5 FUNCTIONAL REQUIREMENTS
5.1 REQUIRED FUNCTIONS AND THEIR AVAILABILITY
Daylight signalling lamps should be suitable for giving light signals which can be clearly distinguished visually as separate signals by an observer.
5.2 RELIABILITY, ACCURACY AND DISCRIMINATION
5.2.1 By day and with an atmospheric transmission of 0.8, the visibility of light signals emitted by daylight signalling lamps should be at least 2 nautical miles, equalling a required luminous intensity of 60,000 cd.
5.2.2 The axial luminous intensity of daylight signalling lamps should reach at least 90% of the maximum luminous intensity.
5.2.3 The luminous intensity of daylight signalling lamps should have its maximum in the centre of the luminous intensity distribution. It should decrease evenly from the centre of luminous intensity distribution.
5.2.4 The half angle of divergence ah should not exceed 9°, the tenth angle of divergence az should not exceed 14°.
5.2.5 The chromaticity of the white signal light should lie within the following corner coordinates of the diagram specified by the International Commission on Illumination (CIE) in CIE Publication No. 2.2:
5.2.6 The effective light emission sectors of daylight signalling lamps should be circular. The sum of switch-on and switch-off times should not exceed 500 ms.
5.3 MALFUNCTIONS, WARNINGS, ALARMS AND INDICATIONS
Daylight signalling lamps should be provided with an indication of their operational status.
6 OPERATIONAL REQUIREMENTS
6.1 ERGONOMY
Daylight signalling lamps and any battery required for operation should be designed in such a way that safe handling in the intended application is ensured. The daylight signalling lamp should be capable of being operated by personnel wearing gloves.
