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Let there be light

technical & practice

Are our offices too bright or just right? The recent Architects' Journal/Zumtobel Staff Lighting debate produced mixed views

A 'slavish' adherence to institutional standards coupled with the UK preference for selling speculative offices with installed lighting is leading to boring, over-lit spaces.

That was the view of a number of top designers and architects to emerge from the recent Architects' Journal/Zumtobel Staff Lighting debate on office lighting.

Leading lighting designer Mark Major of London-based practice Speirs and Major told the London audience that he was greatly concerned that many office spaces had become over-lit. 'The eye can see at all levels but we tend to overcompensate for darkness. Both physiologically and psychologically we can adapt to much lower light levels.'

Fellow lighting designer Lee Prince agreed. He believes that office space planning hasn't moved on since the 1920s.

'In hotels and restaurants, the more sophisticated the place, the lower the light levels, ' says Prince.

'Why shouldn't we give people who work in offices this option?'

The problem is down to developers who install generic office lighting to CIBSE guidelines, believes interior designer Linda Morey Smith.

'It's a misunderstanding of institutional standards, ' said Smith, whose clients include Channel 4, Capital Radio and EMI. 'People just get it too wrong.

'Clients don't want blanket [lighting] coverage. Some just want task lighting with little or no ambient lighting. Media clients especially hate speculative office lighting and just rip it all out.'

Architect Jon Tollit agreed that standards were often to blame. He had a radical solution: 'Light meters should be thrown away - and trampled under foot. We need to start from a totally different criterion.'

'We like to talk to the user in advance rather than accept speculative schemes. I believe there should be a level of enjoyment in work, and people should be happy to be there.

But, of course, it's a difficult concept to measure.'

Zumtobel Staff Lighting managing director Grant Daniels described most British office lighting schemes as 'boring, boring, boring'. This was partly due to standards, but he pointed out that the 500 lux guideline referred to the task area alone. Much more imagination could be used on vertical surfaces and ceilings and in circulation areas such as corridors and stairwells. Achieving better outcomes depended largely on a change of culture, and a greater acceptance of the role of the independent lighting designer. It was suggested that a shift in emphasis from illuminance to luminance could yield better results in interiors.

In the unenviable position of standing up for the property developers was Neil Pennell of Land Securities, author of the lighting section of the British Council for Offices' fit-out guide.

Pennell has been responsible for many large commercial developments, including the Empress State Building in West London and the Bullring in Birmingham. He believes developers are in a difficult position with office lighting in the competitive office market.

'If we don't produce a space with the standard lighting, someone may mark you down for it, ' Pennell said.

Developers were being bombarded with contradictory information on lighting. There's pressure to save energy and keep light levels down, but British Standards still dictated 500 lux on the working plane. 'It's difficult for us to set a brief - it's a real challenge, ' he added.

While designers wanted lighting individually tailored to the client, this was difficult to achieve in the commercial property market.

'The market just doesn't work that way, ' said Pennell. 'We've tried [selling] shell-and-core properties in the past but it just doesn't work. The fact is, the lighting helps to sell the place.'

There were other factors at play too. The litigious climate and emphasis on health and safety, and risk assessment, meant that developers played safe with lighting schemes that are drawn up by an authorised third party.

However, Pennell believes that workplace lighting could be a differentiator in the marketplace if a demonstrable gain could be shown to the prospective tenant.

'There are definite links between visual tasks and light levels, but it's difficult to go beyond that.'

If the evidence of a definite link between office lighting and productivity could be established, perhaps it would lead to more interesting schemes.

'If you could put a value on it, then it would be a different kettle of fish, ' Pennell added.

Developers found an unlikely ally in the shape of biologist Dr Derk-Jan Dijk. He's the director of the Centre for Chronobiology - the study of the body's natural rhythms - and he believes that humans are programmed to deal with high levels of natural light from the sun during the day and lower ones at night. Therefore, current light levels in offices couldn't be described as too high.

'I don't think offices are over-lit.

Our physiology can deal with this.We have evolved, exposed to a lot of light - typically 20,000 lux, even up to 50,000 lux, ' Dijk said.

The natural rhythm of the day should inform how we go about using artificial lighting. The concept of 'darkness as a right' only applied to one time of the day. 'We are diurnal animals and we need to sleep at night.'

He said it was right that hotels and restaurants had much lower lighting levels - this was merely reflecting the times of day when most of the activities were carried out. 'It shouldn't be at all surprising that light levels are low for eating your dinner at 8.30 pm in the evening, ' Dijk added. 'During the day, however, a couple of hundred lux can make you more alert.'

Light affected our hormones, especially melatonin, which controls our sleep-wake cycle - known as the circadian rhythm. The science is a relatively new one, and much experimenting is only now being done.

'As late as the 1960s, people thought that lighting didn't effect the circadian rhythms in humans. We thought we were different from all the animals, ' Djik said. Even blind people had their circadian rhythm controlled by light - and this was demonstrable in experiments. However, how this happens still hasn't been studied effectively.

There is little data on the effects of both natural and artificial light. 'We need to take a totally fresh look at light, ' Djik believes.

Ray Molony is editor of Lighting Equipment News. The Lighting Question Time event was conceived and sponsored by Zumtobel Staff Lighting.

Information on future events can be obtained from Emma Roberts on roberts@uk. zumtobelstaff. co. at

Lighting controls

Lighting controls should, in theory, allow office workers the freedom to set their own lighting levels - but current practice mitigates against any real gains.Basic controls are only installed in speculative offices to comply with CIBSE guidelines, and more elaborate systems are often lost on the workforce.'We put an inordinate effort in controls, 'said architect and designer Jon Tollit, 'but some users put the manuals on the shelf and don't know what switch does what. It's like air conditioning - if you give people buttons to press, they'll press them.'

Smith says that office workers often have too many other things on their mind to use lighting controls effectively.Additionally, people who work side by side often had very different requirements in terms of light levels.Older people had a preference for high levels, while younger workers preferred lower levels combined with task lighting.

There was also evidence that people set the controls at a standard percentage of the light levels, no matter what those light levels were. In one experiment, users commonly set the controls at around 80 per cent, and this didn't change with the upper light level.

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