BSEE LIGHTING


Paul Coggins, Senior Vice President Northern Europe Zumtobel Group, discusses how to get the right light balance for the modern day oce space.


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GETTING THE RIGHT LIGHT Don’t put workers in the shade


n the past, office lighting has often focused only on lighting for the task, which usually meant lighting desk surfaces and avoiding glare on screens. This inadvertently created the so-called “cave effect”, resulting in gloomy offices and drowsy workers. Considering carefully how we light the space around us avoids these problems, helping to create an environment where workers can feel comfortable and alert. Lighting only for visual acuity or to achieve decorative effects is no longer acceptable Lighting must also be friendly to the circadian clock. The circadian rhythm controls our energy level, mood and sense of alertness so when our body clock no longer functions synchronously with the time of the day our reactions slow down, we are less attentive and it becomes more difficult to concentrate.


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New LED lighting technology can control the spectrum of light emitted to mimic this natural cycle and help provide the right type of light at the right time of day. Special cells in the eye detect light and send this information directly to the areas of the brain regulating circadian rhythm and alertness. Light is a stimulant and can increase alertness and performance and recent studies by major universities and health organizations have increased the public's awareness of the close link between light and health. The technology provides new options to help support good health by using the right light, at the right time, for the right task.


The science of how light influences our bodies has advanced hugely in the past two decades. Although we still have much to learn, there are simple principles that every lighting professional can follow to make sure the lighting in an office creates a healthy, comfortable atmosphere. This means not just focusing on lighting for workplace “tasks”, but taking a more holistic approach.


uFor general oce lighng, diuse, well distributed light with a mix of vercal and horizontal illuminaon is important.


The three essential elements to consider when lighting an office are task, space and face. Lighting schemes that successfully combine all three of these elements will create an atmosphere that is pleasant and productive.


Lighting must provide the right level of light for people to carry out tasks effectively. EN12464 specifies luminance levels for various activities but older workers and workers with poorer eyesight may need higher levels of light than others.


Many offices now place an increasing emphasis on flexible working, online, face-to-face meetings and conversations so the lighting must be flexible enough to work well in all of these situations. Computers, tablets and phones with backlit screens are everywhere in the modern office, so glare that could make these difficult to use must also be avoided. Whether it’s a meeting, a video conference or a chat by the water cooler, lighting needs to allow us to see each other’s faces clearly. The key factors are cylindrical illuminance, facial modelling and good colour rendering. EN12464 specifies 150 lux cylindrical illuminance at head height and a modelling index of between 0.3 and 0.6. This creates an environment where we feel comfortable, look good, and can see each other clearly enough read our colleagues’ expressions, mood and body language. It also makes sure that enough light is reaching people’s eyes to keep them alert.


Every workplace is unique and will require the lighting of task, space and face to be considered and balanced differently. But keep these three priorities in mind, and you can be confident that your lighting will keep workers performing effectively. Meeting rooms are all about communication and, whether it’s a discussion between two people across a table or a presentation to a large group, these are the places where people come together to talk, listen and share. Here, the job of lighting is to create an atmosphere for effective communication and facial modelling is obviously important. This is achieved through good vertical and cylindrical illuminance, whilst good horizontal illuminance on work surfaces is also important to enable comfortable reading and writing.


If projectors, monitors or whiteboards are being used for presentations, lighting should avoid creating glare or shadows and lighting controls are important in meeting rooms for a number of reasons.


Firstly, these rooms are used in a variety of ways, as a presentation using a projector may require lights to be dimmed or ensure that only the speaker is illuminated whilst, by contrast, a face-to-face meeting will require the entire room to be lit. Secondly, meeting rooms are likely to benefit from daylight, so energy can be saved by dimming or turning lights off when there is sufficient natural light. Thirdly, meeting rooms tend to be used for short periods, and will sometimes be empty, so presence/absence controls can reduce electricity costs. For general office lighting, diffuse, well distributed light with a mix of vertical and horizontal illumination is important and, additionally, bright ceilings and upper walls also make a huge difference in making a space feel more pleasant. EN12464 specifies light levels for the task area, the immediate surroundings, and areas beyond. It also specifies uniformity levels for task areas, as well as light to walls and ceilings, to make sure there isn’t too much contrast between light and dimmer areas. The colour of light also has an important influence on the ambience of an office. Warmer colour temperatures are associated with relaxation, while cooler lights are considered more appropriate for a work environment. Compromising on colour temperature or colour rendering will have a big impact on the working atmosphere you create. Just as important as making sure there’s enough light in a space is making sure there isn’t too much glare, which can cause headaches and eye strain, as well as making it harder to see what we’re doing and harder to use computers, phones and tablets. Glare can be controlled through careful lighting design and choosing luminaires with good optical design, to keep office workers comfortable and focused.


www.zumtobel.co.uk 24 BUILDING SERVICES & ENVIRONMENTAL ENGINEER MAY 2018 VISIT OUR WEBSITE: www.bsee.co.uk


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The three


essenal elements to consider when lighng an oce are task, space and face. Lighng schemes that successfully combine all three of these elements will create an atmosphere that is pleasant and producve.


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