Office lighting really has to change – to avoid waste, to reduce energy use, to adapt to evolving working practices and, most of all, to put people at the top of the agenda. Three leading lighting designers concerned with the workspace environment give their views on precisely how and where office lighting must move on to meet the needs of the future

Mark Ridler:
Lighting people not machines

In the medium term, lighting in the workplace needs to move further away from lighting for machines and the convenience of the speculative lettings market. The imperative is to create healthy places for people to work in that are ecologically responsible. There is no contradiction here - all of it is possible and affordable, but not if we continue to deliver lighting in the way we have. Only in the UK does the Category A and B system operate, and it is a wasteful way of delivering overlit, bland and oppressive environments.

Recently there has been much good news in terms of the regulations and advice documents. BS 12464 now concentrates on dedicated lighting to task, and a demand that adequate vertical light is played on people's faces. It talks also of correct modelling of facial features. Part L of the Building Regulations looks as if it will embrace a real measure of energy used, rather than obsessing with luminaire/lamp efficiency. The BCO also has a new lighting guide in the pipeline looking at lighting quality, energy efficiency and daylight.

But still there is a demand for too much light. Unfortunately the BS still recommends 500 lux, which is far too much for general VDU use. Every client I've worked for, every post-occupancy review conducted, every worker I've asked, every environment I've commissioned, has asked for and demanded between 250-350 lux. Some 40 per cent lower. Yes, some users need more, but not many and not for long and their particular (and vital) needs can be easily, individually and locally catered for.

I truly believe that lighting equipment is going to move off the ceiling and on to the floor and furniture for a task-based approach. Already highly favoured on the Continent, it is not rocket science, revolutionary or difficult. It's highly flexible - move the desk, and the light follows. Control is intuitive - the switch is mounted on the light so no training or complicated interfaces are required. It's sustainable - absence detection can be easily integrated. It allows individual control - integral dimming can allow those who want more (or less) light to achieve this intuitively as their task, visual acuity, or daylight environment require.

Oh, and they produce a lovely balance of direct and indirect lighting that illuminates faces naturally and lifts the ceiling plane visually. They should be an architect's and engineer's dream, because it leaves the ceiling clean and removes one complete degree of coordination.

Is it likely to happen? Well, yes and no. I'm writing now under this type of lighting, so I practice what I preach. The past two owner/occupier schemes I've designed were done in this fashion. The clients (and architects) are really enthusiastic and the energy in use is likely to be below 3W/sq m. But I'm not naïve. When it is so easy to install an array of luminaires that pays no regard to interior finish, task location, visual communication, human occupation, brand, business activity, individuality and pumps 50 per cent on to grey carpet over 70 per cent of the floor area, why change? Particularly as far too many Cat A schemes are put in a skip as soon as a tenant (who actually knows what they want) takes occupancy.

It really is time to change. It really is time to place people, who live in our light, at the heart of our designs.

Mark Ridler is director of lighting at BDP Lighting

Andrew Bissell:
The daylight issue

The benefits of sunlight and daylight in the working environment are well established. All of the lighting guides and respective office-design guides - such as the one from the BCO - talk about designing daylit spaces and offer criteria for measuring the quantity of daylight within a space. The question then is, how well do we think we are doing at delivering high-quality daylit spaces?

The current measure for daylighting in offices is the daylight factor. The lighting designer and architect develop a facade and space that achieves an average daylight factor and a minimum uniformity. There are also other factors to consider, such as a view out and view of the sky. But if we stop for a moment and question what the daylight factor is, the first criteria we discover is that any analysis is carried out under an overcast sky condition.

Of course when in use the building will experience both sunlight and diffuse daylight. Furthermore, the various facades and end-users will experience sunlight at a variety of positions in the sky. Quite simply we are designing our buildings using unrealistic data and criteria. As we review the existing methodologies further we also find examples where light pipes and light shelves have been analysed under an overcast sky condition.

When you have products that make use of strong directional light, to analyse their benefit using an overcast sky condition is not going to demonstrate their true advantage. Indeed, the design may well discount certain products or facade-design options because the analysis shows them to lower the availability of daylight in a space.

We could say that the current method of using daylight factors only reveals what happens in an office space for a few specific periods of the year. It's a measure of the quantity of potentially available light from an overcast sky. Quite often with spaces designed with daylight factors, when the sun comes out the blinds come down and no one in the office benefits from the available sunlight and daylight.

If we want to improve the office environment in terms of sunlight and daylight we need to look at the availability of light both as a quantity and design the building to ensure the light has the right qualities. In other words, we need to design the facade and space for those who occupy it and accommodate sunlight control and visual quality as part of the design.

In essence we need to move from using a static overcast sky to analysing an office design using a dynamic weather file. With this there needs to be appropriate metrics that describe the quality of light and what is considered the right quality of space. Fortunately, since 2006 there has been such a process and metric - climate-based daylight modelling (CBDM).

CBDM has already been used for designing museums, and introduced by the Education Funding Agency for the Priority Schools Building Programme. The benefits for buildings designed with CBDM include:

• Reduced glazing areas, as the facade design is more specific to the weather data and relative to the building and room design
• Higher quality daylit spaces, that experience the blind-down, lights-on scenario for fewer occasions during the year
• Improved energy efficiency, through a reduction on the electric lighting use and more accurate assessment of the benefits of architectural design features, atrium, light wells and light-redirecting materials.

To see CBDM used more widely will require a series of high-profile projects with end-user feedback and energy figures demonstrating that the building is designed more specifically for the site and end-users. The promotion of CBDM through documents such as the BCO specification would see a wider understanding and agreed targets.

Andrew Bissell is director of Light4 Cundall

Dominic Meyrick:
Facing up to future communication

In the seminal Twenties movie Metropolis, Fritz Lang's vision of the future includes that powerful representation of a technological future hope - face-to-face communication through a viewing screen. In one pivotal scene we see the desperate face of the drone workers' overseer speaking to the aloof factory owner over what is now, in effect, Skype.

The reason the appearance of this technology works so effectively in the film is, of course, its ability to show facial expression, in this case fear. This gives it a clear advantage over the humble telephone. And this is the reason for the likely dominance of this form of communication in the office of the future - though hopefully a range of emotions will be depicted.

The ear gives you some indication of the emotion behind the conversation you are having, but the face, well, that tells so much more. As a younger workforce engages with all the technological advantages the internet can offer, this form of communication will be the major challenge in lighting the office of the future.

As superfast broadband arrives across the country, the jolty, shuddering image of your fellow-worker, whose voice follows the moving mouth on the screen like some badly dubbed Eastern European miniseries from the Seventies, will disappear, to be replaced by high-definition images showing warts-and-all faces and the interiors those faces are in.

There will need to be a significant change in how we light our workplaces to accommodate video internet talk. The old 500 lux in the BS and SLL Lighting Guides, even with the introduction of clarifying cylindrical illuminance - which considers the whole body and face, rather than just the horizontal working plane - will have to change.

Gazing into my crystal ball, I can see that the downlight luminaire on its own will not be enough. Neither will the 100/50/30 rule satisfy this new form of comms. Although, 100 per cent of task illuminance on the desk, complemented by 50 per cent of this value on walls, and 30 per cent on the ceiling has led to specific wallwashing and uplights to reach these values. This does give a better visual all round at the moment, but in the future this straightforward ratio will not be enough - as anyone who has had to light a video-conferencing suite recently knows.

The hierarchy may also need to change as the focus on the horizontal plane, which has been with us since the days of Landolt, wanes, and vertical illumination takes over. Obviously, we don't want to repeat mistakes such as LG3, where lighting disastrously tried to second guess the advances of office-based computer-screen technology - resulting in the cave-effect of Cat 2 louvres - but I suspect the humble webcam will not be able to do it all, and we will have to supplement its advances with targeted lighting design.

The lit, internet-fuelled office environment will need to accommodate people at their desks speaking to each other, as well as group meetings over the net. In this Utopian future, videoconference suites will just be typical meeting rooms, conference-ready as standard, while in-built lighting, by which I mean lighting specifically located to give good vertical illumination at the desk, will move in, perhaps concealed in furniture, screens or even in the cameras themselves.

As I write, I am aware that I didn't shave this morning - that may also have to change as vanity and corporate image will need to be considered and accommodated. People, their personal space and the office environment as a whole will come into the world's view in an instant. Lighting design for offices will never be the same.

Dominic Meyrick is lighting principal-partner at Hoare Lea Lighting

Andrew Bissell:
Rethinking Category A

Office lighting design has matured over the years. It's thanks to the SLL lighting guides, the BSEN document for internal lighting, more educated clients and, of course, more adventurous architects and lighting designers. One area, though that seems static and somewhat behind the times is that of a Category A fit-out.

In many ways the commercial sector, agents and office guides such as the BCO specification dictate what should and should not be included within a Cat A space. As a result, a Cat A office lighting solution will typically be a 300mm x 1500mm or 600mm x 600mm modular light fitting arranged in a rigid grid.

The grid of lights will provide a flat level of light across the whole office working plane to allow the tenant to place their desking anywhere within the space. That also means the space between the desks, the filing areas, the recycling bin area and so on will also have 300-500 lux of light which quite simply isn't needed.

The current approach to office lighting design is very much about putting the light where the people need it. So the desk receives an appropriate level of light and the area between desks will be provided with much less light. This makes for a far more interesting space visually, a far more functional space with regards to the lighting, and a far more energy-efficient space (around 30 per cent).

So we have both a design and energy-efficiency conflict between what is modern office lighting design and what is a typical Cat A space. But we also have a potentially huge waste and sustainability issue with the concept.

Let's assume a Cat A space is fitted with 1000 luminaires. A tenant company takes the space but has its own specification of luminaire supplier. Instantly 1000 luminaires, probably 3,000 to 4,000 lamps, containing mercury, steel, plastic and glass, are disposed of. Ironically, the fitting replacing them will perform in almost exactly the same way as the ones just removed. And if the new design is still based on flexible desk positions then it will be using approximately 30 per more light than a design where only the key work surfaces are lit.

One solution could be that a Cat A lighting scheme has no light fittings at all. Instead, the lighting control, and plug-and-play wiring, are installed ready to accept light fittings. The potential tenant is then shown two or three lighting designs that focus on matching the task areas around the office. Each design has been costed and the products are off the shelf.

This way the lighting design can better suit the end-users, use less energy, be cheaper to buy and avoid the enormous amount of waste inherent in throwing away a typical Cat A lighting design.

To achieve this requires a change in what a spec office tenant believes is the norm, and that can only come from the agents and documents such as the BCO specification. However, realising a change will save materials and energy, and create higher quality office spaces - so it is well worth pursuing.