other light signals.
- Light-emitting devices used to signal the existence of a serious hazard or danger should be the object of special safety checks or be equipped with a spare bulb.
2.3.2. Characteristics and requirements of acoustic signals:
- Acoustic signals should have a higher sound level than that of ambient noise so as to be clearly audible, without being a nuisance. Acoustic signals should not be used when the ambient noise is too intense.
- The tone of an acoustic signal or, when the signal is intermittent, the duration, interval and grouping of impulses should enable it to be properly identified and clearly distinguished from other acoustic signals or ambient noises. Two acoustic signals should not be used at the same time.
- If a device can emit acoustic signals with a variable or intermittent tone or intensity or with a continuous tone or intensity, the former are to be used to indicate a greater degree of hazard or danger with respect to the continuous signal or greater urgency in the required action with respect to the latter.
- The sound of an evacuation signal should be continuous.
2.3.3. Common regulations:
- When set off, a light or acoustic signal shall indicate the need to carry out a particular action and is to be left on while said need persists.
- Once a light or acoustic signal is no longer being emitted, measures are to be immediately taken to allow them to be used again in the case of need.
- The efficacy and proper working of lights and acoustic signals are to be tested before entering into service and subsequently via the required periodic safety checks.
- Intermittent lights and acoustic signals that may be used alternately or complementarily should employ identical coding.
