Change to BS5489:2013 (which replaces BS5489:20003)
In 2013 the British standard was updated to recognise the use of the S/P ratio of a light source to determine the actual visible lighting level.
The ratio of the luminous output of a light source evaluated according to the CIE scotopic spectral luminous efficiency function, V'(λ), to the luminous output evaluated according to the CIE photopic spectral luminous efficiency function, V(λ)
Table A.7 – Variation of lighting level with S/P ratio of light source
|Lighting class||(e.g. Ra <60 Or when s/p ratio of light source is not known or specified)||S/P ratio = 1.2 and Ra ≥60 (e.g. some types of warm white lamp such as metal halide)||S/P ratio = 2 and Ra ≥60 (e.g. Some types of cool white compact fluorescent or LED)|
Table A.5 – Lighting classes for subsidiary roads with low speed traffic
(v ≤ 30 mph) – Mixed traffic without parked cars present
|Traffic Flow||Lighting class|
|Ambient luminance: very low (E1)||Ambient luminance: low (E2)||Ambient luminance: moderate (E3)||Ambient luminance: high (E4)|
NOTE 1 Low speed traffic equates to 20 mph or 30 mph.
NOTE 2 Table A.5 assumes no parked cars – see risk assessment in A.3.3.2.
NOTE 3 If facial recognition is important then an SC lighting class from BS EN 13201-2:2003 can be selected as an additional criterion.
Good colour rendering contributes to better facial recognition.
NOTE 4 To provide for uniformity, the actual value of the maintained average illuminance is not to exceed 1.5 times the value indicated for the class.
NOTE 5 It is recommended that the actual overall uniformity of illuminance Uo be as high as reasonably practicable.
NOTE 6 Grey highlighting indicates situations that would not usually occur in the UK.
NOTE 7 The ambient luminance descriptions E1 to E4 refer to the environmental zone as defined in the ILP guidance notes [N4].
|Environmental zone||Mounting height||Cleaning frequency|
|12 months||24 months||36 months||48 months||60 months||72 months|
Source: The Institution of Lighting Professionals (ILP) www.theilp.org.uk/resources/