Webinar on Building Services: Internal Lighting

Speakers: Alice, Geraldine O’Farrell, Andrew More

[They discuss 'housekeeping' for the session].

Alice: That's the housekeeping done, so without further ado, I'll hand over to our first presenter is Geraldine O'Farrell. Over to you, Geraldine.

Geraldine: Thank you, Alice. Good afternoon, everybody, and welcome to Historic England's webinar on internal lighting for historic buildings and churches. Before we get started, my co-presenter and I would like to introduce ourselves. I'm Geraldine O'Farrell, Senior Building Services Engineer belonging to a small team of National Advisors on Building Services and Energy Management. I advise and write guidance on a range of building services, including external and internal lighting, emergency lighting and exit signage, lightning and surge protection and fire alarms.

Andrew: Hello, I'm Andrew More. I'm also a senior Building Services Engineer. I mostly advise on mechanical services, including heating, ventilation, public health and drainage.

Geraldine: Before we make a proper start, I'd like to let you know about the technical conservation team, of which we are a part. We're a group of technical specialists, including conservators, scientists and engineers, and we undertake research and provide advice and guidance on technical conservation issues. The first link that Alice is posting in the chatroom for you takes you to the main technical advice page on our website, where you can find all our technical advice, all our research reports and PDF guidance documents are free to download from our website. And the second link takes you to the catalogue shown on the right where they're all listed. As you might like to know that we are introducing-- Oh, sorry.

Also, you might like to know that we are introducing a technical conservation newsletter which is planned for the last Tuesday of each month. This will let you know about new technical conservation guidance and publications or any forthcoming technical conservation training events. If you'd like to add your name to the mailing list and haven't already signed up at a previous webinar, just click 'yes' and we'll send you the next edition of the newsletter. Just to be clear, this is for technical conservation guidance and events, not all English publications or training. I realise that some of you will have already signed up at a previous Technical Tuesday webinar, so there's no need to do it again. But if you can't remember, don't worry. We won't sign you up twice. We check addresses and we'll only send one email, so. If everybody would like to tell us whether you'd like to receive that or not, that would be great.

Looks like a pretty high percentage of everybody would like to receive one. Yeah.

Geraldine: Let's go, let's move on then. OK, so here's today's topic. This is what we're going to be discussing and hopefully this will help you take appropriate action to this sort of work or project. Our guidance on internal lighting is available via the website. There you will also find our most recent guidance on external lighting and emergency lighting and exit signage, should you have a project involving all three. This new guidance reflects the massive change in lamp technology in recent years with the dominance of LED, but also discusses other forms of lighting like fluorescent, fibre optics and the conversion of early light fittings into energy efficient light sources. It's important to remember that lighting design is not something that just anyone can do properly. You should, wherever possible, employ a suitably qualified lighting designer or consultant engineer.

Andrew: This guidance is about making you informed clients so that when you decide to update the lighting in your building, you will know what to do and what not to do. The purpose of this guidance is to prevent the installation of bad and inappropriate lighting designs and to understand the impact that lighting has on all of us. Hopefully with this knowledge, you'll be able to achieve more energy efficient and controlled designs that do not waste light on which best suit the activities taking place in the space.

Geraldine: So let's get started. On screen, we can see a selection of early forms of internal lighting. This is by no means all that have ever existed. On the screen, we have a Roman oil lamp, the easily recognisable candle, oil lamps, an acetylene light fixture, which is on the left-hand side bottom, a gas mantel, an early prototype incandescent lamp, and the highly decorative early fluorescent, complete with decorative chandelier-like crystals. Hmm, I wonder if that would make a comeback.

Andrew: Now, I think that the now obsolete but still very familiar electric lamp, sometimes called a light bulb, was invented by either Sir Joseph Swan or by Thomas Edison, depending on whether you're British or American. In fact, neither is completely correct. It was this man, Sir Humphry Davy. Davy was an English chemist and inventor and produced the world's first electric lamp by connecting voltaic piles to charcoal electrodes. A pictorial impression of the arrangement is shown on the top right of the screen. Davy's 1802 invention is known as an electrical arc lamp named for the bright arc of lamp emitted between its two carbon rods. And in the small image in the middle of the screen is a mercury vapour lamp from a fluorescence microscope. It's really the next derivative on from the arc lamp and it operates on similar principles. And if you look closely, you can see the gap between the electrodes right in the middle of the picture. One is very pointed, and one is more blunt ended.

Geraldine: Also, here on screen, we have a variety of early electrical luminaires. The images include examples from John Rylands library in Manchester and Cragside House in Northumberland, which are the little two images on the top of the-- The two on the top of the row to the middle and left-- Sorry, middle and right. Also, we have another example of a very ornate early fluorescent fitting in the middle, at the bottom row. An early mercury fitting, which is shown at the top left and a variety of other ornate domestic fittings with glass shades. It's examples of light fittings like this that we ask you to look out for when working with a heritage building, especially one that has not had much work carried out on it. If you're lucky enough to find late 19th, early 20th century examples, of which these on screen are just but a tiny example, then you should try and incorporate them into your new design or, at the very least, photograph them and record them if that is not possible. Even as old as they are, they can often be reconditioned, rewired and relamped to convert them into useful, energy efficient fittings. We will explore this further later on in the talk with an example.

Here we have a small selection of the various shapes and sizes of incandescent lamps in the first part of the 20th century.

Mass-produced lamps for the domestic market did not really take off until the national grid started to take shape between the World Wars. Until then, a lot of homes, and my own grandmother's was one example, still had gas mantling well into the 1960s with electric light only installed in key rooms such as the living room or principal bedroom.

The final design was not really settled upon until the late 1930s, and that familiar shape has now transcended to LEDs, as we will see in a minute.

Here on the upper left is the familiar light bulb, and on the right are some of the various permutations of LED light sources, including two that have taken the general form and design of their very distant cousin, the first and third in the line to the right.

On the lower left is a fluorescent tube, another familiar light source, and on the right, the LED equivalents. This flexibility means that we can install a similar looking lamp into a heritage light fitting that, for example, once held an incandescent lamp. And the overall appearance will remain the same. But now we will have a much more efficient fitting with the LED replacement giving the same or similar light output in the same colour temperature range whilst using far less energy. A 60-watt incandescent lamp, a typical wattage say, for a table lamp, can now be replaced with an LED light source of anywhere between eight and 15 watts, depending on manufacturer and type.

The respective life of the differing light sources could not be more contrasting, with the incandescent lasting an average of a thousand hours, but the LED will give between 30 and 50,000 hours depending upon the manufacturer. It should be noted that whilst a linear T8 Tube fluorescent tube has a very good operating life of 30,000 hours, a T8 LED tube would last 50,000 hours and some newer models are quoting up to 84,000 hours of life.

The pure poor life cycle of the incandescent was one of the major factors that underpin the EU directive from 2009 that began the process of phasing out all energy inefficient lamp types. The incandescent being the first to go. Early incandescent lamps did not have very good light output, so were often installed without the use of lampshades. The example shown in the image is of an early 20th century church in Swaythling near Southampton, which still has its original and slightly unusual light fittings. You can see the original unmodified light fitting in the smaller photograph to the right. These were painstakingly taken apart, refurbished and rewired so that they could remain both operational and in situ, shown in the middle image. Although now supplemented with hidden high-level spotlights, these fittings were always meant to be used without shades.

Geraldine: The same is of the original light fittings used in the John Rylands Library. You can see this in the left-hand side image. One of the fittings on the main staircase of the library is shown. All the lamps in these ornate light fittings are bare. That is the case for all the original fittings throughout the building. We will see some more in the next slide.

Andrew: On screen, we have some more examples of early light fittings, the first on the left of the screen was found at the bottom of a staircase in a relatively untouched Victorian period house in Liverpool. The middle image is another of the specifically designed light fittings for the John Rylands Library. They all follow a similar design except for the size and quantity of decorative flower heads for the lamp holders. And the image on the right, again, shows a bare lamp, simple chandelier-like design, all part of a central light fitting.

Geraldine: So now we have another question. How many of our audience is actually undergoing or has planned an internal lighting project?

Geraldine: That's roughly 50/50-- Nope, nope. Slightly more people haven't than have. Okay.

Geraldine: It's good to know that some of you will hopefully benefit from today's webinar with your project. OK, shall we move on?

Geraldine: I think most of you, by now, have got some idea of the variety in design of older light fittings. We've merely scraped the surface here and I've not even touched upon the chandelier wall sconce designs that were to be had.

Geraldine: It's now time to review the fundamentals when compiling a scope of works for your lighting design. Setting down what you want to achieve with your design is critical to ensuring that the lighting does all that you require of it. And that the use to which the room or rooms will be put has the best, most effective lighting scheme. Historic England realise that it may not be possible to always reuse existing fittings in such a manner; that they like the space effectively and appropriately for what the room or space is to be used for. But as with a church in Swaythling, sometimes they can be left in place and well-disguised supplementary lighting can take over from the main lighting tasks. If there's no surviving early lighting fittings, then a decision on the style of lighting will depend on the uses to which the room or space is to be put and an honest and contemporary lighting design should be considered. There is absolutely no need for a pastiche of faux period fittings to be used. It is far better to employ the best, most suitable lighting than try and ape another period's design. This is especially true if the building dates from a period when only candles or rush lighting would have been available. As stated earlier, along with your project's scope of works, you will have to make decisions on any existing light fittings and what you're going to do with them.

Geraldine: There exists specialist Heritage Museums, so always think about donating them and thus preserving them for the future rather than just giving them away to architectural salvage where their original context is lost. At least in a museum, they can inform the viewer where the fittings were removed from. Also listed are other factors to be taken into account. In larger grand houses and churches, you will often find delicate fabrics such as silk, wallpaper, wall hangings, tapestries which are used in the interiors. These can be very sensitive to excessive and high UV light. Also to susceptible to damage from inappropriate lighting are paintings, murals, soft furnishings, carpets, wood panelling, paper and leather. The list is a long one. The last point on this slide covers a lot of other considerations. Dimming may well be required to give maximum flexibility to the design. Emergency lighting might be required if the building or certain rooms are accessible to the public or people unfamiliar with the interior. Five-amp sockets should be used instead of using the available 13-amp power sockets for plugging in items such as table lamps if the desired design includes them. And lastly, remote controls or wireless switching may also be needed, especially when considering the damage caused by chasing into historic fabric for switch drops, etc.

Andrew: It should remember that lighting design is not just lux levels and glare factors. It requires some artistry to design a scheme well. A purely technical approach might meet the necessary criteria but will not automatically give you a lighting design that complements the interior. The interior shown on this slide, admittedly predominantly very ornate, and that may require a specific style to best compliment the interiors. A plainer interior, on the other hand, will afford the lighting designer more scope. But the design will depend on what the rooms involved in the design are to be used for and whether that use varies over the course of a typical day. The main objectives of a good lighting design are given on the screen. The first is to ensure that the appropriate level of light to perform the task likely to be carried out is adequate. You need to ensure that you provided the appropriate levels of control over the lighting. You need to ensure that any auxiliary lighting such as that for pictures or table lamps can be controlled separately, if necessary, from the remainder of the room. You need to ensure that the installation is easy to maintain and keep clean. And most importantly of all, in current climate, that all the installation is as energy efficient as it can be.

Geraldine: You should never just dive into a lighting project. The compilation of a design brief or scoping document is essential, especially where the areas involved in the project are for a specific task where there are heritage luminaires still in situ. It is also a timely point in the presentation to remind you that some building service fitments can form part of the building's official listing and therefore are protected. So be careful and check beforehand that Historic England does not place any historic importance on any in situ period fitments. This covers things like radiators as well. On screen are the sorts of issues that a brief should contain. So let's go over each one in turn.

Andrew: You need to establish what the lighting has to achieve. You need to ensure that the correct areas are under discussion, that the end use to which the space is going to be put to is understood and detailed so that the correct lighting and lighting levels are employed. Also, very importantly, if the use to which the space is to be put to changes over the course of a day or even a week, then the lighting needs to adapt to suit and the appropriate controls are employed. Brainstorm ideas and don't discount anything at this early stage.

Geraldine: When you're dealing with heritage interiors, you should remember and take into account, as mentioned earlier on Slide 15, that you may have to deal with highly decorative interiors involving things like heritage wallpaper including silks; painted or decorated services such as murals; objets d'art, including metals and ceramics etc.; carpets and tapestries; wood panelling; paper and leather goods, including books as one example. Poor and inappropriate lighting can fade in brittle fabrics and other materials, plus producing poor colour accuracies of fabrics and paintings. The above issues can be put down to the wrong lamp colour being chosen or the UV – or ultraviolet – radiation in some lamps, which can have an adverse impact on both synthetic and natural polymers, such as plastics, and wood. Think of what happens to a colour polycarbonate after years of sunshine: it becomes brittle and crumbles.

Geraldine: LEDs only creates small amounts of UV because they contain phosphors that convert UV light into white light. In the past, it had been claimed that LEDs emitted no UV. But this is not technically true, so care must be taken and expert advice sought, as necessary, if you encounter any of the fabrics or materials listed earlier.

Andrew: Your brief must contain precise details of which areas of the building are part of the internal works, especially where it's a large building you're working on. A room-by-room schedule is one of the most appropriate methods of ensuring that no part of the project is missed. And likewise, areas to be excluded are noted: the name or number of the room; the existing services contained therein, especially important if these have heritage value; parts to be removed; those to be left; those to be protected or those to be refurbished all need to be clearly detailed. Any special services, decorations or floor finishes also need to be listed and the special protections that they require clearly defined.

Geraldine: This part of the main thrust of the brief should contain details of the light fittings, associated switching and circuitry required and where the fittings should be located. These are all normally shown on a plan or elevation drawing. You should then establish the colour rendering accuracy, or colour rendering index or CRI, and the colour operating temperature of the light sources to be employed.

You can see the variation on colour by changing the CRI, by looking at the central image of the apples. The CRI is the measurement of how colours look under a light source when compared to daylight. The index is measured from zero to 10 and, as shown on screen, the higher the number, the better the accuracy will be. To properly write this part of the brief, you must have established a clear idea of what you want and what the lighting is for. You can see by looking at the chart in the bottom right-hand corner, the variation in colour-operating temperature is now achievable by LEDs. They now cover the temperature range from incandescent at approximately to 2,700 degrees kelvin to 7,000 degrees kelvin, which is equivalent to an overcast day. Along with a variation of shapes and sizes available, their electrically efficient operation makes them the go-to light source. They can also supply a fibre optic array. These are often the most suitable option for display cabinets because of the remote location this arrangement affords the light source. They can be produced in a linear form to incorporate into hidden cove lighting or as energy-efficient substitute light bulbs for use in table lamps, chandeliers and wall sconces.

Andrew: Your new lighting scheme should not try to copy what already exists, unless that is specifically required. Normally, new lighting should be an honest and contemporary addition that harmonises with any existing fixtures and fittings. See the example from the John Rylands Library on the left-hand side of the screen. The left-hand image shows the original bare lamps fittings from around 1900. On the right-hand image shows the modern 21st century fittings. These were manufactured by Concord. And as you can see, they have the same basic design and function, and they are an honest addition. However, when dealing with a blank canvas and the choice of lighting is open to any design of light fitting which best suits the end use of the space. In any case, attention must be paid to achieving good installation with a minimum of damage to the historic fabric. This is often best achieved by using wireless technology, but more about that a bit later on.

Geraldine: New lighting can be broken down into the following categories: decorative, such as pendants, chandeliers, table lamps and wall lighting; architectural such as uplighters, step lights, artwork lighting and recessed down lights; central features - these can be classed as fittings also, such as chandeliers and pendants. As you can see, some are listed under two headings. These are often the central feature of a room. Very decorative, eye-catching and make a strong visual statement. Others, like chandeliers, can often have architectural accent lighting incorporated into them.

Geraldine: The architectural lighting is often the unsung hero. They are meant to be discreet and you shouldn't notice them. They are the functional fittings that do things like illuminate steps or pictures and provide accent lighting, often in combination with decorative fittings.

Geraldine: Recessed illumination should only be used in historical interiors, if their location is to be into new fabric. They should not be installed into original ceiling fabric unless permission is acquired. Any good lighting scheme should have the most suitable and if necessary, flexible control system. As stated back on slide 15, lighting controls is one of the other design issues to consider when compiling your project brief. How much control will depend on the level of sophistication required? A lighting control system does not need to be complicated, just appropriate for the space and achieves what's required. The more flexibility needed of the lighting, then the greater level of lighting management that will probably be needed. It is also an excellent method of making further energy savings to your design. On screen, we have on the right-hand side of the slide a few examples of what to look for if any historic lighting switches have survived. The ornate example at the top of the screen on the right is again from the John Rylands Library. In the middle, we have a graphic illustration of what is meant by daylight controls. The more daylight that enters the room, the closer that the luminaire is to the source of natural light will result in the light in the output from that fitting or fittings being automatically reduced, and vice versa, to a pre-set level required for the activities carried out in that area.

Geraldine: On the left-hand side of the slide, we have examples of a variety of modern switches available. These include the one in the middle, which uses wireless connectivity to enable the luminaires to be switched without the need for chasing the walls. The unit shown in the image is fitted to the luminaires. Bottom left is an illustration of a five-amp socket outlet for table and standard lamps and an illustration of a dimmer switch, which is suitable for use with LEDs. Occupancy controls can also be used to automatically switch off lighting when the room is not in use. Larger projects with a building management system can use this. This can also be used to control and monitor light installations.

Geraldine: Any lighting project involving a historic building must have reversibility at its heart. Any pre-existing holes, channels, openings must be reused rather than create new ones. The wiring examples shown on screen are totally unacceptable. Especially the arrangement shown in the middle picture. How that was ever thought appropriate escapes me. It is absolutely appalling. Chasing historic fabric is also not to be considered without all other locations having been explored, or wireless technology considered such as in the case of items such as switch drops. Any holes or chases required must be agreed in consultation with local planning department, conservation officers and/or us, Historic England. As many tests and trials as is necessary must also be carried out to ensure that the proposed design performs as required.

Geraldine: If necessary, prototypes of any special luminaires should be built to test performance and efficacy where applicable. When dealing with purpose-made luminaires, it is essential that enough experimentation is carried out before final decisions are made. You can source additional general information on lighting and suitable light levels etc. by consulting appropriate guidance such as that provided by British Standards, via the Chartered Institution of Building Services Engineers - or known as CIBSE. Their website will take you to the Society of Light and Lighting. And the Institution of Lighting Professionals, or ILP. Advice on selecting the right low energy lighting can also be found on the Energy Saving Trust and the Health and Safety Executive websites, as two examples.

Andrew: A quick reminder to ensure that you have consulted with Historic England before you start any work on Grade 1 or Grade 2* buildings. We at Historic England are always happy to help and advise. And if you're working on an Anglican listed church, then also remember to involve your Diocesan Advisory Committee as soon as you are able. They are there to provide advice and ultimately give the necessary faculty, if appropriate. And other denominations in the Ecclesiastical Exemption Scheme will have broadly similar arrangements. And finally, your local authority Planning Department conservation officers are also there to help, advise and guide you through the application process.

Geraldine: Another important point to remember is that the electrical contractor you appoint to carry out the installation work, in conjunction with your lighting designer and architect, should be a member of either or one of the trade organisations shown on screen. The meaning of the acronyms are ECA, which stands for the Electrical Contractors Association. NICEIC, that stands for the National Inspection Council for Electrical Installation Contracting, and NAPIT, which stands for the National Association of Professional Inspectors and Testers. In addition to these memberships, the electrical contractor carrying out the works should ideally be familiar and experienced with working on heritage building stock and the unique problems these buildings compose.

Andrew: Health and safety issues mustn't be forgotten. Installing an external lighting, or even internal lighting scheme, will often involve working at height and can involve potentially dangerous locations. Health and safety legislation places a duty of care on contractors, consultants and employees. This is for the benefit of the public and also themselves. All other parties, including clients and all others involved with the design and installation, must comply with the health and safety legislation and ensure that both access and working conditions are safe. On screen, you'll see CDM mentioned. This stands for the Construction Design and Management Regulations, or CDM 2015. This is the main set of regulations for managing the health, safety and welfare of construction work and includes new build, demolition, refurbishment, extensions, conversions, repair and maintenance. And to ascertain whether your project is going to be notifiable for CDM, that will depend on its duration and the number of people working on site. So if your project is expected to exceed 500 person days or where you have over 20 people on site at any one time and the project lasts for over 30 days, then it will be notifiable.

Geraldine: Useful guidance to the main duties with regards to conservation sites can be found on this handy link where all of the main duties are listed. Well, thank you all. We've come to the end of this brief seminar. We hope you that found it informative. On screen are our respective email addresses, should you wish to discuss any project specific or general issues with us. It does not necessarily have to be on this topic. But if it is, we are more than happy to help you with any pre-application advice. And finally, just a quick reminder, again, of the free advice documents available to download from our website. Again, thank you very much.