ILP CPD webinar: British Standard 5489 update


This free CPD webinar focuses on the British Standard for road lighting design. An updated version of BS5489-1 2020 has just been published which includes some significant changes from the previous version. This important update to the Standards means that anyone that specifies public lighting or uses this Standard needs to understand the latest thinking and changes from the previous version.

This CPD webinar is essential for all those specifying or designing lighting for roads, amenity areas or city and town centres. You will learn how to carry out your role more effectively and provide better lighting which benefits the public and the planet.

Our presenters are Nick Smith IEng FILP and Peter Harrison CEng FILP. Nick, from Nick Smith Associates, was the ILP’s representative on the British Standards Institute revision committee, so is the ideal expert to share his knowledge and explain how you can apply this to your work. Peter Harrison is the ILP Technical Director.

The following is covered:

  • Position of BS5489 in the hierarchy of standards and tie into European and international standards
  • Summary of the changes
  • Reasons for road lighting
  • Environmental considerations: obtrusive light and conservation
  • Energy considerations and how this is determined
  • Design classification – determination and the risk assessment
  • Variable lighting considerations for subsidiary roads and traffic routes
  • Maintenance factor determination
  • Scotopic/Photopic (S/P) ratios – how these are used now
  • Glare, glare metrics and how to use them


1Can we have clarity on the following two things:

1) MF details the LM80 B failure fraction is now 1. This does not account for below par LED performance. Therefore, limits the assessment of design life.

2) The standard now mentions obstructions within a calc area. Does this mean Lighting Reality will soon allow 3D blocks, or, is other software more accepted in public realm lighting?
Details for the application of maintenance factors can be found in ILP Guidance Note GN 11, at

The BS committee does determine how software suppliers develop the functionality of their products. May I suggest Lighting Reality is contacted directly regarding this matter.

EN13201-3 suggests obstructions should be disregarded. However, if you consider this is significant then it would be pertinent to include it within the calculation area.
2Has the update expanded on guidance concerning light pollution and safeguarding dark skies?The BS references ILP Guidance Note GN01 2020. The document can be downloaded from the following:
3Considering the volume of funding, and proposed future funding available for sustainable travel, doe’s the update include any guidance for cycle tracks or are we still waiting for the publication of a revised technical guidance.The previous guidance for the lighting of Cycle tracks, TR23, is currently archived. However, it is on the forward workstream for our Technical Committee. Though archived (mainly because it referenced BS5489 2003) most of its recommendations are, we believe, valid, especially with regard to visibility zones. This document is available for ILP members to view through the ‘My ILP’ portal on our website.
4Could you please share a copy of the recording of the live webinar and a PDF copy of the presentation?A recording of the webinar and the presentation slides is available for viewing from our website:
5Considering the changes to the Standard, what would you emphasize as a key change or addition to take away, from today’s webinar, to either include or update in an authority’s specification?The though there are changes with regard to defining relative and absolute photometry and more guidance regarding glare, the main recommendation is in relation to the S/P ratio and this now being used for light sources with Ra less than 60.
6Are there recommendations to use any particular colour temperature warm/ intermediate to street lighting in BS 5489 2020?The BS suggests warmer colour temperatures are more appealing.
7Has there been a study into the effect of specifying TI on spacing and energy consumption?Not aware of any studies as such but using TI during illuminance design may lead to alternative luminaires that give acceptable results with less glare being used with no energy increase. In other words, a better solution.
8Will be possible to receive the BS5489 STANDARD document updated?The BS5489 2020 is available for purchase from BSI shop, there are no free downloads.
9You discussed the removal of Glare class from the British Standard which means TI will be solely responsible? You mentioned C & P class but not M class. Does glare class remain for M class? Can you please explain the justification behind this considering the use of LED lanterns with multi-point lamp sources has created more disability glare complaints and issues than ever before?TI as a means of glare control remains a requirement for luminance lighting design; the ‘M’ classes. For the ‘P’ and ‘C’ classes there is a suggestion that where practical, it would be good practice for TI to be used as a glare metric. Where there are multiple observer positions making TI very difficult the glare classification can be used.
10Would an area programme be able to calculate TI for multiple light sources?The calculation for TI in area illuminance calculations where there are multiple orientations and observer positions would be impractical. In these situations, the Glare Classification should be used.
11Is there any reference to new merging technologies for lighting control like Bluetooth control?BS5489 is a lighting design Standard and does not give details of emerging technologies that do not directly affect lighting levels.
12You mentioned that the section on control gear now references LED Drivers, is this wording exclusive to products with drivers, or inclusive of products that don’t use a traditional LED Driver (e.g. Driverless)?The Standard does not differentiate between embedded and discrete drivers. In previous versions it was called control gear now it is referenced as control gear and drivers.
13Will it be possible for TI% to be calculated in Lighting Reality to demonstrate compliance for C class designs, not easily replicated in the Roadway application?The calculation of TI in software packages is determined by the software supplier. The point made in the presentation was that where possible it is considered good practice for TI to be included in illuminance calculations to give some illustration of likely glare.
14Perhaps I misunderstand, but is not using the S/P ratio not going to raise the energy consumption on projects?The application of the S/P ratio in the previous version was considered a complication by users and was recommended at a time when most designs used sodium light sources. As most designers now use full spectrum light sources, the recommendations now recognise this so the S/P only needs to be applied for light sources with Ra less than 60. The design procedure allows for a risk assessment to be made to ascertain whether there needs to be an adjustment to suit local conditions. In some cases, this may lead to a small increase in energy, but with the vast number of photometric distributions now available, the view is this would not be significant.
15Can Reality now calculate TI% in the Outdoor area calculations?This is a matter to discuss with the software supplier.
16are there any upcoming updates for BS 5489 Part 2 tunnel lighting?BS5489-2 was updated in 2016 and I am not aware it is not currently under review.
17When we do leave the EU, what regulations can we consider to throw on the bonfire?Leaving the EU at the end of 2020 will have no immediate difference to the standing of BS5489. There is an understanding that few, if any, Standards will change in the short to medium term.
18Is the new “ILP Guidance of the calculation of Maintenance Factors” document encapsulated in the updated standard?ILP GN11 Determination of maintenance factors is referenced in BS5489 2020.
19My understanding is that post BREXIT, the UK remains a member of the EU CEN standards group so that there is the same BS EN commonality in most cases.That is my understanding, it is not expected there will be any changes to BS5489 for the immediate future.
20Many councils are now requiring vertical illuminance on windows. How realistic is it to undertake what can be many calculations and attempting to meet predefined levels?I presume this calculation is with regard to the control of obtrusive light. Though appropriately designed street lighting is exempt from being a statutory nuisance, the practicality of these requirements is really a matter of those specifying them.
21Does the new standard recommend that Cool White is no longer used?No, that is a matter of personal choice, though the Standard does suggest that warmer colour temperatures are considered more pleasing.
22In our experience P6 is often difficult to archive especially on retrofit as you tend to break average and end up with poor uniformity or high glare, is there any advice on relaxation or departures from standard for lantern replacement projects.BS5489 Standards are recommendations, they are not mandatory, though they will be considered best practice. To some extent all lighting designs are a compromise and that will be the case in retro-fit projects. Non-compliance with the recommendations will be a matter for engineering judgement really, considering the non-compliance, the extent to which it happens and judging the likely consequence.
23Can the answers to the questions be made available online.A recording of the presentation and the slides used will be made available from ILP website.
24With the move towards using warmer white light LEDs what are your thoughts about the effects on colour rendition regarding CCTV when going from a cooler white light to a warmer white light. One of the selling points for the police from what we’ve been told was that using a cooler white light gave a better colour rendition for identifying people via clothing etc?The widespread use of full spectrum light sources now means that colour rendering differences are not the problem they were when using sodium light sources. BS5489 reflects the widespread use of full spectrum lighting having Ra>60 which should be adequate for good colour rendition.
25Has any guidance been added to the standard regarding pedestrian crossings? Existing guidance details changing colour temperature of discharge lighting to provide additional safety benefit. Will this be addressed with LEDs as the primary system of lighting?BS5489 refers to ILP document PLG02, published in 2013 for recommendations for the lighting of pedestrian crossings.
26Can the ILP set up a series of CPD seminar that target changes? Lots of us don’t have the standard available and need time to understand impacts and changes.ILP will be delivering a series of webinars on technical matters for lighting professionals to keep their CPD up to date. The purchase of Standards funds their review, so they remain current. It will not be possible to cover all the contents of Standards in our webinars. However, if there are areas you would like to see covered please get in touch with our Technical Director, Peter Harrison at
27Please correct me if I am wrong, as relative photometry is the photometric value measurement of the lamp alone and not the whole luminaire should we be not be using absolute photometry for LED luminaires?Absolute photometry is a measure of the luminaire complete that is measured. Relative photometry is a measure of the light source and can be varied to facilitate several dimmed states and be applied to different lens configurations without having to undertake actual final luminaire photometry for every configuration. It is applied in terms of a per 1,000 lumens of measured value.


Posted on

June 3, 2020

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