UPDATE YOUR JOURNEY

The British Standard for road lighting, BS 5489, has been updated to take account of some of the rapid changes in street lighting technology that we have seen in the past few years. Nick Smith and Peter Harrison assess what has changed and what you need to know

By Nick Smith and Peter Harrison

The British standard for road lighting in the UK is British Standard (BS) 5489: Code of practice for the design of road lighting.

The standard is in two parts. Part 1: Lighting of roads and public amenity areas (issued in 2013) and Part 2: Lighting of tunnels (issued in 2016). The latest version of Part 1 is due to be issued this month (June), although the timings are not completely certain, and so this article is intended to examine the recent history of the standard and what it is likely to include.

The international standard for road lighting is CIE 115: Lighting of Roads for Motor and Pedestrian Traffic . The European Standard is EN 13201, which has been adopted as a British Standard, being identified as BS EN 13201. It comprises four parts:

• BS EN 13201-2 Road Lighting. Performance requirements • BS EN 13201-3 Road Lighting. Calculation of performance • BS EN 13201-4 Road Lighting. Methods of measuring lighting performance • BS EN 13201-5 Road Lighting. Energy performance indicators

UPDATED FOR LED

You will notice there is no BS EN 13201-1. EN 13201 is in fact a technical report, which each of the European member states has as its own standard, which in turn gives guidance as to how the standard will be applied. For the UK it is BS 5489. In 2013 the dominant light source was of course the high-pressure sodium (SON). Although there were some full spectrum light sources in use, they tended to be installed in amenity areas and architectural installations. How things have changed!

Now, most designers of road lighting schemes won’t have used SON as a light source for a long time; all schemes now seem to be designed using LEDs. LEDs offer many possibilities, but their light distribution is so precise care needs to be taken to avoid issues with glare and uniformity.

Scotopic vision is the term used for your sight at low light levels, where the eye utilises only the rod receptors for sight. These receptors allow us to see light and dark; black and white which is why, in very low light levels, you cannot discern colours.

Photopic vision is the opposite of this, whereby well-lit conditions encourage the cone receptors, responsible for colour and definition, to be used for sight.

BS 5489 2003 acknowledged this phenomenon by allowing a one class lowering of the lighting recommendations where full spectrum light sources had been used. However, this could only be applied for subsidiary roads using the ‘S’ classes.

Subsequent research suggested the reduction of one lighting class was excessive for some ‘white’ light sources; so the 2013 version of BS 5489 addressed this by introducing the concept of Scotopic/Photopic Ratios (S/P ratios).

The S/P ratio calculates the level of brightness perceived by the human eye of light sources by determining the ratio of Scotopic-to-Photopic lumens emitted. The higher the ratio, the better the light source is at stimulating the eye. Therefore, light sources with high S/P ratios at lower wattages (or dimmed) can provide the same perceived light level as higher wattage, low S/P ratio sources.

Again, this phenomenon can only be applied to subsidiary roads using the ‘S’ or ‘P’ lighting classes as there is no evidence this can be applied to traffic routes or conflict areas where higher lighting levels are prescribed.

HOW THE 2020 VERSION DIFFERS

The 2020 version of BS5489 acknowledges that the main light source now in use is LED. So, where the light source has a colour rendering index or Ra of 60 or more there will be no need to apply the S/P ratio for subsidiary roads, as the tables have been published to assume the use of Ra > 60.

However, if light sources with a lower Ra less than 60, then the S/P ratio needs to be applied to increase the lighting level recommendations.

There are thousands of changes in BS5489-1:2020 when compared to the old standard, some significant and some very subtle.

When BS5489 was published in 2013 the European standard was still in draft format; there were a number of areas where the previous European standard 2003 was referenced as well as the proposed standard 2015 as well.

In the 2020 version those references have obviously been updated, and one example of

this is reference to the S CE and ME classes used in the 2003 standard.

Many of the latest industry documents have been referenced; some 56 were referenced in the final draft. One example is the section on maintenance factors, which has been updated to reference the ILP’s Guidance Note 11/19 Determination of Maintenance Factors, which is available through the ILP’s updated website and the ISO/CIE TS2201:2019 document, which was published last year [1].

Equally, there are parts of the document that have not changed. A good example of this is the section on conflict areas, which is broadly unchanged from the 2013 edition and of course still makes reference to the ILP’s Professional Lighting Guide 02 The Application of Conflict Areas on the Highway [2].

One area that has been added is definitions for absolute and relative photometry as well as a section giving more expanded commentary on the subject too. While BS5489 is a lighting design standard and not a light measurement standard specifically, it was felt that a more concise definition would be beneficial to designers to help them understand the topic better, although neither format is preferred by BS5489.

The significance of what makes a file relative or absolute is not how it is measured. Although this is important, the measurement is done in accordance with the industry recommended practices, guidance and standards – it is how the file is stored, the intensity table file or i-table.

An absolute photometry file has a ‘-1’ in the flux field, which is the documented industry method of defining that file is absolute. The values stored in the i-tables is the measured output by the photometer and not relative to per thousand lumens of the source flux. There is also an updated section about ecology in the new standard. In the past few years, we have begun to understand much better the potential impact of exterior lighting on fauna and flora. As we build on new sites, especially green-field sites, the impact on bats, badgers, birds and other forms of ecology can be significant.

Our knowledge of how these species, or receptors, are impacted by artificial light continues to grow and there is an increasing need to ensure these receptors are protected. BS5489 has a number of external references, including one to the ILP’s 2018 guidance note, GN08 Bats and artificial lighting [3].

FOCUS ON GLARE AND LED

One area of concern when using LEDs, and touched upon already, is with regards to glare.

This is an area that has been significantly modified by way of the application and calculation of glare at the design stage. For example, it has become commonplace for people to utilise the luminous intensity classes or G classes as a way of specifying or deciding the right optic setting or LED product to use.

The latest version of BS5489 now falls into line with the recommendations of EN 13201, suggesting that the function of threshold increment should be calculated for P and C classes as the first choice when (function of ) threshold increment (TI%) cannot be calculated.

If TI% cannot be calculated, like an area design where setting up observers is very complex, the designer can consider the luminous intensity classes as an alternative, but this should not be the only consideration.

Including TI% calculations in an illuminance (P or C) straight roadway calculation is fairly straightforward and would normally be carried out prior to an area design to determine spacing and a suitable optic to use.

In one software, ticking a box will include the TI% results in the quality figures calculated by the software. The TI% is then shown with other quality figures or results. TI is a measure of disability glare expressed as the percentage increase in contrast required between an object and its background for it to be seen equally well with a source of glare present [4]. One question to ask yourself therefore is ‘why would I not want to know something about the lantern I am about to install when it is as simple as ticking a box?’. Other areas that have been updated within the new standard include a section on control gear that now references LED drivers and a new section on constant light output.

In addition, the reference to semi-cylindrical illuminance has been removed, with reference in its place made to vertical illuminance, following consultation with industry researchers.

New sections have been added on smart cities and electric vehicle charging points, with reference made to i n d u s t r y d o c u m e n t s a n d o t h e r recommendations.

LIGHTING SUBSIDIARY ROADS

One of the most significant changes in the standard is the selection of lighting classes for subsidiary roads. It is now assumed that the dominant light source will be white light and the classes available in Annex A assume this to be the case.

The application of S/P ratios previously used to reduce the target illuminance values will no longer be used if the light source has an Ra > 60. In situations where the S/P ratio is < 1, where amber, red or green predominately monochromatic light sources are used, the S/P ratios will be applied in reverse to increase the target luminance because of the poor ability to render colour.

It is not expected this will be carried out extensively, as often in the situations a risk assessment would have already been carried out to determine the change in light source away from a full spectrum source.

It is recommended in the notes that the designer should be familiar with CIE 191 published in 2010 and ILP Professional Lighting Guide 03 L ighting for subsidiary roads when making the choice of lighting class [4].

Finally, some of the other principal drivers for changes to the standard are the consideration of smart cities and how street lighting furniture can be adapted to assist in gathering data.

One example of this is having CMS capable of transmitting the data and sockets or space available to add more receptors over the standard photocell or CMS node. Energy savings, the effect on human health, such as flicker, and recommendations for the control of obtrusive lighting were other key drivers in the update.

As highlighted earlier, BS5489-1:2020 is set to be released this month (June 2020). It will be supported by updates of industry lighting design software as well as a oneday training course that will be available from the ILP (either physical or digital depending on the ongoing coronavirus pandemic restrictions).

As a final note, BS5489-1:2020 was revised by leading experts in the street lighting field from a range of organisations. These included the ILP, CIBSE, SLL, LIA, Highways England, Department for Transport, Scottish Office, a number of leading lantern manufacturers and industry researchers and experts in their field.

• The new BS 5489 will be available to purchase from the BSI’s online shop, which can be accessed through https://www.bsigroup.com/en-GB/standards/

[1] The ILP’s Guidance Note 11/19 Determination of Maintenance Factors is available to download at www.theilp.org.uk and ISO/CIE TS2201:2019 can be bought from ISO by going to https://www.iso.org/standard/72353.html [2], [3], [4] The ILP’s PLG 02 The Application of Conflict Areas on the Highway; GN08 Bats and artificial lighting; and PLG 03 are all available to download at www.theilp.org.uk. The International Commission on Illumination: International Lighting Vocabulary Termlist is available through the CIE online shop at http://eilv.cie.co.at/

Nick Smith IEng FILP MIES is owner of Nick Smith Associates and Peter Harrison MBA CEng FILP is the ILP’s Technical Director

QUALITY CARE COMMISSION

Southampton-based INDO Lighting has worked round the clock with academics and its local NHS trust to develop an innovative respirator that, it is hoped, will not only protect NHS staff working with coronavirus patients but also improve the care they can deliver

By Rebecca Hatch

Throughout the course of the coronavirus pandemic, one constant has been the need, and demand, for NHS frontline and care home workers to have adequate personal protective equipment (PPE).

A specialist lighting journal like this isn’t the place to get into the political rows that have ensued over this issue. But highlighting how the lighting industry has risen to the occasion and been using its expertise to help resolve PPE supply shortages, as well as responding to the wider coronavirus crisis, most definitely is part of our remit.

In last month’s Lighting Journal, we reported on the sterling work that BDP did under intense time pressure to get the first new NHS Nightingale Hospital up and running at London’s ExCeL centre ( ‘Rising to the challenge’ , May 2020, vol 85 no 5).

Another industry name that has responded to the call has been Southampton-based INDO Lighting, in its case joining forces with academics, the NHS and other manufacturing and engineering companies to develop an innovative new Powered Air-purifying Respirator (PAPR) protective device for NHS frontline staff treating patients with Covid-19.

The hood has been developed by INDO from a prototype created by researchers at the University of Southampton and the NIHR Southampton Biomedical Research Centre, as well as clinicians at University Hospital Southampton.

FABRIC HOOD WITH CLEAN AIR FILTER

Known as the ‘PeRSo’, it is a fabric hood that covers the wearer’s head and has a plastic visor to protect the face. A hose then connects to a High Efficiency Particulate Air (HEPA) filter with a belt-mounted blower system, which delivers clean air, and which can be worn continuously for eight to nine hours and is reusable after appropriate cleaning.

Lighting Journal spoke to INDO managing director Rebecca Hatch on 24 April, coincidentally the one-month anniversary of the UK going into lockdown but also the day the first product was submitted for evaluation that, it is hoped, will enable it be rolled out across the NHS. This is her story.

‘The week before lockdown the call came out from government for support and we, like everybody else within the manufacturing industry probably did, registered our interest. We just thought, “if anything comes of it, we will assess the opportunity” [1].

‘During that week things were really up in the air; customers were starting to review if they could take delivery of products ordered pre-lockdown and the INDO leadership team was considering what was best to ensure the safety and security of our employees. And then literally the next day [INDO chairman] Tom Baynham had a call from a contact he had at Southampton University to say, “look we’re working on this project, we want to use a local manufacturer because we want to work together, are you interested?”. Obviously, we said yes.

‘Lockdown started on the Monday and by the weekend we had several video calls with the university and collected the prototype

to begin the R&D assessment in our factory. We then started digging into it, the standards that were required and so on, and just said, “we have to do this”.

‘One of the selling points about the PeRSo, at least for NHS staff, is that it has a clear visor rather than, as with conventional respirators, covering the mouth and nose. The nurses have said it is really important to be able to smile at a patient, which you can’t do with a conventional mask solution. The hood covers the entire head and shoulders protecting the user from breathing in contaminated air.

‘The hose goes down your back into the respirator device, which contains a blower unit with a filter, which is providing them with clean air into the hood. It is a bit noisy but, because it is blowing clean air it is actually quite cool to wear, whereas the other masks often get quite hot and uncomfortable. So far, they are really happy with the fit and everything else.’

INITIAL LOCAL ROLLOUT

At the time of our conversation at the end of April, 1,000 units had already been supplied direct to Southampton Hospital, with a further 4,000 on course to be ddelivered. Rebecca takes up the story again. ‘Hospitals of course talk to hospitals and so all the south coast [hospitals] are aware of PeRSo because they are all in the same deanery. Basingstoke, Bournemouth, Portsmouth, Frimley, they’ve all made enquiries already.

‘Because Southampton was involved with the university project and is doing this as part of a controlled rollout, they have been able to take the units before we’ve got the full BS EN certification. We have started to receive enquiries from further afield, too. As soon as we have certification of the products, in line with the OPSS (Office for Product Safety and Standards) Covid-19 standards then we can begin to dispatch more widely’ [2].

LONG HOURS AND TEAM EFFORT

The certification decision was due by the end of last month, and had been sent off the morning we spoke – the conclusion of what had been an incredibly intense month, and team effort, within the business.

Rebecca continues the story. ‘There are three versions of the PeRSo product, going

WHAT OTHERS HAVE SAID

The hope is the respirator will receive the regulatory approval that will allow it to be used as an alternative to the more conventional FFP3 masks with visors for staff in high-risk clinical areas.

The PeRSo project was initiated by Professor Paul Elkington, a consultant and professor in respiratory medicine at Southampton University, together with Professor Hywel Morgan and colleagues in electronics and computer science and engineering at the university.

Professor Elkington said of the respirator: ‘The HEPA-filtered air removes more than 99.95% of particulate matter and the face mask protects from splashes and accidental touching, so we believe this will significantly reduce the risk of infection further.

‘While the currently-available standard

PPE equipment provides high levels of protection for all staff when used appropriately and in line with infection control guidance, any development which could improve that protection is very welcome,’ he added.

Dr Derek Sandeman, chief medical officer at University Hospital Southampton, said: ‘This is a really exciting development and something we are very proud to be associated with. It highlights the level of expertise and innovation in the city and we have every confidence this will become a very important piece of healthcare equipment globally. Professor Morgan added: ‘This is an excellent example of industry, universities and hospitals combining their expertise and answering the call to develop healthcare solutions for staff and patients in this crisis.’

Have you or your lighting business been involved in helping the NHS or other essential industries during the coronavirus crisis? If so, we’d love to hear your stories. Contact Lighting Journal editor Nic Paton on nic@cormorantmedia.co.uk or go through your local LDC or the team at ILP head office. from a version that uses more readily-available parts right the way through to PeRSo 1 which is completely INDO-designed and manufactured and where we hope to achieve the full-scale volumes – of up to 10,000 a week – of the estimated demand.

‘We’ve had to develop the design of the product to move to high-volume manufacture of particular parts. It has also been a case of restructuring our production lines and sourcing materials as efficiently as we can.

‘The main challenge at the moment is the logistics and the supply chain, and getting the team in the right configuration to be able to do the appropriate checks to be able to pack everything and get it out of the door as quickly as possible. Time is the most crucial factor. The next phase – assuming certification is agreed – will be repurposing our lines and possibly adding in new additional lines into the factory.

‘We have used our existing supply chain as much as we can; people that we already have a relationship with. For example, for the PCB [printed circuit board] that needs to go into the blower unit, we are using our supplier we work with for our street lighting PCBs who is also in Southampton. That is really nice because, obviously, we already have that relationship and that trust. But we have had to expand that supply chain for things like the hoods, where we wouldn’t normally be involved with those kinds of manufacturers.’

It has been a massive effort, but one that has been intensely satisfying. As Rebecca concludes: ‘It is literally a month today – it was 23 March – that lockdown started; it has been four weeks from nothing to where we are now.

‘The team that has been directly working on this, most of them haven’t had a day off or a proper night’s sleep for the last few weeks. The university team, too, worked tirelessly to develop the prototype and support us to ensure progress was made.

‘It has been around the clock, especially as we have been dealing with suppliers from overseas for certain parts as well. Everyone has been hugely dedicated and the speed to market is directly linked to the passion of the combined team.

‘Today, when the first units go off to the notified body, I think everyone will relax a bit, but only for a minute! We’ve all agreed that, unless there are any emergencies, we will try and have a day off this weekend!’

[1] ‘Offer coronavirus (COVID-19) support from your business’, https://www.gov.uk/coronavirus-support-from-business [2] ‘Exemptions from Devices regulations during the coronavirus (COVID-19) outbreak’, Medicines and Healthcare Products Regulatory Agency, March 2020, https://www.gov.uk/guidance/exemptionsfrom-devices-regulations-during-the-coronavirus-covid-19-outbreak

Rebecca Hatch MBA IEng MILP is ILP Vice President – Infrastructure as well as managing director of INDO Lighting

SHOWING OUR APPRECIATION

One of the brighter spots of the long weeks of lockdown between March and May has been the way the country has come together every Thursday night to ‘clap for carers’, with people coming out on to their streets and balconies to celebrate and thank NHS, essential, social care and care home workers for all they have been doing for the nation during the pandemic.

Local and national landmarks have often been lit up as part of this celebration, in the process creating an opportunity for the lighting industry to use its expertise to show its – and our – appreciation for our healthcare workers.

This has been the case – and to stunning effect – in the work of electrical s u p p l i e r Y E S S S E l e c t r i c a l a n d lighting manufacturer, and ILP Premier member, Powerlite, which combined to bathe one of the cooling towers at Drax Power Station, near Selby in North Yorkshire, in blue light in honour of the NHS.

The power station is the UK’s largest, and supplies 5% of the country ’s electricity needs, and is one of a portfolio of electricity generation assets owned by Drax across the UK.

‘We have long worked with Drax; we actually lit their turbine hall – 197 LED lights, 25m up; so a very prestigious job for us that is still today saving them a lot of energy,’ recalls Craig Taylor, industrial and controls specialist at YESSS Electrical.

‘I remember I got the call from one of their electrical engineers on the Saturday night while I was at home watching TV saying they wanted to light one of the cooling towers.

‘The first challenge was the need to light it in blue and the second was how to throw the light that distance. Each cooling tower is 114m tall, 93m in diameter – and you could fit the Statue of Liberty inside each one – so that is a large area to light. The third main challenge was that we needed to get the lights up quickly.

‘Drax needed them in place for the Wednesday to do a trial light-up and then, obviously, to have them ready for the Thursday for the official switch-on and clapping. It was very d i f fi c u l t t o d o a p r o p e r l i g h t i n g scheme in that timeframe because it is “ how much light is good light?” in these situations,’ Craig tells Lighting Journal .

Many local and national landmarks have been illuminated as part of the weekly ‘clap for carers’ during the pandemic lockdown, including the cooling tower of the Drax Power Station in Selby, North Yorkshire

By Amanda Speight

GROUND-LEVEL FLOOD LIGHTING

To help make Drax’s ambition a reality, YESSS Electrical turned to Powerlite along with another lighting manufacturer called Exled.

‘We sourced a couple of fittings off Powerlite and various white fittings off Exled as, unlike Powerlite it couldn’t supply blue light. For the white lights it was quite funny in that various attempts were made to make them bluer, until the correct filter material arrived from Lee Filters,’ says Craig.

‘The lights were installed on the ground about 4m away from the cooling tower, shining up, mounted on a metal framework. It was mostly just a case of running temporary cables around. Although they are very high wattages, we are only talking small cables to power them nowadays, what with LEDs being low wattage obviously.’

One of the challenges was that you only get about 30% of light out of a blue chip compared to a white chip. So to try and measure the distance was very, very difficult.

At Powerlite, we supplied the fittings kind of holding our hands in the air, fingers crossed. But it worked out tremendously; it has been beyond belief really.

The next challenge has been to illuminate the tower all the way round as initially it has just been illuminated from the north-facing side.

The lights used were our Regor LED 11 ‘deep blue’ 950W 24-board LED floodlights, with 60deg spread.

Powerlite and YESSS Electrical have also been working to illuminate the silos at the Scunthorpe steel works, again in appreciation of the NHS and healthcare workers. But more widely, as Craig highlights, like many across the industry, this work has been just one part of a range of activity to try and provide whatever support it can to businesses and the NHS during the pandemic.

‘Like a lot of companies, we have been helping out with the provision of hand sanitiser. We’ve had to furlough a lot of staff, again like most companies, and we’re classed as semi-key workers, so we’re providing spare parts to factories and doing electronic repairs. We’ve also been very busy sourcing hand sanitiser as well as masks, dispensers and coveralls to businesses so they can carry on working,’ explains Craig.

Amanda Speight is an LED lighting specialist